v3.26.1
Financial Instruments and Risk Management (Fair Value for Assets and Liabilities) (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of fair value measurement of assets [line items]    
Total liabilities $ (1,938.8) $ (1,751.9)
Total Assets 6,384.6 5,336.1
Current derivative financial liabilities 128.0 9.1
Non-current derivative financial liabilities 129.1 140.0
Derivative financial assets 2.0 0.0
Derivative financial liabilities (257.1) 149.1
Gold Forward Contracts    
Disclosure of fair value measurement of assets [line items]    
Current derivative financial liabilities 0.0  
Non-current derivative financial liabilities 128.0  
Derivatives | Fuel Options    
Disclosure of fair value measurement of assets [line items]    
Financial assets, at fair value   0.1
Derivatives | Fuel Options | Fair value through OCI    
Disclosure of fair value measurement of assets [line items]    
Financial assets, at fair value   0.1
Level 2    
Disclosure of fair value measurement of assets [line items]    
Fair value, net asset (liability) (255.1) (149.1)
Level 2 | Gold Forward Contracts    
Disclosure of fair value measurement of assets [line items]    
Total liabilities (257.0) (140.0)
Level 2 | Derivatives | Fair value through OCI    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, at fair value 2.0  
Level 2 | Derivatives | Fuel Options | Fair value through OCI    
Disclosure of fair value measurement of assets [line items]    
Financial assets, at fair value 0.1  
Level 2 | Currency Hedging Derivative Instruments | Fair value through OCI    
Disclosure of fair value measurement of assets [line items]    
Total liabilities   9.0
Level 1    
Disclosure of fair value measurement of assets [line items]    
Fair value, net asset (liability) 58.9 24.0
Level 1 | Trading securities | Fair value through OCI    
Disclosure of fair value measurement of assets [line items]    
Total Assets $ 58.9 $ 24.0