Regulatory Matters (Details) $ in Millions			3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 05, 2022 USD ($)	Jul. 01, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) lease	Aug. 11, 2022 USD ($)	Dec. 22, 2021 USD ($)
Regulatory Assets [Line Items]
Allowed equity return not recognized			$ 185		$ 185		$ 199
Allowed equity return recognized			14	$ 12	36	$ 31
Regulatory assets			1,377		1,377		1,395
Non-current regulatory asset			2,212		2,212		2,321
February 2021 Winter Storm Event
Regulatory Assets [Line Items]
Regulatory assets							1,410
Non-current regulatory asset							583
February 2021 Winter Storm Event | Arkansas and Oklahoma Natural Gas Businesses
Regulatory Assets [Line Items]
Regulatory assets							154
Non-current regulatory asset							244
February 2021 Winter Storm
Regulatory Assets [Line Items]
Regulatory assets			1,175		1,175
Non-current regulatory asset			225		225
February 2021 Winter Storm | REP Bad Debt Expense
Regulatory Assets [Line Items]
Regulatory assets			8		8		8
February 2021 Winter Storm | Operation and maintenance expense
Regulatory Assets [Line Items]
Regulatory assets			16		16		15
Houston Electric
Regulatory Assets [Line Items]
Allowed equity return not recognized			83		83		100
Allowed equity return recognized			12	11	33	29
Non-current regulatory asset			768		768		$ 789
Number of leases entered into | lease							2
Houston Electric | February 2021 Winter Storm | REP Bad Debt Expense
Regulatory Assets [Line Items]
Regulatory assets			8		8		$ 8
Houston Electric | February 2021 Winter Storm | Operation and maintenance expense
Regulatory Assets [Line Items]
Regulatory assets			16		16		15
Houston Electric | Public Utility Commission Of Texas
Regulatory Assets [Line Items]
Recovery of deferred costs sought		$ 200
Annual revenue increase from lease agreements		$ 57
Houston Electric | Public Utility Commission Of Texas | Subsequent Event
Regulatory Assets [Line Items]
Potential disallowance of recovery of costs	$ 805
Houston Electric | Public Utility Commission Of Texas | Minimum | Subsequent Event
Regulatory Assets [Line Items]
Estimated financial impact	335
Houston Electric | Public Utility Commission Of Texas | Maximum | Subsequent Event
Regulatory Assets [Line Items]
Estimated financial impact	$ 354
CERC
Regulatory Assets [Line Items]
Allowed equity return not recognized			52		52		51
Allowed equity return recognized			1	$ 0	2	$ 1
Regulatory assets			1,340		1,340		1,371
Non-current regulatory asset			856		856		938
CERC | Minimum
Regulatory Assets [Line Items]
Proposed disallowance of regulatory asset									$ 45
CERC | Maximum
Regulatory Assets [Line Items]
Proposed disallowance of regulatory asset									409
CERC | February 2021 Winter Storm Event
Regulatory Assets [Line Items]
Regulatory liabilities			398		398
Regulatory assets							1,399
Non-current regulatory asset							583
CERC | February 2021 Winter Storm Event | Arkansas and Oklahoma Natural Gas Businesses
Regulatory Assets [Line Items]
Regulatory assets							154
Non-current regulatory asset							$ 244
CERC | February 2021 Winter Storm
Regulatory Assets [Line Items]
Regulatory assets			1,175		1,175
Non-current regulatory asset			$ 225		$ 225
CERC | Attorney General's Office
Regulatory Assets [Line Items]
Regulatory assets									$ 409
CERC | Minnesota Public Utility Commission
Regulatory Assets [Line Items]
Disallowance of regulatory asset								$ 36