Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Regulatory Assets [Line Items]
Current regulatory assets	$ 1,286	$ 1,133
Long-term regulatory assets	5,268	5,380
Southern California Edison
Regulatory Assets [Line Items]
Current regulatory assets	1,286	1,133
Long-term regulatory assets	5,268	5,380
Total regulatory assets	6,554	6,513
Southern California Edison | Regulatory balancing accounts
Regulatory Assets [Line Items]
Current regulatory assets	935	814
Long-term regulatory assets	232	360
Southern California Edison | Power contracts
Regulatory Assets [Line Items]
Current regulatory assets	333	305
Long-term regulatory assets	597	700
Southern California Edison | Other
Regulatory Assets [Line Items]
Current regulatory assets	18	14
Long-term regulatory assets	80	55
Southern California Edison | Deferred income taxes, net of liabilities
Regulatory Assets [Line Items]
Long-term regulatory assets	3,683	3,589
Southern California Edison | Pensions and other postretirement benefits
Regulatory Assets [Line Items]
Long-term regulatory assets	274	271
Southern California Edison | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Long-term regulatory assets	117	118
Southern California Edison | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Long-term regulatory assets	150	153
Southern California Edison | Environmental remediation
Regulatory Assets [Line Items]
Long-term regulatory assets	$ 135	$ 134