Derivative Instruments (Notional Values) (Details) - Southern California Edison - Electric Utility - Gross amounts recognized MWh in Thousands	Dec. 31, 2015 MWh MMcf	Dec. 31, 2014 MWh MMcf
Electricity options, swaps and forwards (GWh)
Derivatives
Notional volumes of derivative instruments	6,221	3,618
Natural gas options, swaps and forwards (Bcf)
Derivatives
Notional volumes of derivative instruments | MMcf	32	83
Congestion revenue rights (GWh)
Derivatives
Notional volumes of derivative instruments	109,740	122,859
Tolling arrangements (GWh)
Derivatives
Notional volumes of derivative instruments	70,663	79,989