Income Taxes (Components of Net Accumulated Deferred Income Tax Liability) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Property and software related	$ 572	$ 523
Nuclear decommissioning trust assets in excess of nuclear ARO liability	441	569
Loss and credit carryforwards	1,657	2,228
Regulatory balancing accounts	18	139
Pension and PBOPs	510	283
Other	582	712
Sub-total	3,780	4,454
Less valuation allowance	29	1,380
Total	3,751	3,074
Deferred tax liabilities:
Property-related	8,709	7,879
Capitalized software costs	285	318
Regulatory balancing accounts	577	625
Nuclear decommissioning trust assets	441	569
PBOPs	227	6
Other	274	497
Total	10,513	9,894
Accumulated deferred income tax liability, net	6,762	6,820
Included in deferred credits and other liabilities	7,214	7,241
Included in current liabilities (assets)	(452)	(421)
Southern California Edison
Deferred tax assets:
Property and software related	571	523
Nuclear decommissioning trust assets in excess of nuclear ARO liability	441	569
Loss and credit carryforwards	205	427
Regulatory balancing accounts	18	139
Pension and PBOPs	321	105
Other	445	544
Sub-total	2,001	2,307
Less valuation allowance	0	0
Total	2,001	2,307
Deferred tax liabilities:
Property-related	8,699	7,869
Capitalized software costs	285	318
Regulatory balancing accounts	577	625
Nuclear decommissioning trust assets	441	569
PBOPs	227	6
Other	171	393
Total	10,400	9,780
Accumulated deferred income tax liability, net	8,399	7,473
Included in deferred credits and other liabilities	8,190	7,737
Included in current liabilities (assets)	$ 209	$ (264)