Commitments and Contingencies (Spent Nuclear Fuel) (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2016	Jun. 30, 2010	May 31, 2018	Oct. 31, 2017	Feb. 28, 2017	Sep. 30, 2016
Schedule Of Commitments And Contingencies [Line Items]
DOE determination of claim reimbursement						$ 56
SCE and other owners of San Onofre and Palo Verde
Schedule Of Commitments And Contingencies [Line Items]
Damages sought		$ 142
Damage award	$ 162
DOE determination of claim reimbursement			$ 45		$ 43
Southern California Edison
Schedule Of Commitments And Contingencies [Line Items]
Damages sought		$ 112
Damage award	$ 124
DOE determination of claim reimbursement			35	$ 58	$ 34
Disallowed claim amount			$ 13