Income Taxes (Components of Net Accumulated Deferred Income Tax Liability) (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Property and software related		$ 675	$ 572
Nuclear decommissioning trust assets in excess of nuclear ARO liability		360	441
Loss and credit carryforwards		1,388	1,657	$ 2,200
Regulatory balancing accounts		21	18
Pension and PBOPs		337	510
Other		499	582
Sub-total		3,280	3,780
Less valuation allowance		32	29
Total		3,248	3,751
Deferred tax liabilities:
Property-related		9,606	8,709
Capitalized software costs		207	285
Regulatory balancing accounts		202	577
Nuclear decommissioning trust assets		360	441
PBOPs		71	227
Other		189	274
Total		10,635	10,513
Accumulated deferred income tax liability, net	[1]	7,387	6,762
Southern California Edison
Deferred tax assets:
Property and software related		675	571
Nuclear decommissioning trust assets in excess of nuclear ARO liability		360	441
Loss and credit carryforwards		0	205
Regulatory balancing accounts		21	18
Pension and PBOPs		154	321
Other		411	445
Sub-total		1,621	2,001
Less valuation allowance		0	0
Total		1,621	2,001
Deferred tax liabilities:
Property-related		9,600	8,699
Capitalized software costs		207	285
Regulatory balancing accounts		202	577
Nuclear decommissioning trust assets		360	441
PBOPs		71	227
Other		161	171
Total		10,601	10,400
Accumulated deferred income tax liability, net	[1]	$ 8,980	$ 8,399

[1] Included in deferred income taxes and credits.