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v3.19.1

Risk and Capital Management - Summary of Sensitivity Analysis Presented in Relation to Insurance Operations Demonstrate Impact on Cash Flows Market Value (Detail) - Currency, commodities, and ratios [Member] R$ in Millions | 12 Months Ended
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Dec. 31, 2018 BRL (R$) | Dec. 31, 2017 BRL (R$)
NTN-C [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | R$ 5,096 | R$ 4,936
DV01 | (2.70) | (2.87)
NTN-B [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | R$ 6,091 | R$ 5,343
DV01 | (7.17) | (6.78)
LTN [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance |  | R$ 279
DV01 |  | (0.09)
Indexed to IPCA [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | R$ 259 | R$ 336
DV01 | (0.06) | (0.10)
Indexed to PRE [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | R$ 10 | R$ 31
Floating assets [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | 4,085 | 5,132
Under agreements to resell [Member] |  |
Disclosure of sensitivity analysis market risk [Line Items] |  |
Account balance | R$ 5,575 | R$ 6,856

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