Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Settlements	$ 3	$ 3	$ 3	$ 4
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	20	13	40	25
Expected return on plan assets	(18)	(21)	(37)	(41)
Recognized net actuarial loss	7	12	14	25
Settlements	3	3	3	4
Net periodic cost (benefit)	13	8	22	15
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	1	1	3	2
Recognized net actuarial loss	0	1	(1)	1
Amortization of prior service benefit	(2)	(3)	(4)	(5)
Net periodic cost (benefit)	$ (1)	$ 0	$ (2)	$ (1)