Pensions and Other Postretirement Benefits (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit pension plan, decrease for remeasurement due to Settlement			$ 309
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer mandatory contributions		$ 5			$ 5
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer mandatory contributions		10			10
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost/(income)		6		$ (6)	205	$ (13)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost/(income)		5		5	11	13
Mandatory Contribution
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to defined benefit pension plans		$ 1		$ 1	$ 2	$ 2
Scenario, Forecast | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost/(income)	$ 220
Scenario, Forecast | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost/(income)	$ 25