v3.10.0.1
Document and Entity Information - USD ($)
9 Months Ended
Sep. 30, 2018
Oct. 22, 2018
Jun. 30, 2017
Entity Information [Line Items]      
Entity Registrant Name CENTERPOINT ENERGY INC.    
Entity Central Index Key 0001130310    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Document Type 10-Q    
Document Period End Date Sep. 30, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus Q3    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   501,191,387  
Entity Current Reporting Status Yes    
Entity Public Float     $ 11,722,467,012
Houston Electric [Member]      
Entity Information [Line Items]      
Entity Registrant Name CENTERPOINT ENERGY HOUSTON ELECTRIC LLC    
Entity Central Index Key 0000048732    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Document Type 10-Q    
Document Period End Date Sep. 30, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus Q3    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   1,000  
Entity Current Reporting Status Yes    
CERC Corp [Member]      
Entity Information [Line Items]      
Entity Registrant Name CENTERPOINT ENERGY RESOURCES CORP    
Entity Central Index Key 0001042773    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Document Type 10-Q    
Document Period End Date Sep. 30, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus Q3    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   1,000  
Entity Current Reporting Status Yes