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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2011	Feb. 13, 2012	Jun. 30, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	CENTERPOINT ENERGY INC
Entity Central Index Key	0001130310
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 8,178,295,805
Entity Common Stock, Shares Outstanding		426,074,270
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011

STATEMENTS OF CONSOLIDATED INCOME - USD ($) $ in Millions	12 Months Ended
STATEMENTS OF CONSOLIDATED INCOME - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statements of Consolidated Income
Revenues	$ 8,450	$ 8,785	$ 8,281
Expenses:
Natural gas	4,055	4,574	4,371
Operation and maintenance	1,835	1,719	1,664
Depreciation and amortization	886	864	743
Taxes other than income taxes	376	379	379
Total	7,152	7,536	7,157
Operating Income	1,298	1,249	1,124
Other Income (Expense):
Gain on marketable securities	19	67	82
Gain (loss) on indexed debt securities	35	(31)	(68)
Interest and other finance charges	(456)	(481)	(513)
Interest on transition and system restoration bonds	(127)	(140)	(131)
Equity in earnings of unconsolidated affiliates	30	29	15
Return on true-up balance	352	0	0
Other, net	23	12	39
Total	(124)	(544)	(576)
Income Before Income Taxes and Extraordinary Item	1,174	705	548
Income tax expense	404	263	176
Income Before Extraordinary Item	770	442	372
Extraordinary Item, net of tax	587	0	0
Net Income	$ 1,357	$ 442	$ 372
Basic Earnings Per Share:
Income Before Extraordinary Item (in dollars per share)	$ 1.81	$ 1.08	$ 1.02
Extraordinary Item, net of tax (in dollars per share)	1.38	0.00	0.00
Net Income (in dollars per share)	3.19	1.08	1.02
Diluted Earnings Per Share:
Income Before Extraordinary Item (in dollars per share)	1.80	1.07	1.01
Extraordinary Item, net of tax (in dollars per share)	1.37	0.00	0.00
Net Income (in dollars per share)	3.17	1.07	1.01
Dividends Declared Per Share (in dollars per share)	$ 0.79	$ 0.78	$ 0.76
Weighted Average Shares Outstanding, Basic (in shares)	425,636,000	409,721,000	365,229,000
Weighted Average Shares Outstanding, Diluted (in shares)	428,724,000	412,776,000	367,681,000

STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME (PARENTHETICAL) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statement of Income and Comprehensive Income [Abstract]
Adjustment to pension and other postretirement plans	$ 7	$ 5	$ 2
Reclassification of deferred loss from cash flow hedges realized in net income	$ 0	$ 0	$ 0

STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statements of Consolidated Comprehensive Income
Net Income	$ 1,357	$ 442	$ 372
Other comprehensive income (loss):
Adjustment to pension and other postretirment plans (net of tax of $2, $5, and $7)	(16)	6	7
Reclassification of deferred loss from cash flow hedges realized in net income (net of tax of $-0-, $-0- and $-0-)	0	1	0
Other comprehensive income (loss)	(16)	7	7
Comprehensive income	$ 1,341	$ 449	$ 379

- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References

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-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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-Name Emerging Issues Task Force (EITF)
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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+ Details

- Definition

This element represents Other Comprehensive Income or Loss, Net of Tax, for the period attributable to the parent entity. Includes deferred gains or losses on qualifying hedges, unrealized holding gains or losses on available-for-sale securities, minimum pension liability, and cumulative translation adjustment.

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- Definition

Net of tax effect of the reclassification adjustment for accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

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+ Details

CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Current Assets:
Cash and cash equivalents, VIE	$ 220	$ 198
Accounts receivable, net, VIE	52	49
Prepaid expenses and other current assets, VIE	42	39
Other Assets:
Regulatory assets, VIE	$ 2,289	$ 2,597

CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Millions

Dec. 31, 2011

Dec. 31, 2010

Current Assets:

Cash and cash equivalents ($198 and $220 related to VIEs at December 31, 2010 and 2011, respectively)

$ 220

$ 199

Investment in marketable securities

386

367

Accounts receivable, net ($49 and $52 related to VIEs at December 31, 2010 and 2011, respectively)

773

835

Accrued unbilled revenues

326

340

Inventory

353

375

Non-trading derivative assets

Taxes receivable

138

Prepaid expense and other current assets ($39 and $42 related to VIEs at December 31, 2010 and 2011, respectively)

192

274

Total current assets

2,337

2,582

Property, Plant and Equipment, net

12,402

11,732

Other Assets:

Goodwill

1,696

Regulatory assets ($2,597 and $2,289 related to VIEs at December 31, 2010 and 2011, respectively)

4,619

3,446

Non-trading derivative assets

Investment in unconsolidated affiliates

472

468

Other

157

172

Total other assets

6,964

5,797

Total Assets

21,703

20,111

Current Liabilities:

Short-term borrowings

^[1]

Current portion of VIE transition and system restoration bonds long-term debt

307

283

Current portion of indexed debt

131

126

Current portion of other long-term debt

Indexed debt securities derivative

197

232

Accounts payable

560

667

Taxes accrued

207

156

Interest accrued

164

171

Non-trading derivative liabilities

Accumulated deferred income taxes, net

507

407

Other

366

438

Total current liabilities

2,593

2,620

Other Liabilities:

Accumulated deferred income taxes, net

3,832

2,934

Non-trading derivative liabilities

Benefit obligations

1,065

906

Regulatory liabilities

1,039

989

Other

305

447

Total other liabilities

6,247

5,292

Long-term Debt:

VIE transition and system restoration bonds

2,215

2,522

Other

6,426

6,479

Total long-term debt

8,641

9,001

Commitments and Contingencies (Note 13)

Shareholders' Equity

4,222

3,198

Total Liabilities and Shareholders' Equity

$ 21,703

$ 20,111

[1]	Includes amounts due or exchangeable within one year of the date noted.

STATEMENTS OF CONSOLIDATED SHAREHOLDERS' EQUITY (PARENTHETICAL) - $ / shares	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statement of Stockholders' Equity [Abstract]
Preference Stock, none outstanding	0	0	0
Cumulative preferred stock par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Cumulative preferred stock shares authorized (in shares)	20,000,000	20,000,000	20,000,000
Common stock shares par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	1,000,000,000	1,000,000,000	1,000,000,000

STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows from Operating Activities:
Net Income	$ 1,357	$ 442	$ 372
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	886	864	743
Amortization of deferred financing costs	30	27	37
Deferred income taxes	443	199	269
Extraordinary item, net of tax	(587)	0	0
Return on true-up balance	(352)	0	0
Unrealized gain on marketable securities	(19)	(67)	(82)
Unrealized loss (gain) on indexed debt securities	(35)	31	68
Write-down of natural gas inventory	11	6	6
Equity in earnings of unconsolidated affiliates, net of distributions	8	13	(3)
Changes in other assets and liabilities:
Accounts receivable and unbilled revenues, net	40	101	283
Inventory	11	(54)	236
Taxes receivable	138	(138)	0
Accounts payable	(81)	(34)	(237)
Fuel cost under recovery	(70)	(9)	(5)
Non-trading derivatives, net	(13)	(5)	28
Margin deposits, net	34	7	116
Interest and taxes accrued	44	(2)	(41)
Net regulatory assets and liabilities	31	14	0
Other current assets	12	(2)	27
Other current liabilities	18	(1)	6
Other assets	(9)	(8)	(1)
Other liabilities	(33)	4	3
Other, net	24	(2)	16
Net cash provided by operating activities	1,888	1,386	1,841
Cash Flows from Investing Activities:
Capital expenditures	(1,303)	(1,509)	(1,160)
Decrease (increase) in restricted cash of transition and system restoration bond companies	(3)	(5)	26
Decrease in notes receivable from unconsolidated affiliates	0	0	323
Investment in unconsolidated affiliates	(12)	(18)	(115)
Cash received from U.S. Department of Energy grant	110	90	0
Other, net	2	22	30
Net cash used in investing activities	(1,206)	(1,420)	(896)
Cash Flows from Financing Activities:
Increase (decrease) in short-term borrowings, net	9	(2)	(98)
Revolving credit facilities, net	0	0	(1,441)
Proceeds from commercial paper, net	102	183	0
Proceeds from long-term debt	550	0	1,165
Payments on long-term debt	(909)	(783)	(222)
Cash paid for debt exchange	(58)	0	0
Debt issuance costs	(24)	(2)	(10)
Payment of common stock dividends	(337)	(319)	(276)
Proceeds from issuance of common stock, net	6	416	504
Other, net	0	0	6
Net cash used in financing activities	(661)	(507)	(372)
Net Increase (Decrease) in Cash and Cash Equivalents	21	(541)	573
Cash and Cash Equivalents at Beginning of Year	199	740	167
Cash and Cash Equivalents at End of Year	220	199	740
Cash Payments:
Interest, net of capitalized interest	565	609	624
Income taxes (refunds), net	(205)	207	(9)
Non-cash transactions:
Accounts payable related to capital expenditures	$ 110	$ 137	$ 84

STATEMENTS OF CONSOLIDATED SHAREHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Preference Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]
Balance (in shares) at Dec. 31, 2008				346
Balance at Dec. 31, 2008				$ 3	$ 3,158	$ (1,008)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance related to benefit and investment plans				$ 0	86
Issuance related to benefit and investment plans (in shares)				7
Issuances related to public offerings				$ 1
Issuances related to public offerings (in shares)				38
Issuances related to public offerings, net of issuance costs					427
Net Income	$ 372					372
Common stock dividends						(276)
Balance (in shares) at Dec. 31, 2009		0	0	391
Balance at Dec. 31, 2009	2,639	$ 0	$ 0	$ 4	3,671	(912)	$ (124)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to pension and postretirement plans							(120)
Net deferred loss from cash flow hedges							(4)
Issuance related to benefit and investment plans				$ 0	114
Issuance related to benefit and investment plans (in shares)				9
Issuances related to public offerings				$ 0
Issuances related to public offerings (in shares)				25
Issuances related to public offerings, net of issuance costs					315
Net Income	442					442
Common stock dividends						(319)
Balance (in shares) at Dec. 31, 2010		0	0	425
Balance at Dec. 31, 2010	3,198	$ 0	$ 0	$ 4	4,100	(789)	(117)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to pension and postretirement plans							(114)
Net deferred loss from cash flow hedges							(3)
Issuance related to benefit and investment plans				$ 0	20
Issuance related to benefit and investment plans (in shares)				1
Issuances related to public offerings				$ 0
Issuances related to public offerings (in shares)				0
Issuances related to public offerings, net of issuance costs					0
Net Income	1,357					1,357
Common stock dividends						(337)
Balance (in shares) at Dec. 31, 2011		0	0	426
Balance at Dec. 31, 2011	$ 4,222	$ 0	$ 0	$ 4	$ 4,120	$ 231	(133)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to pension and postretirement plans							(130)
Net deferred loss from cash flow hedges							$ (3)

Background

12 Months Ended

Dec. 31, 2011

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Background

CenterPoint Energy, Inc. (CenterPoint Energy) is a public utility holding company. CenterPoint Energy’s operating subsidiaries own and operate electric transmission and distribution facilities, natural gas distribution facilities, interstate pipelines and natural gas gathering, processing and treating facilities. As of December 31, 2011, CenterPoint Energy’s indirect wholly owned subsidiaries included:


•	CenterPoint Energy Houston Electric, LLC (CenterPoint Houston), which engages in the electric transmission and distribution business in the Texas Gulf Coast area that includes the city of Houston; and

•

CenterPoint Energy Resources Corp. (CERC Corp. and, together with its subsidiaries, CERC), which owns and operates natural gas distribution systems. Subsidiaries of CERC own interstate natural gas pipelines and gas gathering systems and provide various ancillary services. A wholly owned subsidiary of CERC Corp. offers variable and fixed-price physical natural gas supplies primarily to commercial and industrial customers and electric and gas utilities.

For a description of CenterPoint Energy’s reportable business segments, see Note 16.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 2-6
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Name Statement of Position (SOP)
-Publisher AICPA
-Number 94-6
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Name FASB Interpretation (FIN)
-Publisher FASB
-Number 46R
-Paragraph 4, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6359553&loc=d3e288-107754

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2197480

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6921930&loc=d3e5614-111684

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 915
-SubTopic 235
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6472506&loc=d3e38932-110933

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2209116

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
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-URI http://asc.fasb.org/extlink&oid=6970148&loc=SL6228881-111685

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/subtopic&trid=2122150

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6359566&loc=d3e326-107755

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
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-URI http://asc.fasb.org/subtopic&trid=2122524

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2134480

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS140-4/FIN46(R)-8
-Paragraph 8, C1, C7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Summary of Significant Accounting Policies


(a)	Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.


(b)	Principles of Consolidation

The accounts of CenterPoint Energy and its wholly owned and majority owned subsidiaries are included in the consolidated financial statements. All intercompany transactions and balances are eliminated in consolidation. CenterPoint Energy uses the equity method of accounting for investments in entities in which CenterPoint Energy has an ownership interest between 20% and 50% and exercises significant influence. CenterPoint Energy’s investments in unconsolidated affiliates include a 50% ownership interest in Southeast Supply Header, LLC (SESH) which owns and operates a 274-mile interstate natural gas pipeline and a 50% interest in Waskom Gas Processing Company (Waskom), a Texas general partnership, which owns and operates a natural gas processing plant and natural gas gathering assets. During 2009, CenterPoint Energy invested $137 million in SESH and received a capital distribution of $23 million from SESH. During 2010, CenterPoint Energy invested $20 million in Waskom. Other investments, excluding marketable securities, are carried at cost. As of December 31, 2011, CenterPoint Energy had five variable interest entities (VIEs) consisting of transition and system restoration bond companies which it consolidates. The consolidated VIEs are wholly-owned bankruptcy remote special purpose entities that were formed specifically for the purpose of securitizing transition and system restoration related property. Creditors of CenterPoint Energy have no recourse to any assets or revenues of the transition and system restoration bond companies. The bonds issued by these VIEs are payable only from and secured by transition and system restoration property and the bondholders have no recourse to the general credit of CenterPoint Energy.


(c)	Revenues

CenterPoint Energy records revenue for electricity delivery and natural gas sales and services under the accrual method and these revenues are recognized upon delivery to customers. Electricity deliveries not billed by month-end are accrued based on daily supply volumes, applicable rates and analyses reflecting significant historical trends and experience. Natural gas sales not billed by month-end are accrued based upon estimated purchased gas volumes, estimated lost and unaccounted for gas and currently effective tariff rates. The Interstate Pipelines and Field Services business segments record revenues as transportation and processing services are provided.

(d) Long-lived Assets and Intangibles

CenterPoint Energy records property, plant and equipment at historical cost. CenterPoint Energy expenses repair and maintenance costs as incurred.

CenterPoint Energy periodically evaluates long-lived assets, including property, plant and equipment, and specifically identifiable intangibles, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. The determination of whether an impairment has occurred is based on an estimate of undiscounted cash flows attributable to the assets compared to the carrying value of the assets.

(e) Regulatory Assets and Liabilities

CenterPoint Energy applies the guidance for accounting for regulated operations to the Electric Transmission & Distribution business segment and the Natural Gas Distribution business segment and to portions of the Interstate Pipelines business segment.

CenterPoint Energy’s rate-regulated businesses recognize removal costs as a component of depreciation expense in accordance with regulatory treatment. As of December 31, 2010 and 2011, these removal costs of $868 million and $912 million, respectively, are classified as regulatory liabilities in CenterPoint Energy’s Consolidated Balance Sheets. In addition, a portion of the amount of removal costs that relate to asset retirement obligations has been reclassified from a regulatory liability to an asset retirement liability in accordance with accounting guidance for conditional asset retirement obligations.

(f) Depreciation and Amortization Expense

Depreciation and amortization is computed using the straight-line method based on economic lives or regulatory-mandated recovery periods. Amortization expense includes amortization of regulatory assets and other intangibles.

(g) Capitalization of Interest and Allowance for Funds Used During Construction

Interest and allowance for funds used during construction (AFUDC) are capitalized as a component of projects under construction and are amortized over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction for subsidiaries that apply the guidance for accounting for regulated operations. During 2009, 2010 and 2011, CenterPoint Energy capitalized interest and AFUDC of $5 million, $9 million and $4 million, respectively.

(h) Income Taxes

CenterPoint Energy files a consolidated federal income tax return and follows a policy of comprehensive interperiod tax allocation. CenterPoint Energy uses the asset and liability method of accounting for deferred income taxes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Investment tax credits that were deferred are being amortized over the estimated lives of the related property. A valuation allowance is established against deferred tax assets for which management believes realization is not considered to be more likely than not. CenterPoint Energy recognizes interest and penalties as a component of income tax expense.

(i) Accounts Receivable and Allowance for Doubtful Accounts

Accounts receivable are net of an allowance for doubtful accounts of $25 million at both December 31, 2010 and 2011, respectively. The provision for doubtful accounts in CenterPoint Energy’s Statements of Consolidated Income for 2009, 2010 and 2011 was $36 million, $30 million and $26 million, respectively.

(j) Inventory

Inventory consists principally of materials and supplies and natural gas. Materials and supplies are valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed. Natural gas inventories of CenterPoint Energy’s Competitive Natural Gas Sales and Services business segment are also primarily valued at the lower of average cost or market. Natural gas inventories of CenterPoint Energy’s Natural Gas Distribution business segment are primarily valued at weighted average cost. During 2010 and 2011, CenterPoint Energy recorded $6 million and $11 million, respectively, in write-downs of natural gas inventory to the lower of average cost or market.



	December 31,
	2010		2011
	(in millions)
Materials and supplies	$	164	$	166
Natural gas	211		187
Total inventory	$	375	$	353

(k) Derivative Instruments

CenterPoint Energy is exposed to various market risks. These risks arise from transactions entered into in the normal course of business. CenterPoint Energy utilizes derivative instruments such as physical forward contracts, swaps and options to mitigate the impact of changes in commodity prices and weather on its operating results and cash flows. Such derivatives are recognized in CenterPoint Energy’s Consolidated Balance Sheets at their fair value unless CenterPoint Energy elects the normal purchase and sales exemption for qualified physical transactions. A derivative may be designated as a normal purchase or normal sale if the intent is to physically receive or deliver the product for use or sale in the normal course of business.

CenterPoint Energy has a Risk Oversight Committee composed of corporate and business segment officers that oversees all commodity price, weather and credit risk activities, including CenterPoint Energy’s marketing, risk management services and hedging activities. The committee’s duties are to establish CenterPoint Energy’s commodity risk policies, allocate board-approved commercial risk limits, approve the use of new products and commodities, monitor positions and ensure compliance with CenterPoint Energy’s risk management policies and procedures and limits established by CenterPoint Energy’s board of directors.

CenterPoint Energy’s policies prohibit the use of leveraged financial instruments. A leveraged financial instrument, for this purpose, is a transaction involving a derivative whose financial impact will be based on an amount other than the notional amount or volume of the instrument.

(l) Investments in Other Debt and Equity Securities

CenterPoint Energy reports securities classified as trading at estimated fair value in its Consolidated Balance Sheets, and any unrealized holding gains and losses are recorded as other income (expense) in its Statements of Consolidated Income.

(m) Environmental Costs

CenterPoint Energy expenses or capitalizes environmental expenditures, as appropriate, depending on their future economic benefit. CenterPoint Energy expenses amounts that relate to an existing condition caused by past operations that do not have future economic benefit. CenterPoint Energy records undiscounted liabilities related to these future costs when environmental assessments and/or remediation activities are probable and the costs can be reasonably estimated.

(n) Statements of Consolidated Cash Flows

For purposes of reporting cash flows, CenterPoint Energy considers cash equivalents to be short-term, highly-liquid investments with maturities of three months or less from the date of purchase. In connection with the issuance of transition bonds and system restoration bonds, CenterPoint Energy was required to establish restricted cash accounts to collateralize the bonds that were issued in these financing transactions. These restricted cash accounts are not available for withdrawal until the maturity of the bonds and are not included in cash and cash equivalents. These restricted cash accounts of $39 million and $42 million at December 31, 2010 and 2011, respectively, are included in other current assets in CenterPoint Energy's Consolidated Balance Sheets. Cash and cash equivalents included $198 million and $220 million at December 31, 2010 and 2011, respectively, that was held by CenterPoint Energy’s transition and system restoration bond subsidiaries solely to support servicing the transition and system restoration bonds.

(o) New Accounting Pronouncements

In May 2011, the Financial Accounting Standards Board (FASB) issued new accounting guidance to achieve common fair value measurements and disclosure requirements in generally accepted accounting principles (U.S. GAAP) and International Financial Reporting Standards (IFRS). Some of the provisions of the new accounting guidance include requiring (1) that only nonfinancial assets should be valued based on a determination of their best use, (2) disclosure of quantitative information about unobservable inputs used in Level 3 fair value measurements and (3) disclosure of the level within the fair value hierarchy for each class of assets or liabilities not measured at fair value in the statement of financial position but for which the fair value is disclosed. This new guidance is effective for interim and annual periods beginning after December 15, 2011. CenterPoint Energy expects that the adoption of this new guidance will not have a material impact on its financial position, results of operations or cash flows.

In June 2011, the FASB issued new accounting guidance on the presentation of comprehensive income. The new guidance is intended to improve the overall quality of financial reporting by increasing the prominence of items reported in other comprehensive income and aligning the presentation of other comprehensive income in financial statements prepared in accordance with U.S. GAAP with those prepared in accordance with IFRS. The new guidance requires an entity to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. This new guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2011. Adoption of this new guidance did not have an impact on CenterPoint Energy's financial position, results of operations or cash flows.

In September 2011, the FASB issued new accounting guidance that is intended to simplify how entities test goodwill for impairment. The new accounting guidance permits an entity to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. If, after performing the qualitative assessment, it is determined that the fair value of a reporting unit is more likely than not less than its carrying value, then the quantitative two-step goodwill impairment test that exists under current GAAP must be performed; otherwise, goodwill is deemed to not be impaired and no further testing is required. An entity has the unconditional option to bypass the qualitative assessment and proceed directly to the quantitative assessment. This new guidance is effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. CenterPoint Energy did not elect early adoption, but expects that the adoption of this new guidance will not have a material impact on its financial position, results of operations or cash flows.

In December 2011, the FASB issued new accounting guidance that will require disclosure of information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. The new disclosure requirements mandate that entities disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position as well as disclosure of collateral received and posted in connection with these instruments. This new guidance is effective for annual reporting periods beginning on or after January 1, 2013, and interim periods therein, with retrospective application required. CenterPoint Energy expects that the adoption of this new guidance will not have a material impact on its financial position, results of operations or cash flows.

Management believes the impact of other recently issued standards, which are not yet effective, will not have a material impact on CenterPoint Energy’s consolidated financial position, results of operations or cash flows upon adoption.

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2011

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

(a) Property, Plant and Equipment

Property, plant and equipment includes the following:



	Weighted Average Useful Lives	December 31,
	(Years)	2010		2011
		(in millions)
Electric Transmission & Distribution	29	$	7,586	$	7,827
Natural Gas Distribution	32	3,642		3,959
Competitive Natural Gas Sales and Services	27	71		76
Interstate Pipelines	57	2,594		2,675
Field Services	46	1,583		1,754
Other property	24	529		577
Total		16,005		16,868
Accumulated depreciation and amortization:
Electric Transmission & Distribution		2,805		2,784
Natural Gas Distribution		954		1,069
Competitive Natural Gas Sales and Services		16		20
Interstate Pipelines		265		302
Field Services		43		72
Other property		190		219
Total accumulated depreciation and amortization		4,273		4,466
Property, plant and equipment, net		$	11,732	$	12,402

(b) Depreciation and Amortization

The following table presents depreciation and amortization expense for 2009, 2010 and 2011 (in millions).



	2009		2010		2011
Depreciation expense	$	496	$	531	$	529
Amortization expense	247		333		357
Total depreciation and amortization expense	$	743	$	864	$	886

A reconciliation of the changes in the asset retirement obligation (ARO) liability is as follows (in millions):



	December 31,
	2010			2011
Beginning balance	$	82		$	84
Accretion expense	5			5
Revisions in estimates of cash flows	(3		)	67
Ending balance	$	84		$	156

The decrease of $3 million in the ARO from the revision of the estimate in 2010 is primarily attributable to changes in the estimated lives of some of the assets underlying the liability. The increase of $67 million in the ARO from the revision of estimate in 2011 is primarily attributable to an increase in the disposal costs used in the cash flow assumptions. There were no material additions or settlements during the years ended December 31, 2010 and 2011.

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Goodwill

12 Months Ended

Dec. 31, 2011

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

Goodwill by reportable segment as of both December 31, 2010 and 2011 is as follows (in millions):



Natural Gas Distribution	$	746
Interstate Pipelines	579
Competitive Natural Gas Sales and Services	335
Field Services	25
Other Operations	11
Total	$	1,696

CenterPoint Energy performs its goodwill impairment tests at least annually and evaluates goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. The impairment evaluation for goodwill is performed by using a two-step process. In the first step, the fair value of each reporting unit is compared with the carrying amount of the reporting unit, including goodwill. The estimated fair value of the reporting unit is generally determined on the basis of discounted cash flows. If the estimated fair value of the reporting unit is less than the carrying amount of the reporting unit, then a second step must be completed in order to determine the amount of the goodwill impairment that should be recorded. In the second step, the implied fair value of the reporting unit’s goodwill is determined by allocating the reporting unit’s fair value to all of its assets and liabilities other than goodwill (including any unrecognized intangible assets) in a manner similar to a purchase price allocation. The resulting implied fair value of the goodwill that results from the application of this second step is then compared to the carrying amount of the goodwill and an impairment charge is recorded for the difference.

CenterPoint Energy performed the test at July 1, 2011, its annual impairment testing date, and determined that no impairment charge for goodwill was required. Other intangibles were not material as of December 31, 2010 and 2011.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Regulatory Matters

12 Months Ended

Dec. 31, 2011

Regulated Operations [Abstract]

Regulatory Matters

(a) Regulatory Assets and Liabilities

The following is a list of regulatory assets/liabilities reflected on CenterPoint Energy’s Consolidated Balance Sheets as of December 31, 2010 and 2011:



	December 31,
	2010			2011
	(in millions)
Securitized regulatory assets	$	2,597		$	2,289
True-up Settlement (1)	—			1,684
Unrecognized equity return (2)	(216		)	(600		)
Unamortized loss on reacquired debt	61			56
Pension and postretirement-related regulatory asset (3)	838			975
Other long-term regulatory assets (4)	166			215
Total regulatory assets	3,446			4,619

Estimated removal costs	868			912
Other long-term regulatory liabilities	121			127
Total regulatory liabilities	989			1,039

Total regulatory assets and liabilities, net	$	2,457		$	3,580


(1)	In accordance with a final order from the Public Utility Commission of Texas, (Texas Utility Commission), the true-up settlement at December 31, 2011 was not earning a return. The regulatory asset was securitized in January 2012 as a result of the issuance of the transition bonds described below in Note 5(b).


(2)	As of December 31, 2011, CenterPoint Energy has not recognized an allowed equity return of $600 million because such return will be recognized as it is recovered in rates. During the years ended December 31, 2009, 2010 and 2011, CenterPoint Houston recognized approximately $14 million, $16 million and $21 million, respectively, of the allowed equity return.

(3)

CenterPoint Houston’s actuarially determined pension expense for 2010 and 2011 in excess of the amount being recovered through rates is being deferred for rate making purposes and was addressed in its 2010 rate application pursuant to Texas law. CenterPoint Houston deferred as a regulatory asset $26 million and $16 million in pension and other postemployment expenses during the years ended December 31, 2010 and 2011, respectively. Deferred pension and other postemployment expenses of $58 million and $16 million at December 31, 2010 and 2011, respectively, were not earning a return.


(4)	Other regulatory assets that are not earning a return were not material at December 31, 2010 and 2011.

(b) Resolution of True-Up Appeal

In March 2004, CenterPoint Houston filed a true-up application with the Texas Utility Commission requesting recovery of $3.7 billion, excluding interest, as allowed under the Texas Electric Choice Plan. In December 2004, the Texas Utility Commission issued its final order (True-Up Order) allowing CenterPoint Houston to recover a true-up balance of approximately $2.3 billion, which included interest through August 31, 2004, and provided for adjustment of the amount to be recovered to include interest on the balance until recovery, along with the principal portion of additional excess mitigation credits returned to customers after August 31, 2004 and certain other adjustments. To reflect the impact of the True-Up Order, in 2004 and 2005, CenterPoint Energy recorded a net after-tax extraordinary loss of $947 million.

Various parties, including CenterPoint Houston, appealed the True-Up Order. These appeals were heard first by a district court in Travis County, Texas, then by the Texas Third Court of Appeals and finally by the Texas Supreme Court. In March 2011, the Texas Supreme Court issued a unanimous ruling on such appeals in which it affirmed in part and reversed in part the decision of the Texas Utility Commission. In June 2011, the Texas Supreme Court issued a final mandate remanding the case to the Texas Utility Commission for further proceedings (the Remand Proceeding).

In September 2011, CenterPoint Houston reached an agreement in principle with the staff of the Texas Utility Commission and certain intervenors to settle the issues in the Remand Proceeding (the Settlement). In October 2011, the Texas Utility Commission approved a final order (the Final Order) in the Remand Proceeding consistent with the Settlement. The Final Order provided that (i) CenterPoint Houston was entitled to recover an additional true-up balance of $1.695 billion (the Recoverable True-Up Balance) in the Remand Proceeding, (ii) no further interest would accrue on the Recoverable True-Up Balance, and (iii) CenterPoint Houston would reimburse certain parties for their reasonable rate case expenses.

In October 2011, the Texas Utility Commission also issued a financing order (the Financing Order) that authorized the issuance of transition bonds by CenterPoint Houston to securitize the Recoverable True-Up Balance. In January 2012, CenterPoint Energy Transition Bond Company IV, LLC (Bond Company IV), a new special purpose subsidiary of CenterPoint Houston, issued $1.695 billion of transition bonds in three tranches with interest rates ranging from 0.9012% to 3.0282% and final maturity dates ranging from April 15, 2018 to October 15, 2025. Through the issuance of these transition bonds, CenterPoint Houston recovered the Recoverable True-Up Balance, less approximately $10.4 million of offering expenses. The transition bonds will be repaid over time through a charge imposed on customers in CenterPoint Houston's service territory. The holders of the transition bonds do not have recourse to any assets or revenues of CenterPoint Houston, and the creditors of CenterPoint Houston do not have recourse to any assets or revenues of Bond Company IV, including, without limitation, the transition property transferred to Bond Company IV in connection with the issuance of the transition bonds. The transition property includes the right to impose, collect and receive an irrevocable, non-bypassable charge payable by CenterPoint Houston's retail electric customers.

As a result of the Final Order, CenterPoint Houston recorded a pre-tax extraordinary gain of $921 million ($587 million after taxes of $334 million) and $352 million ($224 million after-tax) of Other Income related to a portion of interest on the appealed amount. An additional $405 million ($258 million after-tax) will be recorded as an equity return over the life of the transition bonds.

CenterPoint Houston

June 2010 Rate Proceeding. As required under the final order in its 2006 rate proceeding, in June 2010, CenterPoint Houston filed an application to change rates with the Texas Utility Commission and the cities in its service area. Following hearings in the fall of 2010, the Texas Utility Commission issued its order in May 2011. In response to motions filed by several parties, including CenterPoint Houston, in June 2011, the Texas Utility Commission issued an order on rehearing, which addressed certain errors and inconsistencies identified in its prior decision. CenterPoint Houston implemented revised rates on September 1, 2011 based on the order on rehearing. The order on rehearing has been appealed to the Texas courts by various parties; however, a procedural schedule has not been established.

