Related-Party Transactions (Details) - Southern California Edison - Subsidiary of Common Parent - Wildfire Liability Insurance - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Wildfire insurance premiums	$ 74		$ 260
Long-term insurance receivable due from affiliate	1,000		1,000		$ 1,000
Prepaid insurance	74		74		13
Current payables due to affiliate	0		0		$ 4
Wildfire insurance expense	$ 41	$ 35	$ 72	$ 71