Regulatory Matters - Narrative (Details) $ in Millions					12 Months Ended
	Apr. 05, 2023 USD ($)	Mar. 23, 2023 USD ($)	Oct. 13, 2022 USD ($)	Jul. 01, 2022 USD ($)	Dec. 31, 2021 lease	Mar. 31, 2023 USD ($)	Mar. 24, 2023 USD ($)	Jan. 04, 2023 USD ($)	Dec. 31, 2022 USD ($)	Oct. 19, 2022 USD ($)	May 10, 2022 USD ($)
Regulatory Assets [Line Items]
Regulatory assets current						$ 269			$ 1,385
Regulatory assets noncurrent						2,499			2,193
Disallowance of regulatory asset						53
Regulatory asset, authorized issuance costs							$ 350
Regulatory Asset Remaining To Recover Through Rates Amount						8			11
Regulatory liability, approximate total gas cost						17			17
February 2021 Winter Storm
Regulatory Assets [Line Items]
Regulatory assets current						102
February 2021 Winter Storm | REP Bad Debt Expense
Regulatory Assets [Line Items]
Regulatory assets						8			8
February 2021 Winter Storm | Operation and maintenance expense
Regulatory Assets [Line Items]
Regulatory assets						16
CERC
Regulatory Assets [Line Items]
Regulatory assets current						227			1,336
Regulatory assets noncurrent						833			844
Regulatory Asset Remaining To Recover Through Rates Amount						8			10
Regulatory liability, approximate total gas cost						17			17
CERC | February 2021 Winter Storm
Regulatory Assets [Line Items]
Regulatory assets current						102
Regulatory assets noncurrent						161
Houston Electric
Regulatory Assets [Line Items]
Regulatory assets noncurrent						818			778
Disallowance of regulatory asset						53
Number of leases entered into | lease					2
Regulatory asset, revenue requirement amount			$ 39
Houston Electric | Subsequent Event
Regulatory Assets [Line Items]
Regulatory asset, revenue requirement amount	$ 188
Houston Electric | February 2021 Winter Storm | REP Bad Debt Expense
Regulatory Assets [Line Items]
Regulatory assets						8			8
Houston Electric | February 2021 Winter Storm | Operation and maintenance expense
Regulatory Assets [Line Items]
Regulatory assets						16
Minnesota Public Utility Commission | CERC
Regulatory Assets [Line Items]
Disallowance of regulatory asset										$ 36
Attorney General's Office | CERC
Regulatory Assets [Line Items]
Regulatory assets										$ 409
IURC
Regulatory Assets [Line Items]
Regulatory asset, estimated qualified costs											$ 360
Regulatory asset, financed qualified costs											350
Regulatory asset, estimated ongoing costs											$ 10
Regulatory asset, authorized issuance costs								$ 350
Regulatory asset, property, plant and equipment						257
Public Utility Commission Of Texas | Houston Electric
Regulatory Assets [Line Items]
Recovery of deferred costs sought				$ 200
Annual revenue increase from lease agreements				$ 57
Public Utility Commission Of Texas | Houston Electric | Subsequent Event
Regulatory Assets [Line Items]
Regulatory asset, revenue requirement amount	$ 39
February 2021 Winter Storm Event
Regulatory Assets [Line Items]
Regulatory asset, approximate total gas cost						2,000
Regulatory assets current									1,175
Regulatory assets noncurrent						161			202
Regulatory liability, amount remaining under prudence review						$ 75
February 2021 Winter Storm Event | Customer Rate Relief Bond Financing
Regulatory Assets [Line Items]
Cash Proceeds Received From Government Grants		$ 1,100
February 2021 Winter Storm Event | CERC
Regulatory Assets [Line Items]
Regulatory assets current									1,175
Regulatory assets noncurrent									$ 202