Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Plans
Pension and Other Postretirement Benefits
Service cost	$ 39	$ 35	$ 78	$ 70
Interest cost	44	42	88	83
Expected return on plan assets	(56)	(57)	(112)	(114)
Amortization of prior service cost	1	1	2	2
Amortization of net loss	9	9	18	18
Expense under accounting standards	37	30	74	59
Regulatory adjustment	(9)	(1)	(18)	(2)
Total expense recognized	28	29	56	57
Net loss reclassified	3	4	6	7
Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Service cost	10	12	20	24
Interest cost	26	28	52	57
Expected return on plan assets	(28)	(29)	(56)	(57)
Amortization of prior service cost	(1)	(3)	(2)	(6)
Amortization of net loss	0	6	0	12
Expense under accounting standards	7	14	14	30
Southern California Edison | Pension Plans
Pension and Other Postretirement Benefits
Service cost	38	34	76	69
Interest cost	41	37	82	75
Expected return on plan assets	(53)	(54)	(106)	(107)
Amortization of prior service cost	1	2	2	3
Amortization of net loss	8	8	16	15
Expense under accounting standards	35	27	70	55
Regulatory adjustment	(9)	(1)	(18)	(2)
Total expense recognized	26	26	52	53
Net loss reclassified	1	2	3	4
Southern California Edison | Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Service cost	10	12	20	24
Interest cost	26	28	52	56
Expected return on plan assets	(28)	(28)	(56)	(56)
Amortization of prior service cost	(1)	(3)	(2)	(6)
Amortization of net loss	0	5	0	11
Expense under accounting standards	$ 7	$ 14	$ 14	$ 29