Equity Securities and Indexed Debt Securities (ZENS) (CenterPoint Energy) - Schedule of Gain (Loss) On Equity Securities (CenterPoint Energy) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	$ (61)	$ 75	$ (78)	$ 52
AT&T Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	(27)	(15)	(37)	0
Charter Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	(67)	90	(160)	52
WBD Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	33	0	33	0
Energy Transfer Common Units
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	0	0	95	0
Energy Transfer Series G Preferred Units
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	0	0	(9)	0
Other
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	$ 0	$ 0	$ 0	$ 0