Derivative Instruments (Notional Values) (Details) - Southern California Edison - Electric Utility - Economic Hedges GWh in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017 GWh Bcfe	Dec. 31, 2016 GWh Bcfe
Electricity options, swaps and forwards (GWh)
Derivative [Line Items]
Notional volumes of derivative instruments	1,731	1,816
Natural gas options, swaps and forwards (Bcf)
Derivative [Line Items]
Notional volumes of derivative instruments | Bcfe	144	36
Congestion revenue rights (GWh)
Derivative [Line Items]
Notional volumes of derivative instruments	63,103	93,319
Tolling arrangements (GWh)
Derivative [Line Items]
Notional volumes of derivative instruments	41,924	61,093