Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (65)	$ (57)	$ (69)	$ (50)
Pension and PBOP – net loss:
Ending Balance	(63)	(55)	(63)	(55)
Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	2	2	6	5
Other	0	0	0	(10)
Change	2	2	6	(5)
Southern California Edison | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(36)	(26)	(39)	(23)
Pension and PBOP – net loss:
Ending Balance	(35)	(25)	(35)	(25)
Southern California Edison | Accumulated Defined Benefit Plans Adjustment
Pension and PBOP – net loss:
Reclassified from accumulated other comprehensive loss	1	1	4	3
Other	0	0	0	(5)
Change	$ 1	$ 1	$ 4	$ (2)