Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension and PBOP – net gain (loss):
Other	$ (4)	$ 0	$ 1
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(43)	(53)
Pension and PBOP – net gain (loss):
Ending balance	(50)	(43)	(53)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net gain (loss):
Other comprehensive (loss) income before reclassifications	(9)	3
Reclassified from accumulated other comprehensive loss	6	7
Other	(4)	0
Change	(7)	10
SCE
Pension and PBOP – net gain (loss):
Other	(5)	0	1
SCE | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(19)	(20)
Pension and PBOP – net gain (loss):
Ending balance	(23)	(19)	$ (20)
SCE | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net gain (loss):
Other comprehensive (loss) income before reclassifications	(3)	(2)
Reclassified from accumulated other comprehensive loss	4	3
Other	(5)	0
Change	$ (4)	$ 1