Revenue (Summary of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 4,644	$ 3,741	$ 10,421	$ 9,377
Accrued unbilled revenue	708		708		$ 488
Southern California Edison
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,220	3,884	9,440	8,642
Alternative revenue programs and other operating revenue	415	(152)	955	706
Total operating revenue	4,635	3,732	10,395	9,348
Receivables related to contracts from customers	1,900		1,900		1,100
Accrued unbilled revenue	708		708		$ 488
Southern California Edison | Earning Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,893	1,862	5,175	4,896
Alternative revenue programs and other operating revenue	233	(30)	467	23
Total operating revenue	2,126	1,832	5,642	4,919
Southern California Edison | Cost- Recovery Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,327	2,022	4,265	3,746
Alternative revenue programs and other operating revenue	182	(122)	488	683
Total operating revenue	$ 2,509	$ 1,900	$ 4,753	$ 4,429