Compensation and Benefit Plans (Changes in Plan Assets and Benefits Obligations Recognized in OCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Unrecognized net loss to be amortized	$ (17)
Unrecognized prior service cost (credit) to be amortized	(1)
Pension Plans
Pension and Other Postretirement Benefits
Net loss	19	$ 5	$ 0
Settlement charges	0	0	(6)
Amortization of net loss	(7)	(9)	(10)
Total recognized in other comprehensive loss	12	(4)	(16)
Total recognized in expense and other comprehensive loss	82	61	76
Unrecognized net loss to be amortized	11
Unrecognized prior service cost (credit) to be amortized	2
Amount of net loss expected to be reclassified from other comprehensive loss	11
SCE | Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Unrecognized net loss to be amortized	(17)
Unrecognized prior service cost (credit) to be amortized	(1)
SCE | Pension Plans
Pension and Other Postretirement Benefits
Net loss	21	5	3
Settlement charges	0	0	0
Amortization of net loss	(5)	(6)	(6)
Total recognized in other comprehensive loss	16	(1)	(3)
Total recognized in expense and other comprehensive loss	80	$ 60	$ 72
Unrecognized net loss to be amortized	8
Unrecognized prior service cost (credit) to be amortized	2
Amount of net loss expected to be reclassified from other comprehensive loss	$ 8