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Risk and Capital Management - Summary of Assessing Minimum Capital Requirements (Detail) - BRL (R$) R$ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Disclosure Of Regulatory Capital Resources [Line Items] |  |
Risk weighted assets | R$ 818,072 | R$ 756,708
Credit risk [member] |  |
Disclosure Of Regulatory Capital Resources [Line Items] |  |
Risk weighted assets | 714,969 | 660,516
Currency, commodities, and ratios [Member] |  |
Disclosure Of Regulatory Capital Resources [Line Items] |  |
Risk weighted assets | 30,270 | 32,915
Operational risk [member] |  |
Disclosure Of Regulatory Capital Resources [Line Items] |  |
Risk weighted assets | R$ 72,833 | R$ 63,277

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