Commitments and Contingencies (MHI Claims) (Details)		1 Months Ended		12 Months Ended
	Apr. 30, 2013 USD ($) invoice	Oct. 31, 2013 USD ($)	Jun. 30, 2010 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2012 USD ($)
SCE
Jointly Owned Utility Plant Interests [Line Items]
Damages sought			$ 112,000,000
SCE | San Onofre | Mitsubishi Heavy Industries Ltd
Jointly Owned Utility Plant Interests [Line Items]
Invoices for reimbursement (number) | invoice	7
Invoices for repair costs	$ 149,000,000
Invoice paid for repair costs	$ 45,000,000
SCE portion of invoice paid for repair costs					$ 35,000,000
SCE | San Onofre | Mitsubishi Heavy Industries Ltd | Minimum
Jointly Owned Utility Plant Interests [Line Items]
Damages sought		$ 4,000,000,000
SCE | San Onofre | Mitsubishi Heavy Industries Ltd
Jointly Owned Utility Plant Interests [Line Items]
Allocated to customer (percent)				50.00%
SCE allocation (percent)				50.00%
Customers' portion of recoveries				$ 282,000,000
SCE | San Onofre | Replacement Steam Generators
Jointly Owned Utility Plant Interests [Line Items]
Warranty period				20 years
Mitsubishi Heavy Industries Ltd | San Onofre
Jointly Owned Utility Plant Interests [Line Items]
Stated liability under the purchase agreement				$ 138,000,000
Asserted counter claim		$ 41,000,000