Equity (Equity Contributions) (Details) - USD ($) $ in Millions							12 Months Ended
	Dec. 18, 2020	Aug. 31, 2020	Jun. 30, 2020	May 26, 2020	Apr. 29, 2020	Feb. 28, 2020	Dec. 31, 2020
SCE
Class of Stock [Line Items]
Equity investment	$ 325	$ 219	$ 100	$ 319	$ 200	$ 269	$ 1,432