Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Current regulatory assets	$ 634	$ 350
Long-term regulatory assets	7,850	7,455
Environmental remediation
Regulatory Assets [Line Items]
Long-term regulatory assets	123	126
Southern California Edison
Regulatory Assets [Line Items]
Current regulatory assets	634	350
Long-term regulatory assets	7,850	7,455
Total regulatory assets	8,484	7,805
Southern California Edison | Regulatory balancing accounts
Regulatory Assets [Line Items]
Current regulatory assets	374	135
Long-term regulatory assets	72	66
Southern California Edison | Energy derivatives and other power contracts
Regulatory Assets [Line Items]
Current regulatory assets	199	150
Long-term regulatory assets	969	947
Southern California Edison | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Current regulatory assets	25	49
Southern California Edison | Other
Regulatory Assets [Line Items]
Current regulatory assets	36	16
Long-term regulatory assets	73	7
Southern California Edison | Deferred income taxes, net of liabilities
Regulatory Assets [Line Items]
Long-term regulatory assets	4,875	4,478
Southern California Edison | Pensions and other postretirement benefits
Regulatory Assets [Line Items]
Long-term regulatory assets	712	710
Southern California Edison | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Long-term regulatory assets	78	80
Southern California Edison | San Onofre
Regulatory Assets [Line Items]
Long-term regulatory assets	772	857
Southern California Edison | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Long-term regulatory assets	$ 176	$ 184