CONTINGENCIES, COMMITMENTS AND RESTRICTIONS ON THE DISTRIBUTION OF PROFITS (Commitments ae-an) (Details) T in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($) T
SOTREQ S.A. \| Mineraçao Usiminas \| Maintenance Services
Disclosure of contingent liabilities [line items]
Unjustified termination clause, period	24 months
Long-term purchase commitment, amount	$ 10.3
National Operator Of The Electric System (ONS) \| Usiminas \| Transmission System
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	18.3
White Martins Gases Industriais LTD \| Usiminas \| Industrial Gas
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	$ 122.8
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	$ 29.3
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	$ 139.1
VLI Multimodal S.A. \| Usiminas \| Port And Accessory Services
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	$ 49.5
VLI Multimodal S.A. \| Usiminas \| Port And Accessory Services \| Bottom of range
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, minimum volume \| T	1,800
VLI Multimodal S.A. \| Usiminas \| Port And Accessory Services \| Top of range
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, minimum volume \| T	2,100
Porto Sudeste do Brasil S.A. \| Mineração Usiminas S.A. \| Ore Export Loading
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	$ 178.3
Long-term purchase commitment, total purchased volume \| T	8,000
MRS Logística S.A \| Usiminas \| Rail Transportation
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	$ 45.4
Long-term purchase commitment, deviation	20.00%
MRS Logística S.A \| Usiminas \| Rail Transportation \| Ipatinga, Brazil
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, minimum volume \| T	750
MRS Logística S.A \| Usiminas \| Rail Transportation \| Cubatao, Brazil
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, minimum volume \| T	402
Petrobras S.A. \| Usiminas \| Petcoke
Disclosure of contingent liabilities [line items]
Long-term purchase commitment, amount	$ 48.4
Long-term purchase commitment, minimum volume \| T	96
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	$ 20.4
Long-term purchase commitment, termination penalty, period one	50.00%
Long-term purchase commitment, termination penalty, period two	25.00%