v3.26.1
CONTINGENCIES, COMMITMENTS AND RESTRICTIONS ON THE DISTRIBUTION OF PROFITS (Commitments ae-ao) (Details)
m³ in Thousands, $ in Millions
 12 Months Ended
Dec. 31, 2025
USD ($)
T
Jul. 31, 2025
T
m³
White Martins Gases Industriais LTD | Usiminas | Industrial Gas    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 85.4  
Long-term purchase commitment, take or pay volume 50.00%  
White Martins WK | Usiminas | Industrial Gas    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 78.8  
Long-term purchase commitment, take or pay volume 47.20%  
VLI Multimodal S.A. | Usiminas | Rail Transportation    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 314.0  
VLI Multimodal S.A. | Usiminas | Port And Accessory Services    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount 58.9  
Porto Sudeste do Brasil S.A. | Mineração Usiminas S.A. | Ore Export Loading    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 164.2  
Long-term purchase commitment, total purchased volume | T 8,000,000  
MRS Logística S.A | Usiminas | Rail Transportation    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 37.8  
Long-term purchase commitment, minimum volume | T 3,500,000  
Long term purchase commitment, maximum volume | T 4,200,000  
Armac Locacao Logistica e Servicos S.A. | Mineração Usiminas S.A. | Internal Material Handling Services    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 14.5  
Long-term purchase commitment, termination penalty, period one 50.00%  
Long-term purchase commitment, termination penalty, period two 25.00%  
Seday Transportes Ltda | Usiminas | Transportation Services    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 11.9  
Petrobras S.A. | Usiminas | Natural Gas    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 346.7  
Minimum daily consumption volume | m³   889
Annual take or pay volume 70.00%  
Petrobras S.A. | Usiminas | Petcoke    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 6.0  
Long-term purchase commitment, minimum volume | T 96,000  
Ical Industria de Calcinacao Ltda | Usiminas | Lime    
Disclosure of contingent liabilities [line items]    
Minimum monthly consumption volume | T   9,282
Ical Industria de Calcinacao Ltda | Usiminas | Limestone    
Disclosure of contingent liabilities [line items]    
Minimum monthly consumption volume | T   23,400
Ical Industria de Calcinacao Ltda | Usiminas | Lime And Limestone    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 16.2  
Annual take or pay volume 100.00%  
BEMISA HOLDING SA | Usiminas | Iron Ore    
Disclosure of contingent liabilities [line items]    
Long-term purchase commitment, amount $ 51.2  
Annual take or pay volume 95.00%