Income Taxes (Components of Net Accumulated Deferred Income Tax Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Property	$ 478	$ 399
Wildfire reserve	847	709
Nuclear decommissioning trust assets in excess of nuclear ARO liability	449	323
Loss and credit carryforwards	1,515	1,375
Regulatory asset	739	798
Pension and postretirement benefits other than pensions, net	170	171
Other	408	188
Sub-total	4,606	3,963
Less: valuation allowance	35	36
Total	4,571	3,927
Deferred tax liabilities:
Property	8,244	7,685
Regulatory liability	570	367
Nuclear decommissioning trust assets	449	323
Other	320	57
Total	9,583	8,432
Accumulated deferred income tax liability, net	5,012	4,505
Unrecognized tax benefits	370	338	$ 432	$ 471
Recorded valuation allowance	30
Loss and Credit Carryforwards
Deferred tax liabilities:
Unrecognized tax benefits	212
SCE
Deferred tax assets:
Property	435	388
Wildfire reserve	847	709
Nuclear decommissioning trust assets in excess of nuclear ARO liability	449	323
Loss and credit carryforwards	253	154
Regulatory asset	739	798
Pension and postretirement benefits other than pensions, net	40	46
Other	416	184
Sub-total	3,179	2,602
Less: valuation allowance	0	0
Total	3,179	2,602
Deferred tax liabilities:
Property	8,234	7,685
Regulatory liability	570	367
Nuclear decommissioning trust assets	449	323
Other	310	54
Total	9,563	8,429
Accumulated deferred income tax liability, net	6,384	5,827
Unrecognized tax benefits	282	249	$ 331	$ 371
SCE | Loss and Credit Carryforwards
Deferred tax liabilities:
Unrecognized tax benefits	130
Capital loss from sale of SoCore Energy
Deferred tax liabilities:
Recorded valuation allowance	$ 5	$ 4