3.26.1 html 3774 1002 1 true 657 0 false 7 false false R1.htm 0000001 - Document - Cover Sheet http://itacunibanco.com/role/Cover Cover Cover 1 false false R2.htm 9952151 - Statement - Consolidated Balance Sheet Sheet http://itacunibanco.com/role/ConsolidatedBalanceSheet Consolidated Balance Sheet Statements 2 false false R3.htm 9952152 - Statement - Consolidated Statement of Income Sheet http://itacunibanco.com/role/ConsolidatedStatementofIncome Consolidated Statement of Income Statements 3 false false R4.htm 9952153 - Statement - Consolidated Statement of Comprehensive Income Sheet http://itacunibanco.com/role/ConsolidatedStatementofComprehensiveIncome Consolidated Statement of Comprehensive Income Statements 4 false false R5.htm 9952154 - Statement - Consolidated Statement of Changes in Stockholders' Equity Sheet http://itacunibanco.com/role/ConsolidatedStatementofChangesinStockholdersEquity Consolidated Statement of Changes in Stockholders' Equity Statements 5 false false R6.htm 9952155 - Statement - Consolidated Statement of Cash Flows Sheet http://itacunibanco.com/role/ConsolidatedStatementofCashFlows Consolidated Statement of Cash Flows Statements 6 false false R7.htm 9952156 - Disclosure - Operations Sheet http://itacunibanco.com/role/Operations Operations Notes 7 false false R8.htm 9952157 - Disclosure - Material accounting policies Sheet http://itacunibanco.com/role/Materialaccountingpolicies Material accounting policies Notes 8 false false R9.htm 9952158 - Disclosure - Business development Sheet http://itacunibanco.com/role/Businessdevelopment Business development Notes 9 false false R10.htm 9952159 - Disclosure - Interbank deposits and securities purchased under agreements to resell Sheet http://itacunibanco.com/role/Interbankdepositsandsecuritiespurchasedunderagreementstoresell Interbank deposits and securities purchased under agreements to resell Notes 10 false false R11.htm 9952160 - Disclosure - Securities at fair value through profit or loss (FVPL) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPL Securities at fair value through profit or loss (FVPL) Notes 11 false false R12.htm 9952161 - Disclosure - Derivatives Sheet http://itacunibanco.com/role/Derivatives Derivatives Notes 12 false false R13.htm 9952162 - Disclosure - Hedge accounting Sheet http://itacunibanco.com/role/Hedgeaccounting Hedge accounting Notes 13 false false R14.htm 9952163 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCI Securities at fair value through other comprehensive income (FVOCI) Notes 14 false false R15.htm 9952164 - Disclosure - Securities at amortized cost (AC) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostAC Securities at amortized cost (AC) Notes 15 false false R16.htm 9952165 - Disclosure - Loan and lease operations Sheet http://itacunibanco.com/role/Loanandleaseoperations Loan and lease operations Notes 16 false false R17.htm 9952166 - Disclosure - Investments in associates and joint ventures Sheet http://itacunibanco.com/role/Investmentsinassociatesandjointventures Investments in associates and joint ventures Notes 17 false false R18.htm 9952167 - Disclosure - Lease operations - Lessee Sheet http://itacunibanco.com/role/LeaseoperationsLessee Lease operations - Lessee Notes 18 false false R19.htm 9952168 - Disclosure - Fixed assets Sheet http://itacunibanco.com/role/Fixedassets Fixed assets Notes 19 false false R20.htm 9952169 - Disclosure - Goodwill and Intangible assets Sheet http://itacunibanco.com/role/GoodwillandIntangibleassets Goodwill and Intangible assets Notes 20 false false R21.htm 9952170 - Disclosure - Deposits Sheet http://itacunibanco.com/role/Deposits Deposits Notes 21 false false R22.htm 9952171 - Disclosure - Financial liabilities designated at fair value through profit or loss Sheet http://itacunibanco.com/role/Financialliabilitiesdesignatedatfairvaluethroughprofitorloss Financial liabilities designated at fair value through profit or loss Notes 22 false false R23.htm 9952172 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds Sheet http://itacunibanco.com/role/Securitiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfunds Securities sold under repurchase agreements and interbank and institutional market funds Notes 23 false false R24.htm 9952173 - Disclosure - Other assets and liabilities Sheet http://itacunibanco.com/role/Otherassetsandliabilities Other assets and liabilities Notes 24 false false R25.htm 9952174 - Disclosure - Stockholders??? equity Sheet http://itacunibanco.com/role/Stockholdersequity Stockholders??? equity Notes 25 false false R26.htm 9952175 - Disclosure - Share-based payment Sheet http://itacunibanco.com/role/Sharebasedpayment Share-based payment Notes 26 false false R27.htm 9952176 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss Sheet http://itacunibanco.com/role/Interestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorloss Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss Notes 27 false false R28.htm 9952177 - Disclosure - Commissions and banking fees Sheet http://itacunibanco.com/role/Commissionsandbankingfees Commissions and banking fees Notes 28 false false R29.htm 9952178 - Disclosure - General and administrative expenses Sheet http://itacunibanco.com/role/Generalandadministrativeexpenses General and administrative expenses Notes 29 false false R30.htm 9952179 - Disclosure - Taxes Sheet http://itacunibanco.com/role/Taxes Taxes Notes 30 false false R31.htm 9952180 - Disclosure - Earnings per share Sheet http://itacunibanco.com/role/Earningspershare Earnings per share Notes 31 false false R32.htm 9952181 - Disclosure - Post-employment benefits Sheet http://itacunibanco.com/role/Postemploymentbenefits Post-employment benefits Notes 32 false false R33.htm 9952182 - Disclosure - Insurance contracts and private pension Sheet http://itacunibanco.com/role/Insurancecontractsandprivatepension Insurance contracts and private pension Notes 33 false false R34.htm 9952183 - Disclosure - Fair value Sheet http://itacunibanco.com/role/Fairvalue Fair value Notes 34 false false R35.htm 9952184 - Disclosure - Provisions, contingent assets and contingent liabilities Sheet http://itacunibanco.com/role/Provisionscontingentassetsandcontingentliabilities Provisions, contingent assets and contingent liabilities Notes 35 false false R36.htm 9952185 - Disclosure - Segment Information Sheet http://itacunibanco.com/role/SegmentInformation Segment Information Notes 36 false false R37.htm 9952186 - Disclosure - Related parties Sheet http://itacunibanco.com/role/Relatedparties Related parties Notes 37 false false R38.htm 9952187 - Disclosure - Risk and Capital Management Sheet http://itacunibanco.com/role/RiskandCapitalManagement Risk and Capital Management Notes 38 false false R39.htm 9952188 - Disclosure - Supplementary information Sheet http://itacunibanco.com/role/Supplementaryinformation Supplementary information Notes 39 false false R40.htm 9952189 - Disclosure - Subsequent event Sheet http://itacunibanco.com/role/Subsequentevent Subsequent event Notes 40 false false R41.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 41 false false R42.