XML 135 R112.htm IDEA: XBRL DOCUMENT
v3.21.1

FINANCIAL INSTRUMENTS - Swap Contracts (Details) R$ in Thousands, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 BRL (R$) USD ($) | Dec. 31, 2019 BRL (R$)
Swap Contracts |  |
Amount receivable |  | R$ 2,846
Amount payable | R$ (971) |
Interest Rate Swap |  |
Swap Contracts |  |
Notional value | $ | 9.9 |
Interest Rate Swap | Maturity in 2020 |  |
Swap Contracts |  |
Notional value |  | 50,000
Amount receivable |  | R$ 2,846
Interest Rate Swap | Maturity in 2020 | CDI |  |
Swap Contracts |  |
Percentage of basis used to calculate interest rate | 111.50% | 111.50%
Interest Rate Swap | Maturity in 2021 |  |
Swap Contracts |  |
Amount payable | R$ (971) |

X
- Definition The percentage of the basis (reference rate) used for calculation of the interest rate. + References No definition available. + Details
Name: | ggb_AdjustmentToInterestRateMultiplier
Namespace Prefix: | ggb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition The amount of a hedging instrument, recognised as an asset. [Refer: Hedging instruments [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 24A -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_HedgingInstrumentAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 24A -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_HedgingInstrumentLiabilities
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The nominal amount of a hedging instrument. [Refer: Hedging instruments [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 23B -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_23B_a&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 24A -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_24A_d&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_NominalAmountOfHedgingInstrument
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_InterestRateSwapContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_HedgingInstrumentsAxis=ggb_HedgingInstrumentMaturingIn2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfInterestRatesAxis=ggb_LocalInterbankDepositCertificateRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_HedgingInstrumentsAxis=ggb_HedgingInstrumentMaturingIn2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |