Income Taxes (Components of Net Accumulated Deferred Income Tax Liability) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Property and software related		$ 399	$ 358
Wildfire reserve		709	0
Nuclear decommissioning trust assets in excess of nuclear ARO liability		323	404
Loss and credit carryforwards		1,375	1,346
Regulatory asset		798	812
Pension and postretirement benefits other than pensions, net		171	178
Other		188	277
Sub-total		3,963	3,375
Less: valuation allowance4		36	28
Total		3,927	3,347
Deferred tax liabilities:
Property-related		7,497	6,970
Capitalized software costs		188	160
Regulatory liability		367	158
Nuclear decommissioning trust assets		323	404
Other		57	140
Total		8,432	7,832
Accumulated deferred income tax liability, net		4,505	4,485
Unrecognized tax benefits		338	432	$ 471	$ 529
Regulatory asset		788	809
Recorded valuation allowance		32
Capital loss from sale of SoCore Energy
Deferred tax liabilities:
Recorded valuation allowance	$ 4	4
Loss And Credit Carryforwards
Deferred tax liabilities:
Unrecognized tax benefits		178
SCE
Deferred tax assets:
Property and software related		388	357
Wildfire reserve		709	0
Nuclear decommissioning trust assets in excess of nuclear ARO liability		323	404
Loss and credit carryforwards		154	150
Regulatory asset		798	812
Pension and postretirement benefits other than pensions, net		46	50
Other		184	236
Sub-total		2,602	2,009
Less: valuation allowance4		0	0
Total		2,602	2,009
Deferred tax liabilities:
Property-related		7,497	6,962
Capitalized software costs		188	160
Regulatory liability		367	158
Nuclear decommissioning trust assets		323	404
Other		54	133
Total		8,429	7,817
Accumulated deferred income tax liability, net		5,827	5,808
Unrecognized tax benefits		249	$ 331	$ 371	$ 353
SCE | Loss And Credit Carryforwards
Deferred tax liabilities:
Unrecognized tax benefits		$ 97