Income Taxes (Rate Reconciliation) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Line Items]
Statutory tax rate (as a percent)				21.00%
(Loss) income from operations before income taxes		$ (326)	$ (517)	$ 357	$ (36)
Provision for income tax at federal statutory rate of 21%		(68)	(108)	75	(7)
Increase (decrease) in income tax from:
State tax, net of federal benefit		(39)	(67)	(28)	(74)
Property-related		(33)	(81)	(159)	(228)
Average rate assumption method ("ARAM") adjustment		87		87
Change related to uncertain tax position					(15)
Insurance benefits		(2)	(5)	(7)	(12)
Wildfire related charges		31		31
Other		(5)	(14)	4	(19)
Total income tax expense (benefit)		$ (29)	$ (275)	$ 3	$ (355)
Effective tax rate (as a percent)		(8.90%)	(53.20%)	0.80%	(986.10%)
State | Plan
Increase (decrease) in income tax from:
Tax refund	$ 60
Tax settlement increase (decrease) on earnings	$ 148
SCE
Income Tax Disclosure [Line Items]
Statutory tax rate (as a percent)				21.00%
(Loss) income from operations before income taxes		$ (268)	$ (469)	$ 492	$ 142
Provision for income tax at federal statutory rate of 21%		(56)	(98)	103	30
Increase (decrease) in income tax from:
State tax, net of federal benefit		(32)	(61)	(17)	(62)
Property-related		(33)	(81)	(159)	(228)
Average rate assumption method ("ARAM") adjustment		87		87
Change related to uncertain tax position					(18)
Insurance benefits		(2)	(5)	(7)	(12)
Wildfire related charges		31		31
Other		(6)	(6)	3	(10)
Total income tax expense (benefit)		$ (11)	$ (251)	$ 41	$ (300)
Effective tax rate (as a percent)		(4.10%)	(53.50%)	8.30%	(211.30%)
Revenue adjustment		$ 0