Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension and PBOP – net loss:
Other	$ (2)	$ 0	$ 0	$ 0
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(48)	(53)	(53)	(56)
Pension and PBOP – net loss:
Ending Balance	(48)	(51)	(48)	(51)
Accumulated Other Comprehensive Loss | Southern California Edison
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18)	(20)	(20)	(22)
Pension and PBOP – net loss:
Ending Balance	(18)	(19)	(18)	(19)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	2	2	5	5
Other	(2)	0	0	0
Change	0	2	5	5
Accumulated Defined Benefit Plans Adjustment | Southern California Edison
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	0	1	2	3
Change	$ 0	$ 1	$ 2	$ 3