Summary of Significant Accounting Policies Revision to Consolidated Statement of Cash Flow (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended		12 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2013 As Reported	Dec. 31, 2013 As Reported	Mar. 31, 2014 Adjustment	Jun. 30, 2014 Adjustment	Sep. 30, 2013 Adjustment	Dec. 31, 2013 Adjustment	Sep. 30, 2014 Southern California Edison	Sep. 30, 2013 Southern California Edison	Dec. 31, 2013 Southern California Edison	Sep. 30, 2013 Southern California Edison As Reported	Dec. 31, 2013 Southern California Edison As Reported	Sep. 30, 2013 Southern California Edison Adjustment	Dec. 31, 2013 Southern California Edison Adjustment
Regulatory impacts of net nuclear decommissioning trust earnings	$ 100	$ 82	$ 76	$ 265	$ 312			$ (183)	$ (236)	$ 100	$ 82	$ 76	$ 265	$ 312	$ (183)	$ (236)
Net cash provided by operating activities	2,027	2,070	2,967	2,253	3,203	67	5	(183)	(236)	2,513	2,163	3,048	2,346	3,284	(183)	(236)
Purchases of nuclear decommissioning trust investments	(5,951)	(4,674)	(5,715)	(4,857)	(5,951)			183	236	(5,951)	(4,674)	(5,715)	(4,857)	(5,951)	183	236
Net cash used by investing activities	$ 2,936	$ 2,905	$ 3,572	$ 3,088	$ 3,808	$ 67	$ 5	$ (183)	$ (236)	$ 2,908	$ 2,882	$ 3,547	$ 3,065	$ 3,783	$ (183)	$ (236)