Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($)	Dec. 19, 2017 USD ($)
Regulatory Assets [Line Items]
Current regulatory assets	$ 1,133	$ 703
Long-term regulatory assets	5,380	4,914
SCE
Regulatory Assets [Line Items]
Current regulatory assets	1,133	703
Long-term regulatory assets	5,380	4,914
Total regulatory assets	6,513	5,617
SCE | Regulatory balancing accounts
Regulatory Assets [Line Items]
Current regulatory assets	814	484
Long-term regulatory assets	360	143
SCE | Power contracts
Regulatory Assets [Line Items]
Current regulatory assets	305	203
Long-term regulatory assets	700	799
SCE | Other
Regulatory Assets [Line Items]
Current regulatory assets	14	16
Long-term regulatory assets	55	51
SCE | Deferred income taxes, net of liabilities
Regulatory Assets [Line Items]
Long-term regulatory assets	3,589	3,143
SCE | Pensions and other postretirement benefits
Regulatory Assets [Line Items]
Long-term regulatory assets	271	271
SCE | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Long-term regulatory assets	118	123
SCE | San Onofre
Regulatory Assets [Line Items]
Long-term regulatory assets	0	72	$ 775
SCE | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Long-term regulatory assets	153	168
SCE | Environmental remediation
Regulatory Assets [Line Items]
Long-term regulatory assets	$ 134	$ 144
SCE | Operating Leases Purchase Power Contracts
Regulatory Assets [Line Items]
Number of Contracts Amended | contract	2
Termination payments next year	$ 100
Termination payments in two years	77
Termination payments in three years	$ 29