Compensation and Benefit Plans (Expense Components) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 14		$ 12
Interest cost	26		28
Expected return on plan assets	(30)		(27)
Amortization of prior service cost	(9)		(9)
Amortization of net loss	7	[1]	12	[1]
Expense under accounting standards	8		16
Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	38		38
Interest cost	42		46
Expected return on plan assets	(57)		(56)
Amortization of prior service cost	1		1
Amortization of net loss	15	[2]	17	[2]
Expense under accounting standards	39		46
Regulatory adjustment (deferred)	17		25
Total expense recognized	56		71
Net loss reclassified	3
Southern California Edison | Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	13		12
Interest cost	26		28
Expected return on plan assets	(30)		(27)
Amortization of prior service cost	(9)		(9)
Amortization of net loss	7	[1]	11	[1]
Expense under accounting standards	7		15
Net loss reclassified	0
Southern California Edison | Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	37		37
Interest cost	41		45
Expected return on plan assets	(57)		(55)
Amortization of prior service cost	1		1
Amortization of net loss	14	[2]	15	[2]
Expense under accounting standards	36		43
Regulatory adjustment (deferred)	17		25
Total expense recognized	53		68
Net loss reclassified	2
Maximum | Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net loss reclassified	$ 1

[1] Includes the amount of net loss reclassified from other comprehensive loss. The amount reclassified for Edison International and SCE was less than $1 million and zero, respectively, for the three months ended March 31, 2013.

[2] Includes the amount of net loss reclassified from other comprehensive loss. The amount reclassified for Edison International and SCE was $3 million and $2 million, respectively, for the three months ended March 31, 2013.