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 42 false false R43.htm 9955511 - Disclosure - Material accounting policies (Policies) Sheet http://itacunibanco.com/role/MaterialaccountingpoliciesPolicies Material accounting policies (Policies) Policies 43 false false R44.htm 9955512 - Disclosure - Material accounting policies (Tables) Sheet http://itacunibanco.com/role/MaterialaccountingpoliciesTables Material accounting policies (Tables) Tables http://itacunibanco.com/role/Materialaccountingpolicies 44 false false R45.htm 9955513 - Disclosure - Interbank deposits and securities purchased under agreements to resell (Tables) Sheet http://itacunibanco.com/role/InterbankdepositsandsecuritiespurchasedunderagreementstoresellTables Interbank deposits and securities purchased under agreements to resell (Tables) Tables http://itacunibanco.com/role/Interbankdepositsandsecuritiespurchasedunderagreementstoresell 45 false false R46.htm 9955514 - Disclosure - Securities at fair value through profit or loss (FVPL) (Tables) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLTables Securities at fair value through profit or loss (FVPL) (Tables) Tables http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPL 46 false false R47.htm 9955515 - Disclosure - Derivatives (Tables) Sheet http://itacunibanco.com/role/DerivativesTables Derivatives (Tables) Tables http://itacunibanco.com/role/Derivatives 47 false false R48.htm 9955516 - Disclosure - Hedge accounting (Tables) Sheet http://itacunibanco.com/role/HedgeaccountingTables Hedge accounting (Tables) Tables http://itacunibanco.com/role/Hedgeaccounting 48 false false R49.htm 9955517 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) (Tables) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCITables Securities at fair value through other comprehensive income (FVOCI) (Tables) Tables http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCI 49 false false R50.htm 9955518 - Disclosure - Securities at amortized cost (AC) (Tables) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostACTables Securities at amortized cost (AC) (Tables) Tables http://itacunibanco.com/role/SecuritiesatamortizedcostAC 50 false false R51.htm 9955519 - Disclosure - Loan and lease operations (Tables) Sheet http://itacunibanco.com/role/LoanandleaseoperationsTables Loan and lease operations (Tables) Tables http://itacunibanco.com/role/Loanandleaseoperations 51 false false R52.htm 9955520 - Disclosure - Investments in associates and joint ventures (Tables) Sheet http://itacunibanco.com/role/InvestmentsinassociatesandjointventuresTables Investments in associates and joint ventures (Tables) Tables http://itacunibanco.com/role/Investmentsinassociatesandjointventures 52 false false R53.htm 9955521 - Disclosure - Lease operations - Lessee (Tables) Sheet http://itacunibanco.com/role/LeaseoperationsLesseeTables Lease operations - Lessee (Tables) Tables http://itacunibanco.com/role/LeaseoperationsLessee 53 false false R54.htm 9955522 - Disclosure - Fixed assets (Tables) Sheet http://itacunibanco.com/role/FixedassetsTables Fixed assets (Tables) Tables http://itacunibanco.com/role/Fixedassets 54 false false R55.htm 9955523 - Disclosure - Goodwill and Intangible assets (Tables) Sheet http://itacunibanco.com/role/GoodwillandIntangibleassetsTables Goodwill and Intangible assets (Tables) Tables http://itacunibanco.com/role/GoodwillandIntangibleassets 55 false false R56.htm 9955524 - Disclosure - Deposits (Tables) Sheet http://itacunibanco.com/role/DepositsTables Deposits (Tables) Tables http://itacunibanco.com/role/Deposits 56 false false R57.htm 9955525 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds (Tables) Sheet http://itacunibanco.com/role/SecuritiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfundsTables Securities sold under repurchase agreements and interbank and institutional market funds (Tables) Tables http://itacunibanco.com/role/Securitiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfunds 57 false false R58.htm 9955526 - Disclosure - Other assets and liabilities (Tables) Sheet http://itacunibanco.com/role/OtherassetsandliabilitiesTables Other assets and liabilities (Tables) Tables http://itacunibanco.com/role/Otherassetsandliabilities 58 false false R59.htm 9955527 - Disclosure - Stockholders??? equity (Tables) Sheet http://itacunibanco.com/role/StockholdersequityTables Stockholders??? equity (Tables) Tables http://itacunibanco.com/role/Stockholdersequity 59 false false R60.htm 9955528 - Disclosure - Share-based payment (Tables) Sheet http://itacunibanco.com/role/SharebasedpaymentTables Share-based payment (Tables) Tables http://itacunibanco.com/role/Sharebasedpayment 60 false false R61.htm 9955529 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss (Tables) Sheet http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossTables Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss (Tables) Tables http://itacunibanco.com/role/Interestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorloss 61 false false R62.htm 9955530 - Disclosure - Commissions and banking fees (Tables) Sheet http://itacunibanco.com/role/CommissionsandbankingfeesTables Commissions and banking fees (Tables) Tables http://itacunibanco.com/role/Commissionsandbankingfees 62 false false R63.htm 9955531 - Disclosure - General and administrative expenses (Tables) Sheet http://itacunibanco.com/role/GeneralandadministrativeexpensesTables General and administrative expenses (Tables) Tables http://itacunibanco.com/role/Generalandadministrativeexpenses 63 false false R64.htm 9955532 - Disclosure - Taxes (Tables) Sheet http://itacunibanco.com/role/TaxesTables Taxes (Tables) Tables http://itacunibanco.com/role/Taxes 64 false false R65.htm 9955533 - Disclosure - Earnings per share (Tables) Sheet http://itacunibanco.com/role/EarningspershareTables Earnings per share (Tables) Tables http://itacunibanco.com/role/Earningspershare 65 false false R66.htm 9955534 - Disclosure - Post-employment benefits (Tables) Sheet http://itacunibanco.com/role/PostemploymentbenefitsTables Post-employment benefits (Tables) Tables http://itacunibanco.com/role/Postemploymentbenefits 66 false false R67.htm 9955535 - Disclosure - Insurance contracts and private pension (Tables) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionTables Insurance contracts and private pension (Tables) Tables http://itacunibanco.com/role/Insurancecontractsandprivatepension 67 false false R68.htm 9955536 - Disclosure - Fair value (Tables) Sheet http://itacunibanco.com/role/FairvalueTables Fair value (Tables) Tables http://itacunibanco.com/role/Fairvalue 68 false false R69.htm 9955537 - Disclosure - Provisions, contingent assets and contingent liabilities (Tables) Sheet http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesTables Provisions, contingent assets and contingent liabilities (Tables) Tables http://itacunibanco.com/role/Provisionscontingentassetsandcontingentliabilities 69 false false R70.htm 9955538 - Disclosure - Segment Information (Tables) Sheet http://itacunibanco.com/role/SegmentInformationTables Segment Information (Tables) Tables http://itacunibanco.com/role/SegmentInformation 70 false false R71.htm 9955539 - Disclosure - Related parties (Tables) Sheet http://itacunibanco.com/role/RelatedpartiesTables Related parties (Tables) Tables http://itacunibanco.com/role/Relatedparties 71 false false R72.htm 9955540 - Disclosure - Risk and Capital Management (Tables) Sheet http://itacunibanco.com/role/RiskandCapitalManagementTables Risk and Capital Management (Tables) Tables http://itacunibanco.com/role/RiskandCapitalManagement 72 false false R73.htm 9955541 - Disclosure - Operations (Details) Sheet http://itacunibanco.com/role/OperationsDetails Operations (Details) Details http://itacunibanco.com/role/Operations 73 false