Summary of Significant Accounting Policies (Deferred Financing Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Regulatory Assets [Line Items]
Regulatory assets	$ 7,455	$ 7,512
Unamortized debt issuance expense	81
SCE
Regulatory Assets [Line Items]
Regulatory assets	7,455	7,512
Unamortized debt issuance expense	71
Amortization of deferred financing costs charged to interest expense	27	28	$ 32
Edison International
Regulatory Assets [Line Items]
Amortization of deferred financing costs charged to interest expense	31	33	$ 36
Unamortized loss on reacquired debt | SCE
Regulatory Assets [Line Items]
Regulatory assets	184	201
Other long-term assets | SCE
Regulatory Assets [Line Items]
Unamortized debt issuance expense	7	7
Other long-term assets | Edison International
Regulatory Assets [Line Items]
Unamortized debt issuance expense	10	11
Long-term debt | SCE
Regulatory Assets [Line Items]
Unamortized debt issuance expense	71	77
Long-term debt | Edison International
Regulatory Assets [Line Items]
Unamortized debt issuance expense	$ 81	$ 81