Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 31	$ 32
Non-service cost (benefit)
Interest cost	31	39
Expected return on plan assets	(54)	(52)
Amortization of net (loss) gain	3	2
Regulatory adjustment	2	(4)
Total non-service cost (benefit)	(18)	(15)
Total expense recognized	13	17
Net loss reclassified	3	2
PBOP Plan
Non-service cost (benefit)
Total non-service cost (benefit)	(9)	(2)
Total expense	0	6
Southern California Edison
Non-service cost (benefit)
Total non-service cost (benefit)	(28)	(19)
Southern California Edison | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	30	31
Non-service cost (benefit)
Interest cost	28	35
Expected return on plan assets	(51)	(49)
Amortization of net (loss) gain	2	1
Regulatory adjustment	2	(4)
Total non-service cost (benefit)	(19)	(17)
Total expense recognized	11	14
Net loss reclassified	2	1
Southern California Edison | PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	8
Non-service cost (benefit)
Interest cost	17	21
Expected return on plan assets	(30)	(28)
Amortization of net (loss) gain	(4)	(1)
Regulatory adjustment	8	6
Total non-service cost (benefit)	(9)	(2)
Total expense	$ 0	$ 6