The order on rehearing provides for a base rate increase for CenterPoint Houston of approximately $14.7 million per year for delivery charges to the REPs and a decrease to charges to wholesale transmission customers of $12.3 million per year. Further, the order adopts a mechanism to track amounts for uncertain tax positions and provide for ultimate recovery of those costs. The order authorizes a return on equity for CenterPoint Houston of 10%, a cost of debt of 6.74%, a capital structure comprised of 55% debt and 45% common equity, and an overall rate of return of 8.21%. The decision also implements CenterPoint Houston’s request to reconcile costs incurred for the advanced metering system (AMS) project and to shorten the period for collecting the AMS surcharge from twelve to six years for residential customers in order to reflect funds received from the U.S. Department of Energy. As part of the process to reconcile AMS costs, $138 million of the capital investment (net of related deferred taxes) used to determine the AMS surcharge was transferred to CenterPoint Houston's rate base and used in calculating delivery rates. As a result of the Texas Utility Commission’s order, CenterPoint Houston anticipates that 2012 operating income will be reduced by approximately $35 million as compared to 2011 performance.

Other. In May 2009, CenterPoint Houston filed an application at the Texas Utility Commission seeking approval of certain estimated 2010 energy efficiency program costs, an energy efficiency performance bonus for 2008 programs, and carrying costs totaling approximately $10 million. The application sought to begin recovery of these costs through a surcharge effective July 1, 2010. In October 2009, the Texas Utility Commission issued its order approving recovery of approximately $8 million to cover the 2010 energy efficiency program costs and a partial performance bonus, plus carrying costs, but disallowed recovery of a performance bonus of $2 million on approximately $10 million in 2008 energy efficiency costs expended pursuant to the terms of a settlement agreement in a prior rate case. CenterPoint Houston began collecting the approved amounts in July 2010. CenterPoint Houston appealed the denial of the full 2008 performance bonus to the 98th district court in Travis County, Texas. In October 2010, the district court upheld the Texas Utility Commission’s decision. In February 2011, CenterPoint Houston appealed the district court’s judgment to the Texas Third Court of Appeals at Austin, Texas. Oral arguments were heard in October 2011, and the case remains pending.

In April 2010, CenterPoint Houston filed an application with the Texas Utility Commission seeking approval of the recovery of $14.4 million related to estimated 2011 energy efficiency program costs, an energy efficiency performance bonus for 2009 programs, and recovery of revenue losses related to the implementation of the 2009 energy efficiency program. The application sought to begin recovery of these costs through a surcharge beginning in January 2011. In November 2010, the Texas Utility Commission issued its order approving recovery of approximately $11 million of the 2011 energy efficiency program costs and a performance bonus, but disallowed recovery of a performance bonus of $2 million on the 2009 energy efficiency costs expended pursuant to the terms of the settlement agreement referenced above. The Texas Utility Commission further concluded that it does not have statutory authority to permit recovery of the approximately $1.4 million in lost revenue associated with 2009 energy efficiency programs. CenterPoint Houston began collecting the approved amounts in January 2011, but has appealed the denial of the full 2009 performance bonus and lost revenue to the 201st district court in Travis County, Texas, where the case remains pending.

In April 2011, CenterPoint Houston filed an application with the Texas Utility Commission seeking approval of the recovery in 2012 of approximately $44.3 million consisting of: (1) estimated 2012 energy efficiency program costs of approximately $35.9 million; (2) an energy efficiency performance bonus of approximately $5.8 million based on CenterPoint Houston’s 2010 program achievements; (3) approximately $2.2 million of lost revenues due to verified and reported 2010 energy savings; and (4) approximately $0.5 million for under-recovery of 2010 program costs. In the preliminary order in this proceeding, the Texas Utility Commission excluded approximately $2.1 million of the requested performance bonus for the 2010 programs and has concluded that it does not have the statutory authority to permit recovery of the requested $2.2 million of lost revenues associated with the 2010 programs. In August 2011, CenterPoint Houston and the parties agreed to forego a hearing and admit evidence supporting the recovery of (1) the estimated 2012 energy efficiency costs of approximately $35.9 million, (2) an energy efficiency performance bonus of approximately $3.6 million, and (3) approximately $0.5 million for under-recovery of 2010 program costs. In December 2011, the Texas Utility Commission issued an order approving recovery of the amounts identified above and CenterPoint Houston began collecting those approved amounts. CenterPoint Houston has filed notification that it reserves its right to appeal the denial of the full 2010 performance bonus and lost revenues. The approved rate adjustments took effect with the commencement of CenterPoint Houston’s January 2012 billing month.

In August 2011, CenterPoint Houston filed a Transmission Cost of Service application with the Texas Utility Commission seeking an increase in annual revenue of approximately $3.4 million. In September 2011, the Texas Utility Commission approved the application and the rates became effective. In November 2011, CenterPoint Houston filed another Transmission Cost of Service application with the Texas Utility Commission seeking an increase in annual revenue of approximately $7.1 million. In January 2012, the Texas Utility Commission approved the application and the rates became effective.

In September 2011, a new rule of the Texas Utility Commission relating to a Distribution Cost Recovery Factor (DCRF) became effective. The new rule permits an electric utility such as CenterPoint Houston to file each year to recover through a separate DCRF a return on changes to certain distribution-related capital investments, net of any changes in distribution-related accumulated deferred income taxes, as well as related changes to depreciation expense and taxes. The utility is allowed to request one DCRF annually unless in the previous year it was found to have earned in excess of its authorized return on equity as calculated in its annual earnings monitoring report on a weather-adjusted basis, in which case the DCRF is not available. The utility is limited to four DCRF filings and then must seek a full rate proceeding before it can request a subsequent DCRF. The rule expires January 1, 2017.

In October 2011, CenterPoint Houston and certain other parties filed a non-unanimous stipulation (Transmission Stipulation) with the Texas Utility Commission to resolve claims related to the “transition mechanism” component of certain invalidated transmission pricing rules. The Transmission Stipulation resolves all remaining claims that arose from or relate to wholesale transmission service and charges within the Electric Reliability Council of Texas, Inc. (ERCOT) for the period from September 1, 1999 to December 31, 1999 during which the Texas Utility Commission had continued to utilize the “transition mechanism” component of the invalidated transmission pricing rules in setting ERCOT transmission rates. The Transmission Stipulation was filed by all parties to the proceeding, except CPS Energy, and was approved by the Texas Utility Commission in January 2012. Under the Transmission Stipulation, CenterPoint Houston's payment of $5.6 million is to be made within 30 days after issuance of a final appealable order. CenterPoint Houston will seek recovery of the payment through its Transmission Cost Recovery Factor mechanism.

Gas Operations

In March 2008, the natural gas distribution business of CERC (Gas Operations) filed a request to change its rates with the Railroad Commission of Texas (Railroad Commission) and the 47 cities in its Texas Coast service territory, an area consisting of approximately 230,000 customers in cities and communities on the outskirts of Houston. In 2008, the Railroad Commission approved the implementation of rates increasing annual revenues by approximately $3.5 million. The approved rates were contested by a coalition of nine cities in an appeal to the 353rd district court in Travis County, Texas. In January 2010, that court reversed the Railroad Commission’s order in part and remanded the matter to the Railroad Commission. In its final judgment, the court ruled that the Railroad Commission lacked authority to impose the approved cost of service adjustment (COSA) mechanism both in those nine cities and in those areas in which the Railroad Commission has original jurisdiction. The Railroad Commission and Gas Operations appealed the court’s ruling on the COSA mechanism to the Texas Third Court of Appeals in Austin, Texas. In October 2011, the Texas Third Court of Appeals reversed the district court's ruling. In December 2011, the Texas Third Court of Appeals denied a motion for rehearing. In February 2012, parties opposed to the decision appealed to the Texas Supreme Court. CenterPoint Energy does not expect the outcome of this matter to have a material adverse impact on its financial condition, results of operations or cash flows. The COSA mechanism was initially effective for three successive years ending in calendar year 2010, but would automatically renew for successive three-year periods unless Gas Operations or the regulatory authority having original jurisdiction gave written notice to discontinue the COSA mechanism by February 1, 2011. Certain cities that agreed to the initial implementation notified Gas Operations by February 1, 2011 of their desire to discontinue the COSA mechanism. In July 2011, Gas Operations requested that the Railroad Commission waive the notice date of February 1, 2011 in order to allow Gas Operations to discontinue the COSA mechanism for the remaining areas, which request was granted in July 2011.

In July 2009, Gas Operations filed a request to change its rates with the Railroad Commission and the 29 cities in its Houston service territory, consisting of approximately 940,000 customers in and around Houston. As finally submitted to the Railroad Commission and the cities, the proposed new rates would have resulted in an overall increase in annual revenue of $20.4 million, excluding carrying costs of approximately $2 million on its gas inventory. In February 2010, the Railroad Commission issued its decision authorizing a revenue increase of $5.1 million annually, reflecting reduced depreciation rates as well as certain other adjustments. The Railroad Commission also approved a surcharge of $0.9 million per year to recover over three years costs associated with damage caused by Hurricane Ike. These rates went into effect in March 2010. Gas Operations and other parties are seeking judicial review of the Railroad Commission’s decision in the 261st district court in Travis County, Texas.

(d) Regulatory Accounting

CenterPoint Energy has a 50% ownership interest in SESH, which owns and operates a 274-mile interstate natural gas pipeline. In 2009, SESH discontinued the use of guidance for accounting for regulated operations, which resulted in CenterPoint Energy recording its share of the effects of such write-offs of SESH’s regulatory assets through non-cash pre-tax charges for the year ended December 31, 2009 of $16 million. These non-cash charges are reflected in equity in earnings of unconsolidated affiliates in the Statements of Consolidated Income. The related tax benefits of $6 million are reflected in the Income Tax Expense line in the Statements of Consolidated Income.

Stock-Based Incentive Compensation Plans and Employee Benefit Plans

12 Months Ended

Dec. 31, 2011

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Incentive Compensation Plans and Employee Benefit Plans

(a) Stock-Based Incentive Compensation Plans

CenterPoint Energy has long-term incentive plans (LTIPs) that provide for the issuance of stock-based incentives, including stock options, performance awards, restricted stock unit awards and restricted and unrestricted stock awards to officers, employees and non-employee directors. Approximately 14 million shares of CenterPoint Energy common stock are authorized under these plans for the issuance of new grants.

Equity awards are granted to employees without cost to the participants. The performance awards granted in 2009, 2010 and 2011 are distributed based upon the achievement of certain objectives over a three-year performance cycle. The stock awards granted in 2009, 2010 and 2011 are subject to the performance condition that total common dividends declared during the three-year vesting period must be at least $2.28, $2.34 and $2.37 per share, respectively. The stock awards generally vest at the end of a three-year period. Upon vesting, both the performance and stock awards are issued to the participants along with the value of dividend equivalents earned over the performance cycle or vesting period. CenterPoint Energy issues new shares in order to satisfy stock-based payments related to LTIPs.

CenterPoint Energy recorded LTIPs compensation expense of $15 million, $17 million and $19 million for the years ended December 31, 2009, 2010 and 2011, respectively. This expense is included in Operation and Maintenance Expense in the Statements of Consolidated Income.

The total income tax benefit recognized related to LTIPs was $6 million, $6 million and $7 million in the years ended December 31, 2009, 2010 and 2011, respectively. No compensation cost related to LTIPs was capitalized as a part of inventory or fixed assets in 2009, 2010 or 2011. The actual tax benefit realized for tax deductions related to LTIPs totaled $6 million, $5 million and $8 million for 2009, 2010 and 2011, respectively.

Compensation costs for the performance and stock awards granted under LTIPs are measured using fair value and expected achievement levels on the grant date. The fair value of awards granted to employees after April 2009 is based on the closing stock price of CenterPoint Energy’s common stock on the grant date. The fair value of awards granted prior to May 2009 was based on the average of the high and low stock price of CenterPoint Energy’s common stock on the grant date. The compensation expense is recorded on a straight-line basis over the vesting period. Forfeitures are estimated on the date of grant based on historical averages. For performance awards with operational goals, the achievement levels are revised as goals are evaluated.

The following tables summarize CenterPoint Energy’s LTIPs activity for 2011:

Stock Options



	Outstanding Options
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Exercise Price		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	3,077		$	19.27
Expired	(1,417	)	31.70
Cancelled	(31	)	31.98
Exercised	(664	)	8.13
Outstanding at December 31, 2011	965		8.28		1.4	$	11
Exercisable at December 31, 2011	965		8.28		1.4	11

Cash received from stock options exercised was $4 million, $9 million and $5 million for 2009, 2010 and 2011, respectively.

CenterPoint Energy has not issued stock options since 2004.

Performance Awards



	Outstanding and Non-Vested Shares
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Grant Date Fair Value		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	3,068		$	13.84
Granted	1,110		15.49
Forfeited or cancelled	(469	)	15.25
Vested and released to participants	(411	)	15.39
Outstanding at December 31, 2011	3,298		13.99		1.0	$	55

The outstanding and non-vested shares displayed in the table above assumes that shares are issued at the maximum performance level. The aggregate intrinsic value reflects the impacts of current expectations of achievement and stock price.

Stock Awards



	Outstanding and Non-Vested Shares
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Grant Date Fair Value		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	1,096		$	13.78
Granted	368		15.81
Forfeited or cancelled	(30	)	14.00
Vested and released to participants	(369	)	14.75
Outstanding at December 31, 2011	1,065		14.14		1.1	$	21

The weighted-average grant-date fair values of awards granted were as follows for 2009, 2010 and 2011:



	Year Ended December 31,
	2009		2010		2011
Performance awards	$	12.42	$	14.21	$	15.49
Stock awards	12.30		14.26		15.81

Valuation Data

The total intrinsic value of awards received by participants was as follows for 2009, 2010 and 2011:



	Year Ended December 31,
	2009		2010		2011
	(in millions)
Stock options exercised	$	2	$	4	$	7
Performance awards	7		5		7
Stock awards	4		4		7

The total grant date fair value of performance and stock awards which vested during the years ended December 31, 2009, 2010 and 2011 was $11 million, $10 million and $12 million, respectively. As of December 31, 2011, there was $18 million of total unrecognized compensation cost related to non-vested performance and stock awards which is expected to be recognized over a weighted-average period of 1.7 years.

(b) Pension and Postretirement Benefits

CenterPoint Energy maintains a non-contributory qualified defined benefit pension plan covering substantially all employees, with benefits determined using a cash balance formula. Under the cash balance formula, participants accumulate a retirement benefit based upon 5% of eligible earnings, which increased from 4% effective January 1, 2009, and accrued interest. Participants are 100% vested in their benefit after completing three years of service. In addition to the non-contributory qualified defined benefit pension plan, CenterPoint Energy maintains unfunded non-qualified benefit restoration plans which allow participants to receive the benefits to which they would have been entitled under CenterPoint Energy’s non-contributory pension plan except for federally mandated limits on qualified plan benefits or on the level of compensation on which qualified plan benefits may be calculated.

CenterPoint Energy provides certain healthcare and life insurance benefits for retired employees on both a contributory and non-contributory basis. Employees become eligible for these benefits if they have met certain age and service requirements at retirement, as defined in the plans. Under plan amendments, effective in early 1999, healthcare benefits for future retirees were changed to limit employer contributions for medical coverage.

Such benefit costs are accrued over the active service period of employees. The net unrecognized transition obligation is being amortized over approximately 20 years.

CenterPoint Energy’s net periodic cost includes the following components relating to pension, including the benefit restoration plan, and postretirement benefits:



	Year Ended December 31,
	2009						2010						2011
	Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits
	(in millions)
Service cost	$	25		$	1		$	31		$	1		$	33		$	1
Interest cost	113			28			102			25			100			24
Expected return on plan assets	(98		)	(9		)	(109		)	(10		)	(115		)	(10		)
Amortization of prior service cost	3			3			3			3			3			3
Amortization of net loss	68			—			59			—			57			1
Amortization of transition obligation	—			7			—			7			—			7
Benefit enhancement	—			—			—			—			—			1
Net periodic cost	$	111		$	30		$	86		$	26		$	78		$	27

CenterPoint Energy used the following assumptions to determine net periodic cost relating to pension and postretirement benefits:



	December 31,
	2009				2010				2011
	Pension Benefits		Post-retirement Benefits		Pension Benefits		Post-retirement Benefits		Pension Benefits		Post-retirement Benefits
Discount rate	6.90	%	6.90	%	5.70	%	5.70	%	5.25	%	5.20	%
Expected return on plan assets	8.00		7.05		8.00		7.05		8.00		7.05
Rate of increase in compensation levels	4.60		—		4.60		—		4.60		—

In determining net periodic benefits cost, CenterPoint Energy uses fair value, as of the beginning of the year, as its basis for determining expected return on plan assets.

The following table summarizes changes in the benefit obligation, plan assets, the amounts recognized in consolidated balance sheets and the key assumptions of CenterPoint Energy’s pension, including benefit restoration, and postretirement plans. The measurement dates for plan assets and obligations were December 31, 2010 and 2011.



	December 31,
	2010						2011
	Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits
	(in millions, except for actuarial assumptions)
Change in Benefit Obligation
Benefit obligation, beginning of year	$	1,866		$	450		$	1,969		$	460
Service cost	31			1			33			1
Interest cost	102			25			100			24
Participant contributions	—			7			—			7
Benefits paid	(115		)	(50		)	(113		)	(40		)
Actuarial loss	85			24			93			41
Early retiree reinsurance program reimbursement	—			—			—			3
Medicare reimbursement	—			3			3			4
Benefit obligation, end of year	1,969			460			2,085			500
Change in Plan Assets
Fair value of plan assets, beginning of year	1,432			146			1,501			144
Employer contributions	8			29			75			21
Participant contributions	—			7			—			7
Benefits paid	(115		)	(50		)	(113		)	(40		)
Actual investment return	176			12			43			6
Fair value of plan assets, end of year	1,501			144			1,506			138
Funded status, end of year	$	(468	)	$	(316	)	$	(579	)	$	(362	)
Amounts Recognized in Balance Sheets
Current liabilities-other	$	(9	)	$	(9	)	$	(9	)	$	(9	)
Other liabilities-benefit obligations	(459		)	(307		)	(570		)	(353		)
Net liability, end of year	$	(468	)	$	(316	)	$	(579	)	$	(362	)
Actuarial Assumptions
Discount rate	5.25		%	5.20		%	4.90		%	4.80		%
Expected return on plan assets	8.00			7.05			8.00			5.50
Rate of increase in compensation levels	4.60			—			4.20			—
Healthcare cost trend rate assumed for the next year	—			8.50			—			8.00
Prescription drug cost trend rate assumed for the next year	—			8.50			—			8.00
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	—			5.50			—			5.50
Year that the healthcare rate reaches the ultimate trend rate	—			2017			—			2017
Year that the prescription drug rate reaches the ultimate trend rate	—			2017			—			2017

The accumulated benefit obligation for all defined benefit pension plans was $1,954 million and $2,064 million as of December 31, 2010 and 2011, respectively.

The expected rate of return assumption was developed by a weighted-average return analysis of the targeted asset allocation of CenterPoint Energy’s plans and the expected real return for each asset class, based on the long-term capital market assumptions, adjusted for investment fees and diversification effects, in addition to expected inflation.

The discount rate assumption was determined by matching the accrued cash flows of CenterPoint Energy’s plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years.

For measurement purposes, healthcare and prescription costs are assumed to increase to 8.00% during 2012, after which this rate decreases until reaching the ultimate trend rate of 5.50% in 2017, except for the 2013 rate which is expected to increase to 9.00% in anticipation of the healthcare exchanges being introduced to the market in 2014.

Amounts recognized in accumulated other comprehensive loss consist of the following:



	December 31,
	2010				2011
	Pension Benefits		Postretirement Benefits		Pension Benefits		Postretirement Benefits
	(in millions)
Unrecognized actuarial loss	$	151	$	18	$	166	$	25
Unrecognized prior service cost	15		7		15		5
Unrecognized transition obligation	—		2		—		1
Net amount recognized in accumulated other comprehensive loss	$	166	$	27	$	181	$	31

The changes in plan assets and benefit obligations recognized in other comprehensive income during 2011 are as follows (in millions):



	Pension Benefits			Postretirement Benefits
Net loss	$	2		$	7
Amortization of net loss	13			—
Prior service credit	(1		)	(4		)
Amortization of prior service credit	1			2
Transition obligation	—			(1		)
Total recognized in comprehensive income	$	15		$	4

The total expense recognized in net periodic costs and other comprehensive income was $93 million and $31 million for pension and postretirement benefits, respectively, for the year ended December 31, 2011.

The amounts in accumulated other comprehensive loss expected to be recognized as components of net periodic benefit cost during 2012 are as follows (in millions):



	Pension Benefits		Postretirement Benefits
Unrecognized actuarial loss	$	13	$	1
Unrecognized prior service cost	1		2
Amounts in accumulated comprehensive income to be recognized in net periodic cost in 2012	$	14	$	3

The following table displays pension benefits related to CenterPoint Energy’s pension plans that have accumulated benefit obligations in excess of plan assets:



	December 31,
	2010				2011
	Pension Qualified		Pension Non-qualified		Pension Qualified		Pension Non-qualified
	(in millions)
Accumulated benefit obligation	$	1,860	$	94	$	1,966	$	98
Projected benefit obligation	1,875		94		1,987		98
Fair value of plan assets	1,501		—		1,506		—

Assumed healthcare cost trend rates have a significant effect on the reported amounts for CenterPoint Energy’s postretirement benefit plans. A 1% change in the assumed healthcare cost trend rate would have the following effects:



	1% Increase		1% Decrease
	(in millions)
Effect on the postretirement benefit obligation	$	18	$	16
Effect on total of service and interest cost	1		1

In managing the investments associated with the benefit plans, CenterPoint Energy’s objective is to preserve and enhance the value of plan assets while maintaining an acceptable level of volatility. These objectives are expected to be achieved through an investment strategy that manages liquidity requirements while maintaining a long-term horizon in making investment decisions and efficient and effective management of plan assets.

As part of the investment strategy discussed above, CenterPoint Energy has adopted and maintains the following weighted average allocation targets for its benefit plans:



	Pension Benefits	Postretirement Benefits
Domestic equity securities	21-31%	14-24%
Global equity securities	7-13%	—
International equity securities	15-21%	3-13%
Emerging markets equity securities	4-8%	—
Debt securities	30-40%	68-78%
Real estate	0-5%	—
Cash	0-2%	0-2%

The following tables set forth by level, within the fair value hierarchy (see Note 8), CenterPoint Energy’s pension plan assets at fair value as of December 31, 2010 and 2011:



	Fair Value Measurements at December 31, 2010
	(in millions)
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	3		$	3		$	—	$	—
Common collective trust funds (1)	890			—			890		—
Corporate bonds:
Investment grade or above	122			—			122		—
Equity securities:
International companies	133			133			—		—
U.S. companies	131			131			—		—
Cash received as collateral from securities lending	112			112			—		—
U.S. government backed agencies bonds	34			34			—		—
U.S. treasuries	62			62			—		—
Mortgage backed securities	8			—			8		—
Asset backed securities	10			—			10		—
Municipal bonds	28			—			28		—
Mutual funds (2)	55			55			—		—
International government bonds	17			—			17		—
Real estate	8			—			—		8
Obligation to return cash received as collateral from securities lending	(112		)	(112		)	—		—
Total	$	1,501		$	418		$	1,075	$	8


(1)	24% of the amount invested in common collective trust funds is in fixed income securities, 42% is in U.S. equities and 34% is in international equities.


(2)	74% of the amount invested in mutual funds is in fixed income securities and 26% is in U.S. equities.



	Fair Value Measurements at December 31, 2011
	(in millions)
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	(11	)	$	(11	)	$	—	$	—
Common collective trust funds (1)	973			—			973		—
Corporate bonds:
Investment grade or above	129			—			129		—
Equity securities:
International companies	128			128			—		—
U.S. companies	94			94			—		—
Cash received as collateral from securities lending	69			69			—		—
U.S. government backed agencies bonds	19			19			—		—
U.S. treasuries	34			34			—		—
Mortgage backed securities	9			—			9		—
Asset backed securities	8			—			8		—
Municipal bonds	39			—			39		—
Mutual funds (2)	54			54			—		—
International government bonds	22			—			22		—
Real estate	8			—			—		8
Obligation to return cash received as collateral from securities lending	(69		)	(69		)	—		—
Total	$	1,506		$	318		$	1,180	$	8


(1)	39% of the amount invested in common collective trust funds is in fixed income securities, 30% is in U.S. equities and 31% is in international equities.


(2)	75% of the amount invested in mutual funds is in international equities and 25% is in U.S. equities.

The pension plan utilized both exchange traded and over-the-counter financial instruments such as futures, interest rate options and swaps that were marked to market daily with the gains/losses settled in the cash accounts. The pension plan did not include any holdings of CenterPoint Energy common stock as of December 31, 2010 or 2011.

The following tables present additional information about the changes in the fair value of the pension plan’s level 3 investments for the years ended December 31, 2010 and 2011:



	Level 3 Investments
	Year Ended December 31, 2010
	(in millions)
	Corporate bonds			Asset backed securities			Real estate			Total
Balance, beginning of year	$	1		$	3		$	9		$	13
Unrealized losses relating to instruments still held at the reporting date	—			—			(1		)	(1		)
Purchases, sales, issuances, and settlement (net)	—			(1		)	—			(1		)
Transfer out of Level 3	(1		)	(2		)	—			(3		)
Balance, end of year	$	—		$	—		$	8		$	8



	Level 3 Investments
	Year Ended December 31, 2011
	(in millions)
	Corporate bonds		Asset backed securities		Real estate		Total
Balance, beginning of year	$	—	$	—	$	8	$	8
Unrealized losses relating to instruments still held at the reporting date	—		—		—		—
Purchases, sales, issuances, and settlement (net)	—		—		—		—
Transfer out of Level 3	—		—		—		—
Balance, end of year	$	—	$	—	$	8	$	8

The following tables present by level, within the fair value hierarchy, CenterPoint Energy’s postretirement plan assets at fair value as of December 31, 2010 and 2011, by asset category:



	Fair Value Measurements at December 31, 2010
	(in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs Level 3)
Mutual funds (1)	$	144	$	144	$	—	$	—
Total	$	144	$	144	$	—	$	—


(1)	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.



	Fair Value Measurements at December 31, 2011
	(in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs Level 3)
Mutual funds (1)	$	138	$	138	$	—	$	—
Total	$	138	$	138	$	—	$	—


(1)	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.

CenterPoint Energy contributed $65 million, $10 million and $14 million to its qualified pension, non-qualified pension and postretirement benefits plans, respectively, in 2011. CenterPoint Energy expects to contribute approximately $116 million, $9 million and $18 million to its qualified pension, non-qualified pension and postretirement benefits plans, respectively, in 2012.

The following benefit payments are expected to be paid by the pension and postretirement benefit plans (in millions):



			Postretirement Benefit Plan
	Pension Benefits		Benefit Payments		Medicare Subsidy Receipts
2012	$	124	$	37	$	(4	)
2013	135		37		(5		)
2014	143		39		(5		)
2015	147		41		(6		)
2016	145		42		(6		)
2017-2021	791		228		(41		)

CenterPoint Energy has a tax-qualified employee savings plan that includes a cash or deferred arrangement under Section 401(k) of the Internal Revenue Code of 1986, as amended (the Code), and an employee stock ownership plan (ESOP) under Section 4975(e)(7) of the Code. Under the plan, participating employees may contribute a portion of their compensation, on a pre-tax or after-tax basis, generally up to a maximum of 50% of eligible compensation. The Company matches 100% of the first 6% of each employee’s compensation contributed. The matching contributions are fully vested at all times.

Participating employees may elect to invest all or a portion of their contributions to the plan in CenterPoint Energy common stock, to have dividends reinvested in additional shares or to receive dividend payments in cash on any investment in CenterPoint Energy common stock, and to transfer all or part of their investment in CenterPoint Energy common stock to other investment options offered by the plan.

The savings plan has significant holdings of CenterPoint Energy common stock. As of December 31, 2011, 19,732,131 shares of CenterPoint Energy’s common stock were held by the savings plan, which represented approximately 24% of its investments. Given the concentration of the investments in CenterPoint Energy’s common stock, the savings plan and its participants have market risk related to this investment.

CenterPoint Energy’s savings plan benefit expenses were $31 million, $34 million and $35 million in 2009, 2010 and 2011, respectively.

(d) Postemployment Benefits

CenterPoint Energy provides postemployment benefits for former or inactive employees, their beneficiaries and covered dependents, after employment but before retirement (primarily healthcare and life insurance benefits for participants in the long-term disability plan). The Company recorded postemployment benefits of $-0-, $1 million income and $7 million expense in 2009, 2010 and 2011, respectively.

Included in “Benefit Obligations” in the accompanying Consolidated Balance Sheets at December 31, 2010 and 2011 was $25 million and $30 million, respectively, relating to postemployment obligations.

(e) Other Non-Qualified Plans

CenterPoint Energy has non-qualified deferred compensation plans that provide benefits payable to directors, officers and certain key employees or their designated beneficiaries at specified future dates, upon termination, retirement or death. Benefit payments are made from the general assets of CenterPoint Energy. During 2009, 2010 and 2011, CenterPoint Energy recorded benefit expense relating to these plans of $6 million, $5 million and $5 million, respectively. Included in “Benefit Obligations” in the accompanying Consolidated Balance Sheets at December 31, 2010 and 2011 was $78 million and $76 million, respectively, relating to deferred compensation plans.

Included in Benefit Obligations in CenterPoint Energy’s Consolidated Balance Sheets at December 31, 2010 and 2011 was $21 million and $25 million, respectively, relating to split-dollar life insurance arrangements.

(f) Change in Control Agreements and Other Employee Matters

CenterPoint Energy has agreements with certain of its officers that generally provide, to the extent applicable, in the case of a change in control of CenterPoint Energy and termination of employment, for severance benefits of up to three times annual base salary plus bonus, and other benefits. These agreements are for a one-year term with automatic renewal unless action is taken by CenterPoint Energy’s board of directors prior to the renewal.

As of December 31, 2011, approximately 30% of CenterPoint Energy’s employees are subject to collective bargaining agreements. Collective bargaining agreements with each of the following bargaining units, which collectively cover approximately 8% of CenterPoint Energy's employees, are scheduled to expire in 2012: United Steel Workers (USW) Local 13-227, Office and Professional Employees International Union (OPEIU) Local 12 Metro, OPEIU Local 12 Mankato and USW Local 13-1. CenterPoint Energy believes it has good relationships with these bargaining units and expects to negotiate new agreements in 2012.

Derivative Instruments

12 Months Ended

Dec. 31, 2011

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments

(a) Non-Trading Activities

Derivative Instruments. CenterPoint Energy enters into certain derivative instruments to manage physical commodity price risks and does not engage in proprietary or speculative commodity trading. These financial instruments do not qualify or are not designated as cash flow or fair value hedges.

