Commitments and Contingencies (Current Wildfire Insurance Coverage) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	May 31, 2019	Dec. 31, 2017
Loss Contingencies [Line Items]
Regulatory assets	$ 5,046,000,000		$ 4,914,000,000
Southern California Edison
Loss Contingencies [Line Items]
Wildfire-specific insurance coverage			1,000,000,000
Self-insured retention	10,000,000		10,000,000
Wildfire insurance expense	237,000,000
Regulatory assets	5,046,000,000		4,914,000,000
Southern California Edison | Wildfire insurance costs
Loss Contingencies [Line Items]
Regulatory assets	$ 63,000,000		$ 0
Southern California Edison | Forecast
Loss Contingencies [Line Items]
Wildfire-specific insurance coverage		$ 1,000,000,000