Commitments and Contingencies (Nuclear Insurance) (Details) - Insurance Claims	12 Months Ended
	Dec. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Federal loss limit, bodily injury and property damage from nuclear incident	$ 13,400,000,000
SCE and other owners of San Onofre and Palo Verde | San Onofre and Palo Verde
Loss Contingencies [Line Items]
Maximum private primary insurance	450,000,000
ANI Facility Form coverage aggregate limit	450,000,000
Minimum federal requirement of nuclear property insurance	1,060,000,000
SCE
Loss Contingencies [Line Items]
Maximum assessment per each nuclear incident	255,000,000
Maximum yearly assessment per nuclear incident	38,000,000
Limit on assessment of retrospective premium adjustments, per year, approximate	$ 52,000,000