The amount of assets representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognised. [Refer: Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2019-01-01
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-Subparagraph d
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

GOODWILL - Goodwill by segment (Details) - BRL (R$) R$ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill by segment
Goodwill	R$ 9,469,311	R$ 9,112,390	R$ 7,891,142	R$ 9,470,016
Brazil
Goodwill by segment
Goodwill	373,135	373,135	373,135
Special Steel
Goodwill by segment
Goodwill	2,969,752	2,854,888	2,487,364
North America
Goodwill by segment
Goodwill	R$ 6,126,424	R$ 5,884,367	R$ 5,030,643