XML 173 R103.htm IDEA: XBRL DOCUMENT
v3.20.1

LOANS AND FINANCING - By Currency (Details) - BRL (R$) R$ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
LOANS AND FINANCING |  |
Total Loans and Financing | R$ 13,138,823 | R$ 13,367,841
Brazilian Real (BRL) |  |
LOANS AND FINANCING |  |
Total Loans and Financing | 111,492 | 2,361,610
U.S. Dollar (USD) |  |
LOANS AND FINANCING |  |
Total Loans and Financing | 12,960,521 | 10,924,355
Other currencies |  |
LOANS AND FINANCING |  |
Total Loans and Financing | R$ 66,810 | R$ 81,876

X
- Definition The amount of outstanding funds that the entity is obligated to repay, excluding notes and debentures. + References No definition available. + Details
Name: | ggb_BorrowingsExcludingNotesAndDebentures
Namespace Prefix: | ggb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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: | srt_CurrencyAxis=currency_BRL
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CurrencyAxis=currency_USD
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CurrencyAxis=ggb_OtherCurrencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |