Compensation and Benefit Plans (Expense Components) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 32	$ 32
Non-service cost
Interest cost	39	35
Expected return on plan assets	(52)	(57)
Amortization of prior service cost	0	1
Amortization of net loss	2	2
Regulatory adjustment (deferred)	(4)	2
Total non-service benefit2	(15)	(17)
Total expense recognized	17	15
Net loss reclassified	2	2
PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	9
Non-service cost
Interest cost	21	21
Expected return on plan assets	(28)	(30)
Amortization of net loss	(1)	0
Regulatory adjustment (deferred)	6	0
Total non-service benefit2	(2)	(9)
Total expense	6	0
Southern California Edison
Non-service cost
Total non-service benefit2	(19)	(26)
Southern California Edison | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	31
Non-service cost
Interest cost	35	32
Expected return on plan assets	(49)	(53)
Amortization of prior service cost	0	1
Amortization of net loss	1	1
Regulatory adjustment (deferred)	(4)	2
Total non-service benefit2	(17)	(17)
Total expense recognized	14	14
Net loss reclassified	1	1
Southern California Edison | PBOP Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	9
Non-service cost
Interest cost	21	21
Expected return on plan assets	(28)	(30)
Amortization of net loss	(1)	0
Regulatory adjustment (deferred)	6	0
Total non-service benefit2	(2)	(9)
Total expense	$ 6	$ 0