v3.26.1
Other Expenses (Income), Net - Schedule (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2026
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]      
Currency losses, net $ 0 $ 1  
Unrealized gains (losses) on change in fair value of derivative instruments, net (78) 8  
Realized losses on change in fair value of derivative instruments, net 115 (20)  
(Gain) loss on sale or disposal of assets, net (2) 2  
Interest income (6) (5)  
Non-operating net periodic benefit cost (1) (2)  
Other, net 13 9  
Other expenses (income), net 259 (1)  
Property insurance recoveries 116    
Tariff and freight costs 47    
Sierre flood      
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]      
Repairs and clean-up costs 0 4  
Excess costs to fulfill customer contracts 0 2  
Sierre flood losses, net of recoveries 0 6  
September Oswego fire      
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]      
Idle fixed costs 22 0  
Repairs and clean-up costs (4) 0  
Excess costs to fulfill customer contracts 406 0  
Property insurance recoveries (163) 0  
Other 4 0  
Sierre flood losses, net of recoveries 265 0  
Sierre business interruption insurance recoveries $ (47) $ 0  
Reversal of accrued costs     $ 23