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Risk and Capital Management - Summary of Risk-Weighted Assets of Market Risk (RWAMINT) (Detail) - BRL (R$) R$ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Disclosure of risk management strategy related to hedge accounting [line items] |  |
Market risk weighted assets | R$ 22,871 | R$ 32,915
Fixed rate denominated in reais | 30,286 | 31,076
Operations subject to commodity price variation | 389 | 361
Operations subject to stock price variation | 362 | 239
Operations subject to risk exposures in gold, foreign currency and foreign exchange variation | 6,801 | 1,217
Internal credit grades [member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Market risk weighted assets | (7,568) |
Fixed rate denominated in Real [Member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Fixed rate denominated in reais | 2,026 | 6,119
Foreign currency coupon [Member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Fixed rate denominated in reais | 19,633 | 17,153
Price index coupon [member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Fixed rate denominated in reais | 8,627 | 7,804
RWAMPAD [Member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Market risk weighted assets | 37,838 | 32,893
Minimum Market Risk Weighted Assets-Standard Aproach | 30,270 | 26,314
RWAMINT [Member] |  |
Disclosure of risk management strategy related to hedge accounting [line items] |  |
Market risk weighted assets | R$ 30,270 | R$ 32,915

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