Pension Plans and Postretirement Benefits Other Than Pensions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012 Pension Plans	Jun. 30, 2011 Pension Plans	Jun. 30, 2012 Pension Plans	Jun. 30, 2011 Pension Plans	Jun. 30, 2012 Pension Plans Southern California Edison Company	Jul. 31, 2012 Pension Plans Southern California Edison Company Subsequent Event	Jun. 30, 2012 Pension Plans Previous Estimate	Jun. 30, 2012 Postretirement Benefits Other Than Pensions	Jun. 30, 2011 Postretirement Benefits Other Than Pensions	Jun. 30, 2012 Postretirement Benefits Other Than Pensions	Jun. 30, 2011 Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Additional plan year contributions	$ 192		$ 192				$ 286	$ 53		$ 53
Employer contributions			73			58				12
Benchmark for employer contributions, collected through customer rates					55
Requested recovery of plan contributions					168
Expense components are:
Service cost	43	43	86	86				13	11	26	22
Interest cost	49	52	98	104				30	33	60	66
Expected return on plan assets	(59)	(60)	(118)	(120)				(27)	(28)	(54)	(56)
Amortization of prior service cost (credit)	1	2	2	4				(9)	(9)	(18)	(18)
Amortization of net loss	18	6	36	12				12	9	24	18
Expense under accounting standards	52	43	104	86				19	16	38	32
Regulatory adjustment (deferred)	27	(6)	54	(12)
Total expense	$ 79	$ 37	$ 158	$ 74