Equity Securities and Indexed Debt Securities (ZENS) (CenterPoint Energy) - Schedule of Securities Classified as Trading (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value	$ 477	$ 541
AT&T Common
Debt and Equity Securities, FV-NI [Line Items]
Balance of investment owned (in shares)	10,212,945	10,212,945
Carrying Value	$ 195	$ 171
Charter Common
Debt and Equity Securities, FV-NI [Line Items]
Balance of investment owned (in shares)	872,503	872,503
Carrying Value	$ 261	$ 339
WBD Common
Debt and Equity Securities, FV-NI [Line Items]
Balance of investment owned (in shares)	2,470,685	2,470,685
Carrying Value	$ 18	$ 28
Other
Debt and Equity Securities, FV-NI [Line Items]
Carrying Value	$ 3	$ 3