During the year ended December 31, 2009, CenterPoint Energy recorded decreased natural gas revenues from unrealized net losses of $80 million and decreased natural gas expense from unrealized net gains of $57 million, a net unrealized loss of $23 million. During the year ended December 31, 2010, CenterPoint Energy recorded increased natural gas revenues from unrealized net gains of $18 million and increased natural gas expense from unrealized net losses of $14 million, a net unrealized gain of $4 million. During the year ended December 31, 2011, CenterPoint Energy recorded increased natural gas revenues from unrealized net gains of $38 million and increased natural gas expense from unrealized net losses of $30 million, a net unrealized gain of $8 million.

Weather Hedges. CenterPoint Energy has weather normalization or other rate mechanisms that mitigate the impact of weather on its gas operations in Arkansas, Louisiana, Oklahoma and a portion of Texas. The remaining Gas Operations jurisdictions do not have such mechanisms. As a result, fluctuations from normal weather may have a significant positive or negative effect on Gas Operations' results in the remaining jurisdictions and in CenterPoint Houston’s service territory.

CenterPoint Energy enters into heating-degree day swaps to mitigate the effect of fluctuations from normal weather on its results of operations and cash flows for the winter heating season. The swaps are based on ten-year normal weather. During the years ended December 31, 2009, 2010 and 2011, CenterPoint Energy recognized losses of $7 million, $6 million and less than $1 million, respectively, related to these swaps. The losses were substantially offset by increased revenues due to colder than normal weather. Weather hedge losses are included in revenues in the Statements of Consolidated Income.

(b) Derivative Fair Values and Income Statement Impacts

The following tables present information about CenterPoint Energy’s derivative instruments and hedging activities. The first two tables provide a balance sheet overview of CenterPoint Energy’s Derivative Assets and Liabilities as of December 31, 2010 and 2011, while the last table provides a breakdown of the related income statement impacts for the years ending December 31, 2010 and 2011.



Fair Value of Derivative Instruments
	December 31, 2010
Total derivatives not designated as hedging instruments	Balance Sheet Location	Derivative Assets Fair Value (2) (3)		Derivative Liabilities Fair Value (2) (3)
		(in millions)
Natural gas contracts (1)	Current Assets	$	55	$	1
Natural gas contracts (1)	Other Assets	15		—
Natural gas contracts (1)	Current Liabilities	10		143
Natural gas contracts (1)	Other Liabilities	—		35
Indexed debt securities derivative	Current Liabilities	—		232
Total		$	80	$	411


(1)	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.


(2)	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 626 billion cubic feet (Bcf) or a net 72 Bcf long position. Of the net long position, basis swaps constitute 63 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 26 Bcf.


(3)	The net of total non-trading derivative assets and liabilities is a $15 million liability as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $84 million.



Fair Value of Derivative Instruments
	December 31, 2011
Total derivatives not designated as hedging instruments	Balance Sheet Location	Derivative Assets Fair Value (2) (3)		Derivative Liabilities Fair Value (2) (3)
		(in millions)
Natural gas contracts (1)	Current Assets	$	88	$	1
Natural gas contracts (1)	Other Assets	20		—
Natural gas contracts (1)	Current Liabilities	15		110
Natural gas contracts (1)	Other Liabilities	—		13
Indexed debt securities derivative	Current Liabilities	—		197
Total		$	123	$	321


(1)	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.


(2)	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 633 Bcf or a net 84 Bcf long position. Of the net long position, basis swaps constitute 74 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 6 Bcf.


(3)	The net of total non-trading derivative assets and liabilities is a $55 million asset as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $56 million.

For CenterPoint Energy’s price stabilization activities of the Natural Gas Distribution business segment, the settled costs of derivatives are ultimately recovered through purchased gas adjustments. Accordingly, the net unrealized gains and losses associated with these contracts are recorded as net regulatory assets. Realized and unrealized gains and losses on other derivatives are recognized in the Statements of Consolidated Income as revenue for retail sales derivative contracts and as natural gas expense for financial natural gas derivatives and non-retail related physical natural gas derivatives. Unrealized gains and losses on indexed debt securities are recorded as Other Income (Expense) in the Statements of Consolidated Income.



Income Statement Impact of Derivative Activity
		Year Ended December 31,
Total derivatives not designated as hedging instruments	Income Statement Location	2010			2011
		(in millions)
Natural gas contracts	Gains (Losses) in Revenue	$	90		$	102
Natural gas contracts (1)	Gains (Losses) in Expense: Natural Gas	(165		)	(144		)
Indexed debt securities derivative	Gains (Losses) in Other Income (Expense)	(31		)	35
Total		$	(106	)	$	(7	)


(1)	The Gains (Losses) in Expense: Natural Gas includes $(115) million and $(107) million of costs in 2010 and 2011, respectively, associated with price stabilization activities of the Natural Gas Distribution business segment that will be ultimately recovered through purchased gas adjustments.

CenterPoint Energy enters into financial derivative contracts containing material adverse change provisions. These provisions could require CenterPoint Energy to post additional collateral if the Standard & Poor’s Ratings Services or Moody’s Investors Service, Inc. credit ratings of CenterPoint Energy, Inc. or its subsidiaries are downgraded. The total fair value of the derivative instruments that contain credit risk contingent features that are in a net liability position at December 31, 2010 and 2011 was $107 million and $39 million, respectively. The aggregate fair value of assets that are already posted as collateral was $31 million and less than $1 million, respectively, at December 31, 2010 and 2011. If all derivative contracts (in a net liability position) containing credit risk contingent features were triggered at December 31, 2010 and 2011, $76 million and $38 million, respectively, of additional assets would be required to be posted as collateral.

(d) Credit Quality of Counterparties

In addition to the risk associated with price movements, credit risk is also inherent in CenterPoint Energy’s non-trading derivative activities. Credit risk relates to the risk of loss resulting from non-performance of contractual obligations by a counterparty. The following table shows the composition of counterparties to the non-trading derivative assets of CenterPoint Energy as of December 31, 2010 and 2011 (in millions):



	December 31, 2010				December 31, 2011
	Investment Grade(1)		Total		Investment Grade(1)		Total
Energy marketers	$	5	$	8	$	1	$	7
Financial institutions	1		1		—		—
Retail end users (2)	—		60		—		100
Total	$	6	$	69	$	1	$	107

(1)

“Investment grade” is primarily determined using publicly available credit ratings and considering credit support (including parent company guaranties) and collateral (including cash and standby letters of credit). For unrated counterparties, CenterPoint Energy determines a synthetic credit rating by performing financial statement analysis and considering contractual rights and restrictions and collateral.


(2)	Retail end users represent customers who have contracted to fix the price of a portion of their physical gas requirements for future periods.

- Definition

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

Fair Value Measurements

Assets and liabilities that are recorded at fair value in the Consolidated Balance Sheets are categorized based upon the level of judgment associated with the inputs used to measure their value. Hierarchical levels, as defined below and directly related to the amount of subjectivity associated with the inputs to fair valuations of these assets and liabilities, are as follows:

Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities at the measurement date. The types of assets carried at Level 1 fair value generally are exchange-traded derivatives and equity securities.

Level 2: Inputs, other than quoted prices included in Level 1, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar instruments in active markets, and inputs other than quoted prices that are observable for the asset or liability. Fair value assets and liabilities that are generally included in this category are derivatives with fair values based on inputs from actively quoted markets. A market approach is utilized to value CenterPoint Energy’s Level 2 assets or liabilities.

Level 3: Inputs are unobservable for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement in its entirety. Unobservable inputs reflect CenterPoint Energy’s judgments about the assumptions market participants would use in pricing the asset or liability since limited market data exists. CenterPoint Energy develops these inputs based on the best information available, including CenterPoint Energy’s own data. A market approach is utilized to value CenterPoint Energy’s Level 3 assets or liabilities.

CenterPoint Energy determines the appropriate level for each financial asset and liability on a quarterly basis and recognizes transfers between levels at the end of the reporting period. CenterPoint Energy also recognizes purchases of Level 3 financial assets and liabilities at their fair value at the end of the reporting period.

The following tables present information about CenterPoint Energy’s assets and liabilities (including derivatives that are presented net) measured at fair value on a recurring basis as of December 31, 2010 and 2011, and indicate the fair value hierarchy of the valuation techniques utilized by CenterPoint Energy to determine such fair value.



	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Netting Adjustments ⁽¹⁾			Balance at December 31, 2010
	(in millions)
Assets
Corporate equities	$	368	$	—	$	—	$	—		$	368
Investments, including money market funds	54		—		—		—			54
Natural gas derivatives	—		73		7		(11		)	69
Total assets	$	422	$	73	$	7	$	(11	)	$	491
Liabilities
Indexed debt securities derivative	$	—	$	232	$	—	$	—		$	232
Natural gas derivatives	8		167		4		(95		)	84
Total liabilities	$	8	$	399	$	4	$	(95	)	$	316


(1)	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $84 million posted with the same counterparties.



	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Netting Adjustments ⁽¹⁾			Balance at December 31, 2011
	(in millions)
Assets
Corporate equities	$	387	$	—	$	—	$	—		$	387
Investments, including money market funds	56		—		—		—			56
Natural gas derivatives	1		112		10		(16		)	107
Total assets	$	444	$	112	$	10	$	(16	)	$	550
Liabilities
Indexed debt securities derivative	$	—	$	197	$	—	$	—		$	197
Natural gas derivatives	19		101		4		(72		)	52
Total liabilities	$	19	$	298	$	4	$	(72	)	$	249


(1)	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $56 million posted with the same counterparties.

The following tables present additional information about assets or liabilities, including derivatives that are measured at fair value on a recurring basis for which CenterPoint Energy has utilized Level 3 inputs to determine fair value:



	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Derivative assets and liabilities, net
	Year Ended December 31,
	2009			2010			2011
	(in millions)
Beginning balance	$	(58	)	$	(6	)	$	3
Total unrealized gains or (losses):
Included in earnings	(1		)	4			6
Included in regulatory assets	(16		)	(1		)	—
Total settlements:
Included in earnings	3			(2		)	(3		)
Included in regulatory assets	66			8			—
Total purchases	—			—			2
Net transfers out of Level 3	—			—			(2		)
Ending balance	$	(6	)	$	3		$	6
The amount of total gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	$	1		$	4		$	5

Estimated Fair Value of Financial Instruments

The fair values of cash and cash equivalents, investments in debt and equity securities classified as "available-for-sale" and "trading" and short-term borrowings are estimated to be approximately equivalent to carrying amounts and have been excluded from the table below. The fair values of non-trading derivative assets and liabilities and CenterPoint Energy’s 2.00% Zero-Premium Exchangeable Subordinated Notes due 2029 (ZENS) indexed debt securities derivative are stated at fair value and are excluded from the table below. The fair value of each debt instrument is determined by multiplying the principal amount of each debt instrument by the market price.



	December 31, 2010				December 31, 2011
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(in millions)
Financial liabilities:
Long-term debt	$	9,303	$	10,071	$	8,994	$	10,049

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13537-108611

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
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-Paragraph 10
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
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-Paragraph 16
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

+ Details

Indexed Debt Securities (ZENS) and Time Warner Securities

12 Months Ended

Dec. 31, 2011

Indexed Debt Securities [Abstract]

Indexed Debt Securities (ZENS) and Time Warner Securities

(a) Investment in Time Warner Securities

In 1995, CenterPoint Energy sold a cable television subsidiary to Time Warner, Inc. (TW) and received TW securities as partial consideration. A subsidiary of CenterPoint Energy now holds 7.2 million shares of TW common stock (TW Common), 1.8 million shares of Time Warner Cable Inc. (TWC) common stock (TWC Common) and 0.7 million shares of AOL, Inc. (AOL) common stock (AOL Common) (together with the TW Common and TWC Common, the TW Securities) which are classified as trading securities and are expected to be held to facilitate CenterPoint Energy’s ability to meet its obligation under the ZENS. Unrealized gains and losses resulting from changes in the market value of the TW Securities are recorded in CenterPoint Energy’s Statements of Consolidated Income.

(b) ZENS

In September 1999, CenterPoint Energy issued ZENS having an original principal amount of $1 billion of which $840 million remain outstanding at December 31, 2011. Each ZENS note was originally exchangeable at the holder’s option at any time for an amount of cash equal to 95% of the market value of the reference shares of TW Common attributable to such note. The number and identity of the reference shares attributable to each ZENS note are adjusted for certain corporate events. As of December 31, 2011, the reference shares for each ZENS note consisted of 0.5 share of TW Common, 0.125505 share of TWC Common and 0.045455 share of AOL Common. CenterPoint Energy pays interest on the ZENS at an annual rate of 2% plus the amount of any quarterly cash dividends paid in respect of the reference shares attributable to the ZENS. The principal amount of ZENS is subject to being increased or decreased to the extent that the annual yield from interest and cash dividends on the reference shares is less than or more than 2.309%. The adjusted principal amount is defined in the ZENS instrument as “contingent principal.” At December 31, 2011, ZENS having an original principal amount of $840 million and a contingent principal amount of $797 million were outstanding and were exchangeable, at the option of the holders, for cash equal to 95% of the market value of reference shares deemed to be attributable to the ZENS. At December 31, 2011, the market value of such shares was approximately $386 million, which would provide an exchange amount of $436 for each $1,000 original principal amount of ZENS. At maturity of the ZENS in 2029, CenterPoint Energy will be obligated to pay in cash the higher of the contingent principal amount of the ZENS or an amount based on the then-current market value of the reference shares, which will include any additional publicly-traded securities distributed with respect to the current reference shares prior to maturity.

The ZENS obligation is bifurcated into a debt component and a derivative component (the holder’s option to receive the appreciated value of the reference shares at maturity). The bifurcated debt component accretes through interest charges at 17.3% annually up to the contingent principal amount of the ZENS in 2029. Such accretion will be reduced by annual cash interest payments, as described above. The derivative component is recorded at fair value and changes in the fair value of the derivative component are recorded in CenterPoint Energy’s Statements of Consolidated Income. Changes in the fair value of the TW Securities held by CenterPoint Energy are expected to substantially offset changes in the fair value of the derivative component of the ZENS.

The following table sets forth summarized financial information regarding CenterPoint Energy’s investment in TW Securities and each component of CenterPoint Energy’s ZENS obligation (in millions).



	TW Securities		Debt Component of ZENS			Derivative Component of ZENS
Balance at December 31, 2008	$	218	$	117		$	133
Accretion of debt component of ZENS	—		21			—
2% interest paid	—		(17		)	—
Loss on indexed debt securities	—		—			68
Gain on TW Common	82		—			—
Balance at December 31, 2009	300		121			201
Accretion of debt component of ZENS	—		22			—
2% interest paid	—		(17		)	—
Loss on indexed debt securities	—		—			31
Gain on TW Securities	67		—			—
Balance at December 31, 2010	367		126			232
Accretion of debt component of ZENS	—		22			—
2% interest paid	—		(17		)	—
Gain on indexed debt securities	—		—			(35		)
Gain on TW Securities	19		—			—
Balance at December 31, 2011	$	386	$	131		$	197

Equity	12 Months Ended
Equity	Dec. 31, 2011
Stockholders' Equity Note [Abstract]
Equity	Equity (a) Capital Stock CenterPoint Energy has 1,020,000,000 authorized shares of capital stock, comprised of 1,000,000,000 shares of $0.01 par value common stock and 20,000,000 shares of $0.01 par value cumulative preferred stock. (b) Shareholder Rights Plan CenterPoint Energy had a Shareholder Rights Plan that stated that each share of its common stock included one associated preferred stock purchase right (Right) which entitled the registered holder to purchase from CenterPoint Energy a unit consisting of one thousandth of a share of Series A Preferred Stock. The Rights expired pursuant to their terms on December 31, 2011.

- Definition

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph d

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 1
-Section B
-Paragraph 7, 11A
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 3, 4, 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 23: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

+ Details

Short Term Borrowings and Long Term Debt

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Short-term Borrowings and Long-term Debt



	December 31, 2010					December 31, 2011
	Long-Term			Current(1)		Long-Term			Current(1)
	(in millions)
Short-term borrowings:
Inventory financing	$	—		$	53	$	—		$	62
Total short-term borrowings	—			53		—			62
Long-term debt:
CenterPoint Energy:
ZENS(2)	—			126		—			131
Senior notes 5.95% to 6.85% due 2015 to 2018	750			—		750			—
Pollution control bonds 4.00% due 2015(3)	151			—		151			—
Pollution control bonds 4.90% to 5.95% due 2015 to 2030(4) (5)	562			19		562			—
CenterPoint Houston:
First mortgage bonds 9.15% due 2021	102			—		102			—
General mortgage bonds 5.60% to 7.00% due 2013 to 2033	1,762			—		1,762			—
Pollution control bonds 3.625% to 5.60% due 2012 to 2027(6)	229			—		183			46
System restoration bonds 1.833% to 4.243% due 2012 to 2022	601			43		556			45
Transition bonds 4.192% to 5.63% due 2012 to 2020	1,921			240		1,659			262
CERC Corp.:
Senior notes 4.50% to 7.875% due 2013 to 2041 (7)	2,747			—		2,693			—
Commercial paper (8)	183			—		285			—
Other	1			—		1			—
Unamortized discount and premium	(8		)	—		(63		)	—
Total long-term debt	9,001			428		8,641			484
Total debt	$	9,001		$	481	$	8,641		$	546


(1)	Includes amounts due or exchangeable within one year of the date noted.


(2)	CenterPoint Energy’s ZENS obligation is bifurcated into a debt component and an embedded derivative component. For additional information regarding ZENS, see Note 9(b). As ZENS are exchangeable for cash at any time at the option of the holders, these notes are classified as a current portion of long-term debt.


(3)	These series of debt are secured by first mortgage bonds of CenterPoint Houston.


(4)	$237 million and $218 million of these series of debt were secured by general mortgage bonds of CenterPoint Houston at December 31, 2010 and 2011, respectively.


(5)	In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf which will remain outstanding and may be remarketed and called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf.


(6)	These series of debt are secured by general mortgage bonds of CenterPoint Houston.


(7)	$550 million senior notes due February 2011 are not reflected in the current portion of long-term debt as of December 31, 2010 because the notes were refinanced in January 2011.


(8)	Classified as long-term debt because the termination date of the facility that backstops the commercial paper is more than one year from the date noted.

(a) Short-term Borrowings

Receivables Facility. CERC’s receivables facility terminated pursuant to its terms on September 14, 2011. As of December 31, 2010, the facility size was $160 million and there were no advances under the facility.

Inventory Financing. Gas Operations has entered into asset management agreements associated with its utility distribution service in Arkansas, north Louisiana and Oklahoma that extend through 2015. Pursuant to the provisions of the agreements, Gas Operations sells natural gas and agrees to repurchase an equivalent amount of natural gas during the winter heating seasons at the same cost, plus a financing charge. These transactions are accounted for as a financing and they had an associated principal obligation of $53 million and $62 million as of December 31, 2010 and 2011, respectively.

(b) Long-term Debt

CERC Corp. Senior Notes. In January 2011, CERC Corp. issued $250 million aggregate principal amount of senior notes due 2021 with an interest rate of 4.50% and $300 million aggregate principal amount of senior notes due 2041 with an interest rate of 5.85%. The proceeds from the issuance of the notes were used for the repayment of $550 million of CERC Corp.’s 7.75% senior notes at their maturity in February 2011. Accordingly, the $550 million senior notes due in February 2011 are reflected as long-term debt as of December 31, 2010.

CERC Corp. Exchange Offer. Also in January 2011, CERC Corp. issued an additional $343 million aggregate principal amount of 4.50% senior notes due 2021 and provided cash consideration of $114 million in exchange for $397 million aggregate principal amount of its 7.875% senior notes due 2013. The premium of $58 million paid on exchanged notes has been deferred and will be amortized to interest expense over the life of the 4.50% senior notes due 2021.

Transition and System Restoration Bonds. As of December 31, 2011, CenterPoint Houston had five special purpose subsidiaries consisting of transition and system restoration bond companies, which it consolidates, including Bond Company IV, which issued transition bonds in January 2012 as described below. The consolidated special purpose subsidiaries are wholly-owned bankruptcy remote entities that were formed solely for the purpose of purchasing and owning transition or system restoration property through the issuance of transition bonds or system restoration bonds and activities incidental thereto. These transition bonds and system restoration bonds are payable only through the imposition and collection of “transition” or “system restoration” charges, as defined in the Texas Public Utility Regulatory Act, which are irrevocable, non-bypassable charges payable by most of CenterPoint Houston's retail electric customers in order to provide recovery of authorized qualified costs. CenterPoint Houston has no payment obligations in respect of the transition and system restoration bonds other than to remit the applicable transition or system restoration charges it collects. Each special purpose entity is the sole owner of the right to impose, collect and receive the applicable transition or system restoration charges securing the bonds issued by that entity. Creditors of CenterPoint Energy or CenterPoint Houston have no recourse to any assets or revenues of the transition and system restoration bond companies (including the transition and system restoration charges), and the holders of transition bonds or system restoration bonds have no recourse to the assets or revenues of CenterPoint Energy or CenterPoint Houston.

In January 2012, Bond Company IV issued $1.695 billion of transition bonds in three tranches with interest rates ranging from 0.9012% to 3.0282% and final maturity dates ranging from April 15, 2018 to October 15, 2025. The transition bonds will be repaid over time through a charge imposed on customers in CenterPoint Houston's service territory.

Pollution Control Bonds. In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf at 100% of their principal amount plus accrued interest pursuant to the mandatory tender provisions of the bonds. The purchased pollution control bonds will remain outstanding and may be remarketed. Prior to the purchase, the pollution control bonds had fixed interest rates ranging from 5.15% to 5.95%. Additionally, in February 2012, CenterPoint Energy called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf at 100% of their principal amount plus accrued interest pursuant to the optional redemption provisions of the bonds. The pollution control bonds called for redemption have a fixed interest rate of 5.25%.

Revolving Credit Facilities. In the third quarter of 2011, the revolving credit facilities of CenterPoint Energy, CenterPoint Houston and CERC Corp. were replaced with five-year revolving credit facilities of similar borrowing capacity. As of December 31, 2010 and 2011, CenterPoint Energy, CenterPoint Houston and CERC Corp. had the following revolving credit facilities and utilization of such facilities (in millions):



	December 31, 2010								December 31, 2011
	Size of Facility		Loans		Letters of Credit		Commercial Paper		Size of Facility		Loans		Letters of Credit		Commercial Paper
CenterPoint Energy	$	1,156	$	—	$	20	$	—	$	1,200	$	—	$	16	$	—
CenterPoint Houston	289		—		4		—		300		—		4		—
CERC Corp.	915		—		—		183		950		—		—		285
Total	$	2,360	$	—	$	24	$	183	$	2,450	$	—	$	20	$	285

CenterPoint Energy’s $1.2 billion credit facility, which is scheduled to terminate September 9, 2016, can be drawn at the London Interbank Offered Rate (LIBOR) plus 175 basis points based on CenterPoint Energy’s current credit ratings. The facility contains a debt (excluding transition and system restoration bonds) to earnings before interest, taxes, depreciation and amortization (EBITDA) covenant (as those terms are defined in the facility). The facility allows for a temporary increase of the permitted ratio in the financial covenant from 5 times to 5.5 times if CenterPoint Houston experiences damage from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that CenterPoint Houston has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive twelve-month period, all or part of which CenterPoint Houston intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date CenterPoint Energy delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of CenterPoint Energy’s certification or (iii) the revocation of such certification.

CenterPoint Houston’s $300 million credit facility, which is scheduled to terminate September 9, 2016, can be drawn at LIBOR plus 150 basis points based on CenterPoint Houston's current credit ratings. The facility contains a debt (excluding transition and system restoration bonds) to total capitalization covenant which limits debt to 65% of the borrower's total capitalization.

CERC Corp.’s $950 million credit facility, which is scheduled to terminate September 9, 2016, can be drawn at LIBOR plus 150 basis points based on CERC Corp.’s current credit ratings. The facility contains a debt to total capitalization covenant which limits debt to 65% of CERC's total capitalization.

Under CenterPoint Energy’s $1.2 billion credit facility, CenterPoint Houston’s $300 million credit facility and CERC Corp.’s $950 million credit facility, an additional utilization fee of 5 basis points applies to borrowings any time more than 50% of the facility is utilized. The spread to LIBOR and the utilization fee fluctuate based on the borrower’s credit rating.

CenterPoint Energy, CenterPoint Houston and CERC Corp. were in compliance with all debt covenants as of December 31, 2011.

Maturities. CenterPoint Energy’s maturities of long-term debt, capital leases and sinking fund requirements, excluding the ZENS obligation, are $353 million in 2012, $1.145 billion in 2013, $1.195 billion in 2014, $669 million in 2015 and $875 million in 2016. These maturities include transition and system restoration bond principal repayments on scheduled payment dates aggregating $307 million in 2012, $330 million in 2013, $235 million in 2014, $249 million in 2015 and $266 million in 2016. These maturities exclude scheduled repayments on transition bonds issued in 2012 of $62 million in 2012, $117 million in 2013, $120 million in 2014, $122 million in 2015 and $126 million in 2016.

Liens. As of December 31, 2011, CenterPoint Houston’s assets were subject to liens securing approximately $253 million of first mortgage bonds. Sinking or improvement fund and replacement fund requirements on the first mortgage bonds may be satisfied by certification of property additions. Sinking fund and replacement fund requirements for 2009, 2010 and 2011 have been satisfied by certification of property additions. The replacement fund requirement to be satisfied in 2012 is approximately $184 million, and the sinking fund requirement to be satisfied in 2012 is approximately $3 million. CenterPoint Energy expects CenterPoint Houston to meet these 2012 obligations by certification of property additions. As of December 31, 2011, CenterPoint Houston’s assets were also subject to liens securing approximately $2.5 billion of general mortgage bonds which are junior to the liens of the first mortgage bonds.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Income Taxes

The components of CenterPoint Energy’s income tax expense were as follows:



	Year Ended December 31,
	2009			2010			2011
	(in millions)
Current income tax expense (benefit):
Federal	$	(103	)	$	40		$	(63	)
State	10			24			24
Total current expense (benefit)	(93		)	64			(39		)
Deferred income tax expense (benefit):
Federal	251			220			432
State	18			(21		)	11
Total deferred expense	269			199			443
Total income tax expense	$	176		$	263		$	404

A reconciliation of the expected federal income tax expense using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows:



	Year Ended December 31,
	2009			2010			2011
	(in millions)
Income before income taxes and extraordinary item	$	548		$	705		$	1,174
Federal statutory income tax rate	35.00		%	35.00		%	35.00		%
Expected federal income tax expense	192			247			411
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	18			2			22
Amortization of investment tax credit	(7		)	(7		)	(6		)
Tax law change in deductibility of retiree health care costs	—			20			—
Increase (decrease) in settled and uncertain income tax positions	(5		)	14			(5		)
Other, net	(22		)	(13		)	(18		)
Total	(16		)	16			(7		)
Total income tax expense	$	176		$	263		$	404
Effective tax rate	32.1		%	37.3		%	34.4		%

CenterPoint Energy recorded a $9 million decrease in tax expense in 2011 related to the release of income tax reserves on the tax normalization issue discussed below, which resulted in a net decrease in tax expense of $5 million for all uncertain tax positions. CenterPoint Energy recorded a net reduction in state income tax expense of approximately $17 million related to lower blended state tax rates and a reduction of the deferred tax liability recorded in December 2011.

CenterPoint Energy recorded a non-cash, $21 million increase to income tax expense in 2010 as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010. The change in tax law, which becomes effective for tax years beginning after December 31, 2012, eliminates the tax deductibility of the portion of retiree health care costs which are reimbursed by Medicare Part D subsidies. Based upon the actuarially determined net present value of lost future retiree health care deductions related to the subsidies, CenterPoint Energy reduced its deferred tax asset by approximately $32 million in March 2010. The portion of the reduction that CenterPoint Energy believes will be recovered through the regulatory process, or approximately $11 million, was recorded as an adjustment to regulatory assets. The remaining $21 million of the reduction in CenterPoint Energy’s deferred tax asset was recorded as a charge to income tax expense in the first quarter of 2010.

In December 2010, certain subsidiaries of CenterPoint Energy were restructured in order to achieve a more tax-efficient reporting structure. As a result of the restructuring, CenterPoint Energy recorded a net reduction in income tax expense of approximately $24 million related to the remeasurement of accumulated deferred income taxes. The net reduction in income tax expense is comprised of a decrease in state income tax expense, net of federal income tax, totaling approximately $29 million and an increase in income tax expense of approximately $5 million related to uncertain income tax positions.

As a result of its settlement with the IRS for tax years 2004 and 2005, CenterPoint Energy recorded an income tax benefit of approximately $11 million in 2009 related to a reduction in the liability for uncertain tax positions of approximately $41 million. The state income tax expense of $18 million for 2009 includes a benefit of approximately $12 million, net of federal income tax, related to adjustments in prior years’ state estimates.

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows:



	December 31,
	2010			2011
	(in millions)
Deferred tax assets:
Current:
Allowance for doubtful accounts	$	11		$	10
Deferred gas costs	32			—
Other	21			7
Total current deferred tax assets	64			17
Non-current:
Loss and credit carryforwards	49			214
Employee benefits	346			363
Other	48			68
Total non-current deferred tax assets before valuation allowance	443			645
Valuation allowance	(3		)	(4		)
Total non-current deferred tax assets, net of valuation allowance	440			641
Total deferred tax assets, net of valuation allowance	504			658
Deferred tax liabilities:
Current:
Unrealized gain on indexed debt securities	391			427
Unrealized gain on TW securities	80			97
Total current deferred tax liabilities	471			524
Non-current:
Depreciation	2,086			2,849
Regulatory assets, net	1,256			1,499
Other	32			125
Total non-current deferred tax liabilities	3,374			4,473
Total deferred tax liabilities	3,845			4,997
Accumulated deferred income taxes, net	$	3,341		$	4,339

Tax Attribute Carryforwards and Valuation Allowance. At December 31, 2011, CenterPoint Energy has approximately $442 million of federal net operating loss carryforwards which begin to expire in 2030 and approximately $352 million of state net operating loss carryforwards which expire in various years between 2012 and 2031. CenterPoint Energy has approximately $6 million of federal capital loss carryforwards and $14 million of federal charitable contribution carryforwards which expire in various years between 2012 and 2030. CenterPoint Energy has approximately $244 million of state capital loss carryforwards which expire in 2017 for which a valuation allowance has been established.

CenterPoint Energy has established a valuation allowance of $1 million for federal net operating loss carryforwards attributable to share based compensation and $3 million for state capital loss carryforwards that based upon management's evaluation may not be realized.

Uncertain Income Tax Positions. The following table reconciles the beginning and ending balance of CenterPoint Energy’s unrecognized tax benefits:



	December 31,
	2009			2010			2011
	(in millions)
Balance, beginning of year	$	117		$	187		$	252
Tax Positions related to prior years:
Additions	56			9			(1		)
Reductions	(25		)	(4		)	(203		)
Tax Positions related to current year:
Additions	56			60			5
Settlements	(17		)	—			(1		)
Lapse of statute of limitations	—			—			(1		)
Balance, end of year	$	187		$	252		$	51

The net decrease in the total amount of unrecognized tax benefits during 2011 is primarily related to the remeasurement of a potential tax normalization violation. As a result of the Settlement, discussed in Note 5(b), CenterPoint Houston has determined that the potential normalization violation has been prevented and consequently, recorded a reduction to the liability for unrecognized income tax benefits of $211 million. The unrecognized tax benefit for the normalization issue was a temporary difference and, therefore, the decrease in the balance thereto resulted in an increase to the deferred tax liability of $202 million and a decrease in income tax expense of $9 million for the release of accrued interest expense. It is reasonably possible that the total amount of unrecognized tax benefits could decrease by an amount between $25 million and $31 million over the next 12 months primarily as a result of the anticipated resolution of CenterPoint Energy’s administrative appeal associated with an IRS examination described below.

