Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Pension and PBOP – net loss:
Other	$ 1	$ (2)	$ (4)	$ 0
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(44)	(48)	(43)	(53)
Pension and PBOP – net loss:
Ending Balance	(42)	(48)	(42)	(48)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	1	2	5	5
Other	1	(2)	(4)	0
Change	2	0	1	5
Southern California Edison
Pension and PBOP – net loss:
Other	0	0	(5)	0
Southern California Edison | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(21)	(18)	(19)	(20)
Pension and PBOP – net loss:
Ending Balance	(20)	(18)	(20)	(18)
Southern California Edison | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	1	0	4	2
Other	0	0	(5)	0
Change	$ 1	$ 0	$ (1)	$ 2