Income Taxes - Schedule of Income Tax Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income tax reconciliation [Abstract]
Income before income taxes	$ 1,417	$ 778	$ 563
Increase (decrease) in tax expense resulting from:
Total income tax expense (benefit)	$ 360	$ 110	$ 80
Houston Electric
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	20.00%	17.00%	14.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 635	$ 457	$ 387
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 133	$ 96	$ 81
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	13	18	15
Excess deferred income tax amortization	(18)	(41)	(42)
Other, net	(3)	3	(1)
Total	(8)	(20)	(28)
Total income tax expense (benefit)	$ 125	$ 76	$ 53
Effective tax rate (as a percent)	20.00%	17.00%	14.00%
CERC Corp
Income tax reconciliation [Abstract]
Income before income taxes	$ 961	$ 466	$ 382
Increase (decrease) in tax expense resulting from:
Total income tax expense (benefit)	$ 236	$ 76	$ 117
Continuing Operations
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	25.00%	14.00%	14.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 1,417	$ 778	$ 563
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 298	$ 163	$ 118
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	46	63	40
State law change, net of federal income tax	0	23	0
State valuation allowance, net of federal income tax	0	(15)	1
Excess deferred income tax amortization	(51)	(75)	(76)
Goodwill Impairment	84	0	39
Net operating loss carryback	0	0	(37)
Other, net	(17)	(3)	(5)
Total	62	(53)	(38)
Total income tax expense (benefit)	$ 360	$ 110	$ 80
Effective tax rate (as a percent)	25.00%	14.00%	14.00%
Continuing Operations | CERC Corp
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	25.00%	16.00%	31.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 961	$ 466	$ 382
Federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Expected federal income tax expense	$ 202	$ 98	$ 80
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	35	31	59
State law change, net of federal income tax	0	9	0
State valuation allowance, net of federal income tax	0	(15)	1
Excess deferred income tax amortization	(28)	(30)	(29)
Goodwill Impairment	30	0	0
Other, net	(3)	1	6
Total	34	(22)	37
Total income tax expense (benefit)	$ 236	$ 76	$ 117
Effective tax rate (as a percent)	25.00%	16.00%	31.00%
Discontinued Operations
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	0.00%	20.00%	21.00%
Income tax reconciliation [Abstract]
Income before income taxes	$ 0	$ 1,019	$ (1,589)
Federal statutory income tax rate (as a percent)	0.00%	21.00%	21.00%
Expected federal income tax expense	$ 0	$ 214	$ (334)
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	0	14	(60)
State law change, net of federal income tax	0	27	0
Goodwill Impairment	0	0	25
Tax impact of sale of Energy Services and Infrastructure Services Disposal Groups	0	0	30
Other, net	0	0	6
Total	0	(13)	1
Total income tax expense (benefit)	$ 0	$ 201	$ (333)
Effective tax rate (as a percent)	0.00%	20.00%	21.00%
Discontinued Operations | CERC Corp
Other Tax Carryforward [Line Items]
Effective tax rate (as a percent)	0.00%	0.00%	3.00%
Income tax reconciliation [Abstract]
Income (loss) before income taxes	$ 0	$ 0	$ (68)
Federal statutory income tax rate (as a percent)	0.00%	0.00%	21.00%
Expected federal income tax expense	$ 0	$ 0	$ (14)
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	0	0	(2)
Goodwill Impairment	0	0	10
Other, net	0	0	4
Total	0	0	12
Total income tax expense (benefit)	$ 0	$ 0	$ (2)
Effective tax rate (as a percent)	0.00%	0.00%	3.00%