Leases (Summary of Lease Expense Components) (Details) - SCE - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lease cost	$ 111	$ 118
Finance lease cost	1	1
Variable lease cost	1,917	2,087
Total lease cost	2,076	2,252
PPA Operating Leases
Lessee, Lease, Description [Line Items]
Total lease cost	2,029	2,206
Other Operating Leases
Lessee, Lease, Description [Line Items]
Lease cost	$ 47	$ 46