Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 2	$ 2	$ 3
Interest cost	110	76	70
Expected return on plan assets	(125)	(165)	(169)
Amortization of unrecognized net loss	35	32	49
Settlements	48	5	3
Regulatory asset decrease			3
Net periodic (benefit) cost	70	(50)	(41)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost
Interest cost	2	1	1
Expected return on plan assets	(3)	(2)	(3)
Amortization of unrecognized net loss	1
Settlements
Regulatory asset decrease
Net periodic (benefit) cost	$ 0	$ (1)	$ (2)