Compensation and Benefit Plans (Unrecognized Compensation Costs) (Details) - Stock options $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Pension and Other Postretirement Benefits [Line Items]
Unrecognized compensation cost, net of expected forfeitures (in millions)	$ 17
Weighted average period (in years)	2 years 3 months 18 days
SCE
Pension and Other Postretirement Benefits [Line Items]
Unrecognized compensation cost, net of expected forfeitures (in millions)	$ 9
Weighted average period (in years)	2 years 3 months 18 days