Income Taxes (Interest and Penalties Related to Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Accrued interest and penalties	$ 52	$ 56
Net after-tax interest and penalties tax expense (benefit)	4	4	$ (62)
SCE
Income Tax Disclosure [Line Items]
Accrued interest and penalties	23	29
Net after-tax interest and penalties tax expense (benefit)	$ 6	$ 3	$ (25)