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Risk and Capital Management - Summary of Internal Rating (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 536,091 | R$ 497,719
Percentage of loan operations and lease operations portfolio | 100.00% | 100.00%
Lower risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 382,925 | R$ 354,628
Satisfactory [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 92,644 | 78,505
Higher Risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 20,951 | 21,147
Credit impaired [member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 39,571 | 44,439
Stage 1 [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 459,626 | R$ 417,386
Percentage of loan operations and lease operations portfolio | 85.70% | 83.90%
Stage 1 [Member] | Lower risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 378,389 | R$ 349,354
Stage 1 [Member] | Satisfactory [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 72,921 | 60,707
Stage 1 [Member] | Higher Risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 8,316 | 7,325
Stage 2 [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 36,894 | R$ 35,894
Percentage of loan operations and lease operations portfolio | 6.90% | 7.20%
Stage 2 [Member] | Lower risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 4,536 | R$ 5,274
Stage 2 [Member] | Satisfactory [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 19,723 | 17,798
Stage 2 [Member] | Higher Risk [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | 12,635 | 12,822
Stage 3 [Member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 39,571 | R$ 44,439
Percentage of loan operations and lease operations portfolio | 7.40% | 8.90%
Stage 3 [Member] | Credit impaired [member] |  |
Disclosure of Credit Quality [Line Items] |  |
Loan operations and lease operations portfolio | R$ 39,571 | R$ 44,439

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