CenterPoint Energy has approximately $10 million, $17 million and $21 million of unrecognized tax benefits that, if recognized, would reduce the effective income tax rate for 2009, 2010 and 2011, respectively. CenterPoint Energy recognizes interest and penalties as a component of income tax expense. CenterPoint Energy recognized approximately $7 million of income tax benefit, $8 million of income tax expense and $13 million of income tax benefit related to interest on uncertain income tax positions during 2009, 2010 and 2011, respectively. CenterPoint Energy had approximately $12 million of interest payable and $1 million of interest receivable on uncertain income tax positions accrued at December 31, 2010 and 2011, respectively.

Tax Audits and Settlements. CenterPoint Energy's consolidated federal income tax returns have been audited and settled through the 2005 tax year. CenterPoint Energy has a tentative closing agreement for tax years 2006 and 2007 with the IRS's Appeals Division pending review by the Joint Committee on Taxation. The most significant adjustment proposed by the IRS relates to the disallowance of CenterPoint Energy’s 2007 casualty loss deduction totaling $603 million associated with the damage caused by Hurricane Ike. CenterPoint Energy is currently under examination by the IRS for tax years 2008 and 2009 and is at various stages of the examination process. CenterPoint Energy has considered the effects of these examinations in its accrual for settled issues and liability for uncertain income tax positions as of December 31, 2011.

Under a tax allocation agreement, CenterPoint Energy and GenOn Energy, Inc. (GenOn) (as successor to the entity formerly known as RRI Energy, Inc., Reliant Resources, Inc., and Reliant Energy, Inc.) have agreed to indemnify each other for tax liabilities arising out of IRS examinations. The IRS has issued a tentative closing agreement to Reliant Resources, Inc. for tax year 2002. The tax deficiency assessed by the IRS is entirely the liability of GenOn with CenterPoint Energy to be indemnified for both tax and interest. Accordingly, CenterPoint Energy has recorded a federal liability of approximately $32 million offset with a receivable from GenOn of $27 million and a deferred tax asset of $5 million pertaining to the federal benefit on the deductibility of interest.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

(a) Natural Gas Supply Commitments

Natural gas supply commitments include natural gas contracts related to CenterPoint Energy’s Natural Gas Distribution and Competitive Natural Gas Sales and Services business segments, which have various quantity requirements and durations, that are not classified as non-trading derivative assets and liabilities in CenterPoint Energy’s Consolidated Balance Sheets as of December 31, 2010 and 2011 as these contracts meet the exception to be classified as "normal purchases contracts" or do not meet the definition of a derivative. Natural gas supply commitments also include natural gas transportation contracts that do not meet the definition of a derivative. As of December 31, 2011, minimum payment obligations for natural gas supply commitments are approximately $467 million in 2012, $449 million in 2013, $353 million in 2014, $219 million in 2015, $151 million in 2016 and $251 million after 2016.

(b) Asset Management Agreements

Gas Operations has entered into asset management agreements associated with its utility distribution service in Arkansas, Louisiana, Mississippi, Oklahoma and Texas. Generally, these asset management agreements are contracts between Gas Operations and an asset manager that are intended to transfer the working capital obligation and maximize the utilization of the assets. In these agreements, Gas Operations agreed to release transportation and storage capacity to other parties to manage gas storage, supply and delivery arrangements for Gas Operations and to use the released capacity for other purposes when it is not needed for Gas Operations. Gas Operations is compensated by the asset manager through payments made over the life of the agreements based in part on the results of the asset optimization. Under the provisions of these asset management agreements, Gas Operations has an obligation to purchase its winter storage requirements from the asset manager. The agreements have varying terms, the longest of which expires in 2016.

The following table sets forth information concerning CenterPoint Energy’s obligations under non-cancelable long-term operating leases at December 31, 2011, which primarily consist of rental agreements for building space, data processing equipment, compression equipment and rights of way (in millions):



2012	$	14
2013	9
2014	7
2015	4
2016	4
2017 and beyond	16
Total	$	54

Total lease expense for all operating leases was $37 million, $77 million and $43 million during 2009, 2010 and 2011, respectively.

(d) Other Commitments

In December 2008, CenterPoint Energy entered into an agreement to purchase software licenses, support and maintenance. As of December 31, 2011, payment obligations under this agreement are $6 million in 2012 and $6 million in 2013.

(e) Long-Term Gas Gathering and Treating Agreements.

CenterPoint Energy Field Services, LLC (CEFS) has entered into long-term agreements with an indirect wholly-owned subsidiary of Encana Corporation (Encana) and an indirect wholly-owned subsidiary of Royal Dutch Shell plc (Shell) to provide gathering and treating services for their natural gas production from certain Haynesville Shale and Bossier Shale formations in Texas and Louisiana.

Under the long-term agreements, Encana or Shell may elect to require CEFS to expand the capacity of its gathering systems by up to an additional 1.3 Bcf per day. CEFS estimates that the cost to expand the capacity of its gathering systems by an additional 1.3 Bcf per day would be as much as $440 million. Encana and Shell would provide incremental volume commitments in connection with an election to expand system capacity.

(f) Legal, Environmental and Other Regulatory Matters

Legal Matters

Gas Market Manipulation Cases. CenterPoint Energy, CenterPoint Houston or their predecessor, Reliant Energy, Incorporated (Reliant Energy), and certain of their former subsidiaries are named as defendants in certain lawsuits described below. Under a master separation agreement between CenterPoint Energy and a former subsidiary, RRI Energy, Inc. (RRI), CenterPoint Energy and its subsidiaries are entitled to be indemnified by RRI and its successors for any losses, including attorneys’ fees and other costs, arising out of these lawsuits. In May 2009, RRI sold its Texas retail business to a subsidiary of NRG Energy, Inc. (NRG)and changed its name to RRI Energy, Inc. In December 2010, Mirant Corporation merged with and became a wholly owned subsidiary of RRI Energy, Inc., and RRI Energy, Inc. changed its name to GenOn Energy, Inc. Neither the sale of the retail business nor the merger with Mirant Corporation alters RRI’s (now GenOn’s) contractual obligations to indemnify CenterPoint Energy and its subsidiaries, including CenterPoint Houston, for certain liabilities, including their indemnification obligations regarding the gas market manipulation litigation, nor does it affect the terms of existing guaranty arrangements for certain GenOn gas transportation contracts discussed below.

A large number of lawsuits were filed against numerous gas market participants in a number of federal and western state courts in connection with the operation of the natural gas markets in 2000-2002. CenterPoint Energy’s former affiliate, RRI, was a participant in gas trading in the California and Western markets. These lawsuits, many of which have been filed as class actions, allege violations of state and federal antitrust laws. Plaintiffs in these lawsuits are seeking a variety of forms of relief, including, among others, recovery of compensatory damages (in some cases in excess of $1 billion), a trebling of compensatory damages, full consideration damages and attorneys’ fees. CenterPoint Energy and/or Reliant Energy were named in approximately 30 of these lawsuits, which were instituted between 2003 and 2009. CenterPoint Energy and its affiliates have been released or dismissed from all but two of such cases. CenterPoint Energy Services, Inc. (CES), a subsidiary of CERC Corp., is a defendant in a case now pending in federal court in Nevada alleging a conspiracy to inflate Wisconsin natural gas prices in 2000-2002. In July 2011, the court issued an order dismissing the plaintiffs' claims against the other defendants in the case, each of whom had demonstrated FERC jurisdictional sales for resale during the relevant period, based on federal preemption. The plaintiffs have appealed this ruling to the United States Court of Appeals for the Ninth Circuit. Additionally, CenterPoint Energy was a defendant in a lawsuit filed in state court in Nevada that was dismissed in 2007, but in March 2010 the plaintiffs appealed the dismissal to the Nevada Supreme Court. CenterPoint Energy believes that neither it nor CES is a proper defendant in these remaining cases and will continue to pursue dismissal from those cases. CenterPoint Energy does not expect the ultimate outcome of these remaining matters to have a material impact on its financial condition, results of operations or cash flows.

Natural Gas Measurement Lawsuits. CERC Corp. and certain of its subsidiaries are defendants in two mismeasurement lawsuits brought against approximately 245 pipeline companies and their affiliates pending in state court in Stevens County, Kansas. In one case (originally filed in May 1999 and amended four times), the plaintiffs purport to represent a class of royalty owners who allege that the defendants have engaged in systematic mismeasurement of the volume of natural gas for more than 25 years. The plaintiffs amended their petition in this suit in July 2003 in response to an order from the judge denying certification of the plaintiffs’ alleged class. In the amendment, the plaintiffs dismissed their claims against certain defendants (including two CERC Corp. subsidiaries), limited the scope of the class of plaintiffs they purport to represent and eliminated previously asserted claims based on mismeasurement of the British thermal unit (Btu) content of the gas. The same plaintiffs then filed a second lawsuit, again as representatives of a putative class of royalty owners in which they assert their claims that the defendants have engaged in systematic mismeasurement of the Btu content of natural gas for more than 25 years. In both lawsuits, the plaintiffs seek compensatory damages, along with statutory penalties, treble damages, interest, costs and fees. In September 2009, the district court in Stevens County, Kansas, denied plaintiffs’ request for class certification of their case and, in March 2010, denied the plaintiffs’ request for reconsideration of that order. The time for seeking review of the district court's decision has now passed.

CERC believes that there has been no systematic mismeasurement of gas and that these lawsuits are without merit. CERC and CenterPoint Energy do not expect the ultimate outcome of the lawsuits to have a material impact on the financial condition, results of operations or cash flows of either CenterPoint Energy or CERC.

Environmental Matters

Manufactured Gas Plant Sites. CERC and its predecessors operated manufactured gas plants (MGPs) in the past. In Minnesota, CERC has completed remediation on two sites, other than ongoing monitoring and water treatment. There are five remaining sites in CERC’s Minnesota service territory. CERC believes that it has no liability with respect to two of these sites.

At December 31, 2011, CERC had accrued $13 million for remediation of these Minnesota sites and the estimated range of possible remediation costs for these sites was $6 million to $41 million based on remediation continuing for 30 to 50 years. The cost estimates are based on studies of a site or industry average costs for remediation of sites of similar size. The actual remediation costs will be dependent upon the number of sites to be remediated, the participation of other potentially responsible parties (PRPs), if any, and the remediation methods used. The Minnesota Public Utility Commission provided for the inclusion in rates of approximately $285,000 annually to fund normal on-going remediation costs. As of December 31, 2011, CERC had collected $5.5 million from insurance companies to be used to mitigate future environmental costs.

In addition to the Minnesota sites, the United States Environmental Protection Agency and other regulators have investigated MGP sites that were owned or operated by CERC or may have been owned by one of its former affiliates. CERC and CenterPoint Energy do not expect the ultimate outcome of these investigations will have a material adverse impact on the financial condition, results of operations or cash flows of either CenterPoint Energy or CERC.

Asbestos. Some facilities owned by CenterPoint Energy contain or have contained asbestos insulation and other asbestos-containing materials. CenterPoint Energy or its subsidiaries have been named, along with numerous others, as a defendant in lawsuits filed by a number of individuals who claim injury due to exposure to asbestos. Some of the claimants have worked at locations owned by subsidiaries of CenterPoint Energy, but most existing claims relate to facilities previously owned by CenterPoint Energy’s subsidiaries. CenterPoint Energy anticipates that additional claims like those received may be asserted in the future. In 2004 and early 2005, CenterPoint Energy sold its generating business, to which most of these claims relate, to a company which is now an affiliate of NRG. Under the terms of the arrangements regarding separation of the generating business from CenterPoint Energy and its sale of that business, ultimate financial responsibility for uninsured losses from claims relating to the generating business has been assumed by the NRG affiliate, but CenterPoint Energy has agreed to continue to defend such claims to the extent they are covered by insurance maintained by CenterPoint Energy, subject to reimbursement of the costs of such defense by the NRG affiliate. Although their ultimate outcome cannot be predicted at this time, CenterPoint Energy intends to continue vigorously contesting claims that it does not consider to have merit and does not expect, based on its experience to date, these matters, either individually or in the aggregate, to have a material adverse effect on CenterPoint Energy’s financial condition, results of operations or cash flows.

Other Environmental. From time to time CenterPoint Energy identifies the presence of environmental contaminants on property where its subsidiaries conduct or have conducted operations. Other such sites involving contaminants may be identified in the future. CenterPoint Energy has and expects to continue to remediate identified sites consistent with its legal obligations. From time to time CenterPoint Energy has received notices from regulatory authorities or others regarding its status as a PRP in connection with sites found to require remediation due to the presence of environmental contaminants. In addition, CenterPoint Energy has been named from time to time as a defendant in litigation related to such sites. Although the ultimate outcome of such matters cannot be predicted at this time, CenterPoint Energy does not expect, based on its experience to date, these matters, either individually or in the aggregate, to have a material adverse effect on CenterPoint Energy’s financial condition, results of operations or cash flows.

Other Proceedings

CenterPoint Energy is involved in other legal, environmental, tax and regulatory proceedings before various courts, regulatory commissions and governmental agencies regarding matters arising in the ordinary course of business. Some of these proceedings involve substantial amounts. CenterPoint Energy regularly analyzes current information and, as necessary, provides accruals for probable liabilities on the eventual disposition of these matters. CenterPoint Energy does not expect the disposition of these matters to have a material adverse effect on CenterPoint Energy’s financial condition, results of operations or cash flows.

(g) Guaranties

Prior to the distribution of CenterPoint Energy’s ownership in RRI to its shareholders, CERC had guaranteed certain contractual obligations of what became RRI’s trading subsidiary. When the companies separated, RRI agreed to secure CERC against obligations under the guaranties RRI had been unable to extinguish by the time of separation. Pursuant to such agreement, as amended in December 2007, RRI (now GenOn) agreed to provide to CERC cash or letters of credit as security against CERC’s obligations under its remaining guaranties for demand charges under certain gas transportation agreements if and to the extent changes in market conditions expose CERC to a risk of loss on those guaranties based on an annual calculation, with any required collateral to be posted each December. The undiscounted maximum potential payout of the demand charges under these transportation contracts, which will be in effect until 2018, was approximately $88 million as of December 31, 2011. Market conditions in the fourth quarters of 2010 and 2011 required posting of security under the agreement, and GenOn posted approximately $7 million in collateral in December 2010 and an additional $21 million of collateral in December 2011. If GenOn should fail to perform the contractual obligations, CERC could have to honor its guarantee and, in such event, collateral provided as security may be insufficient to satisfy CERC’s obligations.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

+ Details

Earnings Per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Earnings Per Share

The following table reconciles numerators and denominators of CenterPoint Energy’s basic and diluted earnings per share calculations:



	For the Year Ended December 31,
	2009		2010		2011
	(in millions, except per share and share amounts)
Basic earnings per share calculation:
Income before extraordinary item	$	372	$	442	$	770
Extraordinary item, net of tax	—		—		587
Net income	$	372	$	442	$	1,357

Weighted average shares outstanding	365,229,000		409,721,000		425,636,000

Basic earnings per share:
Income before extraordinary item	$	1.02	$	1.08	$	1.81
Extraordinary item, net of tax	—		—		1.38
Net income	$	1.02	$	1.08	$	3.19

Diluted earnings per share calculation:
Net income	$	372	$	442	$	1,357

Weighted average shares outstanding	365,229,000		409,721,000		425,636,000
Plus: Incremental shares from assumed conversions:
Stock options ⁽¹⁾	451,000		470,000		347,000
Restricted stock	2,001,000		2,585,000		2,741,000
Weighted average shares assuming dilution	367,681,000		412,776,000		428,724,000

Diluted earnings per share:
Income before extraordinary item	$	1.01	$	1.07	$	1.80
Extraordinary item, net of tax	—		—		1.37
Net income	$	1.01	$	1.07	$	3.17


(1)	Options to purchase 2,372,132 and 1,458,598 shares were outstanding for the years ended December 31, 2009 and 2010, respectively, but were not included in the computation of diluted earnings per share because the options’ exercise price was greater than the average market price of the common shares for the respective years.

Unaudited Quarterly Information

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Text Block]

Unaudited Quarterly Information

Summarized quarterly financial data is as follows:



	Year Ended December 31, 2010
	First Quarter ⁽²⁾		Second Quarter		Third Quarter		Fourth Quarter ⁽³⁾
	(in millions, except per share amounts)
Revenues	$	3,023	$	1,756	$	1,908	$	2,098
Operating income	357		263		327		302
Net income	114		81		123		124

Basic earnings per share(1)	$	0.29	$	0.20	$	0.29	$	0.29

Diluted earnings per share(1)	$	0.29	$	0.20	$	0.29	$	0.29



	Year Ended December 31, 2011
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(in millions, except per share amounts)
Revenues	$	2,587	$	1,837	$	1,881	$	2,145
Operating income	364		303		357		274
Income before extraordinary item(4)	148		119		386		117
Extraordinary item, net of tax(4)	—		—		587		—
Net income	$	148	$	119	$	973	$	117

Basic earnings per share(1):
Income before extraordinary item	$	0.35	$	0.28	$	0.90	$	0.27
Extraordinary item, net of tax	—		—		1.38		—
Net income	$	0.35	$	0.28	$	2.28	$	0.27

Diluted earnings per share(1)
Income before extraordinary item	$	0.35	$	0.28	$	0.90	$	0.27
Extraordinary item, net of tax	—		—		1.37		—
Net income	$	0.35	$	0.28	$	2.27	$	0.27


(1)	Quarterly earnings per common share are based on the weighted average number of shares outstanding during the quarter, and the sum of the quarters may not equal annual earnings per common share.


(2)	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.


(3)	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.


(4)	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Reportable Business Segments

12 Months Ended

Dec. 31, 2011

Segment Reporting [Abstract]

Reportable Business Segments

CenterPoint Energy’s determination of reportable business segments considers the strategic operating units under which CenterPoint Energy manages sales, allocates resources and assesses performance of various products and services to wholesale or retail customers in differing regulatory environments. The accounting policies of the business segments are the same as those described in the summary of significant accounting policies except that some executive benefit costs have not been allocated to business segments. CenterPoint Energy uses operating income as the measure of profit or loss for its business segments.

CenterPoint Energy’s reportable business segments include the following: Electric Transmission & Distribution, Natural Gas Distribution, Competitive Natural Gas Sales and Services, Interstate Pipelines, Field Services and Other Operations. The electric transmission and distribution function (CenterPoint Houston) is reported in the Electric Transmission & Distribution business segment. Natural Gas Distribution consists of intrastate natural gas sales to, and natural gas transportation and distribution for, residential, commercial, industrial and institutional customers. Competitive Natural Gas Sales and Services represents CenterPoint Energy’s non-rate regulated gas sales and services operations. The Interstate Pipelines business segment includes the interstate natural gas pipeline operations. The Field Services business segment includes the non-rate regulated natural gas gathering, processing and treating operations. Other Operations consists primarily of other corporate operations which support all of CenterPoint Energy’s business operations.

Long-lived assets include net property, plant and equipment, goodwill and other intangibles and equity investments in unconsolidated subsidiaries. Intersegment sales are eliminated in consolidation.

Financial data for business segments and products and services are as follows (in millions):



	Revenues from External Customers			Intersegment Revenues			Depreciation and Amortization		Operating Income		Total Assets				Expenditures for Long-Lived Assets
As of and for the year ended December 31, 2009:
Electric Transmission & Distribution	$	2,013	(1)	$	—		$	480	$	545	$	9,755			$	428
Natural Gas Distribution	3,374			10			161		204		4,535				165
Competitive Natural Gas Sales and Services	2,215			15			4		21		1,176				2
Interstate Pipelines(2)	456			142			48		256		3,484				176
Field Services(3)	212			29			15		94		1,045				348
Other	11			—			35		4		2,261			(4)	29
Reconciling Eliminations	—			(196		)	—		—		(2,483		)		—
Consolidated	$	8,281		$	—		$	743	$	1,124	$	19,773			$	1,148
As of and for the year ended December 31, 2010:
Electric Transmission & Distribution	$	2,205	(1)	$	—		$	582	$	567	$	9,817			$	463
Natural Gas Distribution	3,199			14			166		231		4,575				202
Competitive Natural Gas Sales and Services	2,617			34			4		16		1,190				2
Interstate Pipelines(2)	464			137			52		270		3,672				102
Field Services(3)	289			49			25		151		1,803				668
Other	11			—			35		14		2,184			(4)	25
Reconciling Eliminations	—			(234		)	—		—		(3,130		)		—
Consolidated	$	8,785		$	—		$	864	$	1,249	$	20,111			$	1,462
As of and for the year ended December 31, 2011:
Electric Transmission & Distribution	$	2,337	(1)	$	—		$	587	$	623	$	11,221			$	538
Natural Gas Distribution	2,823			18			166		226		4,636				295
Competitive Natural Gas Sales and Services	2,488			23			5		6		1,089				5
Interstate Pipelines(2)	421			132			54		248		3,867				98
Field Services(3)	370			42			37		189		1,894				201
Other	11			—			37		6		2,318			(4)	54
Reconciling Eliminations	—			(215		)	—		—		(3,322		)		—
Consolidated	$	8,450		$	—		$	886	$	1,298	$	21,703			$	1,191

(1)

Sales to affiliates of NRG in 2009, 2010 and 2011 represented approximately $634 million, $583 million and $594 million, respectively, of CenterPoint Houston’s transmission and distribution revenues. Sales to affiliates of Energy Future Holdings Corp. in 2009, 2010 and 2011 represented approximately $182 million, $185 million and $182 million, respectively, of CenterPoint Houston’s transmission and distribution revenues.

(2)

Interstate Pipelines recorded equity income of $7 million, $19 million, and $21 million in the years ended December 31, 2009, 2010 and 2011, respectively, from its 50% interest in SESH, a jointly-owned pipeline. These amounts are included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Interstate Pipelines’ investment in SESH was $422 million, $413 million and $409 million as of December 31, 2009, 2010 and 2011 and is included in Investment in unconsolidated affiliates.

(3)

Field Services recorded equity income of $8 million, $10 million and $9 million for the years ended December 31, 2009, 2010 and 2011, respectively, from its 50% interest in a jointly-owned gas processing plant. These amounts are included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Field Services’ investment in the jointly-owned gas processing plant was $40 million, $55 million and $63 million as of December 31, 2009, 2010 and 2011, respectively, and is included in Investment in unconsolidated affiliates.


(4)	Included in total assets of Other Operations as of December 31, 2009, 2010 and 2011, are pension and other postemployment related regulatory assets of $731 million, $704 million and $796 million, respectively.



	Year Ended December 31,
Revenues by Products and Services:	2009		2010		2011
	(in millions)
Electric delivery sales	$	2,013	$	2,205	$	2,337
Retail gas sales	4,540		4,412		4,019
Wholesale gas sales	902		1,250		1,149
Gas transport	691		785		824
Energy products and services	135		133		121
Total	$	8,281	$	8,785	$	8,450

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
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-Paragraph 34
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 280
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+ Details

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2011
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On January 19, 2012, CenterPoint Energy’s board of directors declared a regular quarterly cash dividend of $0.2025 per share of common stock payable on March 9, 2012, to shareholders of record as of the close of business on February 16, 2012.

Schedule I: Financial Information of Centerpoint Energy, Inc. (Parent Company)

12 Months Ended

Dec. 31, 2011

Condensed Financial Information of Parent Company Only Disclosure [Abstract]

Schedule I - Condensed Financial Information of Centerpoint Energy, Inc. (Parent Company)

CENTERPOINT ENERGY, INC.

SCHEDULE I — CONDENSED FINANCIAL INFORMATION OF

CENTERPOINT ENERGY, INC. (PARENT COMPANY)

STATEMENTS OF INCOME



	For the Year Ended December 31,
	2009			2010			2011
	(in millions)
Expenses:
Operation and Maintenance Expenses	$	(17	)	$	(12	)	$	(12	)
Total	(17		)	(12		)	(12		)
Other Income (Expense):
Interest Income from Subsidiaries	8			8			7
Other Expense	(5		)	(8		)	—
Gain (Loss) on Indexed Debt Securities	(68		)	(31		)	35
Interest Expense to Subsidiaries	(25		)	(26		)	(25		)
Interest Expense	(149		)	(132		)	(123		)
Total	(239		)	(189		)	(106		)
Loss Before Income Taxes, Equity in Subsidiaries and Extraordinary Item	(256		)	(201		)	(118		)
Income Tax Benefit	113			79			50
Loss Before Equity in Subsidiaries and Extraordinary Item	(143		)	(122		)	(68		)
Equity Income of Subsidiaries	515			564			838
Income Before Extraordinary Item	372			442			770
Extraordinary Item, Net of Tax	—			—			587
Net Income	$	372		$	442		$	1,357

See Notes to Condensed Financial Information (Parent Company) and

CenterPoint Energy, Inc. and Subsidiaries Notes to Consolidated Financial Statements in Part II, Item 8

CENTERPOINT ENERGY, INC.

SCHEDULE I — CONDENSED FINANCIAL INFORMATION OF

CENTERPOINT ENERGY, INC. (PARENT COMPANY)

BALANCE SHEETS



	December 31,
	2010			2011
	(in millions)
ASSETS
Current Assets:
Cash and cash equivalents	$	—		$	—
Notes receivable — subsidiaries	530			407
Accounts receivable — subsidiaries	59			53
Other assets	68			43
Total current assets	657			503
Other Assets:
Investment in subsidiaries	6,115			7,538
Notes receivable — subsidiaries	151			151
Other assets	723			822
Total other assets	6,989			8,511
Total Assets	$	7,646		$	9,014
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current Liabilities:
Notes payable — subsidiaries	$	900		$	1,012
Current portion of indexed debt	126			131
Current portion of other long-term debt	19			—
Indexed debt securities derivative	232			197
Accounts payable:
Subsidiaries	27			24
Other	1			—
Taxes accrued	318			426
Interest accrued	19			19
Other	1			1
Total current liabilities	1,643			1,810
Other Liabilities:
Accumulated deferred tax liabilities	124			202
Benefit obligations	460			569
Notes payable — subsidiaries	750			750
Other	10			—
Total non-current liabilities	1,344			1,521
Long-Term Debt	1,461			1,461
Shareholders’ Equity:
Common stock	4			4
Additional paid-in capital	4,100			4,120
Retained earnings (accumulated deficit)	(789		)	231
Accumulated other comprehensive loss	(117		)	(133		)
Total shareholders’ equity	3,198			4,222
Total Liabilities and Shareholders’ Equity	$	7,646		$	9,014

See Notes to Condensed Financial Information (Parent Company) and

CenterPoint Energy, Inc. and Subsidiaries Notes to Consolidated Financial Statements in Part II, Item 8

CENTERPOINT ENERGY, INC.

SCHEDULE I — CONDENSED FINANCIAL INFORMATION OF

CENTERPOINT ENERGY, INC. (PARENT COMPANY)

STATEMENTS OF CASH FLOWS



	For the Year Ended December 31,
	2009			2010			2011
	(in millions)
Operating Activities:
Net income	$	372		$	442		$	1,357
Non-cash items included in net income:
Equity income of subsidiaries	(515		)	(564		)	(838		)
Deferred income tax expense	(19		)	(16		)	149
Amortization of debt issuance costs	5			6			5
Extraordinary item, net of tax	—			—			(587		)
Loss (gain) on indexed debt securities	68			31			(35		)
Changes in working capital:
Accounts receivable/(payable) from subsidiaries, net	86			78			73
Accounts payable	14			(16		)	(1		)
Other current assets	(16		)	(27		)	1
Other current liabilities	59			(111		)	50
Common stock dividends received from subsidiaries	109			9			10
Other	(1		)	6			(62		)
Net cash provided by (used in) operating activities	162			(162		)	122
Investing Activities:
Short-term notes receivable from subsidiaries	(411		)	(37		)	123
Net cash provided by (used in) investing activities	(411		)	(37		)	123
Financing Activities:
Revolving credit facility, net	(264		)	—			—
Payments on long-term debt	—			(490		)	(19		)
Debt issuance costs	—			(2		)	(7		)
Common stock dividends paid	(276		)	(319		)	(337		)
Proceeds from issuance of common stock, net	504			416			6
Short-term notes payable to subsidiaries	285			594			112
Net cash provided by (used in) financing activities	249			199			(245		)
Net Decrease in Cash and Cash Equivalents	—			—			—
Cash and Cash Equivalents at Beginning of Year	—			—			—
Cash and Cash Equivalents at End of Year	$	—		$	—		$	—

See Notes to Condensed Financial Information (Parent Company) and

CenterPoint Energy, Inc. and Subsidiaries Notes to Consolidated Financial Statements in Part II, Item 8

CENTERPOINT ENERGY, INC.

SCHEDULE I — NOTES TO CONDENSED FINANCIAL INFORMATION (PARENT COMPANY)

(1) Background. The condensed parent company financial statements and notes of CenterPoint Energy, Inc. (CenterPoint Energy) should be read in conjunction with the consolidated financial statements and notes of CenterPoint Energy, Inc. and subsidiaries appearing in the Annual Report on Form 10-K. Bank facilities at CenterPoint Energy Houston Electric, LLC and CenterPoint Energy Resources Corp., indirect wholly owned subsidiaries of CenterPoint Energy, limit debt, excluding transition and system restoration bonds, as a percentage of their total capitalization to 65%. These covenants could restrict the ability of these subsidiaries to distribute dividends to CenterPoint Energy.

(2) New Accounting Pronouncements. In May 2011, the Financial Accounting Standards Board (FASB) issued new accounting guidance to achieve common fair value measurements and disclosure requirements in generally accepted accounting principles (U.S. GAAP) and International Financial Reporting Standards (IFRS). Some of the provisions of the new accounting guidance include requiring (1) that only nonfinancial assets should be valued based on a determination of their best use, (2) disclosure of quantitative information about unobservable inputs used in Level 3 fair value measurements and (3) disclosure of the level within the fair value hierarchy for each class of assets or liabilities not measured at fair value in the statement of financial position but for which the fair value is disclosed. This new guidance is effective for interim and annual periods beginning after December 15, 2011. CenterPoint Energy expects that the adoption of this new guidance will not have a material impact on its financial position, results of operations or cash flows.

(3) Long-term Debt. As of December 31, 2010 and 2011, CenterPoint Energy had no borrowings and approximately $20 million and $16 million, respectively, of outstanding letters of credit under its $1.2 billion credit facility. There was no commercial paper outstanding that would have been backstopped by CenterPoint Energy’s $1.2 billion credit facility as of December 31, 2010 and 2011. CenterPoint Energy was in compliance with all debt covenants as of December 31, 2011.

CenterPoint Energy’s $1.2 billion credit facility, which is scheduled to terminate September 9, 2016, can be drawn at the London Interbank Offered Rate (LIBOR) plus 175 basis points based on CenterPoint Energy’s current credit ratings. The facility contains a debt (excluding transition and system restoration bonds) to earnings before interest, taxes, depreciation and amortization (EBITDA) covenant (as those terms are defined in the facility). The facility allows for a temporary increase of the permitted ratio in the financial covenant from 5 times to 5.5 times if CenterPoint Houston experiences damage from a natural disaster in its service territory and CenterPoint Energy certifies to the administrative agent that CenterPoint Houston has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive twelve-month period, all or part of which CenterPoint Houston intends to seek to recover through securitization financing. Such temporary increase in the financial ratio covenant would be in effect from the date CenterPoint Energy delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of CenterPoint Energy’s certification or (iii) the revocation of such certification.

