Commitments and Contingencies (Commitments Textual) (Details) - SCE $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) contract agreement	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Costs incurred for power purchase agreements	$ 3,300	$ 3,200	$ 3,800
Operating leases expense	$ 68	80	96
Renewable Energy Contracts
Unrecorded Unconditional Purchase Obligation [Line Items]
Renewable energy contracts (number) | contract	119
Signed contracts, due in next twelve months	$ 1,516
Signed contracts, due within two years	1,606
Signed contracts, due within three years	1,704
Signed contracts, due within four years	1,776
Signed contracts, due within five years	1,786
Signed contracts, due after five years	$ 22,811
Qualifying Facility Power Purchase Agreements
Unrecorded Unconditional Purchase Obligation [Line Items]
QF contracts (number) | contract	55
Signed contracts, due in next twelve months	$ 187
Signed contracts, due within two years	148
Signed contracts, due within three years	87
Signed contracts, due within four years	39
Signed contracts, due within five years	16
Signed contracts, due after five years	$ 53
Combined Heat and Power Contracts
Unrecorded Unconditional Purchase Obligation [Line Items]
Heat and power contracts (number) | agreement	30
Other Power Purchase Agreements
Unrecorded Unconditional Purchase Obligation [Line Items]
Signed contracts, due in next twelve months	$ 769
Signed contracts, due within two years	604
Signed contracts, due within three years	516
Signed contracts, due within four years	472
Signed contracts, due within five years	420
Signed contracts, due after five years	1,258
Signed contracts, not meeting critical contract provisions
Unrecorded Unconditional Purchase Obligation [Line Items]
Signed contracts, due in next twelve months	53
Signed contracts, due within two years	235
Signed contracts, due within three years	312
Signed contracts, due within four years	554
Signed contracts, due within five years	630
Signed contracts, due after five years	9,100
Other contractual obligations
Unrecorded Unconditional Purchase Obligation [Line Items]
Cost incurred for other commitments	141	182	90
Other commitments due in next twelve months	156
Other commitments due in second year	141
Other commitments due in third year	103
Other commitments due in fourth year	98
Other commitments due in fifth year	82
Other commitments due after fifth year	631
Other contractual obligations not meeting critical contract provisions
Unrecorded Unconditional Purchase Obligation [Line Items]
Other commitments due in next twelve months	3
Other commitments due in second year	24
Other commitments due in third year	94
Other commitments due in fourth year	93
Other commitments due in fifth year	71
Other commitments due after fifth year	478
Operating Leases Purchase Power Contracts
Unrecorded Unconditional Purchase Obligation [Line Items]
Net operating leases expense	1,900	1,700	1,700
Contingent operating lease expense	1,400	1,100	944
Contingent capital lease expense	$ 109	$ 1	$ 1