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Risk and Capital Management - Summary of Risks of Insurance and Private Pension (Detail) - ITAU UNIBANCO HOLDING [Member] - BRL (R$) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Mandatory personal injury caused by motor vehicle [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums |  | R$ 24 | R$ 37
Retained premium |  | R$ 24 | R$ 37
Retention |  | 100.00% | 100.00%
Extended warranty [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums |  |  | R$ 112
Retained premium |  |  | R$ 112
Retention |  |  | 100.00%
Group accident insurance [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums | R$ 690 | R$ 667 | R$ 780
Retained premium | R$ 689 | R$ 666 | R$ 776
Retention | 99.90% | 99.80% | 99.50%
Individual accident [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums | R$ 275 | R$ 290 | R$ 224
Retained premium | R$ 280 | R$ 289 | R$ 212
Retention | 101.80% | 99.80% | 94.80%
Home insurance in market policies credit life [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums | R$ 881 | R$ 623 | R$ 570
Retained premium | R$ 879 | R$ 621 | R$ 570
Retention | 99.80% | 99.70% | 100.00%
Group life [Member] |  |  |
Disclosure of insurance risk [Line Items] |  |  |
Insurance premiums | R$ 934 | R$ 1,001 | R$ 1,278
Retained premium | R$ 937 | R$ 990 | R$ 1,234
Retention | 100.30% | 98.90% | 96.50%

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- Definition Retained premiums. + References No definition available. + Details
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- Definition Retention Percentage + References No definition available. + Details
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- Details
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- Details
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Balance Type: |
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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
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- Details
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- Details
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- Details
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Period Type: |