XML 151 R128.htm IDEA: XBRL DOCUMENT
v3.19.1

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, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Amounts recognized as actuarial gains and losses in the statement of comprehensive income |  |  |
Restriction recognized in Other Comprehensive Income | R$ (43,197) | R$ (1,696) | R$ 3,065
Remeasurements recognized in Other Comprehensive Income | (159,979) | 1,639 | 80,817
Plan assets |  |  |
Amounts recognized as actuarial gains and losses in the statement of comprehensive income |  |  |
Gain (loss) on remeasurement | 253,301 | (232,214) | (109,153)
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$ (370,083) | R$ 235,549 | R$ 186,905

X
- References No definition available. + Details
Name: | ggb_AmountsRecognizedAsActuarialGainsAndLossesInStatementOfComprehensiveIncomeAbstract
Namespace Prefix: | ggb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of other comprehensive income, before tax, related to gains (losses) on restrictions on defined benefit plans. + References No definition available. + Details
Name: | ggb_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRestrictionsOfDefinedBenefitPlans
Namespace Prefix: | ggb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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 2018-01-01 -Paragraph 141 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_c&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_GainLossOnRemeasurementOfNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 91 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_91_b&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_7&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=ifrs-full_DefinedBenefitPlansOtherThanMultiemployerPlansStatePlansAndPlansThatShareRisksBetweenEntitiesUnderCommonControlMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PlanAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PresentValueOfDefinedBenefitObligationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |