XML 152 R198.htm IDEA: XBRL DOCUMENT
v3.20.1

Related Parties - Additional Information (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Text Block [Abstract] |  |
Assets | R$ 48 | R$ 31
Revenue | 7 | 2
Liability | (5,757) | (4,391)
Expense | R$ (35) | R$ (16)

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- Definition Related party transactions assets. + References No definition available. + Details
Name: | itub_RelatedPartyTransactionsAssets
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Related party transactions expense. + References No definition available. + Details
Name: | itub_RelatedPartyTransactionsExpense
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Related party transactions liability. + References No definition available. + Details
Name: | itub_RelatedPartyTransactionsLiability
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Related party transactions revenue. + References No definition available. + Details
Name: | itub_RelatedPartyTransactionsRevenue
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- References No definition available. + Details
Name: | itub_TextblockAbstract
Namespace Prefix: | itub_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration