Summary of Significant Accounting Policies (Uncollectible Allowance) (Details) $ in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2022 USD ($)	Jun. 30, 2021 D	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Gross long-term account receivables			$ 238
Allowance for long-term uncollectible accounts			116
SCE
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 309		188	$ 49
Included in operation and maintenance expenses in earning activities			44	45
Included in operation and maintenance expenses in cost-recovery activities			74	15
Deferred to regulatory memorandum accounts			17	105
Less: write-offs, net of recoveries			14	26
Ending balance			309	188
Number of arrearages days | D		60
Term of payment plans		24 months
Allowance for long-term uncollectible accounts			116
SCE | CAPP
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Less: write-offs, net of recoveries			78
Cash received	185
SCE | Customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	293		175	35
Included in operation and maintenance expenses in earning activities			33	36
Included in operation and maintenance expenses in cost-recovery activities			74	15
Deferred to regulatory memorandum accounts			17	105
Less: write-offs, net of recoveries			6	16
Ending balance			293	175
SCE | All others
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 16		13	14
Included in operation and maintenance expenses in earning activities			11	9
Less: write-offs, net of recoveries			8	10
Ending balance			$ 16	$ 13