Significant Accounting Policies - Summary of Consolidated Companies (Detail)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Country of domicile [member] \| Banco Itau B B A [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Banco Itau Consignado S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Banco Itaucard S.A [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Banco Itauleasing S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Cia. Itau de Capitalizacao [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Premium Bonds
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Dibens Leasing S.A. - Arrendamento Mercantil [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Leasing
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Financeira Itau CBD S.A. Credito, Financiamento e Investimento [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Consumer finance credit
Interest in voting capital	50.00%	50.00%
Interest in total capital	50.00%	50.00%
Country of domicile [member] \| Hipercard Banco Multiplo S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Itauseg Seguradora S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Insurance
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Itau Corretora de Valores S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Securities Broker
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Itau Seguros S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Insurance
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Itau Unibanco SA [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Itau Vida e Previdencia S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Pension plan
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Country of domicile [member] \| Luizacred S.A. Sociedade de Credito, Financiamento e Investimento [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Consumer finance credit
Interest in voting capital	50.00%	50.00%
Interest in total capital	50.00%	50.00%
Country of domicile [member] \| Redecard Instituio de Pagamento S.A. [Member]
Disclosure of subsidiaries [line items]
Incorporation country	Brazil
Activity	Acquirer
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Itau Corpbanca Colombia S.A. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Colombian peso
Incorporation country	Colombia
Activity	Financial institution
Interest in voting capital	49.30%	34.16%
Interest in total capital	49.30%	34.16%
Foreign [member] \| Banco Itau Argentina S.A. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Argentinian peso
Incorporation country	Argentina
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Banco Itau Paraguay S.A. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Guarani
Incorporation country	Paraguay
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Banco Itau (Suisse) SA [Member]
Disclosure of subsidiaries [line items]
Functional currency	Swiss franc
Incorporation country	Switzerland
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Banco Itau Uruguay S.A. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Uruguayan peso
Incorporation country	Uruguay
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Itau Bank, Ltd. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Real
Incorporation country	Cayman Islands
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Itau BBA International plc [Member]
Disclosure of subsidiaries [line items]
Functional currency	US Dollar
Incorporation country	United Kingdom
Activity	Financial institution
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Itau BBA USA Securities Inc. [Member]
Disclosure of subsidiaries [line items]
Functional currency	Real
Incorporation country	United States
Activity	Securities Broker
Interest in voting capital	100.00%	100.00%
Interest in total capital	100.00%	100.00%
Foreign [member] \| Itau CorpBanca [Member]
Disclosure of subsidiaries [line items]
Functional currency	Chilean peso
Incorporation country	Chile
Activity	Financial institution
Interest in voting capital	56.60%	39.22%
Interest in total capital	56.60%	39.22%

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