Summary of Significant Accounting Policies (Revision to Cash Flow) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nuclear decommissioning trusts		$ 76
Total cash provided (used) by operating activities	3,248	2,967	3,334
Purchases of nuclear decommissioning trust investments	(10,123)	(5,715)	(2,337)
Total cash used by investing activities	(3,907)	(3,572)	(5,283)
Scenario, Previously Reported
Nuclear decommissioning trusts		312
Total cash provided (used) by operating activities		3,203
Purchases of nuclear decommissioning trust investments		(5,951)
Total cash used by investing activities		(3,808)
Restatement Adjustment
Nuclear decommissioning trusts		(236)
Total cash provided (used) by operating activities		(236)
Purchases of nuclear decommissioning trust investments		236
Total cash used by investing activities		236
Southern California Edison
Nuclear decommissioning trusts		76
Total cash provided (used) by operating activities	3,660	3,048	4,086
Purchases of nuclear decommissioning trust investments	(10,123)	(5,715)	(2,337)
Total cash used by investing activities	(3,857)	(3,547)	(4,354)
Southern California Edison | Scenario, Previously Reported
Nuclear decommissioning trusts		312
Total cash provided (used) by operating activities		3,284
Purchases of nuclear decommissioning trust investments		(5,951)
Total cash used by investing activities		(3,783)
Southern California Edison | Restatement Adjustment
Nuclear decommissioning trusts		(236)
Total cash provided (used) by operating activities		(236)
Purchases of nuclear decommissioning trust investments		236
Total cash used by investing activities		$ 236