false R74.htm 9955542 - Disclosure - Material accounting policies - Narrative (Details) Sheet http://itacunibanco.com/role/MaterialaccountingpoliciesNarrativeDetails Material accounting policies - Narrative (Details) Details 74 false false R75.htm 9955543 - Disclosure - Material accounting policies - Schedule of Consolidated Companies (Details) Sheet http://itacunibanco.com/role/MaterialaccountingpoliciesScheduleofConsolidatedCompaniesDetails Material accounting policies - Schedule of Consolidated Companies (Details) Details 75 false false R76.htm 9955544 - Disclosure - Business development (Details) Sheet http://itacunibanco.com/role/BusinessdevelopmentDetails Business development (Details) Details http://itacunibanco.com/role/Businessdevelopment 76 false false R77.htm 9955545 - Disclosure - Interbank deposits and securities purchased under agreements to resell (Details) Sheet http://itacunibanco.com/role/InterbankdepositsandsecuritiespurchasedunderagreementstoresellDetails Interbank deposits and securities purchased under agreements to resell (Details) Details http://itacunibanco.com/role/InterbankdepositsandsecuritiespurchasedunderagreementstoresellTables 77 false false R78.htm 9955546 - Disclosure - Securities at fair value through profit or loss (FVPL) - Schedule of Financial Assets And Liabilities (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLScheduleofFinancialAssetsAndLiabilitiesDetails Securities at fair value through profit or loss (FVPL) - Schedule of Financial Assets And Liabilities (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLTables 78 false false R79.htm 9955547 - Disclosure - Securities at fair value through profit or loss (FVPL) - Narrative (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLNarrativeDetails Securities at fair value through profit or loss (FVPL) - Narrative (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLTables 79 false false R80.htm 9955548 - Disclosure - Securities at fair value through profit or loss (FVPL) - Schedule of Cost and Fair Value per Maturity of Financial Assets at Fair Value Through Profit or Loss (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLScheduleofCostandFairValueperMaturityofFinancialAssetsatFairValueThroughProfitorLossDetails Securities at fair value through profit or loss (FVPL) - Schedule of Cost and Fair Value per Maturity of Financial Assets at Fair Value Through Profit or Loss (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughprofitorlossFVPLTables 80 false false R81.htm 9955549 - Disclosure - Derivatives - Schedule of Derivative Financial Instruments Portfolio (Assets And Liabilities) (Details) Sheet http://itacunibanco.com/role/DerivativesScheduleofDerivativeFinancialInstrumentsPortfolioAssetsAndLiabilitiesDetails Derivatives - Schedule of Derivative Financial Instruments Portfolio (Assets And Liabilities) (Details) Details 81 false false R82.htm 9955550 - Disclosure - Derivatives - Narrative (Details) Sheet http://itacunibanco.com/role/DerivativesNarrativeDetails Derivatives - Narrative (Details) Details 82 false false R83.htm 9955551 - Disclosure - Derivatives - Schedule of Derivatives by index and Risk Factor (Details) Sheet http://itacunibanco.com/role/DerivativesScheduleofDerivativesbyindexandRiskFactorDetails Derivatives - Schedule of Derivatives by index and Risk Factor (Details) Details 83 false false R84.htm 9955552 - Disclosure - Derivatives - Schedule of Credit derivatives (Details) Sheet http://itacunibanco.com/role/DerivativesScheduleofCreditderivativesDetails Derivatives - Schedule of Credit derivatives (Details) Details 84 false false R85.htm 9955553 - Disclosure - Derivatives - Schedule of Notional Amount Of Credit Derivatives Purchased (Details) Sheet http://itacunibanco.com/role/DerivativesScheduleofNotionalAmountOfCreditDerivativesPurchasedDetails Derivatives - Schedule of Notional Amount Of Credit Derivatives Purchased (Details) Details 85 false false R86.htm 9955554 - Disclosure - Derivatives - Schedule of Financial Assets Subject To Offsetting, Enforceable Master Netting Arrangements And Similar Agreements (Details) Sheet http://itacunibanco.com/role/DerivativesScheduleofFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsAndSimilarAgreementsDetails Derivatives - Schedule of Financial Assets Subject To Offsetting, Enforceable Master Netting Arrangements And Similar Agreements (Details) Details 86 false false R87.htm 9955555 - Disclosure - Hedge accounting - Narrative (Details) Sheet http://itacunibanco.com/role/HedgeaccountingNarrativeDetails Hedge accounting - Narrative (Details) Details 87 false false R88.htm 9955556 - Disclosure - Hedge accounting - Schedule of Notional Amount And The Fair Value Adjustments Of Hedge Instruments (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofNotionalAmountAndTheFairValueAdjustmentsOfHedgeInstrumentsDetails Hedge accounting - Schedule of Notional Amount And The Fair Value Adjustments Of Hedge Instruments (Details) Details 88 false false R89.htm 9955557 - Disclosure - Hedge accounting - Schedule of Breakdown By Maturity Of The Hedging Strategies (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofBreakdownByMaturityOfTheHedgingStrategiesDetails Hedge accounting - Schedule of Breakdown By Maturity Of The Hedging Strategies (Details) Details 89 false false R90.htm 9955558 - Disclosure - Hedge accounting - Schedule of Hedge Instruments and Book Value of Hedged Item (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofHedgeInstrumentsandBookValueofHedgedItemDetails Hedge accounting - Schedule of Hedge Instruments and Book Value of Hedged Item (Details) Details 90 false false R91.htm 9955559 - Disclosure - Hedge accounting - Schedule Of Hedge Instruments (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleOfHedgeInstrumentsDetails Hedge accounting - Schedule Of Hedge Instruments (Details) Details 91 false false R92.htm 9955560 - Disclosure - Hedge accounting - Schedule of The Financial Position And Performance (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofTheFinancialPositionAndPerformanceDetails Hedge accounting - Schedule of The Financial Position And Performance (Details) Details 92 false false R93.htm 9955561 - Disclosure - Hedge accounting - Schedule of Management Strategy Guidelines (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofManagementStrategyGuidelinesDetails Hedge accounting - Schedule of Management Strategy Guidelines (Details) Details 93 false false R94.htm 9955562 - Disclosure - Hedge accounting - Schedule of Type Of Strategy Is The Currency Risk (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleofTypeOfStrategyIsTheCurrencyRiskDetails Hedge accounting - Schedule of Type Of Strategy Is The Currency Risk (Details) Details 94 false false R95.htm 9955563 - Disclosure - Hedge accounting - Schedule Of Hedge Accounting (Details) Sheet http://itacunibanco.com/role/HedgeaccountingScheduleOfHedgeAccountingDetails Hedge accounting - Schedule Of Hedge Accounting (Details) Details 95 false false R96.htm 9955564 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) - Schedule of Financial Assets at Fair Value through Other Comprehensive Income (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCIScheduleofFinancialAssetsatFairValuethroughOtherComprehensiveIncomeDetails Securities at fair value through other comprehensive income (FVOCI) - Schedule of Financial Assets at Fair Value through Other Comprehensive Income (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCITables 96 false false R97.htm 9955565 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) - Narrative (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCINarrativeDetails Securities at fair value through other comprehensive income (FVOCI) - Narrative (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCITables 97 false false R98.htm 9955566 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) - Schedule of Financial Assets Through Other Comprehensive Income - Securities By Maturity (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCIScheduleofFinancialAssetsThroughOtherComprehensiveIncomeSecuritiesByMaturityDetails Securities at fair value through other comprehensive income (FVOCI) - Schedule of Financial Assets Through Other Comprehensive Income - Securities By Maturity (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCITables 98 false false R99.htm 9955567 - Disclosure - Securities at fair value through other comprehensive income (FVOCI) - Schedule of Reconciliation of Expected Loss for Financial Assets at Fair Value Through Other Comprehensive Instrument- Securities, Segregated by Stages (Details) Sheet http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCIScheduleofReconciliationofExpectedLossforFinancialAssetsatFairValueThroughOtherComprehensiveInstrumentSecuritiesSegregatedbyStagesDetails Securities at fair value through other comprehensive income (FVOCI) - Schedule of Reconciliation of Expected Loss for Financial Assets at Fair Value Through Other Comprehensive Instrument- Securities, Segregated by Stages (Details) Details http://itacunibanco.com/role/SecuritiesatfairvaluethroughothercomprehensiveincomeFVOCITables 99 false false R100.htm 9955568 - Disclosure - Securities at amortized cost (AC) - Schedule of Financial Assets At Amortized Cost (Details) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostACScheduleofFinancialAssetsAtAmortizedCostDetails Securities at amortized cost (AC) - Schedule of Financial Assets At Amortized Cost (Details) Details http://itacunibanco.com/role/SecuritiesatamortizedcostACTables 100 false false R101.htm 9955569 - Disclosure - Securities at amortized cost (AC) - Narrative (Details) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostACNarrativeDetails Securities at amortized cost (AC) - Narrative (Details) Details http://itacunibanco.com/role/SecuritiesatamortizedcostACTables 101 false false R102.htm 9955570 - Disclosure - Securities at amortized cost (AC) - Schedule of Amortized Cost Of Financial Assets At Amortized Cost (Details) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostACScheduleofAmortizedCostOfFinancialAssetsAtAmortizedCostDetails Securities at amortized cost (AC) - Schedule of Amortized Cost Of Financial Assets At Amortized Cost (Details) Details http://itacunibanco.com/role/SecuritiesatamortizedcostACTables 102 false false R103.htm 9955571 - Disclosure - Securities at amortized cost (AC) - Schedule of Reconciliation Of Expected Loss To Financial Assets At Amortized Cost (Details) Sheet http://itacunibanco.com/role/SecuritiesatamortizedcostACScheduleofReconciliationOfExpectedLossToFinancialAssetsAtAmortizedCostDetails Securities at amortized cost (AC) - Schedule of Reconciliation Of Expected Loss To Financial Assets At Amortized Cost (Details) Details http://itacunibanco.com/role/SecuritiesatamortizedcostACTables 103 false false R104.htm 9955572 - Disclosure - Loan and lease operations - Schedule of Composition of Carrying Amount of Loan Operations and Lease Operations by Type Sector of Debtor Maturity and Concentration (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofCompositionofCarryingAmountofLoanOperationsandLeaseOperationsbyTypeSectorofDebtorMaturityandConcentrationDetails Loan and lease operations - Schedule of Composition of Carrying Amount of Loan Operations and Lease Operations by Type Sector of Debtor Maturity and Concentration (Details) Details 104 false false R105.htm 9955573 - Disclosure - Loan and lease operations - Narrative (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsNarrativeDetails Loan and lease operations - Narrative (Details) Details 105 false false R106.htm 9955574 - Disclosure - Loan and lease operations - Schedule of Reconciliation of Gross Portfolio of Loans (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofReconciliationofGrossPortfolioofLoansDetails Loan and lease operations - Schedule of Reconciliation of Gross Portfolio of Loans (Details) Details 106 false false R107.htm 9955575 - Disclosure - Loan and lease operations - Schedule of Reconciliation of Expected Loan Losses for Loan Operations and Lease Operations (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofReconciliationofExpectedLoanLossesforLoanOperationsandLeaseOperationsDetails Loan and lease operations - Schedule of Reconciliation of Expected Loan Losses for Loan Operations and Lease Operations (Details) Details 107 false false R108.htm 9955576 - Disclosure - Loan and lease operations - Schedule of Analysis of Present Value of Minimum Future Payments Receivable from Finance Leases by Maturity (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofAnalysisofPresentValueofMinimumFuturePaymentsReceivablefromFinanceLeasesbyMaturityDetails Loan and lease operations - Schedule of Analysis of Present Value of Minimum Future Payments Receivable from Finance Leases by Maturity (Details) Details 108 false false R109.htm 9955577 - Disclosure - Loan and lease operations - Schedule of Securitization or Transfer of Financial Assets (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofSecuritizationorTransferofFinancialAssetsDetails Loan and lease operations - Schedule of Securitization or Transfer of Financial Assets (Details) Details 109 false false R110.htm 9955578 - Disclosure - Loan and lease operations - Schedule of Finance Lease Income (Details) Sheet http://itacunibanco.com/role/LoanandleaseoperationsScheduleofFinanceLeaseIncomeDetails Loan and lease operations - Schedule of Finance Lease Income (Details) Details 110 false false R111.htm 9955579 - Disclosure - Investments in associates and joint ventures - Schedule of Non-Material Individual Investments (Details) Sheet http://itacunibanco.com/role/InvestmentsinassociatesandjointventuresScheduleofNonMaterialIndividualInvestmentsDetails Investments in associates and joint ventures - Schedule of Non-Material Individual Investments (Details) Details 111 false false R112.htm 9955580 - Disclosure - Investments in associates and joint ventures - Narrative (Details) Sheet http://itacunibanco.com/role/InvestmentsinassociatesandjointventuresNarrativeDetails Investments in associates and joint ventures - Narrative (Details) Details 112 false false R113.htm 9955581 - Disclosure - Lease operations - Lessee - Narrative (Details) Sheet http://itacunibanco.com/role/LeaseoperationsLesseeNarrativeDetails Lease operations - Lessee - Narrative (Details) Details 113 false false R114.htm 9955582 - Disclosure - Lease operations - Lessee - Schedule of Lease Liabilities Undiscounted (Details) Sheet http://itacunibanco.com/role/LeaseoperationsLesseeScheduleofLeaseLiabilitiesUndiscountedDetails Lease operations - Lessee - Schedule of Lease Liabilities Undiscounted (Details) Details 114 false false R115.htm 9955583 - Disclosure - Lease operations - Lessee - Schedule of Amounts Recognized in Statement of Net Income Loss (Details) Sheet http://itacunibanco.com/role/LeaseoperationsLesseeScheduleofAmountsRecognizedinStatementofNetIncomeLossDetails