XML 128 R105.htm IDEA: XBRL DOCUMENT v3.21.1

DEBENTURES - Additional disclosures (Details)	Dec. 31, 2020	Dec. 31, 2019
Debentures | CDI | Average
DEBENTURES
Interest rate (as a percent)	2.90%	6.18%

X

- Definition

The interest rate on borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 7
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_7&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_BorrowingsInterestRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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_DisclosureOfDetailedInformationAboutBorrowingsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ggb_DebenturesMember
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_RangeAxis=srt_ArithmeticAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: