XML 148 R125.htm IDEA: XBRL DOCUMENT v3.19.1

EMPLOYEE BENEFITS - Defined benefit pension plan - Reconciliation of plan assets and liabilities (Details) - Defined benefit pension plan - BRL (R$) R$ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliations of assets and liabilities of the plans
Net	R$ (1,057,849)	R$ (1,084,758)
Defined benefit obligation	(1,057,849)	(1,084,758)
Present value of the defined benefit obligations
Reconciliations of assets and liabilities of the plans
Net	(4,391,251)	(4,314,592)	R$ (4,174,653)	R$ (4,739,299)
Plan assets
Reconciliations of assets and liabilities of the plans
Net	3,568,934	3,456,613	R$ 3,292,890	R$ 3,865,411
Asset ceiling restrictions on recognition of net funded assets
Reconciliations of assets and liabilities of the plans
Net	R$ (235,532)	R$ (226,779)

X

- References

No definition available.

+ Details

Name:	ggb_ReconciliationsOfPlanAssetsAndLiabilitiesAbstract
Namespace Prefix:	ggb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 140
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_140_a&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_LiabilityAssetOfDefinedBenefitPlans
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The amount of deficit in a defined benefit plan. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_RecognisedLiabilitiesDefinedBenefitPlan
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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_PresentValueOfDefinedBenefitObligationMember
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_EffectOfAssetCeilingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: