Income Taxes (Components of Net Accumulated Deferred Income Tax Liability) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Property and software related	$ 600	$ 728
Unrealized gains and losses	491	385
Loss and credit carryforwards	1,515	689
Regulatory balancing accounts	80	89
Pension and PBOPs	275	179
Other	723	696
Sub-total	3,684	2,766
Less valuation allowance	1,017	0
Total	2,667	2,766
Deferred tax liabilities:
Property-related	7,289	6,502
Capitalized software costs	325	324
Regulatory balancing accounts	296	301
Unrealized gains and losses	477	374
Other	471	419
Total	8,858	7,920
Accumulated deferred income tax liability, net	6,191	5,154
Included in deferred credits and other liabilities	6,127	5,065
Included in current liabilities	64	89
Southern California Edison
Deferred tax assets:
Property and software related	600	728
Unrealized gains and losses	477	374
Loss and credit carryforwards	125	15
Regulatory balancing accounts	80	89
Pension and PBOPs	99	173
Other	625	480
Sub-total	2,006	1,859
Less valuation allowance	0	0
Total	2,006	1,859
Deferred tax liabilities:
Property-related	7,279	6,492
Capitalized software costs	325	324
Regulatory balancing accounts	296	301
Unrealized gains and losses	477	374
Other	379	238
Total	8,756	7,729
Accumulated deferred income tax liability, net	6,750	5,870
Included in deferred credits and other liabilities	6,669	5,781
Included in current liabilities	$ 81	$ 89