Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 32	$ 32	$ 64	$ 64
Non-service cost (benefit)
Interest cost	39	35	78	70
Expected return on plan assets	(52)	(56)	(104)	(113)
Amortization of prior service cost	1	0	1	1
Amortization of net (loss) gain	2	2	4	4
Regulatory adjustment	(4)	3	(8)	5
Total non-service cost (benefit)	(14)	(16)	(29)	(33)
Total expense recognized	18	16	35	31
Net loss reclassified	2	2	4	4
PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	10	16	19
Non-service cost (benefit)
Interest cost	21	21	42	42
Expected return on plan assets	(28)	(30)	(56)	(60)
Amortization of prior service cost	0	(1)	0	(1)
Amortization of net (loss) gain	(1)	0	(2)	0
Regulatory adjustment	6	0	12	0
Total non-service cost (benefit)	(2)	(10)	(4)	(19)
Total expense	6	0	12	0
Southern California Edison
Non-service cost (benefit)
Total non-service cost (benefit)	(16)	(27)	(35)	(53)
Southern California Edison | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	31	62	62
Non-service cost (benefit)
Interest cost	36	32	71	64
Expected return on plan assets	(49)	(54)	(98)	(107)
Amortization of prior service cost	1	0	1	1
Amortization of net (loss) gain	2	2	3	3
Regulatory adjustment	(4)	3	(8)	5
Total non-service cost (benefit)	(14)	(17)	(31)	(34)
Total expense recognized	17	14	31	28
Net loss reclassified	2	2	3	3
Southern California Edison | PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	10	16	19
Non-service cost (benefit)
Interest cost	21	21	42	42
Expected return on plan assets	(28)	(30)	(56)	(60)
Amortization of prior service cost	0	(1)	0	(1)
Amortization of net (loss) gain	(1)	0	(2)	0
Regulatory adjustment	6	0	12	0
Total non-service cost (benefit)	(2)	(10)	(4)	(19)
Total expense	$ 6	$ 0	$ 12	$ 0