Income Taxes - Schedule of Income Tax Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income tax reconciliation [Abstract]
Income before income taxes	$ 1,087	$ 1,417	$ 778
Increase (decrease) in tax expense resulting from:
Total income tax expense (benefit)	$ 170	$ 360	$ 110
Houston Electric
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	22.00%	20.00%	17.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 761	$ 635	$ 457
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 160	$ 133	$ 96
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	27	13	18
Excess deferred income tax amortization	(17)	(18)	(41)
Other, net	(2)	(3)	3
Total	8	(8)	(20)
Total income tax expense (benefit)	$ 168	$ 125	$ 76
Effective tax rate (as a percent)	22.00%	20.00%	17.00%
CERC Corp
Income tax reconciliation [Abstract]
Income before income taxes	$ 486	$ 961	$ 466
Increase (decrease) in tax expense resulting from:
Total income tax expense (benefit)	$ (26)	$ 236	$ 76
Consolidated
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	16.00%	25.00%	14.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 1,087	$ 1,417	$ 778
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 228	$ 298	$ 163
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	25	46	63
State valuation allowance, net of federal income tax	0	0	(15)
State law change, net of federal income tax	69	0	23
Equity AFUDC	13	8	6
Excess deferred income tax amortization	(44)	(51)	(75)
Goodwill impairment	0	84	0
Sale of Energy Systems Group	28	0	0
Other, net	15	(9)	3
Total	(58)	62	(53)
Total income tax expense (benefit)	170	$ 360	$ 110
Income tax rate reconciliation, state deferred remeasurement, net of federal income tax	$ (69)
Effective tax rate (as a percent)	16.00%	25.00%	14.00%
Consolidated | CERC Corp
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	(5.00%)	25.00%	16.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 486	$ 961	$ 466
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 102	$ 202	$ 98
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	(40)	35	31
State valuation allowance, net of federal income tax	0	0	(15)
State law change, net of federal income tax	66	0	9
Excess deferred income tax amortization	(23)	(28)	(30)
Goodwill impairment	0	30	0
Other, net	1	(3)	1
Total	(128)	34	(22)
Total income tax expense (benefit)	(26)	$ 236	$ 76
Income tax rate reconciliation, state deferred remeasurement, net of federal income tax	$ (66)
Effective tax rate (as a percent)	(5.00%)	25.00%	16.00%
Discontinued Operations
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	0.00%	0.00%	20.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 0	$ 0	$ 1,019
Federal statutory income tax rate (as a percent)	0.00%	0.00%	21.00%
Expected federal income tax expense	$ 0	$ 0	$ 214
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	0	0	14
State law change, net of federal income tax	0	0	27
Total	0	0	(13)
Total income tax expense (benefit)	$ 0	$ 0	$ 201
Effective tax rate (as a percent)	0.00%	0.00%	20.00%