v3.25.4
Financial Instruments and Risk Management - Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) (Details) - Designated as Hedging Instrument - Cash Flow Hedging - USD ($)
$ in Millions
 3 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Sep. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]      
Derivatives - Foreign Currency contracts $ 20.7   $ 22.9
(Loss)/Gain Recognized in OCI 0.2 $ 20.4  
(Loss)/Gain Reclassified From OCI into Income 2.4 5.7  
Foreign currency contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivatives - Foreign Currency contracts (2.9)   (3.9)
(Loss)/Gain Recognized in OCI (0.6) 12.4  
(Loss)/Gain Reclassified From OCI into Income (1.6) 0.1  
Interest rate swap      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivatives - Foreign Currency contracts 21.0   25.3
(Loss)/Gain Recognized in OCI 0.3 11.7  
(Loss)/Gain Reclassified From OCI into Income 4.6 6.7  
Zinc contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Derivatives - Foreign Currency contracts 2.6   $ 1.5
(Loss)/Gain Recognized in OCI 0.5 (3.7)  
(Loss)/Gain Reclassified From OCI into Income $ (0.6) $ (1.1)