Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Pension and Other post-retirement benefits - net settlements (E)	$ 0	$ 2	$ 0	$ 5
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	0	2	2
Interest cost	18	20	56	60
Expected return on plan assets	(17)	(18)	(52)	(55)
Recognized net actuarial (gain) loss	9	7	25	21
Pension and Other post-retirement benefits - net settlements (E)	0	2	0	5
Net periodic cost (benefit)	11	11	31	33
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	1	2	4	5
Recognized net actuarial (gain) loss	(1)	(1)	(2)	(2)
Amortization of prior service benefit	(2)	(3)	(7)	(7)
Net periodic cost (benefit)	$ (2)	$ (1)	$ (5)	$ (3)