Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pension Plans
Pension and Other Postretirement Benefits
Service cost	$ 34	$ 31	$ 68	$ 62
Non-service cost
Interest cost	26	30	52	61
Expected return on plan assets	(56)	(54)	(112)	(108)
Amortization of prior service cost		1		1
Amortization of net loss	3	3	6	6
Regulatory adjustment (deferred)	4	2	8	4
Total non-service benefit	(23)	(18)	(46)	(36)
Total expense recognized	11	13	22	26
Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Service cost	10	9	20	18
Non-service cost
Interest cost	14	17	28	34
Expected return on plan assets	(27)	(30)	(54)	(60)
Amortization of net loss	(8)	(4)	(16)	(8)
Regulatory adjustment (deferred)	11	8	22	16
Total non-service benefit	(10)	(9)	(20)	(18)
SCE
Non-service cost
Total non-service benefit	(33)	(27)	(66)	(55)
SCE | Pension Plans
Pension and Other Postretirement Benefits
Service cost	33	30	66	60
Non-service cost
Interest cost	24	28	48	56
Expected return on plan assets	(53)	(51)	(106)	(102)
Amortization of prior service cost		1		1
Amortization of net loss	2	2	4	4
Regulatory adjustment (deferred)	4	2	8	4
Total non-service benefit	(23)	(18)	(46)	(37)
Total expense recognized	$ 10	$ 12	$ 20	$ 23