Commitments and Contingencies (Spent Nuclear Fuel) (Details) - USD ($) $ in Millions	1 Months Ended
	Aug. 31, 2018	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
Legal and other costs		$ 2
Damage award, customers	$ 106
Damage award, shareholders	17
DOE determination of claim reimbursement				35	$ 58	$ 34
Disallowed claim amount				$ 13
Southern California Edison | Regulatory balancing and memorandum accounts
Schedule Of Commitments And Contingencies [Line Items]
Damage award, customers	$ 72