CenterPoint Energy’s maturities of long-term debt, excluding the ZENS obligation, are $420 million in 2015. There are no maturities of long-term debt in 2012, 2013, 2014 and 2016.

(4) Guaranties. CenterPoint Energy Services, Inc. (CES), an indirect wholly-owned subsidiary of CenterPoint Energy, provides comprehensive natural gas sales and services to industrial and commercial customers. In order to hedge their exposure to natural gas prices, CES has entered into standard purchase and sale agreements with various counterparties. CenterPoint Energy has guaranteed the payment obligations of CES under certain of these agreements, typically for one-year terms. As of December 31, 2011, CenterPoint Energy had guaranteed $5 million under these agreements.

In September 2009 and April 2010, CenterPoint Energy Field Services, LLC (CEFS), an indirect wholly-owned subsidiary of CenterPoint Energy, entered into long-term agreements with an indirect wholly-owned subsidiary of Encana Corporation (Encana) and an indirect wholly-owned subsidiary of Royal Dutch Shell plc (Shell) to provide gathering and treating services for their natural gas production from certain Haynesville Shale and Bossier Shale formations in Texas and Louisiana. CEFS also acquired jointly-owned gathering facilities from Encana and Shell. Each of the agreements includes acreage dedication and volume commitments for which CEFS has rights to gather Shell’s and Encana’s natural gas production from the dedicated areas.

In connection with the agreements, CEFS commenced gathering and treating services utilizing the acquired facilities. CEFS has expanded the acquired facilities. If Encana or Shell elect, CEFS will further expand the facilities in order to gather and treat additional future volumes. CenterPoint Energy has guaranteed to fund CEFS’ obligations up to $100 million, plus any additional amount related to any expansion or additional services, upon completion of the gathering systems. As of December 31, 2011, CenterPoint Energy had guaranteed CEFS’s obligations up to an amount of $100 million under these agreements.

- Definition

The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.

+ References + Details

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2011

Valuation and Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts Disclosure

CENTERPOINT ENERGY, INC.

SCHEDULE II —VALUATION AND QUALIFYING ACCOUNTS

For the Three Years Ended December 31, 2011



Column A	Column B		Column C					Column D		Column E
			Additions
	Balance at Beginning of Period		Charged to Income			Charged to Other Accounts		Deductions From Reserves (1)		Balance at End of Period
Description	(in millions)
Year Ended December 31, 2011
Accumulated provisions:
Uncollectible accounts receivable	$	25	$	26		$	—	$	26	$	25
Deferred tax asset valuation allowance	3		—			1		—		4
Year Ended December 31, 2010
Accumulated provisions:
Uncollectible accounts receivable	$	24	$	30		$	—	$	29	$	25
Deferred tax asset valuation allowance	5		(2		)	—		—		3
Year Ended December 31, 2009
Accumulated provisions:
Uncollectible accounts receivable	$	35	$	36		$	—	$	47	$	24
Deferred tax asset valuation allowance	5		—			—		—		5


(1)	Deductions from reserves represent losses or expenses for which the respective reserves were created. In the case of the uncollectible accounts reserve, such deductions are net of recoveries of amounts previously written off.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Use of Estimates

Principles of Consolidation

Revenues


	Revenues

Long-lived Assets

Long-lived Assets and Intangibles

CenterPoint Energy records property, plant and equipment at historical cost. CenterPoint Energy expenses repair and maintenance costs as incurred.

Regulatory Assets and Liabilities

Depreciation and Amortization Expense

Capitalization of Interest and Allowance for Funds Used During Construction

Income Tax

Income Taxes

Accounts Receivable and Allowance for Doubtful Accounts

Inventory

Derivative Instruments

Investments in Other Debt and Equity Securities

Environmental Costs

Statement of Consolidated Cash Flows

Statements of Consolidated Cash Flows

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Schedule of Inventory



	December 31,
	2010		2011
	(in millions)
Materials and supplies	$	164	$	166
Natural gas	211		187
Total inventory	$	375	$	353

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2011

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

Property, plant and equipment includes the following:



	Weighted Average Useful Lives	December 31,
	(Years)	2010		2011
		(in millions)
Electric Transmission & Distribution	29	$	7,586	$	7,827
Natural Gas Distribution	32	3,642		3,959
Competitive Natural Gas Sales and Services	27	71		76
Interstate Pipelines	57	2,594		2,675
Field Services	46	1,583		1,754
Other property	24	529		577
Total		16,005		16,868
Accumulated depreciation and amortization:
Electric Transmission & Distribution		2,805		2,784
Natural Gas Distribution		954		1,069
Competitive Natural Gas Sales and Services		16		20
Interstate Pipelines		265		302
Field Services		43		72
Other property		190		219
Total accumulated depreciation and amortization		4,273		4,466
Property, plant and equipment, net		$	11,732	$	12,402

Depreciation and Amortization

The following table presents depreciation and amortization expense for 2009, 2010 and 2011 (in millions).



	2009		2010		2011
Depreciation expense	$	496	$	531	$	529
Amortization expense	247		333		357
Total depreciation and amortization expense	$	743	$	864	$	886

Asset Retirement Obligation

A reconciliation of the changes in the asset retirement obligation (ARO) liability is as follows (in millions):



	December 31,
	2010			2011
Beginning balance	$	82		$	84
Accretion expense	5			5
Revisions in estimates of cash flows	(3		)	67
Ending balance	$	84		$	156

Goodwill (Tables)

12 Months Ended

Dec. 31, 2011

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill by Reportable Segments

Goodwill by reportable segment as of both December 31, 2010 and 2011 is as follows (in millions):



Natural Gas Distribution	$	746
Interstate Pipelines	579
Competitive Natural Gas Sales and Services	335
Field Services	25
Other Operations	11
Total	$	1,696

- Definition

Tabular disclosure of goodwill by reportable segment and in total. Disclosure details may include, but are not limited to, the carrying amount of goodwill, goodwill acquired during the year, goodwill impairment losses recognized, goodwill written-off due to the sale of a business unit, goodwill not yet allocated, and any other changes to goodwill.

+ References + Details

Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2011

Regulated Operations [Abstract]

Schedule of Regulatory Assets and Liabilities

The following is a list of regulatory assets/liabilities reflected on CenterPoint Energy’s Consolidated Balance Sheets as of December 31, 2010 and 2011:



	December 31,
	2010			2011
	(in millions)
Securitized regulatory assets	$	2,597		$	2,289
True-up Settlement (1)	—			1,684
Unrecognized equity return (2)	(216		)	(600		)
Unamortized loss on reacquired debt	61			56
Pension and postretirement-related regulatory asset (3)	838			975
Other long-term regulatory assets (4)	166			215
Total regulatory assets	3,446			4,619

Estimated removal costs	868			912
Other long-term regulatory liabilities	121			127
Total regulatory liabilities	989			1,039

Total regulatory assets and liabilities, net	$	2,457		$	3,580


(1)	In accordance with a final order from the Public Utility Commission of Texas, (Texas Utility Commission), the true-up settlement at December 31, 2011 was not earning a return. The regulatory asset was securitized in January 2012 as a result of the issuance of the transition bonds described below in Note 5(b).


(2)	As of December 31, 2011, CenterPoint Energy has not recognized an allowed equity return of $600 million because such return will be recognized as it is recovered in rates. During the years ended December 31, 2009, 2010 and 2011, CenterPoint Houston recognized approximately $14 million, $16 million and $21 million, respectively, of the allowed equity return.

(3)


(4)	Other regulatory assets that are not earning a return were not material at December 31, 2010 and 2011.

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2011

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Activity in all Stock Based Incentive Compensation Plans

Performance Awards



	Outstanding and Non-Vested Shares
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Grant Date Fair Value		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	3,068		$	13.84
Granted	1,110		15.49
Forfeited or cancelled	(469	)	15.25
Vested and released to participants	(411	)	15.39
Outstanding at December 31, 2011	3,298		13.99		1.0	$	55

The following tables summarize CenterPoint Energy’s LTIPs activity for 2011:

Stock Options



	Outstanding Options
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Exercise Price		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	3,077		$	19.27
Expired	(1,417	)	31.70
Cancelled	(31	)	31.98
Exercised	(664	)	8.13
Outstanding at December 31, 2011	965		8.28		1.4	$	11
Exercisable at December 31, 2011	965		8.28		1.4	11

Valuation Data

The total intrinsic value of awards received by participants was as follows for 2009, 2010 and 2011:



	Year Ended December 31,
	2009		2010		2011
	(in millions)
Stock options exercised	$	2	$	4	$	7
Performance awards	7		5		7
Stock awards	4		4		7

Stock Awards



	Outstanding and Non-Vested Shares
	Year Ended December 31, 2011
	Shares (Thousands)		Weighted-Average Grant Date Fair Value		Remaining Average Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding at December 31, 2010	1,096		$	13.78
Granted	368		15.81
Forfeited or cancelled	(30	)	14.00
Vested and released to participants	(369	)	14.75
Outstanding at December 31, 2011	1,065		14.14		1.1	$	21

The weighted-average grant-date fair values of awards granted were as follows for 2009, 2010 and 2011:



	Year Ended December 31,
	2009		2010		2011
Performance awards	$	12.42	$	14.21	$	15.49
Stock awards	12.30		14.26		15.81

Schedule of Net Pension and Post-retirement Benefit Costs



	December 31,
	2010						2011
	Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits
	(in millions, except for actuarial assumptions)
Change in Benefit Obligation
Benefit obligation, beginning of year	$	1,866		$	450		$	1,969		$	460
Service cost	31			1			33			1
Interest cost	102			25			100			24
Participant contributions	—			7			—			7
Benefits paid	(115		)	(50		)	(113		)	(40		)
Actuarial loss	85			24			93			41
Early retiree reinsurance program reimbursement	—			—			—			3
Medicare reimbursement	—			3			3			4
Benefit obligation, end of year	1,969			460			2,085			500
Change in Plan Assets
Fair value of plan assets, beginning of year	1,432			146			1,501			144
Employer contributions	8			29			75			21
Participant contributions	—			7			—			7
Benefits paid	(115		)	(50		)	(113		)	(40		)
Actual investment return	176			12			43			6
Fair value of plan assets, end of year	1,501			144			1,506			138
Funded status, end of year	$	(468	)	$	(316	)	$	(579	)	$	(362	)
Amounts Recognized in Balance Sheets
Current liabilities-other	$	(9	)	$	(9	)	$	(9	)	$	(9	)
Other liabilities-benefit obligations	(459		)	(307		)	(570		)	(353		)
Net liability, end of year	$	(468	)	$	(316	)	$	(579	)	$	(362	)
Actuarial Assumptions
Discount rate	5.25		%	5.20		%	4.90		%	4.80		%
Expected return on plan assets	8.00			7.05			8.00			5.50
Rate of increase in compensation levels	4.60			—			4.20			—
Healthcare cost trend rate assumed for the next year	—			8.50			—			8.00
Prescription drug cost trend rate assumed for the next year	—			8.50			—			8.00
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	—			5.50			—			5.50
Year that the healthcare rate reaches the ultimate trend rate	—			2017			—			2017
Year that the prescription drug rate reaches the ultimate trend rate	—			2017			—			2017

CenterPoint Energy’s net periodic cost includes the following components relating to pension, including the benefit restoration plan, and postretirement benefits:



	Year Ended December 31,
	2009						2010						2011
	Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits			Pension Benefits			Post-retirement Benefits
	(in millions)
Service cost	$	25		$	1		$	31		$	1		$	33		$	1
Interest cost	113			28			102			25			100			24
Expected return on plan assets	(98		)	(9		)	(109		)	(10		)	(115		)	(10		)
Amortization of prior service cost	3			3			3			3			3			3
Amortization of net loss	68			—			59			—			57			1
Amortization of transition obligation	—			7			—			7			—			7
Benefit enhancement	—			—			—			—			—			1
Net periodic cost	$	111		$	30		$	86		$	26		$	78		$	27

CenterPoint Energy used the following assumptions to determine net periodic cost relating to pension and postretirement benefits:



	December 31,
	2009				2010				2011
	Pension Benefits		Post-retirement Benefits		Pension Benefits		Post-retirement Benefits		Pension Benefits		Post-retirement Benefits
Discount rate	6.90	%	6.90	%	5.70	%	5.70	%	5.25	%	5.20	%
Expected return on plan assets	8.00		7.05		8.00		7.05		8.00		7.05
Rate of increase in compensation levels	4.60		—		4.60		—		4.60		—

Amounts recognized in accumulated other comprehensive loss consist of the following:



	December 31,
	2010				2011
	Pension Benefits		Postretirement Benefits		Pension Benefits		Postretirement Benefits
	(in millions)
Unrecognized actuarial loss	$	151	$	18	$	166	$	25
Unrecognized prior service cost	15		7		15		5
Unrecognized transition obligation	—		2		—		1
Net amount recognized in accumulated other comprehensive loss	$	166	$	27	$	181	$	31

The changes in plan assets and benefit obligations recognized in other comprehensive income during 2011 are as follows (in millions):



	Pension Benefits			Postretirement Benefits
Net loss	$	2		$	7
Amortization of net loss	13			—
Prior service credit	(1		)	(4		)
Amortization of prior service credit	1			2
Transition obligation	—			(1		)
Total recognized in comprehensive income	$	15		$	4

As part of the investment strategy discussed above, CenterPoint Energy has adopted and maintains the following weighted average allocation targets for its benefit plans:



	Pension Benefits	Postretirement Benefits
Domestic equity securities	21-31%	14-24%
Global equity securities	7-13%	—
International equity securities	15-21%	3-13%
Emerging markets equity securities	4-8%	—
Debt securities	30-40%	68-78%
Real estate	0-5%	—
Cash	0-2%	0-2%

The amounts in accumulated other comprehensive loss expected to be recognized as components of net periodic benefit cost during 2012 are as follows (in millions):



	Pension Benefits		Postretirement Benefits
Unrecognized actuarial loss	$	13	$	1
Unrecognized prior service cost	1		2
Amounts in accumulated comprehensive income to be recognized in net periodic cost in 2012	$	14	$	3

The following table displays pension benefits related to CenterPoint Energy’s pension plans that have accumulated benefit obligations in excess of plan assets:



	December 31,
	2010				2011
	Pension Qualified		Pension Non-qualified		Pension Qualified		Pension Non-qualified
	(in millions)
Accumulated benefit obligation	$	1,860	$	94	$	1,966	$	98
Projected benefit obligation	1,875		94		1,987		98
Fair value of plan assets	1,501		—		1,506		—

The following benefit payments are expected to be paid by the pension and postretirement benefit plans (in millions):



			Postretirement Benefit Plan
	Pension Benefits		Benefit Payments		Medicare Subsidy Receipts
2012	$	124	$	37	$	(4	)
2013	135		37		(5		)
2014	143		39		(5		)
2015	147		41		(6		)
2016	145		42		(6		)
2017-2021	791		228		(41		)

Schedule of a One-percent Point Change in the Assumed Health Care Cost Trend Rates



	1% Increase		1% Decrease
	(in millions)
Effect on the postretirement benefit obligation	$	18	$	16
Effect on total of service and interest cost	1		1

Schedule of Fair Value of Financial Assets for Pension and Post-retirement Benefits

The following tables present additional information about the changes in the fair value of the pension plan’s level 3 investments for the years ended December 31, 2010 and 2011:



	Level 3 Investments
	Year Ended December 31, 2010
	(in millions)
	Corporate bonds			Asset backed securities			Real estate			Total
Balance, beginning of year	$	1		$	3		$	9		$	13
Unrealized losses relating to instruments still held at the reporting date	—			—			(1		)	(1		)
Purchases, sales, issuances, and settlement (net)	—			(1		)	—			(1		)
Transfer out of Level 3	(1		)	(2		)	—			(3		)
Balance, end of year	$	—		$	—		$	8		$	8



	Level 3 Investments
	Year Ended December 31, 2011
	(in millions)
	Corporate bonds		Asset backed securities		Real estate		Total
Balance, beginning of year	$	—	$	—	$	8	$	8
Unrealized losses relating to instruments still held at the reporting date	—		—		—		—
Purchases, sales, issuances, and settlement (net)	—		—		—		—
Transfer out of Level 3	—		—		—		—
Balance, end of year	$	—	$	—	$	8	$	8

The following tables present by level, within the fair value hierarchy, CenterPoint Energy’s postretirement plan assets at fair value as of December 31, 2010 and 2011, by asset category:



	Fair Value Measurements at December 31, 2010
	(in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs Level 3)
Mutual funds (1)	$	144	$	144	$	—	$	—
Total	$	144	$	144	$	—	$	—


(1)	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.



	Fair Value Measurements at December 31, 2011
	(in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs Level 3)
Mutual funds (1)	$	138	$	138	$	—	$	—
Total	$	138	$	138	$	—	$	—


(1)	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.

The following tables set forth by level, within the fair value hierarchy (see Note 8), CenterPoint Energy’s pension plan assets at fair value as of December 31, 2010 and 2011:



	Fair Value Measurements at December 31, 2010
	(in millions)
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	3		$	3		$	—	$	—
Common collective trust funds (1)	890			—			890		—
Corporate bonds:
Investment grade or above	122			—			122		—
Equity securities:
International companies	133			133			—		—
U.S. companies	131			131			—		—
Cash received as collateral from securities lending	112			112			—		—
U.S. government backed agencies bonds	34			34			—		—
U.S. treasuries	62			62			—		—
Mortgage backed securities	8			—			8		—
Asset backed securities	10			—			10		—
Municipal bonds	28			—			28		—
Mutual funds (2)	55			55			—		—
International government bonds	17			—			17		—
Real estate	8			—			—		8
Obligation to return cash received as collateral from securities lending	(112		)	(112		)	—		—
Total	$	1,501		$	418		$	1,075	$	8


(1)	24% of the amount invested in common collective trust funds is in fixed income securities, 42% is in U.S. equities and 34% is in international equities.


(2)	74% of the amount invested in mutual funds is in fixed income securities and 26% is in U.S. equities.



	Fair Value Measurements at December 31, 2011
	(in millions)
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash	$	(11	)	$	(11	)	$	—	$	—
Common collective trust funds (1)	973			—			973		—
Corporate bonds:
Investment grade or above	129			—			129		—
Equity securities:
International companies	128			128			—		—
U.S. companies	94			94			—		—
Cash received as collateral from securities lending	69			69			—		—
U.S. government backed agencies bonds	19			19			—		—
U.S. treasuries	34			34			—		—
Mortgage backed securities	9			—			9		—
Asset backed securities	8			—			8		—
Municipal bonds	39			—			39		—
Mutual funds (2)	54			54			—		—
International government bonds	22			—			22		—
Real estate	8			—			—		8
Obligation to return cash received as collateral from securities lending	(69		)	(69		)	—		—
Total	$	1,506		$	318		$	1,180	$	8


(1)	39% of the amount invested in common collective trust funds is in fixed income securities, 30% is in U.S. equities and 31% is in international equities.


(2)	75% of the amount invested in mutual funds is in international equities and 25% is in U.S. equities.

- Definition

Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate.

+ References + Details

- Definition

Tabular disclosure of one or more of the entity's defined benefit pension plans or one or more other defined benefit postretirement plans, separately for pension plans and other postretirement benefit plans including the entity's schedule of fair value of plan assets for defined benefit or other postretirement plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 4, 7, 16, 20, 21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=6930749&loc=d3e4179-114921

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2410-114920

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2439-114920

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2417-114920

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Value of Derivative Instruments



Fair Value of Derivative Instruments
	December 31, 2010
Total derivatives not designated as hedging instruments	Balance Sheet Location	Derivative Assets Fair Value (2) (3)		Derivative Liabilities Fair Value (2) (3)
		(in millions)
Natural gas contracts (1)	Current Assets	$	55	$	1
Natural gas contracts (1)	Other Assets	15		—
Natural gas contracts (1)	Current Liabilities	10		143
Natural gas contracts (1)	Other Liabilities	—		35
Indexed debt securities derivative	Current Liabilities	—		232
Total		$	80	$	411


(1)	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.


(2)	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 626 billion cubic feet (Bcf) or a net 72 Bcf long position. Of the net long position, basis swaps constitute 63 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 26 Bcf.


(3)	The net of total non-trading derivative assets and liabilities is a $15 million liability as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $84 million.



Fair Value of Derivative Instruments
	December 31, 2011
Total derivatives not designated as hedging instruments	Balance Sheet Location	Derivative Assets Fair Value (2) (3)		Derivative Liabilities Fair Value (2) (3)
		(in millions)
Natural gas contracts (1)	Current Assets	$	88	$	1
Natural gas contracts (1)	Other Assets	20		—
Natural gas contracts (1)	Current Liabilities	15		110
Natural gas contracts (1)	Other Liabilities	—		13
Indexed debt securities derivative	Current Liabilities	—		197
Total		$	123	$	321


(1)	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.


(2)	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 633 Bcf or a net 84 Bcf long position. Of the net long position, basis swaps constitute 74 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 6 Bcf.


(3)	The net of total non-trading derivative assets and liabilities is a $55 million asset as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $56 million.

Income Statement Impact of Derivative Activity



Income Statement Impact of Derivative Activity
		Year Ended December 31,
Total derivatives not designated as hedging instruments	Income Statement Location	2010			2011
		(in millions)
Natural gas contracts	Gains (Losses) in Revenue	$	90		$	102
Natural gas contracts (1)	Gains (Losses) in Expense: Natural Gas	(165		)	(144		)
Indexed debt securities derivative	Gains (Losses) in Other Income (Expense)	(31		)	35
Total		$	(106	)	$	(7	)


(1)	The Gains (Losses) in Expense: Natural Gas includes $(115) million and $(107) million of costs in 2010 and 2011, respectively, associated with price stabilization activities of the Natural Gas Distribution business segment that will be ultimately recovered through purchased gas adjustments.

Credit Quality of Counterparties

The following table shows the composition of counterparties to the non-trading derivative assets of CenterPoint Energy as of December 31, 2010 and 2011 (in millions):



	December 31, 2010				December 31, 2011
	Investment Grade(1)		Total		Investment Grade(1)		Total
Energy marketers	$	5	$	8	$	1	$	7
Financial institutions	1		1		—		—
Retail end users (2)	—		60		—		100
Total	$	6	$	69	$	1	$	107

(1)


(2)	Retail end users represent customers who have contracted to fix the price of a portion of their physical gas requirements for future periods.

- Definition

Tabular disclosure of the location and amount of gains and losses reported in the statement of financial performance, or when applicable, the statement of financial position. For example, (a) gains and losses recognized in the income statement on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges and (b) gains and losses initially recognized in other comprehensive income on derivative instruments designated and qualifying as cash flow hedges.

+ References + Details

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on a Recurring Basis



	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Netting Adjustments ⁽¹⁾			Balance at December 31, 2010
	(in millions)
Assets
Corporate equities	$	368	$	—	$	—	$	—		$	368
Investments, including money market funds	54		—		—		—			54
Natural gas derivatives	—		73		7		(11		)	69
Total assets	$	422	$	73	$	7	$	(11	)	$	491
Liabilities
Indexed debt securities derivative	$	—	$	232	$	—	$	—		$	232
Natural gas derivatives	8		167		4		(95		)	84
Total liabilities	$	8	$	399	$	4	$	(95	)	$	316


(1)	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $84 million posted with the same counterparties.



	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Netting Adjustments ⁽¹⁾			Balance at December 31, 2011
	(in millions)
Assets
Corporate equities	$	387	$	—	$	—	$	—		$	387
Investments, including money market funds	56		—		—		—			56
Natural gas derivatives	1		112		10		(16		)	107
Total assets	$	444	$	112	$	10	$	(16	)	$	550
Liabilities
Indexed debt securities derivative	$	—	$	197	$	—	$	—		$	197
Natural gas derivatives	19		101		4		(72		)	52
Total liabilities	$	19	$	298	$	4	$	(72	)	$	249


(1)	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $56 million posted with the same counterparties.

Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs



	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Derivative assets and liabilities, net
	Year Ended December 31,
	2009			2010			2011
	(in millions)
Beginning balance	$	(58	)	$	(6	)	$	3
Total unrealized gains or (losses):
Included in earnings	(1		)	4			6
Included in regulatory assets	(16		)	(1		)	—
Total settlements:
Included in earnings	3			(2		)	(3		)
Included in regulatory assets	66			8			—
Total purchases	—			—			2
Net transfers out of Level 3	—			—			(2		)
Ending balance	$	(6	)	$	3		$	6
The amount of total gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	$	1		$	4		$	5

Estimated Fair Value of Financial Instruments, Debt Instruments



	December 31, 2010				December 31, 2011
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(in millions)
Financial liabilities:
Long-term debt	$	9,303	$	10,071	$	8,994	$	10,049

- Definition

Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).

+ References + Details

- Definition

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.

+ References + Details

- Definition

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 14
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15
-Subparagraph b-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph a, c(1), c(2), c(3), d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph c(2), d, e, f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 19
-Subparagraph a, b, c(1), d(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 10
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-Topic 825
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6447952&loc=d3e13220-108610

+ Details

Indexed Debt Securities (ZENS) and Time Warner Securities (Tables)

12 Months Ended

Dec. 31, 2011

Indexed Debt Securities [Abstract]

Summarized Financial Information on Investment in Time Warner Securities and Indexed Debt Security Obligation



	TW Securities		Debt Component of ZENS			Derivative Component of ZENS
Balance at December 31, 2008	$	218	$	117		$	133
Accretion of debt component of ZENS	—		21			—
2% interest paid	—		(17		)	—
Loss on indexed debt securities	—		—			68
Gain on TW Common	82		—			—
Balance at December 31, 2009	300		121			201
Accretion of debt component of ZENS	—		22			—
2% interest paid	—		(17		)	—
Loss on indexed debt securities	—		—			31
Gain on TW Securities	67		—			—
Balance at December 31, 2010	367		126			232
Accretion of debt component of ZENS	—		22			—
2% interest paid	—		(17		)	—
Gain on indexed debt securities	—		—			(35		)
Gain on TW Securities	19		—			—
Balance at December 31, 2011	$	386	$	131		$	197

- Definition

Tabular disclosure of investments in certain debt and equity securities (and certain other trading assets) which include all debt and equity securities (other than those equity securities accounted for under the equity or cost methods of accounting) with readily determinable fair values. Other trading assets include assets that are carried on the balance sheet at fair value and held for trading purposes. A debt security represents a creditor relationship with an enterprise that is in the form of a security. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities (and other trading assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 3, 19, 20, 21, 22, 137
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 320
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-Paragraph 2
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-Name Accounting Standards Codification
-Topic 320
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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
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-Paragraph 10
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Debt Security
-URI http://asc.fasb.org/extlink&oid=6509901
-Topic 320

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Equity Security
-URI http://asc.fasb.org/extlink&oid=6511694
-Topic 320

+ Details

Short Term Borrowings and Long Term Debt (Tables)

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Schedule of Short-term Borrowings and Long-term Debt



	December 31, 2010					December 31, 2011
	Long-Term			Current(1)		Long-Term			Current(1)
	(in millions)
Short-term borrowings:
Inventory financing	$	—		$	53	$	—		$	62
Total short-term borrowings	—			53		—			62
Long-term debt:
CenterPoint Energy:
ZENS(2)	—			126		—			131
Senior notes 5.95% to 6.85% due 2015 to 2018	750			—		750			—
Pollution control bonds 4.00% due 2015(3)	151			—		151			—
Pollution control bonds 4.90% to 5.95% due 2015 to 2030(4) (5)	562			19		562			—
CenterPoint Houston:
First mortgage bonds 9.15% due 2021	102			—		102			—
General mortgage bonds 5.60% to 7.00% due 2013 to 2033	1,762			—		1,762			—
Pollution control bonds 3.625% to 5.60% due 2012 to 2027(6)	229			—		183			46
System restoration bonds 1.833% to 4.243% due 2012 to 2022	601			43		556			45
Transition bonds 4.192% to 5.63% due 2012 to 2020	1,921			240		1,659			262
CERC Corp.:
Senior notes 4.50% to 7.875% due 2013 to 2041 (7)	2,747			—		2,693			—
Commercial paper (8)	183			—		285			—
Other	1			—		1			—
Unamortized discount and premium	(8		)	—		(63		)	—
Total long-term debt	9,001			428		8,641			484
Total debt	$	9,001		$	481	$	8,641		$	546


(1)	Includes amounts due or exchangeable within one year of the date noted.


(2)	CenterPoint Energy’s ZENS obligation is bifurcated into a debt component and an embedded derivative component. For additional information regarding ZENS, see Note 9(b). As ZENS are exchangeable for cash at any time at the option of the holders, these notes are classified as a current portion of long-term debt.


(3)	These series of debt are secured by first mortgage bonds of CenterPoint Houston.


(4)	$237 million and $218 million of these series of debt were secured by general mortgage bonds of CenterPoint Houston at December 31, 2010 and 2011, respectively.


(5)	In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf which will remain outstanding and may be remarketed and called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf.


(6)	These series of debt are secured by general mortgage bonds of CenterPoint Houston.


(7)	$550 million senior notes due February 2011 are not reflected in the current portion of long-term debt as of December 31, 2010 because the notes were refinanced in January 2011.


(8)	Classified as long-term debt because the termination date of the facility that backstops the commercial paper is more than one year from the date noted.

