XML 272 R220.htm IDEA: XBRL DOCUMENT
v3.19.1

Risk and Capital Management - Summary of Position of Accounts Subject to Interest Rate Risk (Parenthetical) (Detail) R$ in Millions | Dec. 31, 2017 BRL (R$)
--- | ---
Disclosure of position of accounts subject to interest rate risk [Abstract] |
Operations designated at fair value through profit or loss | R$ 102

X
- Definition Disclosure of position of accounts subject to interest rate risk [Abstract] + References No definition available. + Details
Name: | itub_DisclosureOfPositionOfAccountsSubjectToInterestRateRiskAbstract
Namespace Prefix: | itub_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans and receivables designated as at fair value through profit or loss. + References No definition available. + Details
Name: | itub_LoansAndReceivablesDesignatedAsAtFairValueThroughProfitOrLoss
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant