v3.25.2
Contingencies (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Applicability, Impact and Conclusion of Environmental Loss Contingencies [Abstract]    
Environmental contingency accrual $ 189.6 $ 197.5
Loss Contingencies [Line Items]    
Accrued Environmental Loss Contingencies, Noncurrent $ 132.5 106.7
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Accrued liabilities  
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration] Accrued liabilities  
Environmental Loss Contingency, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other noncurrent liabilities  
Accrued Environmental Loss Contingencies, Current $ 57.1 $ 90.8
New Wales Phase II East Stack    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 9.0  
New Wales Phase II West Stack    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 77.0  
Brazilian subsidiary judicial and administrative proceedings    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 86.4  
Brazilian subsidiary labor claims    
Loss Contingencies [Line Items]    
Loss Contingency Accrual 64.5  
Maximum | Brazilian subsidiary judicial and administrative proceedings    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 610.1  
Maximum | Brazilian Non Income Tax Proceedings    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 700.5  
Maximum | Brazilian Non Income Tax Proceedings | Indemnification Agreement Vale S.A.    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 207.4  
Maximum | Brazilian Non Income Tax Proceedings | PIS And Cofins Cases    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy 379.6  
Maximum | Brazilian subsidiary labor claims    
Loss Contingencies [Line Items]    
Maximum potential liabilitiy $ 401.3