Schedule of Revolving Credit Facilities and Utilization of Such Facilities

As of December 31, 2010 and 2011, CenterPoint Energy, CenterPoint Houston and CERC Corp. had the following revolving credit facilities and utilization of such facilities (in millions):



	December 31, 2010								December 31, 2011
	Size of Facility		Loans		Letters of Credit		Commercial Paper		Size of Facility		Loans		Letters of Credit		Commercial Paper
CenterPoint Energy	$	1,156	$	—	$	20	$	—	$	1,200	$	—	$	16	$	—
CenterPoint Houston	289		—		4		—		300		—		4		—
CERC Corp.	915		—		—		183		950		—		—		285
Total	$	2,360	$	—	$	24	$	183	$	2,450	$	—	$	20	$	285

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Income Tax Expense

The components of CenterPoint Energy’s income tax expense were as follows:



	Year Ended December 31,
	2009			2010			2011
	(in millions)
Current income tax expense (benefit):
Federal	$	(103	)	$	40		$	(63	)
State	10			24			24
Total current expense (benefit)	(93		)	64			(39		)
Deferred income tax expense (benefit):
Federal	251			220			432
State	18			(21		)	11
Total deferred expense	269			199			443
Total income tax expense	$	176		$	263		$	404

Reconciliation of Expected Federal Income Tax Expense to Actual

A reconciliation of the expected federal income tax expense using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows:



	Year Ended December 31,
	2009			2010			2011
	(in millions)
Income before income taxes and extraordinary item	$	548		$	705		$	1,174
Federal statutory income tax rate	35.00		%	35.00		%	35.00		%
Expected federal income tax expense	192			247			411
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	18			2			22
Amortization of investment tax credit	(7		)	(7		)	(6		)
Tax law change in deductibility of retiree health care costs	—			20			—
Increase (decrease) in settled and uncertain income tax positions	(5		)	14			(5		)
Other, net	(22		)	(13		)	(18		)
Total	(16		)	16			(7		)
Total income tax expense	$	176		$	263		$	404
Effective tax rate	32.1		%	37.3		%	34.4		%

Tax Assets and Liabilities

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows:



	December 31,
	2010			2011
	(in millions)
Deferred tax assets:
Current:
Allowance for doubtful accounts	$	11		$	10
Deferred gas costs	32			—
Other	21			7
Total current deferred tax assets	64			17
Non-current:
Loss and credit carryforwards	49			214
Employee benefits	346			363
Other	48			68
Total non-current deferred tax assets before valuation allowance	443			645
Valuation allowance	(3		)	(4		)
Total non-current deferred tax assets, net of valuation allowance	440			641
Total deferred tax assets, net of valuation allowance	504			658
Deferred tax liabilities:
Current:
Unrealized gain on indexed debt securities	391			427
Unrealized gain on TW securities	80			97
Total current deferred tax liabilities	471			524
Non-current:
Depreciation	2,086			2,849
Regulatory assets, net	1,256			1,499
Other	32			125
Total non-current deferred tax liabilities	3,374			4,473
Total deferred tax liabilities	3,845			4,997
Accumulated deferred income taxes, net	$	3,341		$	4,339

Rollforward of Unrecognized Tax Benefits

Uncertain Income Tax Positions. The following table reconciles the beginning and ending balance of CenterPoint Energy’s unrecognized tax benefits:



	December 31,
	2009			2010			2011
	(in millions)
Balance, beginning of year	$	117		$	187		$	252
Tax Positions related to prior years:
Additions	56			9			(1		)
Reductions	(25		)	(4		)	(203		)
Tax Positions related to current year:
Additions	56			60			5
Settlements	(17		)	—			(1		)
Lapse of statute of limitations	—			—			(1		)
Balance, end of year	$	187		$	252		$	51

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies Disclosure [Abstract]

Lease Commitments



2012	$	14
2013	9
2014	7
2015	4
2016	4
2017 and beyond	16
Total	$	54

- Definition

Tabular disclosure of a lessee's leasing arrangements including: (1) the basis on which contingent rental payments are determined, (2) the existence and terms of renewal or purchase options and escalation clauses, (3) restrictions imposed by lease arrangements, such as those concerning dividends, additional debt, and further leasing, (4) rent holidays, rent concessions, or leasehold improvement incentives and unusual provisions or conditions. Disclosure may also include the specific period used to amortize material leasehold improvements made at the inception of the lease or during the lease term. Additionally, for operating leases having initial or remaining noncancelable lease terms in excess of one year: (a) future minimum rental payments required as of the date of the latest balance sheet presented, in the aggregate and for each of the five succeeding fiscal years, (b) the total of minimum rentals to be received in the future under noncancelable subleases as of the date of the latest balance sheet presented, and (c) for all operating leases, rental expense for each period for which an income statement is presented, with separate amounts for minimum rentals, contingent rentals, and sublease rentals. Rental payments under leases with terms of a month or less that were not renewed need not be included.

+ References + Details

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Basic and Diluted Earnings Per Share

The following table reconciles numerators and denominators of CenterPoint Energy’s basic and diluted earnings per share calculations:



	For the Year Ended December 31,
	2009		2010		2011
	(in millions, except per share and share amounts)
Basic earnings per share calculation:
Income before extraordinary item	$	372	$	442	$	770
Extraordinary item, net of tax	—		—		587
Net income	$	372	$	442	$	1,357

Weighted average shares outstanding	365,229,000		409,721,000		425,636,000

Basic earnings per share:
Income before extraordinary item	$	1.02	$	1.08	$	1.81
Extraordinary item, net of tax	—		—		1.38
Net income	$	1.02	$	1.08	$	3.19

Diluted earnings per share calculation:
Net income	$	372	$	442	$	1,357

Weighted average shares outstanding	365,229,000		409,721,000		425,636,000
Plus: Incremental shares from assumed conversions:
Stock options ⁽¹⁾	451,000		470,000		347,000
Restricted stock	2,001,000		2,585,000		2,741,000
Weighted average shares assuming dilution	367,681,000		412,776,000		428,724,000

Diluted earnings per share:
Income before extraordinary item	$	1.01	$	1.07	$	1.80
Extraordinary item, net of tax	—		—		1.37
Net income	$	1.01	$	1.07	$	3.17


(1)	Options to purchase 2,372,132 and 1,458,598 shares were outstanding for the years ended December 31, 2009 and 2010, respectively, but were not included in the computation of diluted earnings per share because the options’ exercise price was greater than the average market price of the common shares for the respective years.

Unaudited Quarterly Information (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data

Summarized quarterly financial data is as follows:



	Year Ended December 31, 2010
	First Quarter ⁽²⁾		Second Quarter		Third Quarter		Fourth Quarter ⁽³⁾
	(in millions, except per share amounts)
Revenues	$	3,023	$	1,756	$	1,908	$	2,098
Operating income	357		263		327		302
Net income	114		81		123		124

Basic earnings per share(1)	$	0.29	$	0.20	$	0.29	$	0.29

Diluted earnings per share(1)	$	0.29	$	0.20	$	0.29	$	0.29



	Year Ended December 31, 2011
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(in millions, except per share amounts)
Revenues	$	2,587	$	1,837	$	1,881	$	2,145
Operating income	364		303		357		274
Income before extraordinary item(4)	148		119		386		117
Extraordinary item, net of tax(4)	—		—		587		—
Net income	$	148	$	119	$	973	$	117

Basic earnings per share(1):
Income before extraordinary item	$	0.35	$	0.28	$	0.90	$	0.27
Extraordinary item, net of tax	—		—		1.38		—
Net income	$	0.35	$	0.28	$	2.28	$	0.27

Diluted earnings per share(1)
Income before extraordinary item	$	0.35	$	0.28	$	0.90	$	0.27
Extraordinary item, net of tax	—		—		1.37		—
Net income	$	0.35	$	0.28	$	2.27	$	0.27


(1)	Quarterly earnings per common share are based on the weighted average number of shares outstanding during the quarter, and the sum of the quarters may not equal annual earnings per common share.


(2)	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.


(3)	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.


(4)	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).

Reportable Business Segments (Tables)

12 Months Ended

Dec. 31, 2011

Segment Reporting [Abstract]

Financial Data for Business Segments

Financial data for business segments and products and services are as follows (in millions):



	Revenues from External Customers			Intersegment Revenues			Depreciation and Amortization		Operating Income		Total Assets				Expenditures for Long-Lived Assets
As of and for the year ended December 31, 2009:
Electric Transmission & Distribution	$	2,013	(1)	$	—		$	480	$	545	$	9,755			$	428
Natural Gas Distribution	3,374			10			161		204		4,535				165
Competitive Natural Gas Sales and Services	2,215			15			4		21		1,176				2
Interstate Pipelines(2)	456			142			48		256		3,484				176
Field Services(3)	212			29			15		94		1,045				348
Other	11			—			35		4		2,261			(4)	29
Reconciling Eliminations	—			(196		)	—		—		(2,483		)		—
Consolidated	$	8,281		$	—		$	743	$	1,124	$	19,773			$	1,148
As of and for the year ended December 31, 2010:
Electric Transmission & Distribution	$	2,205	(1)	$	—		$	582	$	567	$	9,817			$	463
Natural Gas Distribution	3,199			14			166		231		4,575				202
Competitive Natural Gas Sales and Services	2,617			34			4		16		1,190				2
Interstate Pipelines(2)	464			137			52		270		3,672				102
Field Services(3)	289			49			25		151		1,803				668
Other	11			—			35		14		2,184			(4)	25
Reconciling Eliminations	—			(234		)	—		—		(3,130		)		—
Consolidated	$	8,785		$	—		$	864	$	1,249	$	20,111			$	1,462
As of and for the year ended December 31, 2011:
Electric Transmission & Distribution	$	2,337	(1)	$	—		$	587	$	623	$	11,221			$	538
Natural Gas Distribution	2,823			18			166		226		4,636				295
Competitive Natural Gas Sales and Services	2,488			23			5		6		1,089				5
Interstate Pipelines(2)	421			132			54		248		3,867				98
Field Services(3)	370			42			37		189		1,894				201
Other	11			—			37		6		2,318			(4)	54
Reconciling Eliminations	—			(215		)	—		—		(3,322		)		—
Consolidated	$	8,450		$	—		$	886	$	1,298	$	21,703			$	1,191

(1)

(2)

(3)


(4)	Included in total assets of Other Operations as of December 31, 2009, 2010 and 2011, are pension and other postemployment related regulatory assets of $731 million, $704 million and $796 million, respectively.

Revenues by Products and Services



	Year Ended December 31,
Revenues by Products and Services:	2009		2010		2011
	(in millions)
Electric delivery sales	$	2,013	$	2,205	$	2,337
Retail gas sales	4,540		4,412		4,019
Wholesale gas sales	902		1,250		1,149
Gas transport	691		785		824
Energy products and services	135		133		121
Total	$	8,281	$	8,785	$	8,450

- Definition

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

+ References + Details

Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Significant Accounting Policies [Line Items]
Minimum ownership interest percentage for investments recorded using the equity method (in hundredths)	20.00%
Maximum ownership interest percentage for investments recorded using the equity method (in hundredths)	50.00%
Length of Southeast Supply Header's interstate natural gas pipeline (in miles)	274
Investment during the period in Southeast Supply Header, LLC			$ 137
Capital distribution received during the period from Southeast Supply Header, LLC			23
Investment during the period in Waskom		$ 20
Number of consolidated variable interest entities	5
Amount of removal costs recognized as a component of depreciation expense recorded as a regulatory liability	$ 912	868
Amount of capitalized interest and allowance for funds used during construction	4	9	5
Allowance for doubtful accounts	25	25
Provision for doubtful accounts	26	30	$ 36
Write-Downs of Natural Gas Inventory to Lower of Cost or Market	11	6
Materials and supplies	166	164
Natural gas	187	211
Total inventory	$ 353	375
Maximum number of months from date of purchase to maturity to be classified as cash equivalent (in months)	P3M
Restricted cash accounts	$ 42	39
Amount of cash and cash equivalents that is held by transition and system restoration bond subsidiaries solely to support servicing the transition and system restoration bonds.	$ 220	$ 198
Southeast Supply Header, LLC [Member]
Significant Accounting Policies [Line Items]
Percentage of ownership interest	50.00%
Waskom Gas Processing Company [Member]
Significant Accounting Policies [Line Items]
Percentage of ownership interest	50.00%

Property, Plant and Equipment (Details) $ in Millions	12 Months Ended
Property, Plant and Equipment (Details) $ in Millions	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 16,868	$ 16,005
Total accumulated depreciation and amortization	4,466	4,273
Property, plant and equipment, net	12,402	11,732
Depreciation and amortization [Abstract]
Depreciation expense	529	531	$ 496
Amortization expense	357	333	247
Total depreciation and amortization expense	886	864	743
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	84	82
Accretion expense	5	5
Revisions in estimates of cash flows	67	(3)
Ending balance	156	84	$ 82
Revisions in estimates of cash flows	67	(3)
Electric Transmission and Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	7,827	7,586
Total accumulated depreciation and amortization	$ 2,784	2,805
Property, plant and equipment, useful life, weighted average (in years)	29
Natural Gas Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 3,959	3,642
Total accumulated depreciation and amortization	$ 1,069	954
Property, plant and equipment, useful life, weighted average (in years)	32
Competitive Natural Gas Sales and Services [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 76	71
Total accumulated depreciation and amortization	$ 20	16
Property, plant and equipment, useful life, weighted average (in years)	27
Interstate Pipelines [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 2,675	2,594
Total accumulated depreciation and amortization	$ 302	265
Property, plant and equipment, useful life, weighted average (in years)	57
Field Services [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 1,754	1,583
Total accumulated depreciation and amortization	$ 72	43
Property, plant and equipment, useful life, weighted average (in years)	46
Other property [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 577	529
Total accumulated depreciation and amortization	$ 219	$ 190
Property, plant and equipment, useful life, weighted average (in years)	24

Goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Goodwill Reporting Information [Line Items]
Goodwill	$ 1,696	$ 1,696
Natural Gas Distribution [Member]
Goodwill Reporting Information [Line Items]
Goodwill	746	746
Interstate Pipelines [Member]
Goodwill Reporting Information [Line Items]
Goodwill	579	579
Competitive Natural Gas Sales and Services [Member]
Goodwill Reporting Information [Line Items]
Goodwill	335	335
Field Services [Member]
Goodwill Reporting Information [Line Items]
Goodwill	25	25
Other Operations [Member]
Goodwill Reporting Information [Line Items]
Goodwill	$ 11	$ 11

- Definition

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph e
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 43
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 68
-Subparagraph l
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6905597&loc=d3e13816-109267

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 72
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph e
-Clause 1
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Regulatory Matters (Regulatory Assets and Liabilities) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

$ 4,619

$ 3,446

Total regulatory liabilities

1,039

989

Total regulatory assets and liabilities, net

3,580

2,457

Amount of allowed equity return on the true-up balance that has not been recognized

600

Amount of allowed equity return on the true-up balance that was recognized in the period

$ 14

Amount of pension and postemployment benefits deferred as regulatory asset

Remaining amounts of regulatory assets for which no return on investment during recovery period is provided

Securitized regulatory asset [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

2,289

2,597

True-up Settlement [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

^[1]

1,684

Unrecognized equity return [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

^[2]

(600)

(216)

Unamortized loss on reacquired debt [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

Pension and rostretirement-related regulatory asset [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

^[3]

975

838

Other long-term regulatory assets [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory assets

^[4]

215

166

Estimated removal costs [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory liabilities

912

868

Other long-term regulatory liabilities [Member]

Schedule of Regulatory Assets and Liabilities [Line Items]

Total regulatory liabilities

$ 127

$ 121

[1]	In accordance with a final order from the Public Utility Commission of Texas, (Texas Utility Commission), the true-up settlement at December 31, 2011 was not earning a return. The regulatory asset was securitized in January 2012 as a result of the issuance of the transition bonds described below in Note 5(b).
[2]	As of December 31, 2011, CenterPoint Energy has not recognized an allowed equity return of $600 million because such return will be recognized as it is recovered in rates. During the years ended December 31, 2009, 2010 and 2011, CenterPoint Houston recognized approximately $14 million, $16 million and $21 million, respectively, of the allowed equity return.
[3]	CenterPoint Houston’s actuarially determined pension expense for 2010 and 2011 in excess of the amount being recovered through rates is being deferred for rate making purposes and was addressed in its 2010 rate application pursuant to Texas law. CenterPoint Houston deferred as a regulatory asset $26 million and $16 million in pension and other postemployment expenses during the years ended December 31, 2010 and 2011, respectively. Deferred pension and other postemployment expenses of $58 million and $16 million at December 31, 2010 and 2011, respectively, were not earning a return.
[4]	Other regulatory assets that are not earning a return were not material at December 31, 2010 and 2011.

Regulatory Matters (Resolution of True-Up Appeal) (Details) $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Jan. 31, 2012 USD ($) tranches	Dec. 31, 2005 USD ($)	Sep. 30, 2011 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2004 USD ($)	Mar. 31, 2004 USD ($)
Subsequent Event [Line Items]
Initial amount of true-up application								$ 3,700.0
Amount awarded in final true-up order by the Texas Utility Commission							$ 2,300.0
Net after-tax extraordinary gain (loss)		$ (947.0)	$ 587.0
Additional Amount Allowed By District Court On True Up Appeal			1,695.0
Extraordinary Item, Gain (Loss), Gross			921.0
Tax Effect of Extraordinary Item, Gain (Loss)			334.0
Return on true-up balance			352.0	$ 352.0	$ 0.0	$ 0.0
Return on True-Up Balance after tax			$ 224.0
Equity Return portion of Recoverable True-Up Balance pre-tax				405.0
Equity Return portion of Recoverable True-Up Balance after-tax				$ 258.0
Issuance of Debt [Member] \| Bond Company IV [Member]
Subsequent Event [Line Items]
Transition bonds issued to recover true-up costs	$ 1,695.0
Number of tranches of transition bonds \| tranches	3
Minimum interest rate on transition bonds	0.9012%
Maximum interest rate on transition bonds	3.0282%
Offering expenses	$ 10.4

Regulatory Matters (Rate Proceedings) (Details) $ in Millions	1 Months Ended											9 Months Ended	12 Months Ended
	Nov. 30, 2011 USD ($)	Oct. 31, 2011 USD ($)	Aug. 31, 2011 USD ($)	Apr. 30, 2011 USD ($)	Feb. 28, 2011 USD ($)	Nov. 30, 2010 USD ($)	Apr. 30, 2010 USD ($)	Feb. 28, 2010 USD ($)	Oct. 31, 2009 USD ($)	Jul. 31, 2009 USD ($)	May 31, 2009 USD ($)	Sep. 30, 2011	Dec. 31, 2008 USD ($)	Jan. 31, 2010	Mar. 31, 2008
Regulated Operations [Abstract]
Amount of approved base rate increase per year					$ 14.7
Amount of approved decrease on charges to wholesale transmission customers					$ 12.3
Approved rate of return on equity (in hundredths)					10.00%
Approved cost of debt (in hundredths)					6.74%
Approved percentage of capital structure based on equity (in hundredths)					55.00%
Approved percentage of capital structure based on long-term debt (in hundredths)					45.00%
Approved percentage of overall rate of return (in hundredths)					8.21%
Original term of the residential AMS surcharge (in years)					12
Approved reduction in duration of residential AMS surcharge related to the reconciliation plan (in years)					6
AMS rate base used to determine AMS surcharge, transferred to CentPoint Houston's rate base					$ 138.0
Estimated reduction in annual operating income					$ 35.0
Amount of 2010 energy efficiency program costs submitted for reimbursement											$ 10.0
Amount of partial performance bonus approved by the Texas Utility Commission related to 2010 energy efficiency program									$ 8.0
Amount of bonus on 2008 energy efficiency program costs disallowed									2.0
Amount of 2008 energy efficiency program costs submitted for reimbursement									$ 10.0
Approximate amount of costs related to various energy efficiency programs							$ 14.4
Amount of partial performance bonus approved by the Texas Utility Commission related to 2011 energy efficiency program						$ 11.0
Portion of requested amount excluded from recovery which relates to performance bonus						2.0
Portion of requested amount excluded from recovery as relates to lost revenues						$ 1.4
Total amount of application seeking approval of recovery of various costs				$ 44.3
Portion of application seeking recovery of energy efficiency program costs				35.9
Portion of application seeking an energy efficiency performance bonus based on 2010 program achievements				5.8
Portion of application seeking recovery of lost revenues due to verified and reported 2010 energy savings				2.2
Portion of application seeking for under-recovery of 2010 program costs				0.5
Amount excluded from performance bonus for prior year's program				$ 2.1
Lost Revenues associated with 2010 programs			$ 2.2
Energy Efficiency Costs			35.9
Energy Efficiency Performance Bonus			3.6
Under Recovery of 2010 Program Costs			0.5
Tranmission Cost of Service Annual Revenue Increase	$ 7.1		$ 3.4
Number of DCRF requests allowed per year												1
Number of DCRF filings allowed												4
Payment under Transmission Stipulation		$ 5.6
Number of days after issuance of final appealable order payment made		30
Regulatory Assets [Line Items]
Number of cities in Texas Coast service area (in number of cities)															47
Approximate number of customers in cities and communities on the outskirts of Houston (in number of customers)															230,000
Increase in annual revenues from approved rate increases for gas operations in Texas Coast service area													$ 3.5
Number of cities that contested the new rates in the Texas Coast service area (in number of cities)														9
Number of years COSA initially effective					3
Automatic Renewal period for COSA					3
Number of cities in Houston service area (in number of cities)										29
Approximate number of customers in and around Houston (in number of customers)										940,000
Proposed increase in annual revenues from gas operations in Houston service area										$ 20.4
Amount of carrying costs of gas inventory excluded from rate increase										$ 2.0
Amount of approved annual revenue increase in gas operations in the Houston area								$ 5.1
Approved amount of surcharge in gas operations to recover Hurricane Ike costs								$ 0.9
Number of years for the surcharge to recover Hurricane Ike costs (in years)								3

Regulatory Matters (Southeast Supply Header LLC) (Details) - Southeast Supply Header, LLC [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2010
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage (in hundredths)		50.00%
Length of the interstate natural gas pipeline (in miles)		274
Pre-tax charges December 31, 2010	$ (16)
Tax Benefit	$ 6

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Stock Based Incentive Compensation) (Details) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Years $ / shares shares	Dec. 31, 2010 USD ($) $ / shares shares	Dec. 31, 2009 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under long-term incentive plans (in shares) \| shares	14,000
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Income tax benefit recognized related to LTIPs \| $	$ 7	$ 6	$ 6
Actual tax benefit realized for tax deductions related to LTIPs \| $	$ 8	$ 5	$ 6
Vesting period (in years)	three-year
Dividends declared during the vesting period (in dollars per share)	$ 2.37	$ 2.34	$ 2.28
Changes in shares outstanding under all long-term incentive plans, additional disclosures [Abstract]
Cash received from options exercised \| $	$ 5	$ 9	$ 4
Summary of nonvested shares [Roll Forward]
Weighted average period of recognition (in years) \| Years	1.7
Unrecognized compensation cost related to non-vested performance and stock awards \| $	$ 18
Total grant date fair values of performance and stock awards which vested during the period \| $	$ 12	$ 10	11
Stock Options [Member]
Changes in shares outstanding under all long-term incentive plans, additional disclosures [Abstract]
Number of options outstanding, beginning balance (in shares) \| shares	3,077
Number of options expired (in shares) \| shares	(1,417)
Number of options cancelled (in shares) \| shares	(31)
Number of options exercised (in shares) \| shares	(664)
Number of options outstanding, ending balance (in shares) \| shares	965	3,077
Number of exercisable options (in shares) \| shares	965
Weighted average exercise price per option, outstanding, beginning of period (in dollars per share)	$ 19.27
Weighted average exercise price per option expired (in dollars per share)	31.70
Weighted average exercise price per option cancelled (in dollars per share)	31.98
Weighted average exercise price per option exercised (in dollars per share)	8.13
Weighted average exercise price per option, outstanding, end of period (in dollars per share)	8.28	$ 19.27
Weighted average exercise price per exercisable option (in dollars per share)	$ 8.28
Remaining average contractual life of options outstanding (in years) \| Years	1.40
Remaining average contractual life of exercisable options (in years) \| Years	1.40
Aggregate intrinsic value of options outstanding \| $	$ 11
Aggregate intrinsic value of exercisable options \| $	11
Summary of nonvested shares [Roll Forward]
Total intrinsic value of stock options exercised in the period \| $	$ 7	$ 4	$ 2
Performance Awards [Member]
Summary of nonvested shares [Roll Forward]
Nonvested, beginning of period (in shares) \| shares	3,068
Granted (in shares) \| shares	1,110
Forfeited or cancelled (in shares) \| shares	(469)
Vested and released to participants (in shares) \| shares	(411)
Nonvested, end of period (in shares) \| shares	3,298	3,068
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)	$ 13.84
Weighted average grant date fair values of awards granted (in dollars per share)	15.49	$ 14.21	$ 12.42
Weighted average grant date fair value, forfeited or cancelled (in dollars per share)	15.25
Weighted average grant date fair value, vested and released to participants (in dollars per share)	15.39
Weighted average grant date fair value, nonvested, end of period (in dollars per share)	$ 13.99	$ 13.84
Remaining average contractual life of nonvested shares outstanding (in years) \| Years	1.0
Aggregate intrinsic value of non-vested shares outstanding \| $	$ 55
Total intrinsic value of awards vested in the period \| $	$ 7	$ 5	$ 7
Weighted average grant date fair values of awards granted (in dollars per share)	$ 15.49	$ 14.21	$ 12.42
Stock Awards [Member]
Summary of nonvested shares [Roll Forward]
Nonvested, beginning of period (in shares) \| shares	1,096
Granted (in shares) \| shares	368
Forfeited or cancelled (in shares) \| shares	(30)
Vested and released to participants (in shares) \| shares	(369)
Nonvested, end of period (in shares) \| shares	1,065	1,096
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)	$ 13.78
Weighted average grant date fair values of awards granted (in dollars per share)	15.81	$ 14.26	$ 12.30
Weighted average grant date fair value, forfeited or cancelled (in dollars per share)	14.00
Weighted average grant date fair value, vested and released to participants (in dollars per share)	14.75
Weighted average grant date fair value, nonvested, end of period (in dollars per share)	$ 14.14	$ 13.78
Remaining average contractual life of nonvested shares outstanding (in years) \| Years	1.1
Aggregate intrinsic value of non-vested shares outstanding \| $	$ 21
Total intrinsic value of awards vested in the period \| $	$ 7	$ 4	$ 4
Weighted average grant date fair values of awards granted (in dollars per share)	$ 15.81	$ 14.26	$ 12.30
Operation And Maintenance Expense Member
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
LTIP compensation expense \| $	$ 19	$ 17	$ 15
Inventory or Fixed Assets [Member]
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
LTIP compensation expense \| $	$ 0	$ 0	$ 0

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Pension and Postretirement Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension and Postretirement Benefits [Abstract]
New percentage of eligible earnings used to determine retirement benefits (in hundredths)	5.00%
Old percentage of eligible earnings used to determine retirement benefits (in hundredths)	4.00%
Percent vested	100.00%
Pension plan minimum vesting period (in years)	three
Approximate amortization period of transition obligation (in years)	20 years
Change in plan assets [Rollforward]
Fair value of plan assets at beginning of year	$ 1,501
Fair value of plan assets at end of year	1,506	$ 1,501
Amounts recognized in balance sheets
Other liabilities-benefit obligations	(1,065)	(906)
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Accumulated benefit obligation for all defined benefit pension plans	$ 2,064	1,954
Annualized individual discount rates based on time period, minimum	6 months
Annualized individual discount rates based on time period, maximum	99 years
Effect of a one-percentage point change in assumed health care cost trend rates
Effect of a one-percentage point increase on total service and interest cost	$ 1
Effect of a one-percentage point decrease on total service and interest cost	1
Effect of a one-percentage point increase on post-retirement benefit obligation	18
Effect of a one-percentage point decrease on post-retirement benefit obligation	16
Pension Plan [Member]
Components of net periodic costs [Abstract]
Service cost	33	31	$ 25
Interest cost	100	102	113
Expected return on plan assets	(115)	(109)	(98)
Amortization of prior service cost	3	3	3
Amortization of net loss	57	59	68
Amortization of transition obligation	0	0	0
Benefit enhancement	0	0	0
Net periodic cost	$ 78	$ 86	$ 111
Assumptions used to determine net periodic benefit (income) cost
Discount rate (in hundredths)	5.25%	5.70%	6.90%
Expected return on plan assets (in hundredths)	8.00%	8.00%	8.00%
Rate of increase in compensation levels (in hundredths)	4.60%	4.60%	4.60%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	$ 1,969	$ 1,866
Service Cost	33	31
Interest Cost	100	102
Participant contributions	0	0
Benefits paid	(113)	(115)
Actuarial loss	93	85
Early retiree reinsurance program reimbursement	0	0
Medicare reimbursement	3	0
Benefit obligation at end of year	2,085	1,969	$ 1,866
Change in plan assets [Rollforward]
Fair value of plan assets at beginning of year	1,501	1,432
Employer contributions	75	8
Participant contributions	0	0
Benefits paid	(113)	(115)
Actual investment return	43	176
Fair value of plan assets at end of year	1,506	1,501	1,432
Funded status of plan
Funded status at end of year	(579)	(468)
Amounts recognized in balance sheets
Current liabilities - other	(9)	(9)
Other liabilities-benefit obligations	(570)	(459)
Net liability, end of year	$ (579)	$ (468)
Actuarial Assumptions [Abstract]
Discount rate (in hundredths)	4.90%	5.25%
Expected return on plan assets (in hundredths)	8.00%	8.00%
Rate of increase in compensation levels (in hundredths)	4.20%	4.60%
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care costs trend rate assumed for next year (in hundredths)	0.00%	0.00%
Healthcare and prescription drug cost trend rate assumed for next year (in hundredths)	0.00%	0.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) (in hundredths)	0.00%	0.00%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss	$ 166	$ 151
Unrecognized prior service cost	15	15
Unrecognized transition obligation	0	0
Net amount recognized in accumulated other comprehensive loss	181	166
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss	2
Amortization of net loss	13
Prior service credit	(1)
Amortization of prior service credit	1
Transition obligation	0
Total recognized in comprehensive income	15
Total expense recognized in net periodic cost and other comprehensive income	93
Amounts that will be amortized from accumulated other comprehensive loss in next fiscal year
Unrecognized actuarial loss	13
Unrecognized prior service cost	1
Amounts in comprehensive income to be recognized in net periodic cost in 2012	$ 14
Weighted average target allocations
Domestic equity securities, minimum (in hundredths)	21.00%
Domestic equity securities, maximum (in hundredths)	31.00%
Global equity securities, minimum (in hundredths)	7.00%
Global equity securities, maximum (in hundredths)	13.00%
International equity securities, minimum (in hundredths)	15.00%
International equity securities, maximum (in hundredths)	21.00%
Emerging market equity securities, minimum (in hundredths)	4.00%
Emerging market equity securities, maximum (in hundredths)	8.00%
Debt securities, minimum (in hundredths)	30.00%
Debt securities, maximum (in hundredths)	40.00%
Real Estate, minimum (in hundredths)	0.00%
Real Estate, maximum (in hundredths)	5.00%
Cash, minimum (in hundredths)	0.00%
Cash, maximum (in hundredths)	2.00%
Pension Plan [Member] \| Qualified Pension Plan [Member]
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	$ 1,966	1,860
Projected benefit obligation	1,987	1,875
Fair value of plan assets	1,506	1,501
Pension Plan [Member] \| Non-qualified Pension Plan [Member]
Pension benefits that have accumulated benefit obligations in excess of plan assets
Accumulated benefit obligation	98	94
Projected benefit obligation	98	94
Fair value of plan assets	0	0
Postretirement Benefits [Member]
Components of net periodic costs [Abstract]
Service cost	1	1	1
Interest cost	24	25	28
Expected return on plan assets	(10)	(10)	(9)
Amortization of prior service cost	3	3	3
Amortization of net loss	1	0	0
Amortization of transition obligation	7	7	7
Benefit enhancement	1	0	0
Net periodic cost	$ 27	$ 26	$ 30
Assumptions used to determine net periodic benefit (income) cost
Discount rate (in hundredths)	5.20%	5.70%	6.90%
Expected return on plan assets (in hundredths)	7.05%	7.05%	7.05%
Rate of increase in compensation levels (in hundredths)	0.00%	0.00%	0.00%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	$ 460	$ 450
Service Cost	1	1
Interest Cost	24	25
Participant contributions	7	7
Benefits paid	(40)	(50)
Actuarial loss	41	24
Early retiree reinsurance program reimbursement	3	0
Medicare reimbursement	4	3
Benefit obligation at end of year	500	460	$ 450
Change in plan assets [Rollforward]
Fair value of plan assets at beginning of year	144	146
Employer contributions	21	29
Participant contributions	7	7
Benefits paid	(40)	(50)
Actual investment return	6	12
Fair value of plan assets at end of year	138	144	$ 146
Funded status of plan
Funded status at end of year	(362)	(316)
Amounts recognized in balance sheets
Current liabilities - other	(9)	(9)
Other liabilities-benefit obligations	(353)	(307)
Net liability, end of year	$ (362)	$ (316)
Actuarial Assumptions [Abstract]
Discount rate (in hundredths)	4.80%	5.20%
Expected return on plan assets (in hundredths)	5.50%	7.05%
Rate of increase in compensation levels (in hundredths)	0.00%	0.00%
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care costs trend rate assumed for next year (in hundredths)	8.00%	8.50%
Healthcare and prescription drug cost trend rate assumed for next year (in hundredths)	8.00%	8.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) (in hundredths)	5.50%	5.50%
Year that healthcare rate reaches the ultimate trend rate	2017	2017
Year that prescription drug rate reaches the ultimate trend rate	2017	2017
Prescription drug cost trend rate assumed for 2013 (in hundreths)	9.00%
Amounts recognized in accumulated other comprehensive loss
Unrecognized actuarial loss	$ 25	$ 18
Unrecognized prior service cost	5	7
Unrecognized transition obligation	1	2
Net amount recognized in accumulated other comprehensive loss	31	$ 27
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net loss	7
Amortization of net loss	0
Prior service credit	(4)
Amortization of prior service credit	2
Transition obligation	(1)
Total recognized in comprehensive income	4
Total expense recognized in net periodic cost and other comprehensive income	31
Amounts that will be amortized from accumulated other comprehensive loss in next fiscal year
Unrecognized actuarial loss	1
Unrecognized prior service cost	2
Amounts in comprehensive income to be recognized in net periodic cost in 2012	$ 3
Weighted average target allocations
Domestic equity securities, minimum (in hundredths)	14.00%
Domestic equity securities, maximum (in hundredths)	24.00%
Global equity securities, minimum (in hundredths)	0.00%
Global equity securities, maximum (in hundredths)	0.00%
International equity securities, minimum (in hundredths)	3.00%
International equity securities, maximum (in hundredths)	13.00%
Emerging market equity securities, minimum (in hundredths)	0.00%
Emerging market equity securities, maximum (in hundredths)	0.00%
Debt securities, minimum (in hundredths)	68.00%
Debt securities, maximum (in hundredths)	78.00%
Real Estate, minimum (in hundredths)	0.00%
Real Estate, maximum (in hundredths)	0.00%
Cash, minimum (in hundredths)	0.00%
Cash, maximum (in hundredths)	2.00%

