Related-Party Transactions (Details) - Southern California Edison - Subsidiary of Common Parent - Wildfire Liability Insurance - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Wildfire insurance premiums	$ 186
Long-term insurance receivable due from affiliate	1,000		$ 1,000
Prepaid insurance	169		13
Current payables due to affiliate	62		$ 4
Wildfire insurance expense	$ 31	$ 36

Amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership, due after 1 year (or 1 business cycle).

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+ Details