Derivative Instruments and Hedging Activities (Notional Values) (Details) (Southern California Edison, Electric Utility, Economic hedges)	Dec. 31, 2012 GWh	Dec. 31, 2011 GWh
Electricity options, swaps and forwards (GWh)
Derivatives
Notional volumes of derivative instruments	15,884	30,811
Natural gas options, swaps and forwards (Bcf)
Derivatives
Notional volumes of derivative instruments	100	300
Congestion revenue rights (GWh)
Derivatives
Notional volumes of derivative instruments	149,774	166,163
Tolling arrangements (GWh)
Derivatives
Notional volumes of derivative instruments	101,485	104,154