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Plan Assets) (Details)
$ in Millions

12 Months Ended

Dec. 31, 2011

USD ($)

Dec. 31, 2010

USD ($)

Dec. 31, 2009

USD ($)

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

$ 1,506

$ 1,501

Percentage of investment in common collective funds allocated to fixed income securities (in hundredths)

39.00%

24.00%

Percentage of investment in common collective funds allocated to U.S. equities (in hundredths)

30.00%

42.00%

Percentage of investment in common collective funds allocated to international equities (in hundredths)

31.00%

34.00%

Percentage of investment in mutual funds allocated to international equities

75.00%

Percentage of investment in mutual funds allocated to fixed income securities (in hundredths)

74.00%

Percentage of investment in mutual funds allocated to U.S. equities (in hundredths)

25.00%

26.00%

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Percentage of investment in mutual funds allocated to fixed income securities under the postretirement plan (in hundredths)

73.00%

Percentage of investment in mutual funds allocated to U.S. equity securities under the postretirement plan (in hundredths)

19.00%

Percentage of investment in mutual funds allocated to international equity securities under the postretirement plan (in hundredths)

8.00%

Savings Plan [Abstract]

Maximum percentage of eligible compensation employees may contribute to the savings plan (in hundredths)

50.00%

Percentage of employer match under the savings plan (in hundredths)

100% of the first 6% of each employee’s compensation contributed

Number of Common stock held by the savings plan (in shares) | shares

19,732,131

Percentage of investment in common stocks (in hundredths)

24.00%

Savings plan benefit expense

$ 35

$ 34

$ 31

Postemployment Benefits [Abstract]

Postemployment benefit income (expense)

(7)

Postemployment benefit obligations

Other Non-Qualified Plans [Abstract]

Benefit expense related to deferred compensation plans

Other non-qualified plans benefit obligations deferred compensation

Benefit obligations related to split-dollar life insurance arrangements

$ 25

Maximum number of times annual base salary included in severance benefits for certain officers in a change of control (in number of times)

Length of agreements including severance benefits (in years)

one-year

Cash [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

$ (11)

Common Collective Trust Funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

973

^[1]

890

^[2]

Corporate bonds rated Investment grade or higher [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

129

122

International equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

128

133

U.S. equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

131

Cash received as collateral from securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

112

U.S. government back agencies bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

U.S. treasuries [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Mortgage backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Asset backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Municipal bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[3]

^[4]

International government bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Real estate [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Obligation to return cash received as collateral from securities lending [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

(69)

(112)

Fair Value, Inputs, Level 1 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

318

418

Fair Value, Inputs, Level 1 [Member] | Cash [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

(11)

Fair Value, Inputs, Level 1 [Member] | Common Collective Trust Funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[1]

^[2]

Fair Value, Inputs, Level 1 [Member] | Corporate bonds rated Investment grade or higher [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | International equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

128

133

Fair Value, Inputs, Level 1 [Member] | U.S. equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

131

Fair Value, Inputs, Level 1 [Member] | Cash received as collateral from securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

112

Fair Value, Inputs, Level 1 [Member] | U.S. government back agencies bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | U.S. treasuries [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Mortgage backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Asset backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Municipal bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[3]

^[4]

Fair Value, Inputs, Level 1 [Member] | International government bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Real estate [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 1 [Member] | Obligation to return cash received as collateral from securities lending [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

(69)

(112)

Fair Value, Inputs, Level 2 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

1,180

1,075

Fair Value, Inputs, Level 2 [Member] | Cash [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Common Collective Trust Funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

973

^[1]

890

^[2]

Fair Value, Inputs, Level 2 [Member] | Corporate bonds rated Investment grade or higher [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

129

122

Fair Value, Inputs, Level 2 [Member] | International equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | U.S. equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Cash received as collateral from securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | U.S. government back agencies bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | U.S. treasuries [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Mortgage backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Asset backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Municipal bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[3]

^[4]

Fair Value, Inputs, Level 2 [Member] | International government bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Real estate [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 2 [Member] | Obligation to return cash received as collateral from securities lending [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Cash [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Common Collective Trust Funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[1]

^[2]

Fair Value, Inputs, Level 3 [Member] | Corporate bonds rated Investment grade or higher [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | International equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | U.S. equities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Cash received as collateral from securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | U.S. government back agencies bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | U.S. treasuries [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Mortgage backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Asset backed securities [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Municipal bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[3]

^[4]

Fair Value, Inputs, Level 3 [Member] | International government bonds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Real estate [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Fair Value, Inputs, Level 3 [Member] | Obligation to return cash received as collateral from securities lending [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Pension Plan [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

1,506

1,501

1,432

Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]

Pension benefit payments 2012

124

Pension benefit payments 2013

135

Pension benefit payments 2014

143

Pension benefit payments 2015

147

Pension benefit payments 2016

145

Postretirement benefit payments 2017 - 2021

791

Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Balance, beginning of year

Unrealized losses relating to instruments still held at the reporting date

(1)

Purchases, sales, issuances, and settlement (net)

(1)

Transfer out of Level 3

(3)

Balance, end of year

Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate bonds rated Investment grade or higher [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Balance, beginning of year

Unrealized losses relating to instruments still held at the reporting date

Purchases, sales, issuances, and settlement (net)

Transfer out of Level 3

(1)

Balance, end of year

Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Asset backed securities [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Balance, beginning of year

Unrealized losses relating to instruments still held at the reporting date

Purchases, sales, issuances, and settlement (net)

(1)

Transfer out of Level 3

(2)

Balance, end of year

Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Real estate [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Balance, beginning of year

Unrealized losses relating to instruments still held at the reporting date

(1)

Purchases, sales, issuances, and settlement (net)

Transfer out of Level 3

Balance, end of year

Postretirement Benefits [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

138

144

$ 146

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Total contributions to the plans during the period

Estimated future contributions in the next fiscal year

Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]

Postretirement benefit payments 2012

Postretirement benefit payments 2013

Postretirement benefit payments 2014

Postretirement benefit payments 2015

Postretirement benefit payments 2016

Postretirement benefit payments 2017 - 2021

228

Medicare subsidy receipts - 2012

(4)

Medicare subsidy receipts - 2013

(5)

Medicare subsidy receipts - 2014

(5)

Medicare subsidy receipts - 2015

(6)

Medicare subsidy receipts - 2016

(6)

Medicare subsidy receipts - 2017 - 2021

(41)

Postretirement Benefits [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

138

^[5]

144

^[6]

Postretirement Benefits [Member] | Fair Value, Inputs, Level 1 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

138

144

Postretirement Benefits [Member] | Fair Value, Inputs, Level 1 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

138

^[5]

144

^[6]

Postretirement Benefits [Member] | Fair Value, Inputs, Level 2 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Postretirement Benefits [Member] | Fair Value, Inputs, Level 2 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[5]

^[6]

Postretirement Benefits [Member] | Fair Value, Inputs, Level 3 [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

Postretirement Benefits [Member] | Fair Value, Inputs, Level 3 [Member] | Mutual funds [Member]

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]

Pension plan assets, fair value

^[5]

$ 0

^[6]

Qualified Pension Plan [Member] | Pension Plan [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Total contributions to the plans during the period

Estimated future contributions in the next fiscal year

116

Non-qualified Pension Plan [Member] | Pension Plan [Member]

Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]

Total contributions to the plans during the period

Estimated future contributions in the next fiscal year

$ 9

[1]	39% of the amount invested in common collective trust funds is in fixed income securities, 30% is in U.S. equities and 31% is in international equities.
[2]	24% of the amount invested in common collective trust funds is in fixed income securities, 42% is in U.S. equities and 34% is in international equities.
[3]	75% of the amount invested in mutual funds is in international equities and 25% is in U.S. equities.
[4]	74% of the amount invested in mutual funds is in fixed income securities and 26% is in U.S. equities.
[5]	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.
[6]	73% of the amount invested in mutual funds is in fixed income securities, 19% is in U.S. equities and 8% is in international equities.

Stock-Based Incentive Compensation Plans and Employee Benefit Plans (Change in Control Agreements and Other Employee Matters) (Details)	Dec. 31, 2011
Workforce Subject to Collective Bargaining Arrangements [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage (in hundredths)	30.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage (in hundredths)	8.00%

Derivative Instruments (Details)
$ in Millions

12 Months Ended

Dec. 31, 2011

USD ($)

Years

Dec. 31, 2010

USD ($)

Dec. 31, 2009

USD ($)

Derivatives, Fair Value [Line Items]

Increased (decreased) natural gas revenues from the unrealized net gains (losses) of derivative instruments

$ 38

$ 18

$ (80)

Increased (decreased) natural gas expense from the unrealized net (gains) losses of derivative instruments

(57)

Net unrealized gain (loss) from derivative instruments

$ 8

$ 4

$ (23)

Term of normal weather used as the basis for weather hedges (in years)

Losses recognized from weather hedges

$ 1

$ 6

$ 7

Derivatives, Fair Value [Abstract]

Derivative gross volumes (Bcf)

633

626

Net long position (Bcf)

Amount of net long position constituted by basis swaps (Bcf)

Amount of net long position comprised of price stabilization activities of the Natural Gas Distribution business segment (Bcf)

Total non-trading derivative assets and liabilities net of collateral

$ 55

$ (15)

Collateral netting

Derivative Instruments, Gain (Loss) [Abstract]

Total fair value of the derivative instruments that contain credit risk contingent features that are in a net liability position

107

The aggregate fair value of assets already posted as collateral

Credit Risk Contingent Features assets

Credit Quality of Counterparties [Abstract]

Investment Grade

^[1]

Total

107

Energy marketers [Member]

Credit Quality of Counterparties [Abstract]

Investment Grade

^[1]

Total

Financial institutions [Member]

Credit Quality of Counterparties [Abstract]

Investment Grade

^[1]

Total

Retail end users [Member]

Credit Quality of Counterparties [Abstract]

Investment Grade

^[1],[2]

Total

^[2]

100

Derivatives Not Designated as Hedging Instruments [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

123

^[3],[4]

^[5],[6]

Derivative liabilities fair value

321

^[3],[4]

411

^[5],[6]

Derivative Instruments, Gain (Loss) [Abstract]

Unrealized gains and losses in the Statements of Consolidated Income

(7)

(106)

Gains (Losses) in Revenue [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivative Instruments, Gain (Loss) [Abstract]

Unrealized gains and losses in the Statements of Consolidated Income

102

Gains (Losses) in Expense: Natural Gas [Member] | Natural gas contracts [Member]

Derivative Instruments, Gain (Loss) [Abstract]

Costs associated with price stabilization activities of the Natural Gas Distribution business segment included in Expenses

(107)

(115)

Gains (Losses) in Expense: Natural Gas [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivative Instruments, Gain (Loss) [Abstract]

Unrealized gains and losses in the Statements of Consolidated Income

^[7]

(144)

(165)

Gains (Losses) in Other Income (Expense) [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Indexed debt securities derivative [Member]

Derivative Instruments, Gain (Loss) [Abstract]

Unrealized gains and losses in the Statements of Consolidated Income

(31)

Current Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

^[3],[4],[8]

^[5],[6],[9]

Derivative liabilities fair value

^[3],[4],[8]

^[5],[6],[9]

Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

^[3],[4],[8]

^[5],[6],[9]

Derivative liabilities fair value

^[3],[4],[8]

^[5],[6],[9]

Current Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

^[3],[4],[8]

^[5],[6],[9]

Derivative liabilities fair value

110

^[3],[4],[8]

143

^[5],[6],[9]

Current Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Indexed debt securities derivative [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

^[3],[4]

^[5],[6]

Derivative liabilities fair value

197

^[3],[4]

232

^[5],[6]

Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Natural gas contracts [Member]

Derivatives, Fair Value [Abstract]

Derivative assets fair value

^[3],[4],[8]

^[5],[6],[9]

Derivative liabilities fair value

$ 13

^[3],[4],[8]

$ 35

^[5],[6],[9]

[1]	“Investment grade” is primarily determined using publicly available credit ratings and considering credit support (including parent company guaranties) and collateral (including cash and standby letters of credit). For unrated counterparties, CenterPoint Energy determines a synthetic credit rating by performing financial statement analysis and considering contractual rights and restrictions and collateral.
[2]	Retail end users represent customers who have contracted to fix the price of a portion of their physical gas requirements for future periods.
[3]	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 633 Bcf or a net 84 Bcf long position. Of the net long position, basis swaps constitute 74 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 6 Bcf.
[4]	The net of total non-trading derivative assets and liabilities is a $55 million asset as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $56 million.
[5]	The fair value shown for natural gas contracts is comprised of derivative gross volumes totaling 626 billion cubic feet (Bcf) or a net 72 Bcf long position. Of the net long position, basis swaps constitute 63 Bcf and volumes associated with price stabilization activities of the Natural Gas Distribution business segment constitute 26 Bcf.
[6]	The net of total non-trading derivative assets and liabilities is a $15 million liability as shown on CenterPoint Energy’s Consolidated Balance Sheets, and is comprised of the natural gas contracts derivative assets and liabilities separately shown above offset by collateral netting of $84 million.
[7]	The Gains (Losses) in Expense: Natural Gas includes $(115) million and $(107) million of costs in 2010 and 2011, respectively, associated with price stabilization activities of the Natural Gas Distribution business segment that will be ultimately recovered through purchased gas adjustments.
[8]	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.
[9]	Natural gas contracts are subject to master netting arrangements and are presented on a net basis in the Consolidated Balance Sheets. This netting causes derivative assets (liabilities) to be ultimately presented net in a liability (asset) account within the Consolidated Balance Sheets.

Fair Value Measurements (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Assets

Corporate equities

$ 387

$ 368

Investments, including money market funds

Natural gas derivatives

107

Total assets

550

491

Liabilities

Indexed debt securities derivative

197

232

$ 201

$ 133

Natural gas derivatives

Total liabilities

249

316

Cash collateral posted with counterparties

$ 56

Total settlements:

Interest rate of CenterPoint Energy Zero Premium Exchangeable Subordinated Notes (in hundredths)

2.00%

Zero Premium Exchangeable Subordinated Notes Maturity Date

2029

Carrying amount [Member]

Liabilities

Long-term debt

$ 8,994

9,303

Fair value [Member]

Liabilities

Long-term debt

10,049

10,071

Derivative Financial Instruments, Assets and Liabilities, Net [Member]

Fair value measurement using significant unobservable input (level 3) reconciliation [Roll Forward]

Beginning balance

(6)

(58)

Total unrealized gains or (losses):

Included in earnings

(1)

Included in regulatory assets

(1)

(16)

Total settlements:

Included in earnings

(3)

(2)

Included in regulatory assets

Total purchases

Net transfers into level 3

(2)

Ending balance

(6)

The amount of total gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date

$ 1

Quoted prices in active markets for identical assets (Level 1) [Member]

Assets

Corporate equities

387

368

Investments, including money market funds

Natural gas derivatives

Total assets

444

422

Liabilities

Indexed debt securities derivative

Natural gas derivatives

Total liabilities

Significant other observable inputs (Level 2) [Member]

Assets

Corporate equities

Investments, including money market funds

Natural gas derivatives

112

Total assets

112

Liabilities

Indexed debt securities derivative

197

232

Natural gas derivatives

101

167

Total liabilities

298

399

Significant unobservable inputs (Level 3) [Member]

Assets

Corporate equities

Investments, including money market funds

Natural gas derivatives

Total assets

Liabilities

Indexed debt securities derivative

Natural gas derivatives

Total liabilities

Netting Adjustments [Member]

Assets

Corporate equities

^[1]

^[2]

Investments, including money market funds

^[1]

^[2]

Natural gas derivatives

(16)

^[1]

(11)

^[2]

Total assets

(16)

^[1]

(11)

^[2]

Liabilities

Indexed debt securities derivative

^[1]

^[2]

Natural gas derivatives

(72)

^[1]

(95)

^[2]

Total liabilities

$ (72)

^[1]

$ (95)

^[2]

[1]	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $56 million posted with the same counterparties.
[2]	Amounts represent the impact of legally enforceable master netting agreements that allow CenterPoint Energy to settle positive and negative positions and also include cash collateral of $84 million posted with the same counterparties.

Indexed Debt Securities (ZENS) and Time Warner Securities (Details) shares in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) shares	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Zero Premium Exchangeable Subordinated Notes [Abstract]
Issuance date of CenterPoint Energy Zero Premium Exchangeable Subordinated Notes	9/1/1999
Interest rate of CenterPoint Energy Zero Premium Exchangeable Subordinated Notes (in hundredths)	2.00%
Due date of CenterPoint Energy Zero Premium Exchangeable Subordinated Notes	2029
Original principal amount of Zero Premium Exchangeable Subordinated Notes issued by CenterPoint Energy in September 1999	$ 1,000,000,000
Outstanding amount of Zero Premium Exchangeable Subordinated Notes issued by CenterpPoint Energy in September 1999	$ 840,000,000
Percentage of market value of referenced shares of Time Warner Common each zero premium exchangeable subordinated note could be exchanged for cash (in hundredths)	95.00%
Referenced common shares
Stated interest rate of CenterPoint Energy Zero Premium Exchangeable Subordinated Notes (in hundredths)	2.00%
Target annual yield from interest and cash dividends on referenced shares before principal amount of indexed debt securities is increased or decreased (in hundredths)	2.309%
Outstanding amount of indexed debt securities issued by CenterPoint Energy in September 1999	$ 840,000,000
Contingent principal amount of indexed debt securities issued by CenterpPoint Energy in September 1999 and outstanding and exchangeable	$ 797,000,000
Percentage of market value of referenced shares of Time Warner Common each original indexed security note could be exchanged for cash (in hundredths)	95.00%
The market value of referenced shares of TW Common, TWC Common and AOL common for each indexed debt security	$ 386,000,000
The cash exchange amount from referenced shares per $1,000 face amount of individual notes	436
Face amount of each indexed debt security notes issued by CenterPoint Energy in September 1999	$ 1,000
The accretion rate for interest charges on bifurcated debt component of indexed debt securities (in hundredths)	17.30%
TW Securities
TW Securities	$ 367,000,000	$ 300,000,000	$ 218,000,000
Gain on TW Securities	19,000,000	67,000,000	82,000,000
TW Securities	386,000,000	367,000,000	300,000,000
Debt component of ZENS
Debt Component of ZENS	126,000,000	121,000,000	117,000,000
Accretion of debt component of ZENS	22,000,000	22,000,000	21,000,000
2 % interest paid	(17,000,000)	(17,000,000)	(17,000,000)
Debt Component of ZENS	131,000,000	126,000,000	121,000,000
Derivative component of ZENS
Derivative Component of ZENS	232,000,000	201,000,000	133,000,000
Loss (gain) on indexed debt securities	(35,000,000)	31,000,000	68,000,000
Derivative Component of ZENS	$ 197,000,000	$ 232,000,000	$ 201,000,000
TW Common [Member]
Schedule of Trading Securities [Line Items]
Number of shares of common stock held by subsidiary of CenterPoint Energy (in shares) \| shares	7.2
Referenced common shares
The referenced shares of common stock for each zero premium exchangeable subordinated note (in shares)	0.5
TWC Common [Member]
Schedule of Trading Securities [Line Items]
Number of shares of common stock held by subsidiary of CenterPoint Energy (in shares) \| shares	1.8
Referenced common shares
The referenced shares of common stock for each zero premium exchangeable subordinated note (in shares)	0.125505
AOL Common [Member]
Schedule of Trading Securities [Line Items]
Number of shares of common stock held by subsidiary of CenterPoint Energy (in shares) \| shares	0.7
Referenced common shares
The referenced shares of common stock for each zero premium exchangeable subordinated note (in shares)	0.045455

Equity (Details) - $ / shares	12 Months Ended
Equity (Details) - $ / shares	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stockholders' Equity Note [Abstract]
Capital stock shares authorized (in shares)	1,020,000,000
Common stock shares authorized (in shares)	1,000,000,000	1,000,000,000	1,000,000,000
Common stock shares par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Cumulative preferred stock shares authorized (in shares)	20,000,000	20,000,000	20,000,000
Cumulative preferred stock par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Stock Issuance [Abstract]
Number of preference stock purchase rights included with every share of common stock (in shares)	1
Series A Preference Stock share available for purchase per common share held (in shares)	0.001

Short Term Borrowings and Long Term Debt (Schedule of Debt) (Details) - USD ($)
$ in Millions

1 Months Ended

12 Months Ended

Feb. 29, 2012

Jan. 31, 2011

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Short term borrowings:

Total short term borrowings

^[1]

$ 62

$ 53

Long-term debt:

Long term debt

8,641

9,001

Long term debt, current maturities

^[1]

484

428

Short Term Borrowings And Current Portion Long Term Debt

^[1]

546

481

Purchased aggregate principal amount of debt

909

783

$ 222

Inventory financing [Member]

Short term borrowings:

Total short term borrowings

^[1]

Other long term debt [Member]

Long-term debt:

Long term debt

Long term debt, current maturities

^[1]

Unamortized discount and premium [Member]

Long-term debt:

Long term debt

(63)

(8)

Long term debt, current maturities

^[1]

CenterPoint Energy [Member]

Long-term debt:

Long term debt

1,461

Purchased aggregate principal amount of debt

490

$ 0

CenterPoint Energy [Member] | ZENS [Member]

Long-term debt:

Long term debt

^[2]

Long term debt, current maturities

^[1],[2]

131

126

CenterPoint Energy [Member] | Senior notes due 2015 to 2018 [Member]

Long-term debt:

Long term debt

750

Long term debt, current maturities

^[1]

$ 0

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

5.95%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

6.85%

CenterPoint Energy [Member] | Pollution control bonds due 2015 [Member]

Long-term debt:

Long term debt

^[3]

$ 151

151

Long term debt, current maturities

^[1],[3]

$ 0

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

^[4]

4.00%

CenterPoint Energy [Member] | Pollution control bonds due 2015 to 2030 [Member]

Long-term debt:

Long term debt

^[5],[6]

$ 562

562

Long term debt, current maturities

^[1],[5],[6]

$ 0

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

^[7],[8]

4.90%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

^[7],[8]

5.95%

Amount of debt secured by general mortgage bonds

$ 218

237

CenterPoint Houston [Member] | First mortgage bonds due 2021 [Member]

Long-term debt:

Long term debt

102

Long term debt, current maturities

^[1]

$ 0

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

9.15%

CenterPoint Houston [Member] | General mortgage bonds due 2013 to 2033 [Member]

Long-term debt:

Long term debt

$ 1,762

1,762

Long term debt, current maturities

^[1]

$ 0

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

5.60%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

7.00%

CenterPoint Houston [Member] | Pollution control bonds due 2012 to 2027 [Member]

Long-term debt:

Long term debt

^[9]

$ 183

229

Long term debt, current maturities

^[1],[9]

$ 46

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

^[10]

3.625%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

^[10]

5.60%

CenterPoint Houston [Member] | System restoration bonds due 2012 to 2022 [Member]

Long-term debt:

Long term debt

$ 556

601

Long term debt, current maturities

^[1]

$ 45

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

1.833%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

4.243%

CenterPoint Houston [Member] | Transition Bonds due 2012 to 2020 [Member]

Long-term debt:

Long term debt

$ 1,659

1,921

Long term debt, current maturities

^[1]

$ 262

240

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

4.192%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

5.63%

CERC Corp [Member] | Senior notes 2013 to 2041 [Member]

Long-term debt:

Long term debt

^[11]

$ 2,693

2,747

Long term debt, current maturities

^[1],[11]

$ 0

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

^[12]

4.50%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

7.875%

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

7.75%

Debt refinanced

^[11]

$ 550

CERC Corp [Member] | Commercial Paper [Member]

Long-term debt:

Long term debt

^[13]

$ 285

183

Long term debt, current maturities

^[1],[13]

$ 0

Repurchased Debt [Member] | CenterPoint Energy [Member] | Pollution control bonds due 2015 to 2030 [Member]

Long-term debt:

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

5.15%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

5.95%

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

5.25%

Purchased aggregate principal amount of debt

$ 275

Called for redemption

$ 100

[1]	Includes amounts due or exchangeable within one year of the date noted.
[2]	CenterPoint Energy’s ZENS obligation is bifurcated into a debt component and an embedded derivative component. For additional information regarding ZENS, see Note 9(b). As ZENS are exchangeable for cash at any time at the option of the holders, these notes are classified as a current portion of long-term debt.
[3]	These series of debt are secured by first mortgage bonds of CenterPoint Houston.
[4]	These series of debt are secured by first mortgage bonds of CenterPoint Houston.
[5]	$237 million and $218 million of these series of debt were secured by general mortgage bonds of CenterPoint Houston at December 31, 2010 and 2011, respectively.
[6]	In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf which will remain outstanding and may be remarketed and called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf.
[7]	$237 million and $218 million of these series of debt were secured by general mortgage bonds of CenterPoint Houston at December 31, 2010 and 2011, respectively.
[8]	In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf which will remain outstanding and may be remarketed and called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf.
[9]	These series of debt are secured by general mortgage bonds of CenterPoint Houston.
[10]	These series of debt are secured by general mortgage bonds of CenterPoint Houston.
[11]	$550 million senior notes due February 2011 are not reflected in the current portion of long-term debt as of December 31, 2010 because the notes were refinanced in January 2011.
[12]	$550 million senior notes due February 2011 are not reflected in the current portion of long-term debt as of December 31, 2010 because the notes were refinanced in January 2011.
[13]	Classified as long-term debt because the termination date of the facility that backstops the commercial paper is more than one year from the date noted.

Short Term Borrowings and Long Term Debt (Short-term Borrowings) (Details) - USD ($)
$ in Millions

Dec. 31, 2011

Dec. 31, 2010

Short-term Debt [Line Items]

Short-term borrowings

^[1]

$ 62

$ 53

CERC Corp. receivables facility [Member]

Short-term Debt [Line Items]

Receivables Facility Advance Capacity

160

Short-term borrowings

$ 0

[1]	Includes amounts due or exchangeable within one year of the date noted.

Short Term Borrowings and Long Term Debt (CERC Corp Senior Notes and Exchange Offer) (Details) - CERC Corp [Member] - USD ($)
$ in Millions

1 Months Ended

12 Months Ended

Jan. 31, 2011

Dec. 31, 2011

Senior notes 2013 to 2041 [Member]

Debt Instrument [Line Items]

Debt refinanced

^[1]

$ 550

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

7.75%

Senior notes issued, due 2021 (CERC Corp senior notes) [Member]

Debt Instrument [Line Items]

Amount of senior notes not reflected in current portion of long-term debt (CERC Corporation senior notes)

$ 250

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

4.50%

Senior notes issued, due 2041 (CERC Corp senior notes) [Member]

Debt Instrument [Line Items]

Amount of senior notes not reflected in current portion of long-term debt (CERC Corporation senior notes)

$ 300

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

5.85%

Senior notes issued, due 2021 (CERC exchange offer) [Member]

Debt Instrument [Line Items]

Amount of senior notes not reflected in current portion of long-term debt (CERC Corporation senior notes)

$ 343

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

4.50%

Unamortized debt issuance cost

$ 58

Amount of cash consideration provided related to CERC exchange offer

$ 114

Exchanged senior debt, due 2013 [Member]

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

7.875%

Extinguishment of debt, aggregate principal amount

$ 397

[1]	$550 million senior notes due February 2011 are not reflected in the current portion of long-term debt as of December 31, 2010 because the notes were refinanced in January 2011.

Short Term Borrowings and Long Term Debt (Pollution Controlled Bonds) (Details) - USD ($)
$ in Millions

1 Months Ended

12 Months Ended

Feb. 29, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Debt Instrument [Line Items]

Purchased aggregate principal amount of debt

$ 909

$ 783

$ 222

CenterPoint Energy [Member]

Debt Instrument [Line Items]

Purchased aggregate principal amount of debt

$ 19

$ 490

$ 0

CenterPoint Energy [Member] | Pollution control bonds due 2015 to 2030 [Member]

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

^[1],[2]

4.90%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

^[1],[2]

5.95%

CenterPoint Energy [Member] | Pollution control bonds due 2015 to 2030 [Member] | Repurchased Debt [Member]

Debt Instrument [Line Items]

Purchased aggregate principal amount of debt

$ 275

Extinguishment of debt, aggregate principal amount

$ 100

Extinguishment of debt, purchase price percentage of principal (in hundredths)

100.00%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum (in hundredths)

5.15%

Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum (in hundredths)

5.95%

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

5.25%

[1]	$237 million and $218 million of these series of debt were secured by general mortgage bonds of CenterPoint Houston at December 31, 2010 and 2011, respectively.
[2]	In February 2012, CenterPoint Energy purchased $275 million aggregate principal amount of pollution control bonds issued on its behalf which will remain outstanding and may be remarketed and called for a March 2012 redemption of $100 million aggregate principal amount of pollution control bonds issued on its behalf.

