Risk Management and Hedging Activities - NPC - Derivative Contract Volumes (Details) - NPC - Commodity derivatives MWh in Millions, Dth in Millions	12 Months Ended
	Dec. 31, 2023 Dth MWh	Dec. 31, 2022 Dth MWh
Electricity purchases, net
Notional Amounts of Outstanding Derivative Positions [Line Items]
Notional amount, energy | MWh	1	2
Natural gas purchases
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | Dth	132	109