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10. INTANGIBLE ASSETS (Details 3) | 12 Months Ended
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Dec. 31, 2019
Packaging [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Measurement of recoverable value | Discounted Cash Flow |
Cash flow projection | Until 2029 + perpetuity |
Gross Margin | Gross margin updated based on historical data, impacts of business restructuring and market trends |
Cost atualization | Cost based on historical data of each product and impacts of business restructuring |
Perpetual growth rate | Without growth |
Packaging [Member] | Top of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 8.00% |
Mining [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Measurement of recoverable value | Discounted Cash Flow |
Cash flow projection | Until 2054 |
Gross Margin | Reflects projection of costs due to the progress of the mining plan as well as startup and ramp up of projects. Price and exchange rate projected according industry reports. |
Cost atualization | Updated costs based on historical data, progress of mining plan as well as startup and ramp up of projects |
Perpetual growth rate | Without perpetuity |
Mining [Member] | Top of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 10.00% |
Mining [Member] | Bottom of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 12.00% |
Other Steel [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Measurement of recoverable value | Discounted Cash Flow |
Cash flow projection | Until 2029 + perpetuity |
Gross Margin | Gross margin updated based on historical data and market trends |
Cost atualization | Updated costs based on historical data and market trends |
Perpetual growth rate | Without growth |
Other Steel [Member] | Top of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 10.00% |
Other Steel [Member] | Bottom of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 12.00% |
Flat Steel [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Measurement of recoverable value | Discounted Cash Flow | [1]
Cash flow projection | Until 2029 + perpetuity | [1]
Gross Margin | Without growth | [1]
Cost atualization | Updated costs based on historical data and market trends | [1]
Perpetual growth rate | Growth of 1.4% p.a in real terms updated by long term inflation of 1.7% p.a. of the Euro zone | [1]
Flat Steel [Member] | Top of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 10.00% | [1]
Flat Steel [Member] | Bottom of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 12.00% | [1]
Logistic [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Measurement of recoverable value | Discounted Cash Flow | [2]
Cash flow projection | Until 2027 | [2]
Gross Margin | Growth of 1.4% p.a in real terms updated by long term inflation of 1.7% p.a. of the Euro zone | [2]
Cost atualization | Costs based on historical data and market trends | [2]
Perpetual growth rate | Without perpetuity | [2]
Logistic [Member] | Top of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 5.09% | [2]
Logistic [Member] | Bottom of Range [Member] |  |
Disclosure of detailed information about intangible assets [line items] |  |
Discount rate | 5.41% | [2]
[1] | Refer to assets of subsidiary Lusosider, located in Portugal. The discount rate was applied on the discounted cash flow prepared in Euros, the functional currency of this subsidiary.
[2] | Refer to assets of subsidiary FTL Ferrovia Transnordestina Logistica S.A.

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- Definition The description of the basis on which the cash-generating unit's (group of units') recoverable amount has been determined (ie value in use or fair value less costs of disposal). [Refer: Cash-generating units [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The discount rate applied to cash flow projections for a cash-generating unit (group of units). [Refer: Cash-generating units [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph d -Clause v -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_d_v&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph e -Clause v -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_e_v&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The description of the justification for using any growth rate to extrapolate cash flow projections that exceeds the long-term average growth rate for the products, industries or country (countries) in which the entity operates, or for the market to which a cash-generating unit (group of units) is dedicated. [Refer: Cash-generating units [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph d -Clause iv -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_d_iv&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The description of key assumptions on which management has based its cash flow projections for the period covered by the most recent budgets/forecasts for a cash-generating unit (group of units). Key assumptions are those to which the unit's (group of units') recoverable amount is most sensitive. [Refer: Cash-generating units [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph d -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_d_i&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 135 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_135_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The description of key assumptions on which management has based its determination of fair value less costs of disposal for a cash-generating unit (group of units). Key assumptions are those to which the unit's (group of units') recoverable amount is most sensitive. [Refer: Cash-generating units [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 134 -Subparagraph e -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_134_e_i&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 130 -Subparagraph f -Clause iii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_f_iii&doctype=Standard -URIDate 2019-03-27 + Details
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