Lease operations - Lessee - Schedule of Amounts Recognized in Statement of Net Income Loss (Details) Details 115 false false R116.htm 9955584 - Disclosure - Fixed assets - Schedule of Fixed Assets (Details) Sheet http://itacunibanco.com/role/FixedassetsScheduleofFixedAssetsDetails Fixed assets - Schedule of Fixed Assets (Details) Details 116 false false R117.htm 9955585 - Disclosure - Fixed assets - Narrative (Details) Sheet http://itacunibanco.com/role/FixedassetsNarrativeDetails Fixed assets - Narrative (Details) Details 117 false false R118.htm 9955586 - Disclosure - Goodwill and Intangible assets - Schedule of Goodwill and Intangible Assets (Details) Sheet http://itacunibanco.com/role/GoodwillandIntangibleassetsScheduleofGoodwillandIntangibleAssetsDetails Goodwill and Intangible assets - Schedule of Goodwill and Intangible Assets (Details) Details 118 false false R119.htm 9955587 - Disclosure - Goodwill and Intangible assets - Narrative (Details) Sheet http://itacunibanco.com/role/GoodwillandIntangibleassetsNarrativeDetails Goodwill and Intangible assets - Narrative (Details) Details 119 false false R120.htm 9955588 - Disclosure - Deposits (Details) Sheet http://itacunibanco.com/role/DepositsDetails Deposits (Details) Details http://itacunibanco.com/role/DepositsTables 120 false false R121.htm 9955589 - Disclosure - Financial liabilities designated at fair value through profit or loss (Details) Sheet http://itacunibanco.com/role/FinancialliabilitiesdesignatedatfairvaluethroughprofitorlossDetails Financial liabilities designated at fair value through profit or loss (Details) Details http://itacunibanco.com/role/Financialliabilitiesdesignatedatfairvaluethroughprofitorloss 121 false false R122.htm 9955590 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Financial Assets and Liabilities (Details) Sheet http://itacunibanco.com/role/SecuritiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfundsScheduleofFinancialAssetsandLiabilitiesDetails Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Financial Assets and Liabilities (Details) Details 122 false false R123.htm 9955591 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Interbank Market Debt (Details) Sheet http://itacunibanco.com/role/SecuritiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfundsScheduleofInterbankMarketDebtDetails Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Interbank Market Debt (Details) Details 123 false false R124.htm 9955592 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Institutional Market Debt (Details) Sheet http://itacunibanco.com/role/SecuritiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfundsScheduleofInstitutionalMarketDebtDetails Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Institutional Market Debt (Details) Details 124 false false R125.htm 9955593 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Subordinated Debt, Including Perpetual Debts (Details) Sheet http://itacunibanco.com/role/SecuritiessoldunderrepurchaseagreementsandinterbankandinstitutionalmarketfundsScheduleofSubordinatedDebtIncludingPerpetualDebtsDetails Securities sold under repurchase agreements and interbank and institutional market funds - Schedule of Subordinated Debt, Including Perpetual Debts (Details) Details 125 false false R126.htm 9955594 - Disclosure - Other assets and liabilities - Schedule of Other Assets (Details) Sheet http://itacunibanco.com/role/OtherassetsandliabilitiesScheduleofOtherAssetsDetails Other assets and liabilities - Schedule of Other Assets (Details) Details 126 false false R127.htm 9955595 - Disclosure - Other assets and liabilities -Schedule of Other Liabilities (Details) Sheet http://itacunibanco.com/role/OtherassetsandliabilitiesScheduleofOtherLiabilitiesDetails Other assets and liabilities -Schedule of Other Liabilities (Details) Details 127 false false R128.htm 9955596 - Disclosure - Stockholders??? equity - Narrative (Details) Sheet http://itacunibanco.com/role/StockholdersequityNarrativeDetails Stockholders??? equity - Narrative (Details) Details 128 false false R129.htm 9955597 - Disclosure - Stockholders' equity - Schedule of Change in Shares of Paid-in Capital in the Beginning and End of the Period (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofChangeinSharesofPaidinCapitalintheBeginningandEndofthePeriodDetails Stockholders' equity - Schedule of Change in Shares of Paid-in Capital in the Beginning and End of the Period (Details) Details 129 false false R130.htm 9955598 - Disclosure - Stockholders' equity - Schedule of Cost of Shares Purchased and Average Cost of Treasury Shares and Market Price (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofCostofSharesPurchasedandAverageCostofTreasurySharesandMarketPriceDetails Stockholders' equity - Schedule of Cost of Shares Purchased and Average Cost of Treasury Shares and Market Price (Details) Details 130 false false R131.htm 9955599 - Disclosure - Stockholders' equity - Schedule of Calculation of Dividends and Interest on Capital (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofCalculationofDividendsandInterestonCapitalDetails Stockholders' equity - Schedule of Calculation of Dividends and Interest on Capital (Details) Details 131 false false R132.htm 9955600 - Disclosure - Stockholders' equity - Schedule of Stockholders Compensation (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofStockholdersCompensationDetails Stockholders' equity - Schedule of Stockholders Compensation (Details) Details 132 false false R133.htm 9955601 - Disclosure - Stockholders' equity - Schedule of Capital Reserves and Revenue Reserves (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofCapitalReservesandRevenueReservesDetails Stockholders' equity - Schedule of Capital Reserves and Revenue Reserves (Details) Details 133 false false R134.htm 9955602 - Disclosure - Stockholders' equity - Schedule of Non-Controlling Interests (Details) Sheet http://itacunibanco.com/role/StockholdersequityScheduleofNonControllingInterestsDetails Stockholders' equity - Schedule of Non-Controlling Interests (Details) Details 134 false false R135.htm 9955603 - Disclosure - Share-based payment - Narrative (Details) Sheet http://itacunibanco.com/role/SharebasedpaymentNarrativeDetails Share-based payment - Narrative (Details) Details 135 false false R136.htm 9955604 - Disclosure - Share-based payment - Schedule of Expenses on Share-Based Payment Plans (Details) Sheet http://itacunibanco.com/role/SharebasedpaymentScheduleofExpensesonShareBasedPaymentPlansDetails Share-based payment - Schedule of Expenses on Share-Based Payment Plans (Details) Details 136 false false R137.htm 9955605 - Disclosure - Share-based payment - Schedule of Changes in Share-Based Compensation Plan (Details) Sheet http://itacunibanco.com/role/SharebasedpaymentScheduleofChangesinShareBasedCompensationPlanDetails Share-based payment - Schedule of Changes in Share-Based Compensation Plan (Details) Details 137 false false R138.htm 9955606 - Disclosure - Share-based payment - Schedule of Change in Share-Based Variable Compensation (Details) Sheet http://itacunibanco.com/role/SharebasedpaymentScheduleofChangeinShareBasedVariableCompensationDetails Share-based payment - Schedule of Change in Share-Based Variable Compensation (Details) Details 138 false false R139.htm 9955607 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Interest and Similar Income (Details) Sheet