v3.26.1
Schedule of Derivatives (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2027
Derivative Instruments, Gain (Loss) [Line Items]          
Cost of goods sold $ 2,617.4 $ 1,335.5 $ 4,770.9 $ 2,572.9  
Other income (expense), net (16.0) 3.1 (44.6) 0.2  
Interest expense (89.8) (43.1) (179.4) (86.0)  
Gain on Business Combination Derivative 0.0 46.3 12.9 68.2  
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net 12.5 2.8 2.3 3.7  
Foreign Exchange Forward [Member] | Dowlais Group plc | Not Designated as Hedging Instrument [Member]          
Derivative Instruments, Gain (Loss) [Line Items]          
Gain on Business Combination Derivative 0.0 46.3 12.9 68.2  
Foreign Exchange Forward [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member]          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivative, Gain (Loss) on Derivative, Net $ 4.0 $ (1.9) $ 6.5 $ (6.0)  
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Cost of goods sold Cost of goods sold Cost of goods sold Cost of goods sold  
Foreign Exchange Forward [Member] | Cash Flow Hedging [Member] | Forecast [Member] | Cost of goods sold          
Derivative Instruments, Gain (Loss) [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months         $ 10.1
Currency Swap [Member] | Fair Value Hedging | Designated as Hedging Instrument [Member]          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivative, Gain (Loss) on Derivative, Net $ 6.9 $ (17.0) $ 20.7 $ (25.0)  
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other income (expense), net Other income (expense), net Other income (expense), net Other income (expense), net  
Currency Swap [Member] | Fair Value Hedging | Forecast [Member] | Other Income (Expense), net          
Derivative Instruments, Gain (Loss) [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months         0.0
Interest Rate Swap [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member]          
Derivative Instruments, Gain (Loss) [Line Items]          
Derivative, Gain (Loss) on Derivative, Net $ (0.1) $ 0.4 $ (0.4) $ 1.4  
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Interest expense Interest expense Interest expense Interest expense  
Interest Rate Swap [Member] | Cash Flow Hedging [Member] | Forecast [Member] | Interest Expense, Operating and Nonoperating          
Derivative Instruments, Gain (Loss) [Line Items]          
Cash flow hedge gain (loss) to be reclassified within twelve months         $ 1.9