Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 12,652	$ 13,866	$ 14,187
Pension and PBOP – net loss:
Other comprehensive (loss) income, net of tax	(9)	(7)	10
Ending balance	15,496	12,652	13,866
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(50)	(43)	(53)
Pension and PBOP – net loss:
Other	(10)	(4)
Other comprehensive (loss) income, net of tax	(19)	(7)
Ending balance	(69)	(50)	(43)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Other comprehensive loss before reclassifications	(14)	(9)
Reclassified from accumulated other comprehensive loss	5	6
SCE
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	13,785	14,672	14,483
Pension and PBOP – net loss:
Other comprehensive (loss) income, net of tax	(11)	(4)	1
Ending balance	17,827	13,785	14,672
SCE | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(23)	(19)	(20)
Pension and PBOP – net loss:
Other	(5)	(5)
Other comprehensive (loss) income, net of tax	(16)	(4)
Ending balance	(39)	(23)	$ (19)
SCE | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Other comprehensive loss before reclassifications	(14)	(3)
Reclassified from accumulated other comprehensive loss	$ 3	$ 4