Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension and PBOP – net loss:
Other	$ 2	$ 0
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(53)	(56)
Pension and PBOP – net loss:
Ending Balance	(49)	(54)
Accumulated Other Comprehensive Loss | Southern California Edison
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(20)	(22)
Pension and PBOP – net loss:
Ending Balance	(18)	(21)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	2	2
Other	2	0
Change	4	2
Accumulated Defined Benefit Plans Adjustment | Southern California Edison
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	1	1
Other	1	0
Change	$ 2	$ 1