Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 4	$ 8	$ 8
Interest cost	9	8	18	17
Expected return on plan assets	$ (11)	$ (11)	$ (22)	$ (23)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Amortization of prior service cost (credit)	$ 0	$ 0	$ 0	$ 0
Net loss recognition	0	1	1	2
Net periodic benefit cost	2	2	5	4
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	1
Interest cost	1	2	3	4
Expected return on plan assets	$ (1)	$ (1)	$ (2)	$ (2)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Amortization of prior service cost (credit)	$ 0	$ (1)	$ 0	$ (1)
Net loss recognition	0	0	0	0
Net periodic benefit cost	$ 1	$ 1	$ 2	$ 2