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EMPLOYEE BENEFITS - Defined benefit pension plan - Actuarial gains and losses (Details) - Defined benefit pension plan - BRL (R$) R$ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amounts recognized as actuarial gains and losses in the statement of comprehensive income
Restriction recognized in Other Comprehensive Income	R$ (42,317)	R$ (94,198)	R$ (43,197)
Remeasurements recognized in Other Comprehensive Income	90,114	65,946	(159,979)
Plan assets
Amounts recognized as actuarial gains and losses in the statement of comprehensive income
Gain (loss) on remeasurement	(334,675)	(386,767)	253,301
Present value of the defined benefit obligations
Amounts recognized as actuarial gains and losses in the statement of comprehensive income
Gain (loss) on remeasurement	R$ 467,106	R$ 546,911	R$ (370,083)

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- References

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- Definition

The amount of other comprehensive income, before tax, related to gains (losses) on restrictions on defined benefit plans.

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- Definition

The decrease (increase) in a net defined benefit liability (asset) resulting from the remeasurement of that net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2020-01-01
-Paragraph 141
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- Definition

The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income, before tax; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)]

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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