Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension and PBOP – net loss:
Other	$ 0	$ 0	$ (4)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(69)	(50)
Pension and PBOP – net loss:
Ending balance	(69)	(69)	(50)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Other comprehensive loss before reclassifications	(8)	(14)
Reclassified from accumulated other comprehensive loss	8	5
Other	0	(10)
Change	0	(19)
SCE
Pension and PBOP – net loss:
Other	0	0	(5)
SCE | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(39)	(23)
Pension and PBOP – net loss:
Ending balance	(41)	(39)	$ (23)
SCE | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Other comprehensive loss before reclassifications	(7)	(14)
Reclassified from accumulated other comprehensive loss	5	3
Other	0	(5)
Change	$ (2)	$ (16)