Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension and PBOP – net loss:
Other	$ 0	$ 0	$ (5)	$ 2
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(46)	(49)	(43)	(53)
Pension and PBOP – net loss:
Ending Balance	(44)	(48)	(44)	(48)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	2	1	4	3
Other	0	0	(5)	2
Change	2	1	(1)	5
Southern California Edison
Pension and PBOP – net loss:
Other	0	(1)	(5)	0
Southern California Edison | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(22)	(18)	(19)	(20)
Pension and PBOP – net loss:
Ending Balance	(21)	(18)	(21)	(18)
Southern California Edison | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	1	1	3	2
Other	0	(1)	(5)	0
Change	$ 1	$ 0	$ (2)	$ 2