http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossScheduleofInterestandSimilarIncomeDetails Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Interest and Similar Income (Details) Details 139 false false R140.htm 9955608 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Interest and Similar Expense (Details) Sheet http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossScheduleofInterestandSimilarExpenseDetails Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Interest and Similar Expense (Details) Details 140 false false R141.htm 9955609 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Financial Assets and Liabilities at Fair Value Through Profit or Loss (Details) Sheet http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossScheduleofFinancialAssetsandLiabilitiesatFairValueThroughProfitorLossDetails Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Schedule of Financial Assets and Liabilities at Fair Value Through Profit or Loss (Details) Details 141 false false R142.htm 9955610 - Disclosure - Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Narrative (Details) Sheet http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossNarrativeDetails Interest and similar income and expenses and income of financial assets and liabilities at fair value through profit or loss - Narrative (Details) Details http://itacunibanco.com/role/InterestandsimilarincomeandexpensesandincomeoffinancialassetsandliabilitiesatfairvaluethroughprofitorlossTables 142 false false R143.htm 9955611 - Disclosure - Commissions and banking fees (Details) Sheet http://itacunibanco.com/role/CommissionsandbankingfeesDetails Commissions and banking fees (Details) Details http://itacunibanco.com/role/CommissionsandbankingfeesTables 143 false false R144.htm 9955612 - Disclosure - General and administrative expenses (Details) Sheet http://itacunibanco.com/role/GeneralandadministrativeexpensesDetails General and administrative expenses (Details) Details http://itacunibanco.com/role/GeneralandadministrativeexpensesTables 144 false false R145.htm 9955613 - Disclosure - Taxes - Schedule of Calculation of Tax Rates (Details) Sheet http://itacunibanco.com/role/TaxesScheduleofCalculationofTaxRatesDetails Taxes - Schedule of Calculation of Tax Rates (Details) Details 145 false false R146.htm 9955614 - Disclosure - Taxes - Schedule of Breakdown of Income Tax and Social Contribution Expense (Details) Sheet http://itacunibanco.com/role/TaxesScheduleofBreakdownofIncomeTaxandSocialContributionExpenseDetails Taxes - Schedule of Breakdown of Income Tax and Social Contribution Expense (Details) Details 146 false false R147.htm 9955615 - Disclosure - Taxes - Schedule of Deferred Tax Asset Balance and Respective Changes (Details) Sheet http://itacunibanco.com/role/TaxesScheduleofDeferredTaxAssetBalanceandRespectiveChangesDetails Taxes - Schedule of Deferred Tax Asset Balance and Respective Changes (Details) Details 147 false false R148.htm 9955616 - Disclosure - Taxes - Narrative (Details) Sheet http://itacunibanco.com/role/TaxesNarrativeDetails Taxes - Narrative (Details) Details 148 false false R149.htm 9955617 - Disclosure - Taxes - Schedule of Realization and Present Value of Tax Credits and From Provision for Deferred Income Tax and Social Contribution (Details) Sheet http://itacunibanco.com/role/TaxesScheduleofRealizationandPresentValueofTaxCreditsandFromProvisionforDeferredIncomeTaxandSocialContributionDetails Taxes - Schedule of Realization and Present Value of Tax Credits and From Provision for Deferred Income Tax and Social Contribution (Details) Details 149 false false R150.htm 9955618 - Disclosure - Taxes - Schedule of Tax Liabilities (Details) Sheet http://itacunibanco.com/role/TaxesScheduleofTaxLiabilitiesDetails Taxes - Schedule of Tax Liabilities (Details) Details 150 false false R151.htm 9955619 - Disclosure - Earnings per share - Schedule of Earnings Per Share (Details) Sheet http://itacunibanco.com/role/EarningspershareScheduleofEarningsPerShareDetails Earnings per share - Schedule of Earnings Per Share (Details) Details 151 false false R152.htm 9955620 - Disclosure - Earnings per share - Schedule of Diluted Earnings Per Share (Details) Sheet http://itacunibanco.com/role/EarningspershareScheduleofDilutedEarningsPerShareDetails Earnings per share - Schedule of Diluted Earnings Per Share (Details) Details 152 false false R153.htm 9955621 - Disclosure - Earnings per share (Details) Sheet http://itacunibanco.com/role/EarningspershareDetails Earnings per share (Details) Details http://itacunibanco.com/role/EarningspershareTables 153 false false R154.htm 9955622 - Disclosure - Post-employment benefits - Schedule of Main Assumptions used in Actuarial Valuation of Retirement Plans (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofMainAssumptionsusedinActuarialValuationofRetirementPlansDetails Post-employment benefits - Schedule of Main Assumptions used in Actuarial Valuation of Retirement Plans (Details) Details 154 false false R155.htm 9955623 - Disclosure - Post-employment benefits - Schedule of Allocation of Assets by Category Segmented into Quoted and Not Quoted in Active Market (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofAllocationofAssetsbyCategorySegmentedintoQuotedandNotQuotedinActiveMarketDetails Post-employment benefits - Schedule of Allocation of Assets by Category Segmented into Quoted and Not Quoted in Active Market (Details) Details 155 false false R156.htm 9955624 - Disclosure - Post-employment benefits - Narrative (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsNarrativeDetails Post-employment benefits - Narrative (Details) Details 156 false false R157.htm 9955625 - Disclosure - Post-employment benefits - Schedule of Change in Net Amount Recognized in Balance Sheet (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofChangeinNetAmountRecognizedinBalanceSheetDetails Post-employment benefits - Schedule of Change in Net Amount Recognized in Balance Sheet (Details) Details 157 false false R158.htm 9955626 - Disclosure - Post-employment benefits - Schedule of Defined Benefit Contribution (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofDefinedBenefitContributionDetails Post-employment benefits - Schedule of Defined Benefit Contribution (Details) Details 158 false false R159.htm 9955627 - Disclosure - Post-employment benefits - Schedule of Maturity Profile of Defined Benefit Liabilities (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofMaturityProfileofDefinedBenefitLiabilitiesDetails Post-employment benefits - Schedule of Maturity Profile of Defined Benefit Liabilities (Details) Details 159 false false R160.htm 9955628 - Disclosure - Post-employment benefits - Schedule of Sensitivity of Defined Benefit Obligation (Details) Sheet http://itacunibanco.com/role/PostemploymentbenefitsScheduleofSensitivityofDefinedBenefitObligationDetails Post-employment benefits - Schedule of Sensitivity of Defined Benefit Obligation (Details) Details 160 false false R161.htm 9955629 - Disclosure - Insurance contracts and private pension - Schedule of Insurance Contracts and Private Pension Portfolios and Measurement Approach (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofInsuranceContractsandPrivatePensionPortfoliosandMeasurementApproachDetails Insurance contracts and private pension - Schedule of Insurance Contracts and Private Pension Portfolios and Measurement Approach (Details) Details 161 false false R162.htm 9955630 - Disclosure - Insurance