21 Employees benefits (Details 3) - BRL (R$) R$ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of employee benefits [Line Items]
Actuarial gains/(losses) on obligations	R$ 585,968	R$ (790,473)	R$ (124,971)
Actuarial gains/(losses) recorded as other comprehensive income	(80,059)	445,206	113,869
Total gains/(losses)	505,909	(345,267)	(11,102)
Deferred income tax and social contribution - G1 Plan	5,243	(17,792)	108
Valuation adjustments to equity	511,152	(363,059)	(10,994)
G1 Plan [member]
Summary of employee benefits [Line Items]
Actuarial gains/(losses) on obligations	64,637	(392,876)	(114,188)
Actuarial gains/(losses) recorded as other comprehensive income	(80,059)	445,206	113,869
Total gains/(losses)	(15,422)	52,330	(319)
Deferred income tax and social contribution - G1 Plan	5,243	(17,792)	108
Valuation adjustments to equity	(10,179)	34,538	(211)
G0 plan [member]
Summary of employee benefits [Line Items]
Actuarial gains/(losses) on obligations	521,331	(397,597)	(10,783)
Actuarial gains/(losses) recorded as other comprehensive income	0	0	0
Total gains/(losses)	521,331	(397,597)	(10,783)
Deferred income tax and social contribution - G1 Plan	0	0	0
Valuation adjustments to equity	R$ 521,331	R$ (397,597)	R$ (10,783)

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)]

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

The decrease (increase) in the net defined benefit liability (asset) resulting from settlements. Settlements are transactions that eliminate all further legal or constructive obligations for part or all of the benefits provided under a defined benefit plan, other than a payment of benefits to, or on behalf of, employees that is set out in the terms of the plan and included in the actuarial assumptions. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]; Actuarial assumptions [member]]

+ References

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

The gains (losses) on financial assets at fair value through profit or loss. [Refer: Financial assets at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 20
-Subparagraph a
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-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a_i&doctype=Standard
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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)]

+ References

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

The amount of deferred tax assets net of deferred tax liabilities, when the absolute amount of deferred tax assets is greater than the absolute amount of deferred tax liabilities. [Refer: Deferred tax assets; Deferred tax liabilities]

+ References

No definition available.

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- Definition

Its represents information related to summary of employee benefits.

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