Regulatory Matters - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 3,716	$ 2,112
Total current regulatory assets	1,395	18
Non-current regulatory assets	2,321	2,094
Total Regulatory Liabilities	3,174	3,520
Total Current Regulatory Liabilities	21	72
Total Non-Current Regulatory Liabilities	3,153	3,448
Regulatory liabilities related to TCJA
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,389	1,484
Estimated removal costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,304	1,470
Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	481	566
Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total current regulatory assets	1,256
Future Amounts Recoverable From Ratepayers
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	693	760
Future Amounts Recoverable From Ratepayers | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	412	550
Future Amounts Recoverable From Ratepayers | Asset retirement obligations & other
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	240	173
Future Amounts Recoverable From Ratepayers | Net deferred income taxes
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	41	37
Amounts Deferred For Future Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	1,921	339
Amounts Deferred For Future Recovery | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	29	9
Amounts Deferred For Future Recovery | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	1,528
Amounts Deferred For Future Recovery | Cost recovery riders
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	124	221
Amounts Deferred For Future Recovery | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	105	36
Amounts Deferred For Future Recovery | Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	94	90
Amounts Deferred For Future Recovery | Decoupling Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	25	2
Amounts Deferred For Future Recovery | COVID-19 incremental costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	23	23
Amounts Deferred For Future Recovery | Emergency generation costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	21
Amounts Deferred For Future Recovery | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(28)	(42)
Amounts Currently Recovered In Customer Rates
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	1,102	1,013
Amounts Currently Recovered In Customer Rates | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	28	37
Amounts Currently Recovered In Customer Rates | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	72	7
Amounts Currently Recovered In Customer Rates | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	66
Amounts Currently Recovered In Customer Rates | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	43	55
Amounts Currently Recovered In Customer Rates | Tax Cuts and Jobs Act Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	48	25
Amounts Currently Recovered In Customer Rates | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(171)	(187)
Amounts Currently Recovered In Customer Rates | Authorized trackers and cost deferrals
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	504	332
Amounts Currently Recovered In Customer Rates | Securitized regulatory assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	420	633
Amounts Currently Recovered In Customer Rates | Unamortized loss on reacquired debt and hedging
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	92	111
Amounts Currently Recovered In Customer Rates, Earning Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	558
Amounts Currently Recovered In Customer Rates, Not Earning A Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 175
Remaining weighted average period for which no return on investment during recovery period is provided	11 years
Houston Electric
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 789	848
Total current regulatory assets	0	0
Non-current regulatory assets	789	848
Total Regulatory Liabilities	1,172	1,295
Total Current Regulatory Liabilities	20	43
Total Non-Current Regulatory Liabilities	1,152	1,252
Houston Electric | Regulatory liabilities related to TCJA
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	738	764
Houston Electric | Estimated removal costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	229	231
Houston Electric | Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	205	300
Houston Electric | Future Amounts Recoverable From Ratepayers
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	74	64
Houston Electric | Future Amounts Recoverable From Ratepayers | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
Houston Electric | Future Amounts Recoverable From Ratepayers | Asset retirement obligations & other
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	45	39
Houston Electric | Future Amounts Recoverable From Ratepayers | Net deferred income taxes
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	29	25
Houston Electric | Amounts Deferred For Future Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	188	79
Houston Electric | Amounts Deferred For Future Recovery | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
Houston Electric | Amounts Deferred For Future Recovery | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0
Houston Electric | Amounts Deferred For Future Recovery | Cost recovery riders
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
Houston Electric | Amounts Deferred For Future Recovery | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	105	36
Houston Electric | Amounts Deferred For Future Recovery | Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	57	38
Houston Electric | Amounts Deferred For Future Recovery | Decoupling Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
Houston Electric | Amounts Deferred For Future Recovery | COVID-19 incremental costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	8	5
Houston Electric | Amounts Deferred For Future Recovery | Emergency generation costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	21
Houston Electric | Amounts Deferred For Future Recovery | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(3)	0
Houston Electric | Amounts Currently Recovered In Customer Rates
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	527	705
Houston Electric | Amounts Currently Recovered In Customer Rates | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	24	31
Houston Electric | Amounts Currently Recovered In Customer Rates | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
Houston Electric | Amounts Currently Recovered In Customer Rates | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0
Houston Electric | Amounts Currently Recovered In Customer Rates | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	43	55
Houston Electric | Amounts Currently Recovered In Customer Rates | Tax Cuts and Jobs Act Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	46	20
Houston Electric | Amounts Currently Recovered In Customer Rates | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(97)	(137)
Houston Electric | Amounts Currently Recovered In Customer Rates | Authorized trackers and cost deferrals
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	24	30
Houston Electric | Amounts Currently Recovered In Customer Rates | Securitized regulatory assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	420	633
Houston Electric | Amounts Currently Recovered In Customer Rates | Unamortized loss on reacquired debt and hedging
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	67	73
Houston Electric | Amounts Currently Recovered In Customer Rates, Earning Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	459
Houston Electric | Amounts Currently Recovered In Customer Rates, Not Earning A Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 67
Remaining weighted average period for which no return on investment during recovery period is provided	23 years
CERC Corp
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 1,866	238
Total current regulatory assets	1,289	18
Non-current regulatory assets	577	220
Total Regulatory Liabilities	980	1,255
Total Current Regulatory Liabilities	1	29
Total Non-Current Regulatory Liabilities	979	1,226
CERC Corp | Regulatory liabilities related to TCJA
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	400	421
CERC Corp | Estimated removal costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	452	656
CERC Corp | Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	128	178
CERC Corp | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total current regulatory assets	1,182
CERC Corp | Future Amounts Recoverable From Ratepayers
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	199	132
CERC Corp | Future Amounts Recoverable From Ratepayers | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	5	4
CERC Corp | Future Amounts Recoverable From Ratepayers | Asset retirement obligations & other
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	192	125
CERC Corp | Future Amounts Recoverable From Ratepayers | Net deferred income taxes
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	2	3
CERC Corp | Amounts Deferred For Future Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	1,556	76
CERC Corp | Amounts Deferred For Future Recovery | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	29	9
CERC Corp | Amounts Deferred For Future Recovery | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	1,454
CERC Corp | Amounts Deferred For Future Recovery | Cost recovery riders
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
CERC Corp | Amounts Deferred For Future Recovery | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
CERC Corp | Amounts Deferred For Future Recovery | Other Regulatory Assets (Liabilities)
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	37	52
CERC Corp | Amounts Deferred For Future Recovery | Decoupling Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	25	2
CERC Corp | Amounts Deferred For Future Recovery | COVID-19 incremental costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	15	18
CERC Corp | Amounts Deferred For Future Recovery | Emergency generation costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0
CERC Corp | Amounts Deferred For Future Recovery | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(4)	(5)
CERC Corp | Amounts Currently Recovered In Customer Rates
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	111	30
CERC Corp | Amounts Currently Recovered In Customer Rates | Benefit obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	4	6
CERC Corp | Amounts Currently Recovered In Customer Rates | Gas Recovery
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	40	7
CERC Corp | Amounts Currently Recovered In Customer Rates | Extraordinary Gas Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	66
CERC Corp | Amounts Currently Recovered In Customer Rates | Storm Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
CERC Corp | Amounts Currently Recovered In Customer Rates | Tax Cuts and Jobs Act Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	2	5
CERC Corp | Amounts Currently Recovered In Customer Rates | Unrecognized equity return
Schedule of Regulatory Assets and Liabilities [Line Items]
Unrecognized equity return	(12)	(8)
CERC Corp | Amounts Currently Recovered In Customer Rates | Authorized trackers and cost deferrals
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	11	20
CERC Corp | Amounts Currently Recovered In Customer Rates | Securitized regulatory assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	0
CERC Corp | Amounts Currently Recovered In Customer Rates | Unamortized loss on reacquired debt and hedging
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	0	$ 0
CERC Corp | Amounts Currently Recovered In Customer Rates, Earning Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	7
CERC Corp | Amounts Currently Recovered In Customer Rates, Not Earning A Return
Schedule of Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 69
Remaining weighted average period for which no return on investment during recovery period is provided	2 years