Commitments and Contingencies (Nuclear Insurance) (Details) - USD ($)		9 Months Ended
	Jan. 05, 2018	Sep. 30, 2020
Nuclear Insurance | San Onofre
Schedule Of Commitments And Contingencies [Line Items]
Federal limit on public liability claims from nuclear incident, approximate		$ 560,000,000
Nuclear Insurance | Palo Verde
Schedule Of Commitments And Contingencies [Line Items]
Federal limit on liability claims for bodily injury and property damage from a nuclear incident		13,800,000,000
SCE and other owners of San Onofre and Palo Verde | Nuclear Insurance | San Onofre
Schedule Of Commitments And Contingencies [Line Items]
Loss limit, property damage insurance, federal minimum requirement		50,000,000
SCE and other owners of San Onofre and Palo Verde | Nuclear Insurance | Palo Verde
Schedule Of Commitments And Contingencies [Line Items]
Loss limit, property damage insurance, federal minimum requirement		1,100,000,000
Southern California Edison | Palo Verde
Schedule Of Commitments And Contingencies [Line Items]
Maximum per incident	$ 65,000,000
Maximum per incident, annually	10,000,000
Maximum per incident, prior events	255,000,000
Maximum per incident, prior events, annually	$ 38,000,000
Southern California Edison | Nuclear Insurance
Schedule Of Commitments And Contingencies [Line Items]
Limit on assessment of retrospective premium adjustments, per year, approximate		$ 30,000,000