contracts and private pension - Narrative (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionNarrativeDetails Insurance contracts and private pension - Narrative (Details) Details 162 false false R163.htm 9955631 - Disclosure - Insurance contracts and private pension - Schedule of Reconciliation of Insurance (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofReconciliationofInsuranceDetails Insurance contracts and private pension - Schedule of Reconciliation of Insurance (Details) Details 163 false false R164.htm 9955632 - Disclosure - Insurance contracts and private pension - Schedule of Reconciliation of Insurance One (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofReconciliationofInsuranceOneDetails Insurance contracts and private pension - Schedule of Reconciliation of Insurance One (Details) Details 164 false false R165.htm 9955633 - Disclosure - Insurance contracts and private pension - Schedule of Reconciliation of Private Pension (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofReconciliationofPrivatePensionDetails Insurance contracts and private pension - Schedule of Reconciliation of Private Pension (Details) Details 165 false false R166.htm 9955634 - Disclosure - Insurance contracts and private pension - Schedule of Reconciliation of Private Pension One (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofReconciliationofPrivatePensionOneDetails Insurance contracts and private pension - Schedule of Reconciliation of Private Pension One (Details) Details 166 false false R167.htm 9955635 - Disclosure - Insurance contracts and private pension - Schedule of Contractual Service Margin (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofContractualServiceMarginDetails Insurance contracts and private pension - Schedule of Contractual Service Margin (Details) Details 167 false false R168.htm 9955636 - Disclosure - Insurance contracts and private pension - Schedule of Discount Rates (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofDiscountRatesDetails Insurance contracts and private pension - Schedule of Discount Rates (Details) Details 168 false false R169.htm 9955637 - Disclosure - Insurance contracts and private pension - Schedule of Claims Development (Details) Sheet http://itacunibanco.com/role/InsurancecontractsandprivatepensionScheduleofClaimsDevelopmentDetails Insurance contracts and private pension - Schedule of Claims Development (Details) Details 169 false false R170.htm 9955638 - Disclosure - Fair value - Schedule of Breakdown of Fair Value Hierarchy Levels (Details) Sheet http://itacunibanco.com/role/FairvalueScheduleofBreakdownofFairValueHierarchyLevelsDetails Fair value - Schedule of Breakdown of Fair Value Hierarchy Levels (Details) Details 170 false false R171.htm 9955639 - Disclosure - Fair value - Schedule of Breakdown of Fair Value Hierarchy Levels for Derivative Assets and Liabilities (Details) Sheet http://itacunibanco.com/role/FairvalueScheduleofBreakdownofFairValueHierarchyLevelsforDerivativeAssetsandLiabilitiesDetails Fair value - Schedule of Breakdown of Fair Value Hierarchy Levels for Derivative Assets and Liabilities (Details) Details 171 false false R172.htm 9955640 - Disclosure - Fair value - Schedule of Level 3 Recurring Fair Value Changes (Details) Sheet http://itacunibanco.com/role/FairvalueScheduleofLevel3RecurringFairValueChangesDetails Fair value - Schedule of Level 3 Recurring Fair Value Changes (Details) Details 172 false false R173.htm 9955641 - Disclosure - Fair value - Schedule of Sensitivity Analyses Operations (Details) Sheet http://itacunibanco.com/role/FairvalueScheduleofSensitivityAnalysesOperationsDetails Fair value - Schedule of Sensitivity Analyses Operations (Details) Details 173 false false R174.htm 9955642 - Disclosure - Fair value - Schedule of Estimated Fair Value for Financial Assets and Liabilities (Details) Sheet http://itacunibanco.com/role/FairvalueScheduleofEstimatedFairValueforFinancialAssetsandLiabilitiesDetails Fair value - Schedule of Estimated Fair Value for Financial Assets and Liabilities (Details) Details 174 false false R175.htm 9955643 - Disclosure - Fair value - Narrative (Details) Sheet http://itacunibanco.com/role/FairvalueNarrativeDetails Fair value - Narrative (Details) Details 175 false false R176.htm 9955644 - Disclosure - Provisions, contingent assets and contingent liabilities - Schedule of Civil, Labor and Other Risks Provisions (Details) Sheet http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesScheduleofCivilLaborandOtherRisksProvisionsDetails Provisions, contingent assets and contingent liabilities - Schedule of Civil, Labor and Other Risks Provisions (Details) Details 176 false false R177.htm 9955645 - Disclosure - Provisions, contingent assets and contingent liabilities - Schedule of Social Security Provisions (Details) Sheet http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesScheduleofSocialSecurityProvisionsDetails Provisions, contingent assets and contingent liabilities - Schedule of Social Security Provisions (Details) Details 177 false false R178.htm 9955646 - Disclosure - Provisions, contingent assets and contingent liabilities - Narrative (Details) Sheet http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesNarrativeDetails Provisions, contingent assets and contingent liabilities - Narrative (Details) Details http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesTables 178 false false R179.htm 9955647 - Disclosure - Provisions, contingent assets and contingent liabilities - Schedule of Guarantees of Contingencies, Provisions and Legal Obligations (Details) Sheet http://itacunibanco.com/role/ProvisionscontingentassetsandcontingentliabilitiesScheduleofGuaranteesofContingenciesProvisionsandLegalObligationsDetails Provisions, contingent assets and contingent liabilities - Schedule of Guarantees of Contingencies, Provisions and Legal Obligations (Details) Details 179 false false R180.htm 9955648 - Disclosure - Segment Information - Schedule of Operating Segments (Details) Sheet http://itacunibanco.com/role/SegmentInformationScheduleofOperatingSegmentsDetails Segment Information - Schedule of Operating Segments (Details) Details 180 false false R181.htm 9955649 - Disclosure - Segment Information - Narrative (Details) Sheet http://itacunibanco.com/role/SegmentInformationNarrativeDetails Segment Information - Narrative (Details) Details 181 false false R182.htm 9955650 - Disclosure - Segment Information - Schedule of Result of Non-Current Assets and Main Services and Products by Geographic Region (Details) Sheet http://itacunibanco.com/role/SegmentInformationScheduleofResultofNonCurrentAssetsandMainServicesandProductsbyGeographicRegionDetails Segment Information - Schedule of Result of Non-Current Assets and Main Services and Products by Geographic Region (Details) Details 182 false false R183.htm 9955651 - Disclosure - Related parties - Schedule of Transactions Between Related Parties (Details) Sheet http://itacunibanco.com/role/RelatedpartiesScheduleofTransactionsBetweenRelatedPartiesDetails Related parties - Schedule of Transactions Between Related Parties (Details) Details 183 false false R184.htm 9955652 - Disclosure - Related parties - Narrative (Details) Sheet http://itacunibanco.com/role/RelatedpartiesNarrativeDetails Related parties - Narrative (Details) Details 184 false false R185.htm 9955653 - Disclosure - Related parties - Schedule of Compensation and Benefits of Key Management Personnel (Details) Sheet http://itacunibanco.com/role/RelatedpartiesScheduleofCompensationandBenefitsofKeyManagementPersonnelDetails Related parties - Schedule of Compensation and Benefits of Key Management Personnel (Details) Details 185 false false R186.htm 9955654 - Disclosure - Risk and Capital Management - Schedule of Financial Assets at Amortized Cost and at Fair Value (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofFinancialAssetsatAmortizedCostandatFairValueDetails Risk and Capital Management - Schedule of Financial Assets at Amortized Cost and at Fair Value (Details) Details 186 false false R187.htm 9955655 - Disclosure - Risk and Capital Management - Schedule of Maximum Exposure of Financial Assets to Credit Risk (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofMaximumExposureofFinancialAssetstoCreditRiskDetails Risk and Capital Management - Schedule of Maximum Exposure of Financial Assets to Credit Risk (Details) Details 187 false false R188.htm 9955656 - Disclosure - Risk and Capital Management - Schedule of Loan and Lease Operations (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofLoanandLeaseOperationsDetails Risk and Capital Management - Schedule of Loan and Lease Operations (Details) Details 188 false false R189.htm 9955657 - Disclosure - Risk and Capital Management - Schedule of Other Financial Assets (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofOtherFinancialAssetsDetails Risk and Capital Management - Schedule of Other Financial Assets (Details) Details 189 false false R190.htm 9955658 - Disclosure - Risk and Capital Management - Schedule of Breakdown of Indicators of Credit Quality (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofBreakdownofIndicatorsofCreditQualityDetails Risk and Capital Management - Schedule of Breakdown of Indicators of Credit Quality (Details) Details 190 false false R191.htm 9955659 - Disclosure - Risk and Capital Management - Schedule of Internal Rating (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofInternalRatingDetails Risk and Capital Management - Schedule of Internal Rating (Details) Details 191 false false R192.htm 9955660 - Disclosure - Risk and Capital Management - Schedule of Maximum Exposure of Other Financial Assets by Type and Classification of Credit Risk (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofMaximumExposureofOtherFinancialAssetsbyTypeandClassificationofCreditRiskDetails Risk and Capital Management - Schedule of Maximum Exposure of Other Financial Assets by Type and Classification of Credit Risk (Details) Details 192 false false R193.htm 9955661 - Disclosure - Risk and Capital Management - Schedule of Financial Assets Individually Evaluated Classified by Rating (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofFinancialAssetsIndividuallyEvaluatedClassifiedbyRatingDetails Risk and Capital Management - Schedule of Financial Assets Individually Evaluated Classified by Rating (Details) Details 193 false false R194.htm 9955662 - Disclosure - Risk and Capital Management - Schedule of Collateral for Loans and Financial Lease Operations (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofCollateralforLoansandFinancialLeaseOperationsDetails Risk and Capital Management - Schedule of Collateral for Loans and Financial Lease Operations (Details) Details 194 false false R195.htm 9955663 - Disclosure - Risk and Capital Management - Narrative (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementNarrativeDetails Risk and Capital Management - Narrative (Details) Details 195 false false R196.htm 9955664 - Disclosure - Risk and Capital Management - Schedule Of Var Total - Historical Simulation (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleOfVarTotalHistoricalSimulationDetails Risk and Capital Management - Schedule Of Var Total - Historical Simulation (Details) Details 196 false false R197.htm 9955665 - Disclosure - Risk and Capital Management - Schedule of Position of Accounts Subject to Interest Rate Risk (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofPositionofAccountsSubjecttoInterestRateRiskDetails Risk and Capital Management - Schedule of Position of Accounts Subject to Interest Rate Risk (Details) Details 197 false false R198.htm 9955666 - Disclosure - Risk and Capital Management - Schedule of Primary Source of Funding (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofPrimarySourceofFundingDetails Risk and Capital Management - Schedule of Primary Source of Funding (Details) Details 198 false false R199.htm 9955667 - Disclosure - Risk and Capital Management - Schedule of Off Balance Commitments (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofOffBalanceCommitmentsDetails Risk and Capital Management - Schedule of Off Balance Commitments (Details) Details 199 false false R200.htm 9955668 - Disclosure - Risk and Capital Management - Schedule of Contractual Maturities of Assets and Liabilities Explanatory (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofContractualMaturitiesofAssetsandLiabilitiesExplanatoryDetails Risk and Capital Management - Schedule of Contractual Maturities of Assets and Liabilities Explanatory (Details) Details 200 false false R201.htm 9955669 - Disclosure - Risk and Capital Management - Schedule of Composition of Capital Adequacy (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofCompositionofCapitalAdequacyDetails Risk and Capital Management - Schedule of Composition of Capital Adequacy (Details) Details 201 false false R202.htm 9955670 - Disclosure - Risk and Capital Management - Schedule of Risk Weighted Assets (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofRiskWeightedAssetsDetails Risk and Capital Management - Schedule of Risk Weighted Assets (Details) Details 202 false false R203.htm 9955671 - Disclosure - Risk and Capital Management - Schedule of Sensitivity Analysis (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofSensitivityAnalysisDetails Risk and Capital Management - Schedule of Sensitivity Analysis (Details) Details 203 false false R204.htm 9955672 - Disclosure - Risk and Capital Management - Schedule of Maturity Analysis of Estimated Undiscounted Future Cash Flows (Details) Sheet http://itacunibanco.com/role/RiskandCapitalManagementScheduleofMaturityAnalysisofEstimatedUndiscountedFutureCashFlowsDetails Risk and Capital Management - Schedule of Maturity Analysis of Estimated Undiscounted Future Cash Flows (Details) Details 204 false false R205.htm 9955673 - Disclosure - Supplementary information (Details) Sheet http://itacunibanco.com/role/SupplementaryinformationDetails Supplementary information (Details) Details http://itacunibanco.com/role/Supplementaryinformation 205 false false R206.htm 9955674 - Disclosure - Subsequent event (Details) Sheet http://itacunibanco.com/role/SubsequenteventDetails Subsequent event (Details) Details http://itacunibanco.com/role/Subsequentevent 206 false false All Reports Book All Reports itub-20251231.htm itub-20251231.xsd itub-20251231_cal.xml itub-20251231_def.xml itub-20251231_lab.xml itub-20251231_pre.xml itub-20251231_g1.jpg itub-20251231_g10.jpg itub-20251231_g11.jpg itub-20251231_g12.jpg itub-20251231_g13.jpg itub-20251231_g14.jpg itub-20251231_g15.jpg itub-20251231_g16.jpg itub-20251231_g2.jpg itub-20251231_g3.jpg itub-20251231_g4.jpg itub-20251231_g5.jpg itub-20251231_g6.jpg itub-20251231_g7.jpg itub-20251231_g8.jpg itub-20251231_g9.jpg http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full true true