Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Plans
Pension and Other Postretirement Benefits
Service cost	$ 36	$ 39	$ 72	$ 78
Interest cost	41	44	82	88
Expected return on plan assets	(53)	(56)	(106)	(112)
Settlement costs	8	0	8	0
Amortization of prior service cost	1	1	2	2
Amortization of net loss	5	9	10	18
Expense under accounting standards	38	37	68	74
Regulatory adjustment	(3)	(9)	(6)	(18)
Total expense recognized	35	28	62	56
Net loss reclassified	2	3	5	6
PBOP Plan
Pension and Other Postretirement Benefits
Service cost	9	10	18	20
Interest cost	24	26	48	52
Expected return on plan assets	(27)	(28)	(54)	(56)
Amortization of prior service cost	(1)	(1)	(2)	(2)
Expense under accounting standards	5	7	10	14
Southern California Edison | Pension Plans
Pension and Other Postretirement Benefits
Service cost	35	38	70	76
Interest cost	37	41	74	82
Expected return on plan assets	(50)	(53)	(100)	(106)
Amortization of prior service cost	1	1	2	2
Amortization of net loss	4	8	8	16
Expense under accounting standards	27	35	54	70
Regulatory adjustment	(3)	(9)	(6)	(18)
Total expense recognized	24	26	48	52
Net loss reclassified	1	1	3	3
Southern California Edison | PBOP Plan
Pension and Other Postretirement Benefits
Service cost	9	10	18	20
Interest cost	24	26	48	52
Expected return on plan assets	(27)	(28)	(54)	(56)
Amortization of prior service cost	(1)	(1)	(2)	(2)
Expense under accounting standards	$ 5	$ 7	$ 10	$ 14