Commitments and Contingencies (MHI Claims) (Details)		1 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2013 USD ($) invoice	Oct. 31, 2013 USD ($)	Jun. 30, 2010 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2012 USD ($)
Southern California Edison
Schedule Of Commitments And Contingencies [Line Items]
Damages sought			$ 112,000,000
San Onofre | Southern California Edison | Mitsubishi Heavy Industries Ltd
Schedule Of Commitments And Contingencies [Line Items]
Number of invoices for reimbursement | invoice	7
Invoiced amount for reimbursement	$ 149,000,000
Invoiced amount paid for reimbursement	$ 45,000,000
Share of invoice paid					$ 35,000,000
San Onofre | Southern California Edison | Mitsubishi Heavy Industries Ltd | Minimum
Schedule Of Commitments And Contingencies [Line Items]
Damages sought		$ 4,000,000,000
San Onofre | Southern California Edison | Mitsubishi Heavy Industries Ltd
Schedule Of Commitments And Contingencies [Line Items]
Ratepayer allocation of recovery from recoveries				50.00%
Entity allocation of recovery from recoveries				50.00%
Ratepayer allocation of recovery from recoveries, initial amount of settlement				$ 282,000,000
San Onofre | Southern California Edison | Replacement Steam Generators
Schedule Of Commitments And Contingencies [Line Items]
Warranty period				20 years
San Onofre | Mitsubishi Heavy Industries Ltd
Schedule Of Commitments And Contingencies [Line Items]
Maximum liability per purchase agreement for damages				$ 138,000,000
Asserted counterclaim		$ 41,000,000