Revenue (Summary of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 2,970	$ 3,741	$ 2,812	$ 2,824	$ 3,009	$ 4,269	$ 2,815	$ 2,564	$ 12,347	$ 12,657	$ 12,320
SCE
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									11,167	12,130
Alternative revenue programs and other operating revenue									1,139	481
Total operating revenue	2,958	$ 3,732	2,800	$ 2,816	2,994	$ 4,260	$ 2,803	$ 2,554	12,306	12,611	12,254
Receivables from contracts with customers	1,100								1,100
Accrued unbilled revenues	$ 488				$ 482				488	482
SCE | Earning Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									6,512	6,519
Alternative revenue programs and other operating revenue									166	41
Total operating revenue									6,678	6,560	6,611
SCE | Cost- Recovery Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									4,655	5,611
Alternative revenue programs and other operating revenue									973	440
Total operating revenue									$ 5,628	$ 6,051	$ 5,643
California Public Utilities Commission | General Rate Case, 2018 | SCE
Disaggregation of Revenue [Line Items]
Reduction in revenue			$ 265