Commitments and Contingencies (Undiscounted Future Minimum Expected Payments for Power Purchase Agreements) (Details) - SCE $ in Millions	Dec. 31, 2016 USD ($)
Renewable Energy Contracts
Unrecorded Unconditional Purchase Obligation [Line Items]
2017	$ 1,516
2018	1,606
2019	1,704
2020	1,776
2021	1,786
Thereafter	22,811
Total future commitments	31,199
Qualifying Facility Power Purchase Agreements
Unrecorded Unconditional Purchase Obligation [Line Items]
2017	187
2018	148
2019	87
2020	39
2021	16
Thereafter	53
Total future commitments	530
Other Power Purchase Agreements
Unrecorded Unconditional Purchase Obligation [Line Items]
2017	769
2018	604
2019	516
2020	472
2021	420
Thereafter	1,258
Total future commitments	$ 4,039