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31. FINANCIAL INSTRUMENTS AND RISK MANAGEMENT (Details 2) - Put option - SAAG [member] - BRL (R$) R$ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of financial liabilities [line items]
Balance	R$ 483	R$ 419	R$ 312
Adjustment to fair value	53	64	107
Balance	R$ 536	R$ 483	R$ 419

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- Definition

Adjustment to fair value of options.

+ References

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- Definition

The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 55
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-URIDate 2020-01-01

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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