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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	$ (206)	$ (12)	$ (284)	$ 40
AT&T Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	(57)	(18)	(94)	(18)
Charter Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	(144)	6	(304)	58
WBD Common
Debt and Equity Securities, FV-NI [Line Items]
Gain (loss) on equity securities	(5)	0	28	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