Derivative Instruments (Notional Values) (Details) - SCE - Electric Utility - Gross amounts recognized MWh in Thousands	Dec. 31, 2016 Bcfe MWh	Dec. 31, 2015 Bcfe MWh
Electricity options, swaps and forwards (GWh)
Derivatives
Notional volumes of derivative instruments	1,816	6,221
Natural gas options, swaps and forwards (Bcf)
Derivatives
Notional volumes of derivative instruments | Bcfe	36	32
Congestion revenue rights (GWh)
Derivatives
Notional volumes of derivative instruments	93,319	109,740
Tolling arrangements (GWh)
Derivatives
Notional volumes of derivative instruments	61,093	70,663