Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 35	$ 30	$ 105	$ 89
Interest cost	41	48	124	141
Expected return on plan assets	(57)	(61)	(171)	(178)
Settlement costs	0	35	0	35
Amortization of prior service cost	1	1	3	4
Amortization of net loss	9	1	27	3
Expense under accounting standards	29	54	88	94
Regulatory adjustment	(1)	(2)	(4)	59
Total expense recognized	28	52	84	153
Net loss related to lump-sum payments to retirees reclassified		2		2
Net loss reclassified	4	2	11	5
Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12	10	36	32
Interest cost	29	28	86	82
Expected return on plan assets	(28)	(28)	(85)	(84)
Amortization of prior service cost	(3)	(9)	(9)	(27)
Amortization of net loss	5	0	17	0
Expense under accounting standards	15	1	45	3
Southern California Edison | Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	35	29	104	87
Interest cost	38	44	113	132
Expected return on plan assets	(53)	(56)	(160)	(168)
Settlement costs	0	33	0	33
Amortization of prior service cost	1	1	4	3
Amortization of net loss	7	0	22	1
Expense under accounting standards	28	51	83	88
Regulatory adjustment	(2)	(2)	(4)	59
Total expense recognized	26	49	79	147
Net loss reclassified	2	1	6	3
Southern California Edison | Postretirement Benefits Other Than Pensions
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12	10	36	32
Interest cost	28	27	84	81
Expected return on plan assets	(28)	(28)	(84)	(84)
Amortization of prior service cost	(3)	(9)	(9)	(27)
Amortization of net loss	6	0	17	0
Expense under accounting standards	$ 15	$ 0	$ 44	$ 2