XML 144 R92.htm IDEA: XBRL DOCUMENT
v3.19.1

Derivatives - Schedule of Notional Amount of Purchased Credit Derivatives (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Disclosure Of Information About Notional Amounts Of Credit Derivative Portfolios [Line Items] |  |
Notional amount of credit protection sold | R$ (6,853) | R$ (6,416)
Notional amount of credit protection purchased with identical underlying amount | 1,471 | 3,694
Net position | (5,382) | 2,722
Credit default swaps [member] |  |
Disclosure Of Information About Notional Amounts Of Credit Derivative Portfolios [Line Items] |  |
Notional amount of credit protection sold | (6,853) | (6,416)
Notional amount of credit protection purchased with identical underlying amount | 1,471 | 3,694
Net position | R$ (5,382) | R$ 2,722

X
- Definition Line items representing information about notional amounts of credit derivative portfolios. + References No definition available. + Details
Name: | itub_DisclosureOfInformationAboutNotionalAmountsOfCreditDerivativePortfoliosLineItems
Namespace Prefix: | itub_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net position. + References No definition available. + Details
Name: | itub_NetPosition
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Notional amountof credit protection purchasedwith identical underlying amount. + References No definition available. + Details
Name: | itub_NotionalAmountofCreditProtectionPurchasedwithIdenticalUnderlyingAmount
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Notional amountof credit protection sold. + References No definition available. + Details
Name: | itub_NotionalAmountofCreditProtectionSold
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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