Equity Securities and Indexed Debt Securities (ZENS) (CenterPoint Energy) - Summarized Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	$ 510
Beginning balance	7
Beginning balance	578
Gain (loss) on indexed debt securities	27	$ (325)	$ (50)
Gain (loss) on ZENS-related securities	31	(227)	(172)
Ending balance	541	510
Ending balance	5	7
Ending balance	605	578
ZENS-Related Securities
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	507	820	871
Accretion of debt component of ZENS	0	0	0
2% interest paid	0	0	0
Redemption of Series A Preferred Stock	0	0	0
Gain (loss) on indexed debt securities	0	0	0
Gain (loss) on ZENS-related securities	31	(313)	(51)
Ending balance	538	507	820
Debt Component Of ZENS
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	7	10	15
Accretion of debt component of ZENS	17	17	17
2% interest paid	(17)	(17)	(17)
Redemption of Series A Preferred Stock	(2)	(3)	(5)
Gain (loss) on indexed debt securities	0	0	0
Gain (loss) on ZENS-related securities	0	0	0
Ending balance	5	7	10
Derivative Component Of ZENS
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	578	903	953
Accretion of debt component of ZENS	0	0	0
2% interest paid	0	0	0
Redemption of Series A Preferred Stock	0	0	0
Gain (loss) on indexed debt securities	27	(325)	(50)
Gain (loss) on ZENS-related securities	0	0	0
Ending balance	$ 605	$ 578	$ 903