Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 17,223	$ 15,544	$ 15,949	$ 15,496
Pension and PBOP - net loss:
Other comprehensive income, net of tax	2	2	4	4
Ending balance	17,313	16,446	17,313	16,446
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(67)	(67)	(69)	(69)
Pension and PBOP - net loss:
Ending balance	(65)	(65)	(65)	(65)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP - net loss:
Reclassified from accumulated other comprehensive loss	2	2	4	4
Other comprehensive income, net of tax	2	2	4	4
SCE
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	19,522	18,046	18,650	17,827
Pension and PBOP - net loss:
Other comprehensive income, net of tax	1	1	3	3
Ending balance	19,887	18,781	19,887	18,781
SCE | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(39)	(37)	(41)	(39)
Pension and PBOP - net loss:
Ending balance	(38)	(36)	(38)	(36)
SCE | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP - net loss:
Reclassified from accumulated other comprehensive loss	1	1	3	3
Other comprehensive income, net of tax	$ 1	$ 1	$ 3	$ 3