Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Plans
Pension and Other Postretirement Benefits
Service cost	$ 39	$ 35	$ 117	$ 105
Interest cost	44	41	132	124
Expected return on plan assets	(56)	(57)	(168)	(171)
Amortization of prior service cost	1	1	3	3
Amortization of net loss	9	9	27	27
Expense under accounting standards	37	29	111	88
Regulatory adjustment	(9)	(2)	(27)	(4)
Total expense recognized	28	27	84	84
Net loss reclassified	3	4	9	11
Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Service cost	10	12	30	36
Interest cost	26	29	78	86
Expected return on plan assets	(28)	(28)	(84)	(85)
Amortization of prior service cost	(1)	(3)	(3)	(9)
Amortization of net loss	0	5	0	17
Expense under accounting standards	7	15	21	45
Southern California Edison | Pension Plans
Pension and Other Postretirement Benefits
Service cost	38	35	114	104
Interest cost	41	38	123	113
Expected return on plan assets	(53)	(53)	(159)	(160)
Amortization of prior service cost	1	1	3	4
Amortization of net loss	8	7	24	22
Expense under accounting standards	35	28	105	83
Regulatory adjustment	(9)	(2)	(27)	(4)
Total expense recognized	26	26	78	79
Net loss reclassified	2	2	5	6
Southern California Edison | Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Service cost	10	12	30	36
Interest cost	26	28	78	84
Expected return on plan assets	(28)	(28)	(84)	(84)
Amortization of prior service cost	(1)	(3)	(3)	(9)
Amortization of net loss	0	6	0	17
Expense under accounting standards	$ 7	$ 15	$ 21	$ 44