Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 2	$ 3	$ 3
Interest cost	76	70	92
Expected return on plan assets	(165)	(169)	(173)
Amortization of unrecognized net loss	32	49	48
Settlements and curtailments	5	3	10
Regulatory asset decrease		3
Net periodic (benefit) cost	(50)	(41)	(20)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost
Interest cost	1	1	2
Expected return on plan assets	(2)	(3)	(3)
Amortization of unrecognized net loss			(1)
Settlements and curtailments			(1)
Regulatory asset decrease
Net periodic (benefit) cost	$ (1)	$ (2)	$ (3)