Derivative Instruments (Notional Values) (Details) - SCE	9 Months Ended	12 Months Ended
	Sep. 30, 2021 GWh Bcfe	Dec. 31, 2020 GWh Bcfe
Electricity options, swaps and forwards (GWh)
Derivatives
Notional volumes of derivative instruments	1,036	1,581
Natural gas options, swaps and forwards (Bcf)
Derivatives
Notional volumes of derivative instruments | Bcfe	50	34
Congestion revenue rights (GWh)
Derivatives
Notional volumes of derivative instruments	41,573	41,151