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2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Direct | Subsidiary 1 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Islands VII Corp. | CSN Islands VII Corp.
Interest in subsidiaries | 100.00% | 100.00%
Core business | Financial transactions | Financial transactions
Direct | Subsidiary 2 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Islands IX Corp. (1) | CSN Islands XI Corp.
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions | Financial transactions
Direct | Subsidiary 3 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Islands X Corp. (1) | CSN Islands XII Corp.
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions | Financial transactions
Direct | Subsidiary 4 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Islands XI Corp. | CSN Minerals S.L.U.
Interest in subsidiaries | 100.00% | 100.00%
Core business | Financial transactions | Equity interests
Direct | Subsidiary 5 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Islands XII Corp. | CSN Export Europe, S.L.U.
Interest in subsidiaries | 100.00% | 100.00%
Core business | Financial transactions | Financial transactions and Equity interests
Direct | Subsidiary 6 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Minerals S.L.U. (1) | CSN Metals S.L.U.
Interest in subsidiaries |  | 100.00%
Core business | Equity interests | Equity interests and Financial transactions
Direct | Subsidiary 7 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Export Europe, S.L.U. (1) | CSN Americas S.L.U.
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions and Equity interests | Equity interests and Financial transactions
Direct | Subsidiary 8 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Metals S.L.U. (1) | CSN Steel S.L.U.
Interest in subsidiaries |  | 100.00%
Core business | Equity interests and Financial transactions | Equity interests and Financial transactions
Direct | Subsidiary 9 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Americas S.L.U. (1) | TdBB S.A
Interest in subsidiaries |  | 100.00%
Core business | Equity interests and Financial transactions | Equity interests
Direct | Subsidiary 10 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Steel S.L.U. | Sepetiba Tecon S.A.
Interest in subsidiaries | 100.00% | 99.99%
Core business | Equity interests and Financial transactions | Port services
Direct | Subsidiary 11 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | TdBB S.A (*) | Minérios Nacional S.A.
Interest in subsidiaries | 100.00% | 99.99%
Core business | Equity interests | Mining and Equity interests
Direct | Subsidiary 12 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Sepetiba Tecon S.A. | Companhia Florestal do Brasil
Interest in subsidiaries | 99.99% | 99.99%
Core business | Port services | Reforestation
Direct | Subsidiary 13 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Minérios Nacional S.A. | Estanho de Rondônia S.A.
Interest in subsidiaries | 99.99% | 99.99%
Core business | Mining and Equity interests | Tin Mining
Direct | Subsidiary 14 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia Florestal do Brasil | Companhia Metalúrgica Prada
Interest in subsidiaries | 99.99% | 99.99%
Core business | Reforestation | Manufacture of containers and distribution of steel products
Direct | Subsidiary 15 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Estanho de Rondônia S.A. | CSN Gestão de Recursos Financeiros Ltda.
Interest in subsidiaries | 99.99% | 99.99%
Core business | Tin Mining | Management of funds and securities portfolio
Direct | Subsidiary 16 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia Metalúrgica Prada | CSN Mineração S.A.
Interest in subsidiaries | 99.99% | 87.52%
Core business | Manufacture of containers and distribution of steel products | Mining and Equity interests
Direct | Subsidiary 17 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Gestão de Recursos Financeiros Ltda. (*) | CSN Energia S.A.
Interest in subsidiaries | 99.99% | 99.99%
Core business | Management of funds and securities portfolio | Sale of electric power
Direct | Subsidiary 18 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Mineração S.A. | FTL - Ferrovia Transnordestina Logística S.A.
Interest in subsidiaries | 87.52% | 90.78%
Core business | Mining and Equity interests | Railroad logistics
Direct | Subsidiary 19 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Energia S.A. | Nordeste Logística S.A.
Interest in subsidiaries | 99.99% | 99.99%
Core business | Sale of electric power | Port services
Direct | Subsidiary 20 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | FTL - Ferrovia Transnordestina Logística S.A. | CGPAR - Construção Pesada S.A. (3)
Interest in subsidiaries | 91.69% |
Core business | Railroad logistics | Mining support services and Equity interests
Direct | Subsidiary 21 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Nordeste Logística S.A. |
Interest in subsidiaries | 99.99% |
Core business | Port services |
Direct | Subsidiary 22 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Aceros México CSN (2) |
Interest in subsidiaries | 0.08% |
Core business | Commercial representation, sales of steel and related activities |
Direct | Subsidiary 23 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Inova Ltd.(3) |
Interest in subsidiaries | 100.00% |
Core business | Advisory and implementation of new development projects |
Direct | Joint Operation 1 | Proportionate Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Joint operations name | Itá Energética S.A. | Itá Energética S.A.
Interest in joint operations | 48.75% | 48.75%
Core business | Electric power generation | Electric power generation
Direct | Joint Operation 2 | Proportionate Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Joint operations name | Consórcio da Usina Hidrelétrica de Igarapava | Consórcio da Usina Hidrelétrica de Igarapava
Interest in joint operations | 17.92% | 17.92%
Core business | Electric power consortium | Electric power generation
Direct | Joint Ventures 1 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Joint ventures name | MRS Logística S.A. | MRS Logistica S.A.
Interest in joint ventures | 18.64% | 18.64%
Core business | Railroad transportation | Railroad transportation
Direct | Joint Venture 2 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Joint ventures name | Aceros Del Orinoco S.A. | Aceros Del Orinoco S.A.
