Commitments and Contingencies (Spent Nuclear Fuel) (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2016	Jun. 30, 2010	Apr. 30, 2018	Mar. 31, 2018	Oct. 31, 2017	Feb. 28, 2017	Sep. 30, 2016
Schedule Of Commitments And Contingencies [Line Items]
DOE determination of claim reimbursement							$ 56.0
SCE and other owners of San Onofre and Palo Verde
Schedule Of Commitments And Contingencies [Line Items]
Damages sought		$ 142.0
Damage award	$ 162.0
DOE determination of claim reimbursement						$ 43.0
Southern California Edison
Schedule Of Commitments And Contingencies [Line Items]
Damages sought		$ 112.0
Damage award	$ 124.0
DOE determination of claim reimbursement				$ 44.0	$ 58.0	$ 34.0
Disallowed claim amount				$ 14.0
Subsequent event
Schedule Of Commitments And Contingencies [Line Items]
Request for Recovery			$ 1.2