Commodity Derivatives (Details) MWh in Millions, MMBTU in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022 USD ($) MMBTU MWh	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) MMBTU MWh	Sep. 30, 2021 USD ($)	Dec. 31, 2021 MWh MMBTU
Other Derivative Instruments
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities		$ 0	$ 62	$ 103	$ 75
Cash Flow Hedge Commodity [Member]
Derivative [Line Items]
Commodity contracts designated as cash flow hedges		$ 0		$ 0
Electric Commodity [Member]
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]
Derivative, Nonmonetary Notional Amount | MWh	[1],[2]	82		82		80
Natural Gas Commodity
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]
Derivative, Nonmonetary Notional Amount | MMBTU	[1],[2]	151		151		156
Natural Gas Commodity | Other Derivative Instruments
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities		$ (6)	$ 57	$ (3)	$ 57

[1] Not reflective of net positions in the underlying commodities.

[2] Notional amounts for options included on a gross basis but weighted for the probability of exercise.