Interest in joint ventures | 31.82% | 31.82%
Core business | Dormant company | Dormant company
Direct | Joint Venture 3 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Joint ventures name | CBSI - Companhia Brasileira de Serviços de Infraestrutura | CBSI - Companhia Brasileira de Serviços de Infraestrutura
Interest in joint ventures | 50.00% | 50.00%
Core business | Equity interests and product sales and iron ore | Equity interests and product sales and iron ore
Direct | Joint Venture 4 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Joint ventures name | Transnordestina Logística S.A. | Transnordestina Logística S.A.
Interest in joint ventures | 46.30% | 46.30%
Core business | Railroad logistics | Railroad logistics
Direct | Associate 1 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Associates name | Arvedi Metalfer do Brasil S.A. | Arvedi Metalfer do Brasil S.A.
Interest in associates | 20.00% | 20.00%
Core business | Metallurgy and Equity interests | Metallurgy Equity interests
Indirect | Subsidiary 1 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia Siderúrgica Nacional | Companhia Siderúrgica Nacional LLC
Interest in subsidiaries |  | 100.00%
Core business | Steel | Steel
Indirect | Subsidiary 2 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Lusosider Projectos Siderúrgicos S.A. | CSN Europe Lda.
Interest in subsidiaries |  |
Core business | Equity interests and product sales | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 3 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Lusosider Aços Planos, S. A. | CSN Ibéria Lda.
Interest in subsidiaries |  |
Core business | Steel and Equity interests | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 4 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Resources S.A. | Lusosider Projectos Siderúrgicos S.A.
Interest in subsidiaries |  | 99.94%
Core business | Financial transactions and Equity interests | Equity interests and product sales
Indirect | Subsidiary 5 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia Brasileira de Latas | Lusosider Aços Planos, S. A.
Interest in subsidiaries |  | 99.99%
Core business | Sale of cans and containers in general and Equity interests | Steel and Equity interests
Indirect | Subsidiary 6 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia de Embalagens Metálicas MMSA | CSN Resources S.A.
Interest in subsidiaries |  | 100.00%
Core business | Production and sale of cans and related activities | Financial transactions and Equity interests
Indirect | Subsidiary 7 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Companhia de Embalagens Metálicas - MTM | Companhia Brasileira de Latas
Interest in subsidiaries |  | 99.99%
Core business | Production and sale of cans and related activities | Sale of cans and containers in general and Equity interests
Indirect | Subsidiary 8 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Steel Holdings 1, S.L.U. | Companhia de Embalagens Metálicas MMSA
Interest in subsidiaries |  | 99.67%
Core business | Financial transactions, product sales and Equity interests | Production and sale of cans and related activities
Indirect | Subsidiary 9 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Productos Siderúrgicos S.L. | Companhia de Embalagens Metálicas - MTM
Interest in subsidiaries |  | 99.67%
Core business | Financial transactions, product sales and Equity interests | Production and sale of cans and related activities
Indirect | Subsidiary 10 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | Stalhwerk Thüringen GmbH | CSN Steel Holdings 1, S.L.U.
Interest in subsidiaries |  | 100.00%
Core business | Production and sale of long steel and related activities | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 11 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Steel Sections UK Limited (*) | CSN Productos Siderúrgicos S.L.
Interest in subsidiaries |  | 100.00%
Core business | Sale of long steel | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 12 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Steel Sections Polska Sp.Z.o.o | Stalhwerk Thüringen GmbH
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions, product sales and Equity interests | Production and sale of long steel and related activities
Indirect | Subsidiary 13 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Asia Limited | CSN Steel Sections UK Limited
Interest in subsidiaries |  | 100.00%
Core business | Commercial representation | Sale of long steel
Indirect | Subsidiary 14 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Mining Holding, S.L | CSN Steel Sections Polska Sp.Z.o.o
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions, product sales and Equity interests | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 15 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Mining GmbH | CSN Asia Limited
Interest in subsidiaries |  | 100.00%
Core business | Financial transactions, product sales and Equity interests | Commercial representation
Indirect | Subsidiary 16 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name | CSN Mining Asia Limited (8) | CSN Mining Holding, S.L
Interest in subsidiaries |  | 87.52%
Core business | Commercial representation | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 17 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name |  | CSN Mining GmbH
Interest in subsidiaries |  | 87.52%
Core business |  | Financial transactions, product sales and Equity interests
Indirect | Subsidiary 18 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name |  | CSN Mining Asia Limited
Interest in subsidiaries |  | 87.52%
Core business |  | Commercial representation
Indirect | Subsidiary 19 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name |  | Aceros México CSN
Interest in subsidiaries |  | 100.00%
Core business |  | Commercial representation,sale of steel and related activity
Indirect | Subsidiary 20 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name |  | Lusosider Ibérica S.A.
Interest in subsidiaries |  | 99.94%
Core business |  | Steel, commercial and industrial activities and equity interests
Indirect | Subsidiary 21 | Full Consolidation |  |
Disclosure of subsidiaries [line items] |  |
Subsidiary name |  | CSN Mining Portugal, Unipessoal Lda.
Interest in subsidiaries |  | 87.52%
Core business |  | Sale and commercial representation
Indirect | Joint Ventures 1 | Equity Method |  |
Disclosure of subsidiaries [line items] |  |
Joint ventures name | MRS Logística S.A. | MRS Logistica S.A.
Interest in joint ventures | 16.30% | 16.30%
Core business | Railroad transportation | Railroad transportation

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