Document and Entity Information - USD ($)	3 Months Ended
	Mar. 31, 2019	Apr. 25, 2019	Jun. 30, 2018
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	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		502,173,861
Entity Current Reporting Status	Yes
Entity Public Float			$ 11,873,304,802
Entity Small Business	false
Entity Emerging Growth Company	false
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	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,000
Entity Current Reporting Status	Yes
Entity Public Float			0
Entity Small Business	false
Entity Emerging Growth Company	false
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	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,000
Entity Current Reporting Status	Yes
Entity Public Float			$ 0
Entity Small Business	false
Entity Emerging Growth Company	false