Compensation and Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	1 Months Ended		3 Months Ended		9 Months Ended				3 Months Ended				9 Months Ended
	Sep. 30, 2012 Southern California Edison Work Force Reduction San Onofre	Aug. 31, 2012 Southern California Edison Work Force Reduction San Onofre Minimum positions	Aug. 31, 2012 Southern California Edison Work Force Reduction San Onofre Maximum positions	Sep. 30, 2012 Pension Plans	Sep. 30, 2011 Pension Plans	Sep. 30, 2012 Pension Plans	Sep. 30, 2011 Pension Plans	Sep. 30, 2012 Pension Plans Southern California Edison	Sep. 30, 2012 Pension Plans Previous Estimate	Sep. 30, 2012 Postretirement Benefits Other Than Pensions		Sep. 30, 2011 Postretirement Benefits Other Than Pensions		Sep. 30, 2012 Postretirement Benefits Other Than Pensions		Sep. 30, 2011 Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Plan year contributions				$ 180		$ 180			$ 286
Employer contributions						156								17
Additional plan year contributions										48				48
Requested recovery of plan contributions								168
Expense components are:
Service cost				49	43	135	129			13		11		39		33
Interest cost				49	52	147	156			30		33		90		99
Special termination benefits										3	[1]	0	[1]	3	[1]	0	[1]
Expected return on plan assets				(56)	(60)	(174)	(180)			(27)		(28)		(81)		(84)
Amortization of prior service cost (credit)				1	2	3	6			(9)		(9)		(27)		(27)
Amortization of net loss				21	6	57	18			12		9		36		27
Expense under accounting standards				64	43	168	129			22		16		60		48
Regulatory adjustment (deferred)				(57)	(6)	(3)	(18)
Total expense				7	37	165	111
Expected number of positions to be eliminated		730	1,500
Cash severance costs	$ 30

[1] Due to the reduction in the workforce at San Onofre, Edison International has incurred costs for enhanced retiree health care coverage. See below for further information.