Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 31	$ 32	$ 95	$ 96
Non-service cost (benefit)
Interest cost	38	35	116	105
Expected return on plan assets	(52)	(56)	(156)	(169)
Amortization of prior service cost	0	1	1	2
Amortization of net (loss) gain	2	2	6	6
Regulatory adjustment	(4)	2	(12)	7
Total non-service cost (benefit)	(16)	(16)	(45)	(49)
Total expense recognized	15	16	50	47
Net loss reclassified	2	2	6	6
PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	10	24	29
Non-service cost (benefit)
Interest cost	21	21	63	63
Expected return on plan assets	(28)	(31)	(84)	(91)
Amortization of prior service cost	(1)	0	(1)	(1)
Amortization of net (loss) gain	0	0	(2)	0
Regulatory adjustment	5	0	17	0
Total non-service cost (benefit)	(3)	(10)	(7)	(29)
Total expense	5	0	17	0
Southern California Edison
Non-service cost (benefit)
Total non-service cost (benefit)	(19)	(26)	(54)	(79)
Southern California Edison | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	31	93	93
Non-service cost (benefit)
Interest cost	35	32	106	96
Expected return on plan assets	(48)	(52)	(146)	(159)
Amortization of prior service cost	0	1	1	2
Amortization of net (loss) gain	1	1	4	4
Regulatory adjustment	(4)	2	(12)	7
Total non-service cost (benefit)	(16)	(16)	(47)	(50)
Total expense recognized	15	15	46	43
Net loss reclassified	2	1	5	4
Southern California Edison | PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	10	24	29
Non-service cost (benefit)
Interest cost	21	21	63	63
Expected return on plan assets	(28)	(31)	(83)	(91)
Amortization of prior service cost	(1)	0	(1)	(1)
Amortization of net (loss) gain	0	0	(2)	0
Regulatory adjustment	5	0	17	0
Total non-service cost (benefit)	(3)	(10)	(6)	(29)
Total expense	$ 5	$ 0	$ 18	$ 0