XML 207 R155.htm IDEA: XBRL DOCUMENT
v3.19.1

Interest and similar income and expense and net gain (loss) on investment securities and derivatives - Summary of Interest, Similar Income of Financial Assets at Amortized Cost and at Fair Value Through Other Comprehensive Income (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | R$ 110,324 | R$ 122,703 | R$ 138,764
Central Bank compulsory deposits [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 5,063 | 7,201 | 6,920
Interbank deposits [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 1,080 | 744 | 674
Securities purchased under agreements to resell [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 17,365 | 25,711 | 34,162
Financial assets at fair value through other comprehensive income [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 9,194 | 8,886 | 11,160
Financial assets at amortised cost, category [member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 2,614 | 3,017 | 3,822
Loan and lease operations [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | 73,640 | 75,568 | 80,124
Other financial asset [Member] |  |  |
Disclosure Of Interest Income [Line Items] |  |  |
Interest and similar income | R$ 1,368 | R$ 1,576 | R$ 1,902

X
- Definition Disclosure of Interest Income [Line Items] + References No definition available. + Details
Name: | itub_DisclosureOfInterestIncomeLineItems
Namespace Prefix: | itub_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Interest and similar income. + References No definition available. + Details
Name: | itub_InterestAndSimilarIncome
Namespace Prefix: | itub_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=itub_CentralBankCompulsoryDepositsMemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=itub_InterbankDepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=itub_SecuritiesPurchasedUnderAgreementsToResellMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=itub_LoanAndLeaseOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=itub_OtherFinancialAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |