Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($)
Regulatory Assets [Line Items]
Current regulatory assets	$ 1,009	$ 1,133
Long-term regulatory assets	6,088	5,380
SCE
Regulatory Assets [Line Items]
Current regulatory assets	1,009	1,133
Long-term regulatory assets	6,088	5,380
Total regulatory assets	7,097	6,513
SCE | Regulatory balancing and memorandum accounts
Regulatory Assets [Line Items]
Current regulatory assets	798	814
Long-term regulatory assets	981	360
SCE | Power contracts
Regulatory Assets [Line Items]
Current regulatory assets	189	305
Long-term regulatory assets	434	700
SCE | Other
Regulatory Assets [Line Items]
Current regulatory assets	22	14
Long-term regulatory assets	62	55
SCE | Deferred income taxes, net of liabilities
Regulatory Assets [Line Items]
Long-term regulatory assets	4,026	3,589
SCE | Pension and other postretirement benefits
Regulatory Assets [Line Items]
Long-term regulatory assets	87	271
SCE | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Long-term regulatory assets	119	118
SCE | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Long-term regulatory assets	142	153
SCE | Environmental remediation
Regulatory Assets [Line Items]
Long-term regulatory assets	$ 237	$ 134
SCE | Operating Leases Purchase Power Contracts
Regulatory Assets [Line Items]
Number of power purchase agreements | contract	2
Termination payments in two years	$ 206