Risk Management and Hedging Activities - PAC - Derivative Contract Volumes (Details) - PAC - Commodity derivatives MWh in Millions, Dth in Millions	Dec. 31, 2021 MWh Dth	Dec. 31, 2020 MWh Dth
Electricity purchases (sales), net
Notional Amounts of Outstanding Derivative Positions [Line Items]
Electricity purchases (sales), net | MWh	2	(1)
Natural gas purchases
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | Dth	106	100