Related Party Transactions (Houston Electric and CERC) - Schedule of Amounts Charged For Services (Details) - Operation And Maintenance Expense - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Houston Electric
Related Party Transaction [Line Items]
Net affiliate service charges (billings)	$ (10)	$ 15	$ (7)
CERC Corp
Related Party Transaction [Line Items]
Net affiliate service charges (billings)	10	(15)	7
CenterPoint Energy | Houston Electric
Related Party Transaction [Line Items]
Corporate service charges	173	167	189
CenterPoint Energy | CERC Corp
Related Party Transaction [Line Items]
Corporate service charges	$ 236	$ 237	$ 257