Revenue (Summary of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 2,790	$ 2,824
Accrued unbilled revenue	409		$ 488
Southern California Edison
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,342	2,459
Alternative revenue programs and other operating revenue	438	357
Total operating revenue	2,780	2,816
Receivables related to contracts from customers	1,000		1,100
Accrued unbilled revenue	409		$ 488
Southern California Edison | Earning Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,624	1,502
Alternative revenue programs and other operating revenue	117	48
Total operating revenue	1,741	1,550
Southern California Edison | Cost- Recovery Activities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	718	957
Alternative revenue programs and other operating revenue	321	309
Total operating revenue	$ 1,039	$ 1,266