Compensation and Benefit Plans (Expense Components) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 35		$ 30
Interest cost	41		45
Expected return on plan assets	(57)		(57)
Amortization of prior service cost	1		1
Amortization of net loss	9	[1]	1	[1]
Expense under accounting standards	29		20
Regulatory adjustment	(1)		31
Total expense recognized	28		51
Net loss reclassified	3		2
Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12		11
Interest cost	29		27
Expected return on plan assets	(28)		(28)
Amortization of prior service cost	(3)		(9)
Amortization of net loss	6		0
Expense under accounting standards	16		1
Southern California Edison | Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	35		29
Interest cost	38		44
Expected return on plan assets	(53)		(56)
Amortization of prior service cost	1		1
Amortization of net loss	7	[1]	0	[1]
Expense under accounting standards	28		18
Regulatory adjustment	(1)		31
Total expense recognized	27		49
Net loss reclassified	2		1
Southern California Edison | Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12		11
Interest cost	28		27
Expected return on plan assets	(28)		(28)
Amortization of prior service cost	(3)		(9)
Amortization of net loss	6		0
Expense under accounting standards	$ 15		$ 1

[1] 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, 2015, and $2 million and $1 million, respectively, for the three months ended March 31, 2014.