Derivative Instruments (Notional Values) (Details) (Southern California Edison, Electric Utility, Economic hedges)	Mar. 31, 2015 GWh	Dec. 31, 2014 GWh
Electricity options, swaps and forwards (GWh)
Derivatives
Notional volumes of derivative instruments	3,044	3,618
Natural gas options, swaps and forwards (Bcf)
Derivatives
Notional volumes of derivative instruments	62	83
Congestion revenue rights (GWh)
Derivatives
Notional volumes of derivative instruments	112,090	122,859
Tolling arrangements (GWh)
Derivatives
Notional volumes of derivative instruments	77,684	79,989