Equity Securities and Indexed Debt Securities (ZENS) (CenterPoint Energy) - Summarized Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	$ 1,439
Indexed debt, net	7	$ 10
Indexed debt securities derivative	578	903
Gain (loss) on indexed debt securities	(325)	(50)	$ 60
Gain (loss) on ZENS-related securities	(227)	(172)	49
Ending balance	510	1,439
ZENS-Related Securities
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	820	871	822
Accretion of debt component of ZENS	0	0	0
2% interest paid	0	0	0
Distribution to ZENS holders	0	0	0
Gain (loss) on indexed debt securities	0	0	0
Gain (loss) on ZENS-related securities	(313)	(51)	49
Ending balance	507	820	871
Debt Component Of ZENS
Debt and Equity Securities, FV-NI [Line Items]
Indexed debt, net	7	10	15	$ 19
Accretion of debt component of ZENS	17	17	17
2% interest paid	(17)	(17)	(16)
Distribution to ZENS holders	(3)	(5)	(5)
Gain (loss) on indexed debt securities	0	0	0
Gain (loss) on ZENS-related securities	0	0	0
Derivative Component Of ZENS
Debt and Equity Securities, FV-NI [Line Items]
Indexed debt securities derivative	578	903	953	$ 893
Accretion of debt component of ZENS	0	0	0
2% interest paid	0	0	0
Distribution to ZENS holders	0	0	0
Gain (loss) on indexed debt securities	(325)	(50)	60
Gain (loss) on ZENS-related securities	$ 0	$ 0	$ 0