Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 31	$ 31	$ 93	$ 95
Non-service cost (benefit)
Interest cost	31	38	92	116
Expected return on plan assets	(55)	(52)	(163)	(156)
Amortization of prior service cost	0	0	1	1
Amortization of net (loss) gain	3	2	9	6
Regulatory adjustment	2	(4)	6	(12)
Total non-service cost (benefit)	(19)	(16)	(55)	(45)
Total expense recognized	12	15	38	50
PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	8	28	24
Non-service cost (benefit)
Interest cost	17	21	51	63
Expected return on plan assets	(29)	(28)	(89)	(84)
Amortization of net (loss) gain	(5)	0	(13)	(2)
Regulatory adjustment	8	5	24	17
Total non-service cost (benefit)	(10)	(3)	(28)	(7)
Total expense	0	5	0	17
Southern California Edison
Non-service cost (benefit)
Total non-service cost (benefit)	(28)	(19)	(83)	(54)
Southern California Edison | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	31	91	93
Non-service cost (benefit)
Interest cost	29	35	85	106
Expected return on plan assets	(51)	(48)	(153)	(146)
Amortization of prior service cost	0	0	1	1
Amortization of net (loss) gain	2	1	6	4
Regulatory adjustment	2	(4)	6	(12)
Total non-service cost (benefit)	(18)	(16)	(55)	(47)
Total expense recognized	13	15	36	46
Southern California Edison | PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	8	28	24
Non-service cost (benefit)
Interest cost	17	21	51	63
Expected return on plan assets	(29)	(28)	(89)	(84)
Amortization of prior service cost	(1)	(1)	(1)	(1)
Amortization of net (loss) gain	(5)	0	(13)	(2)
Regulatory adjustment	8	5	24	17
Total non-service cost (benefit)	(10)	(3)	(28)	(7)
Total expense	$ 0	$ 5	$ 0	$ 17