v3.26.3
Pensions and Other Postretirement Benefits (Additional Information) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2026
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2026
Pension            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Net periodic benefit cost   $ 6 $ 10 $ 18 $ 26  
Other Postretirement Benefits            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Net periodic benefit cost   $ 4 $ 5 $ 13 $ 15  
Scenario, Forecast | Pension            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Net periodic benefit cost           $ 40
Scenario, Forecast | Pension | Minimum | Mandatory Contribution            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Contributions to defined benefit pension plans $ 5          
Scenario, Forecast | Pension | Maximum | Mandatory Contribution            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Contributions to defined benefit pension plans $ 15