Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1	$ 1
Interest cost	24	28
Expected return on plan assets	(29)	(32)
Amortization of unrecognized net loss	7	9
Net periodic cost	3	6
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost
Interest cost	1	1
Expected return on plan assets	(1)	(1)
Amortization of unrecognized net loss
Net periodic cost	$ 0	$ 0