Short Term Borrowings and Long Term Debt (Long-term Debt) (Details) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2012 USD ($) tranches	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)
Long-term debt:
Special purpose subsidiaries		5
Line of Credit Facility [Abstract]
Size of Facility		$ 2,450	$ 2,360
Loans		0	0
Letters of Credit		20	24
Commercial Paper		285	183
Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract]
2012		353
2013		1,145
2014		1,195
2015		669
2016		875
Transition and system restoration bond annual principal repayments included in annual maturities of long term debt [Abstract]
2012		307
2013		330
2014		235
2015		249
2016		266
2012 Transition bond annual principal repayments excluded from annual maturities of long-term debt [Abstract]
2012		62
2013		117
2014		120
2015		122
2016		126
Replacement fund requirements to be satisfied in 2012		184
Sinking fund requirements to be satisfied in 2012		3
CenterPoint Energy [Member]
Line of Credit Facility [Abstract]
Size of Facility		1,200	1,156
Loans		0	0
Letters of Credit		16	20
Commercial Paper		$ 0	0
Revolving credit facility borrowing rate		Libor + .0175
Debt to EBITDA covenant ratio, before amendment		5
Debt to EBITDA covenant ratio, amendment		5.5
System restoration costs threshold for increase in permitted debt to EBITDA covenant ratio		$ 100
Percentage of utilization of credit facility		more than 50%
Utilization fee on borrowings exceeding fifty percent of total credit facility (in hundredths)		0.0005
CenterPoint Houston [Member]
Line of Credit Facility [Abstract]
Size of Facility		$ 300	289
Loans		0	0
Letters of Credit		4	4
Commercial Paper		$ 0	0
Revolving credit facility borrowing rate		Libor + .0150
Percentage on limitation of debt to total capitalization under covenant (in hundredths)		65.00%
Percentage of utilization of credit facility		more than 50%
Utilization fee on borrowings exceeding fifty percent of total credit facility (in hundredths)		0.0005
CenterPoint Houston [Member] \| First mortgage bonds due 2021 [Member]
Line of Credit Facility [Abstract]
Secured debt amount with asset liens		$ 253
CenterPoint Houston [Member] \| General mortgage bonds due 2013 to 2033 [Member]
Line of Credit Facility [Abstract]
Secured debt amount with asset liens		2,500
CERC Corp [Member]
Line of Credit Facility [Abstract]
Size of Facility		950	915
Loans		0	0
Letters of Credit		0	0
Commercial Paper		$ 285	$ 183
Revolving credit facility borrowing rate		Libor + .0150
Percentage on limitation of debt to total capitalization under covenant (in hundredths)		65.00%
Percentage of utilization of credit facility		more than 50%
Utilization fee on borrowings exceeding fifty percent of total credit facility (in hundredths)		0.0005
Bond Company IV [Member] \| Bonds Due 2018 to 2025 [Member]
Long-term debt:
Transition bonds issued to recover true-up costs	$ 1,695
Line of Credit Facility [Abstract]
Number of tranches of transition bonds \| tranches	3
Minimum interest rate on transition bonds	0.9012%
Maximum interest rate on transition bonds	3.0282%

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011	Dec. 31, 2009
Current income tax expense (benefit):
Federal		$ (63)	$ 40	$ (103)
State		24	24	10
Total current expense (benefit)		(39)	64	(93)
Deferred income tax expense (benefit):
Federal		432	220	251
State		11	(21)	18
Total deferred expense		443	199	269
Total income tax expense		404	263	176
Income tax reconciliation [Abstract]
Income before income taxes and extraordinary item		$ 1,174	$ 705	$ 548
Federal statutory income tax rate (in hundredths)		35.00%	35.00%	35.00%
Expected federal income tax expense		$ 411	$ 247	$ 192
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax		22	2	18
Amortization of investment tax credit		(6)	(7)	(7)
Tax law change in deductibility of retiree health care costs		0	20	0
Increase (decrease) in settled and uncertain income tax positions		(5)	14	(5)
Other, net		(18)	(13)	(22)
Total		(7)	16	(16)
Total income tax expense		$ 404	$ 263	$ 176
Effective tax rate (in hundredths)		34.40%	37.30%	32.10%
Amount of non-cash recorded to income tax expense as result of change in tax law			$ 21
Amount of reduction to deferred tax assets due to actuarially determined net present value of lost future health care deductions	$ 32
Amount of adjustment to regulatory assets due to actuarially determined net present value of lost future health care deductions	11
Amount of reduction to deferred tax assets, recorded to income tax expense, due to actuarially determined net present value of lost future health care deductions			21
Amount of decrease in income tax expense recorded related to effects of re-measuring accumulated deferred income taxes	24	$ 17	24
Amount of net reduction to income tax expense from state income tax expense, net of federal income tax			29
Increase in income tax expense related to uncertain tax positions			5
Income tax benefit resulting from IRS settlement				$ 11
Reduction in the liability for uncertain tax positions				41
State income tax expense		$ 22	2	18
Benefit net of federal income tax effect related to state income tax adjustments				12
Current:
Allowance for doubtful accounts	11				$ 10
Deferred gas costs	32				0
Other	21				7
Total current deferred tax assets	64				17
Non-current:
Loss and credit carryforwards	49				214
Employee benefits	346				363
Other	48				68
Total non-current deferred tax assets before valuation allowance	443				645
Valuation allowance	(3)				(4)
Total non-current deferred tax assets, net of valuation allowance	440				641
Total deferred tax assets, net of valuation allowance	504				658
Current:
Unrealized gain on indexed debt securities	391				427
Unrealized gain on marketable securities	80				97
Total current deferred tax liabilities	471				524
Non-current:
Depreciation	2,086				2,849
Regulatory assets, net	1,256				1,499
Other	32				125
Total non-current deferred tax liabilities	3,374				4,473
Total deferred tax liabilities	3,845				4,997
Accumulated deferred income taxes, net	3,341				4,339
Federal net operating loss carryforwards					442
State net operating loss carryforwards					352
Range of years where state net operating loss carryforwards expire.		2012 and 2031
Valuation allowance of state capital loss carryforwards					3
State capital loss carryforwards					244
Expiration date of state capital loss carryforwards		2017
Balance, beginning of year		$ 252	187	117
Tax Positions related to prior years:
Additions		(1)	9	56
Reductions		(203)	(4)	(25)
Tax Positions related to current year:
Additions		5	60	56
Settlements		(1)	0	(17)
Lapse of statute of limitations		(1)	0	0
Balance, end of year	252	252	187	117	51	$ 187
Reduction to liability for unrecognized tax benefits recorded		211
Increase in deferred tax liability		202
Decrease in income tax expense for the release of accrued interest expense		9
Range of change possible in unrecognized tax benefits over the next 12 months, minimum					25
Range of change possible in unrecognized tax benefits over the next 12 months, maximum					31
Unrecognized tax benefits that, if recognized, would reduce the effective income tax rate for the year	17				21	$ 10
Income tax expense (benefit) recognized in interest on uncertain income tax positions during the year		$ (13)	$ 8	$ (7)
Accrued interest on uncertain income tax positions at the end of the year	$ 12				(1)
Amount of Internal Revenue Service disallowance of casualty loss					603
Amount of estimated liability included in taxes receivable associated with increase in income taxes					32
Amount of indemnification receivable					27
Pertaining to the federal benefit on the deductibility of interest					5
Federal [Member]
Other Tax Carryforward [Line Items]
Other tax carryforwards, expiration dates		2012 and 2030
Federal [Member] \| Capital Loss Carryforward [Member]
Other Tax Carryforward [Line Items]
Tax carryforward					6
Federal [Member] \| Charitable Contribution Carryforward [Member]
Other Tax Carryforward [Line Items]
Tax carryforward					14
Federal [Member] \| Share Based Compensation [Member]
Other Tax Carryforward [Line Items]
Net opearting loss carryforwards					$ 1

Commitments and Contingencies (Details)	12 Months Ended
Commitments and Contingencies (Details)	Dec. 31, 2011 USD ($) volume Years	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Operating Leases, Future Minimum Payments Due [Abstract]
2012	$ 14,000,000
2013	9,000,000
2014	7,000,000
2015	4,000,000
2016	4,000,000
2017 and beyond	16,000,000
Total	54,000,000
Total lease expense for all operating leases	$ 43,000,000	$ 77,000,000	$ 37,000,000
Legal Environmental And Other Regulatory Matters Legal Matters Gas Market Manipulation Cases Abstract
Recovery of compensatory damages sought by plaintiffs	in excess of $1 billion
Approximate number of gas market manipulation lawsuits naming CenterPoint and/or Reliant Energy (in number of lawsuits)	30
Number of gas market manipulation lawsuits pending for CenterPoint and its affiliates (in number of lawsuits)	2
Number of gas market mismeasurement lawsuits pending for CenterPoint and its affiliates (in number of lawsuits)	2
Approximate number of pipeline companies named in the mismeasurement lawsuits (in number of companies)	245
Number of gas measurement lawsuits seeking class certification and has four amendments (in number of cases)	1
Number of times gas measurement lawsuit was amended (in number of amendments)	4
Number of years the plaintiffs claim the defendants have engaged in the systematic mismeasurement of natural gas (in years) \| Years	25
Number of CenterPoint subsidiaries dismissed from the claims of the plaintiff (in number of claims)	2
Number of sites where remediation is complete, other than ongoing operations (in number of sites)	2
Number of remaining sites in the Minnesota service territory (in number of sites)	5
Number of the remaining sites in the Minnesota service territory where the company believes it has no liability (in number of sites)	2
Amount accrued for remediation of Minnesota sites (in number of sites)	$ 13,000,000
Minimum estimated remediation costs for the Minnesota sites	6,000,000
Maximum estimated remediation costs for the Minnesota sites	$ 41,000,000
Minimum years of remediation for the Minnesota sites (in years) \| Years	30
Maximum years of remediation for the Minnesota sites (in years) \| Years	50
Annual amount included in rates to fund normal on-going remediation costs	$ 285,000
Amount collected from insurance companies to be used for future environmental remediation	5,500,000
Approximate amount of undiscounted demand charges under the transportation contracts	88,000,000
Approximate amount of collateral posted as security on transportation contracts	$ 21,000,000	$ 7,000,000
Long-Term Gas Gathering and Treating Agreements [Member]
Schedule of Capital Expansion Projects [Abstract]
Potential additional natural gas capacity per day under potential additional expansion election (in billion cubic feet) \| volume	1.3
Total costs of potential additional expansion	$ 440,000,000
Natural Gas supply commitments [Member]
Recorded unconditional purchase obligation [Line Items]
2012	467,000,000
2013	449,000,000
2014	353,000,000
2015	219,000,000
2016	151,000,000
After 2016	251,000,000
Software licenses [Member]
Recorded unconditional purchase obligation [Line Items]
2012	6,000,000
2013	$ 6,000,000

Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

^[2]

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

^[3]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Basic earnings per share calculation:

Income before extraordinary item

$ 117

^[1]

$ 386

^[1]

$ 119

^[1]

$ 148

^[1]

$ 770

$ 442

$ 372

Extraordinary Item, net of tax

^[1]

587

^[1]

587

Net Income

$ 117

$ 973

$ 119

$ 148

$ 124

$ 123

$ 81

$ 114

$ 1,357

$ 442

$ 372

Weighted average shares outstanding (in shares)

425,636,000

409,721,000

365,229,000

Income before extraordinary item

$ 0.27

^[4]

$ 0.90

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 1.81

$ 1.08

$ 1.02

Extraordinary item, net of tax

0.00

^[4]

1.38

^[4]

0.00

^[4]

0.00

^[4]

1.38

0.00

Net income

$ 0.27

^[4]

$ 2.28

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 0.29

^[4]

$ 0.29

^[4]

$ 0.20

^[4]

$ 0.29

^[4]

$ 3.19

$ 1.08

$ 1.02

Diluted earnings per share calculation:

Net Income

$ 117

$ 973

$ 119

$ 148

$ 124

$ 123

$ 81

$ 114

$ 1,357

$ 442

$ 372

Weighted average shares outstanding (in shares)

425,636,000

409,721,000

365,229,000

Plus: Incremental shares from assumed conversions:

Stock options (in shares)

^[5]

347,000

470,000

451,000

Restricted stock (in shares)

2,741,000

2,585,000

2,001,000

Weighted average shares assuming dilution (in shares)

428,724,000

412,776,000

367,681,000

Income before extraordinary item

$ 0.27

^[4]

$ 0.90

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 1.80

$ 1.07

$ 1.01

Extraordinary item, net of tax

0.00

^[4]

1.37

^[4]

0.00

^[4]

0.00

^[4]

1.37

0.00

Net income

$ 0.27

^[4]

$ 2.27

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 0.29

^[4]

$ 0.29

^[4]

$ 0.20

^[4]

$ 0.29

^[4]

$ 3.17

$ 1.07

$ 1.01

Outstanding shares with the options to purchase not included in the computation of diluted earnings per share (in shares)

1,458,598

2,372,132

[1]	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).
[2]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[3]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.
[4]	Quarterly earnings per common share are based on the weighted average number of shares outstanding during the quarter, and the sum of the quarters may not equal annual earnings per common share.
[5]	Options to purchase 2,372,132 and 1,458,598 shares were outstanding for the years ended December 31, 2009 and 2010, respectively, but were not included in the computation of diluted earnings per share because the options’ exercise price was greater than the average market price of the common shares for the respective years.

Unaudited Quarterly Information (Details) - USD ($)
$ / shares in Units, $ in Millions

1 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2005

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Selected Quarterly Financial Information [Abstract]

Revenues

$ 2,145

$ 1,881

$ 1,837

$ 2,587

$ 2,098

^[1]

$ 1,908

$ 1,756

$ 3,023

^[2]

$ 8,450

$ 8,785

$ 8,281

Operating income

274

357

303

364

302

^[1]

327

263

357

^[2]

1,298

1,249

1,124

Income before extraordinary item

117

^[3]

386

^[3]

119

^[3]

148

^[3]

770

442

372

Extraordinary Item, net of tax

^[3]

587

^[3]

587

Net Income

$ 117

$ 973

$ 119

$ 148

$ 124

^[1]

$ 123

$ 81

$ 114

^[2]

$ 1,357

$ 442

$ 372

Basic Earnings Per Share:

Income before extraordinary item

$ 0.27

^[4]

$ 0.90

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 1.81

$ 1.08

$ 1.02

Extraordinary item, net of tax

0.00

^[4]

1.38

^[4]

0.00

^[4]

0.00

^[4]

1.38

0.00

Basic earnings per share

0.27

^[4]

2.28

^[4]

0.28

^[4]

0.35

^[4]

$ 0.29

^[1],[4]

$ 0.29

^[4]

$ 0.20

^[4]

$ 0.29

^[2],[4]

3.19

1.08

1.02

Diluted Earnings Per Share:

Income before extraordinary item

0.27

^[4]

0.90

^[4]

0.28

^[4]

0.35

^[4]

1.80

1.07

1.01

Extraordinary item, net of tax

0.00

^[4]

1.37

^[4]

0.00

^[4]

0.00

^[4]

1.37

0.00

Diluted earnings per share

$ 0.27

^[4]

$ 2.27

^[4]

$ 0.28

^[4]

$ 0.35

^[4]

$ 0.29

^[1],[4]

$ 0.29

^[4]

$ 0.20

^[4]

$ 0.29

^[2],[4]

$ 3.17

$ 1.07

$ 1.01

Amount of charge to income tax expense as result of change in tax law

$ 21

Gain (Loss) on Sale of Property

$ 21

Amount of decrease in income tax expense recorded related to effects of re-measuring accumulated deferred income taxes

$ 24

$ 17

$ 24

Net after-tax extraordinary gain (loss)

$ (947)

$ 587

Return on True-Up Balance after tax

$ 224

[1]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[2]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.
[3]	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).
[4]	Quarterly earnings per common share are based on the weighted average number of shares outstanding during the quarter, and the sum of the quarters may not equal annual earnings per common share.

Reportable Business Segments (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Segment Reporting Information [Line Items]

Revenues

$ 2,145

$ 1,881

$ 1,837

$ 2,587

$ 2,098

^[1]

$ 1,908

$ 1,756

$ 3,023

$ 8,450

$ 8,785

$ 8,281

Intersegment Revenues

Depreciation and Amortization

886

864

743

Operating Income (Loss)

274

$ 357

$ 303

$ 364

302

^[1]

$ 327

$ 263

$ 357

1,298

1,249

1,124

Total Assets

21,703

20,111

21,703

20,111

19,773

Expenditures for Long-Lived Assets

1,191

1,462

1,148

Equity income

Electric Transmission & Distribution [Member]

Segment Reporting Information [Line Items]

Revenues

^[3]

2,337

2,205

2,013

Intersegment Revenues

Depreciation and Amortization

587

582

480

Operating Income (Loss)

623

567

545

Total Assets

11,221

9,817

11,221

9,817

9,755

Expenditures for Long-Lived Assets

538

463

428

Sales to subsidiaries of NRG Retail LLC in CenterPoint Houston's transmission and distribution revenues

594

583

634

Sales to subsidiaries of TXU Energy in CenterPoint Houston's transmission and distribution revenues

182

185

182

Natural Gas Distribution [Member]

Segment Reporting Information [Line Items]

Revenues

2,823

3,199

3,374

Intersegment Revenues

Depreciation and Amortization

166

161

Operating Income (Loss)

226

231

204

Total Assets

4,636

4,575

4,636

4,575

4,535

Expenditures for Long-Lived Assets

295

202

165

Competitive Natural Gas Sales and Services [Member]

Segment Reporting Information [Line Items]

Revenues

2,488

2,617

2,215

Intersegment Revenues

Depreciation and Amortization

Operating Income (Loss)

Total Assets

1,089

1,190

1,089

1,190

1,176

Expenditures for Long-Lived Assets

Interstate Pipelines [Member]

Segment Reporting Information [Line Items]

Revenues

^[4]

421

464

456

Intersegment Revenues

^[4]

132

137

142

Depreciation and Amortization

^[4]

Operating Income (Loss)

^[4]

248

270

256

Total Assets

^[4]

$ 3,867

$ 3,672

3,867

3,672

3,484

Expenditures for Long-Lived Assets

^[4]

102

176

Equity income

^[4]

$ 21

$ 19

$ 7

Interest in jointly-owned asset (in hundredths)

50.00%

^[4]

50.00%

^[4]

50.00%

Investment in unconsolidated affiliate

^[4]

$ 409

$ 413

$ 409

$ 413

$ 422

Field Services [Member]

Segment Reporting Information [Line Items]

Revenues

^[5]

370

289

212

Intersegment Revenues

^[5]

Depreciation and Amortization

^[5]

Operating Income (Loss)

^[5]

189

151

Total Assets

^[5]

$ 1,894

$ 1,803

1,894

1,803

1,045

Expenditures for Long-Lived Assets

^[5]

201

668

348

Equity income

^[5]

$ 9

$ 10

$ 8

Interest in jointly-owned asset (in hundredths)

50.00%

^[5]

50.00%

^[5]

50.00%

Investment in unconsolidated affiliate

^[5]

$ 63

$ 55

$ 63

$ 55

$ 40

Other Operations [Member]

Segment Reporting Information [Line Items]

Revenues

Intersegment Revenues

Depreciation and Amortization

Operating Income (Loss)

Total Assets

^[6]

2,318

2,184

2,318

2,184

2,261

Expenditures for Long-Lived Assets

Pension and other postemployment related regulatory assets included in total assets of Other Operations

796

704

796

704

731

Reconciling Eliminations [Member]

Segment Reporting Information [Line Items]

Revenues

Intersegment Revenues

(215)

(234)

(196)

Depreciation and Amortization

Operating Income (Loss)

Total Assets

$ (3,322)

$ (3,130)

(3,322)

(3,130)

(2,483)

Expenditures for Long-Lived Assets

$ 0

[1]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[2]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.
[3]	Sales to affiliates of NRG in 2009, 2010 and 2011 represented approximately $634 million, $583 million and $594 million, respectively, of CenterPoint Houston’s transmission and distribution revenues. Sales to affiliates of Energy Future Holdings Corp. in 2009, 2010 and 2011 represented approximately $182 million, $185 million and $182 million, respectively, of CenterPoint Houston’s transmission and distribution revenues.
[4]	Interstate Pipelines recorded equity income of $7 million, $19 million, and $21 million in the years ended December 31, 2009, 2010 and 2011, respectively, from its 50% interest in SESH, a jointly-owned pipeline. These amounts are included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Interstate Pipelines’ investment in SESH was $422 million, $413 million and $409 million as of December 31, 2009, 2010 and 2011 and is included in Investment in unconsolidated affiliates.
[5]	Field Services recorded equity income of $8 million, $10 million and $9 million for the years ended December 31, 2009, 2010 and 2011, respectively, from its 50% interest in a jointly-owned gas processing plant. These amounts are included in Equity in earnings of unconsolidated affiliates under the Other Income (Expense) caption. Field Services’ investment in the jointly-owned gas processing plant was $40 million, $55 million and $63 million as of December 31, 2009, 2010 and 2011, respectively, and is included in Investment in unconsolidated affiliates.
[6]	Included in total assets of Other Operations as of December 31, 2009, 2010 and 2011, are pension and other postemployment related regulatory assets of $731 million, $704 million and $796 million, respectively.

Reportable Business Segments (Revenues by Products and Services) (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

^[1]

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Revenues by Products and Services:

Electric delivery sales

$ 2,337

$ 2,205

$ 2,013

Retail gas sales

4,019

4,412

4,540

Wholesale gas sales

1,149

1,250

902

Gas transport

824

785

691

Energy products and services

121

133

135

Total

$ 2,145

$ 1,881

$ 1,837

$ 2,587

$ 2,098

$ 1,908

$ 1,756

$ 3,023

$ 8,450

$ 8,785

$ 8,281

[1]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[2]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.

Subsequent Events (Details) - Dividend Declared [Member]	1 Months Ended
	Jan. 19, 2012 USD ($)
Subsequent Event [Line Items]
Subsequent Event, Date	Jan. 19, 2012
Subsequent Event, Amount	$ 0.2025

Schedule I: Financial Information of Centerpoint Energy, Inc. (Parent Company) (Statements of Income) (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

^[2]

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

^[3]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Expenses:

Operation and Maintenance Expenses

$ (1,835)

$ (1,719)

$ (1,664)

Total

(7,152)

(7,536)

(7,157)

Other Income (Expense):

Other Expense

Gain (Loss) on Indexed Debt Securities

(31)

(68)

Interest Expense

(456)

(481)

(513)

Total

(124)

(544)

(576)

Loss Before Income Taxes, Equity in Subsidiaries and Extraordinary Item

1,174

705

548

Income Tax Benefit

(404)

(263)

(176)

Income Before Extraordinary Item

$ 117

^[1]

$ 386

^[1]

$ 119

^[1]

$ 148

^[1]

770

442

372

Extraordinary Item, Net of Tax

^[1]

587

^[1]

587

Net Income

$ 117

$ 973

$ 119

$ 148

$ 124

$ 123

$ 81

$ 114

1,357

442

372

CenterPoint Energy [Member]

Expenses:

Operation and Maintenance Expenses

(12)

(17)

Total

(12)

(17)

Other Income (Expense):

Interest Income from Subsidiaries

Other Expense

(8)

(5)

Gain (Loss) on Indexed Debt Securities

(31)

(68)

Interest Expense to Subsidiaries

(25)

(26)

(25)

Interest Expense

(123)

(132)

(149)

Total

(106)

(189)

(239)

Loss Before Income Taxes, Equity in Subsidiaries and Extraordinary Item

(118)

(201)

(256)

Income Tax Benefit

113

Loss Before Equity in Subsidiaries and Extraordinary Item

(68)

(122)

(143)

Equity Income of Subsidiaries

838

564

515

Income Before Extraordinary Item

770

442

372

Extraordinary Item, Net of Tax

587

Net Income

$ 1,357

$ 442

$ 372

[1]	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).
[2]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[3]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.

Schedule I: Financial Information of Centerpoint Energy, Inc. (Parent Company) (Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Current Assets:
Cash and cash equivalents	$ 220	$ 199	$ 740	$ 167
Other assets	192	274
Total current assets	2,337	2,582
Other Assets:
Other assets	157	172
Total other assets	6,964	5,797
Total Assets	21,703	20,111	19,773
Current Liabilities:
Current portion of indexed debt	131	126	121	117
Current portion of other long-term debt	46	19
Indexed debt securities derivative	197	232	201	133
Accounts payable:
Other	366	438
Total current liabilities	2,593	2,620
Other Liabilities:
Accumulated deferred tax liabilities	3,832	2,934
Benefit obligations	1,065	906
Other	305	447
Total other liabilities	6,247	5,292
Long-Term Debt	8,641	9,001
Shareholders' Equity:
Total shareholders' equity	4,222	3,198	2,639
Total Liabilities and Shareholders' Equity	21,703	20,111
CenterPoint Energy [Member]
Current Assets:
Cash and cash equivalents	0	0	$ 0	$ 0
Notes receivable - subsidiaries	407	530
Accounts receivable - subsidiaries	53	59
Other assets	43	68
Total current assets	503	657
Other Assets:
Investment in subsidiaries	7,538	6,115
Notes receivable - subsidiaries	151	151
Other assets	822	723
Total other assets	8,511	6,989
Total Assets	9,014	7,646
Current Liabilities:
Notes payable - subsidiaries	1,012	900
Current portion of indexed debt	131	126
Current portion of other long-term debt	0	19
Indexed debt securities derivative	197	232
Accounts payable:
Subsidiaries	24	27
Other	0	1
Taxes accrued	426	318
Interest accrued	19	19
Other	1	1
Total current liabilities	1,810	1,643
Other Liabilities:
Accumulated deferred tax liabilities	202	124
Benefit obligations	569	460
Notes payable - subsidiaries	750	750
Other	0	10
Total other liabilities	1,521	1,344
Long-Term Debt	1,461	1,461
Shareholders' Equity:
Common stock	4	4
Additional paid-in capital	4,120	4,100
Retained earnings (accumulated deficit)	231	(789)
Accumulated other comprehensive loss	(133)	(117)
Total shareholders' equity	4,222	3,198
Total Liabilities and Shareholders' Equity	$ 9,014	$ 7,646

Schedule I: Financial Information of Centerpoint Energy, Inc. (Parent Company) (Statements of Cash Flows) (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Operating Activities:

Net Income

$ 117

$ 973

$ 119

$ 148

$ 124

^[1]

$ 123

$ 81

$ 114

^[2]

$ 1,357

$ 442

$ 372

Non-cash items included in net income:

Deferred income tax expense

443

199

269

Amortization of debt issuance costs

Extraordinary item, net of tax

^[3]

$ (587)

^[3]

$ 0

^[3]

(587)

Unrealized loss (gain) on indexed debt securities

(35)

Changes in working capital:

Accounts payable

(81)

(34)

(237)

Other current assets

(2)

Other current liabilities

(1)

Other

(2)

Net cash provided by (used in) operating activities

1,888

1,386

1,841

Investing Activities:

Net cash provided by (used in) investing activities

(1,206)

(1,420)

(896)

Financing Activities:

Revolving credit facility, net

(1,441)

Payments on long-term debt

(909)

(783)

(222)

Debt issuance costs

(24)

(2)

(10)

Common stock dividends paid

(337)

(319)

(276)

Proceeds from issuance of common stock, net

416

504

Net cash provided by (used in) financing activities

(661)

(507)

(372)

Net Decrease in Cash and Cash Equivalents

(541)

573

Cash and Cash Equivalents at Beginning of Year

199

740

199

740

167

Cash and Cash Equivalents at End of Year

220

199

220

199

740

CenterPoint Energy [Member]

Operating Activities:

Net Income

1,357

442

372

Non-cash items included in net income:

Equity income of subsidiaries

(838)

(564)

(515)

Deferred income tax expense

149

(16)

(19)

Amortization of debt issuance costs

Extraordinary item, net of tax

(587)

Unrealized loss (gain) on indexed debt securities

(35)

Changes in working capital:

Accounts receivable/(payable) from subsidiaries, net

Accounts payable

(1)

(16)

Other current assets

(27)

(16)

Other current liabilities

(111)

Common stock dividends received from subsidiaries

109

Other

(62)

(1)

Net cash provided by (used in) operating activities

122

(162)

162

Investing Activities:

Short-term notes receivable from subsidiaries

123

(37)

(411)

Net cash provided by (used in) investing activities

123

(37)

(411)

Financing Activities:

Revolving credit facility, net

(264)

Payments on long-term debt

(19)

(490)

Debt issuance costs

(7)

(2)

Common stock dividends paid

(337)

(319)

(276)

Proceeds from issuance of common stock, net

416

504

Short-term notes payable to subsidiaries

112

594

285

Net cash provided by (used in) financing activities

(245)

199

249

Net Decrease in Cash and Cash Equivalents

Cash and Cash Equivalents at Beginning of Year

$ 0

Cash and Cash Equivalents at End of Year

$ 0

[1]	During the fourth quarter of 2010, CenterPoint Energy recorded a $21 million gain on the sale of non-strategic gathering assets by its Field Services business segment. CenterPoint Energy also recorded a $24 million decrease in income tax expense related to the effects of re-measuring accumulated deferred income taxes associated with the restructuring of certain subsidiaries.
[2]	During the first quarter of 2010, CenterPoint Energy recorded a $21 million charge to income tax expense as a result of a change in tax law upon the enactment in March 2010 of the Patient Protection and Affordable Care Act and the related Health Care and Education Reconciliation Act of 2010.
[3]	During the third quarter of 2011, CenterPoint Energy recorded an extraordinary gain of $587 million, after-tax, related to the Final Order and a $224 million, after-tax, return on true-up balance included in Income before extraordinary item related to a portion of interest on the appealed amount as discussed in Note 5(b).

Schedule I: Financial Information of Centerpoint Energy, Inc. (Parent Company) (Note Disclosures) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)
Notes to Financial Statements of Parent, Long-Term Debt:
Maximum amount of credit facility	$ 2,450	$ 2,360
CenterPoint Energy [Member]
Notes to Financial Statements of Parent Background:
Maximum percentage of debt to capitalization of indirect wholly owned subsidiaries that could restrict dividend distributions (in hundredths)	65.00%
Notes to Financial Statements of Parent, Long-Term Debt:
Amount of outstanding letters of credit	$ 16	20
Maximum amount of credit facility	1,200	1,156
Commercial paper outstanding	$ 0	$ 0
First drawn cost of credit facility based on credit rating	London Interbank Offered Rate (LIBOR) plus 175 basis points
Original maximum debt to earnings ratio allowed under credit facility covenants	5
Amended temporary maximum debt to earning ratio allowed under credit facility covenants	5.5
Minimum amount of system restoration costs incurred in a calendar year which allows temporary increase of permitted ration of debt to earnings	$ 100
Debt Maturities in 2012	0
Debt Maturities in 2013	0
Debt Maturities in 2014	0
Debt Maturities in 2015	420
Debt Maturities in 2016	$ 0
Typical term for obligations of subsidiary guaranteed by Company (in years)	1
Amount of outstanding guarantee	$ 5
Maximum amount of guarantees reduce to plus any additional amounts related to expansion of services upon completion of gathering systems	100
Total guarantee amount for expenses of subsidiary in gathering and treating services under agreements	$ 100

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Uncollectible accounts receivable [Member]

Movement in Valuation Allowances and Reserves [Roll Forward]

Balance at Beginning of Period

$ 25

$ 24

$ 35

Additions Charged to Income

Additions Charged to Other Accounts

Deductions From Reserves

^[1]

Balance at End of Period

Deferred tax asset valuation allowance [Member]

Movement in Valuation Allowances and Reserves [Roll Forward]

Balance at Beginning of Period

Additions Charged to Income

(2)

Additions Charged to Other Accounts

Deductions From Reserves

^[1]

Balance at End of Period

$ 4

$ 3

$ 5

[1]	Deductions from reserves represent losses or expenses for which the respective reserves were created. In the case of the uncollectible accounts reserve, such deductions are net of recoveries of amounts previously written off.