v3.25.2
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 9 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Sep. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]          
Derivatives - Foreign Currency contracts $ 21.3   $ 21.3   $ 39.2
(Loss)/Gain Recognized in OCI (10.5) $ 7.2 4.9 $ (1.3)  
(Loss)/Gain Reclassified From OCI into Income 6.5 6.9 22.8 18.0  
Foreign currency contracts          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivatives - Foreign Currency contracts (7.7)   (7.7)   (4.6)
(Loss)/Gain Recognized in OCI (9.7) 0.2      
(Loss)/Gain Reclassified From OCI into Income 0.3 0.4      
Interest rate swap          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivatives - Foreign Currency contracts 29.8   29.8   39.8
(Loss)/Gain Recognized in OCI (1.4) 4.0 6.9 2.7  
(Loss)/Gain Reclassified From OCI into Income 5.1 7.7 16.9 23.5  
Zinc contracts          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivatives - Foreign Currency contracts (0.8)   (0.8)   $ 4.0
(Loss)/Gain Recognized in OCI 0.6 3.0 (1.4) (2.1)  
(Loss)/Gain Reclassified From OCI into Income $ 1.1 $ (1.2) 3.4 (6.5)  
Foreign currency contracts          
Derivative Instruments, Gain (Loss) [Line Items]          
(Loss)/Gain Recognized in OCI     (0.6) (1.9)  
(Loss)/Gain Reclassified From OCI into Income     $ 2.5 $ 1.0