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Risk and Capital Management - Summary of Assets and Liabilities According to Their Remaining Contractual Maturities, Considering Their Undiscounted Flows (Parenthetical) (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of assets and liabilities according to their remaining contractual maturities [Line Items] |  |  |
Deposits in Central Bank | R$ 94,148 | R$ 98,837 |
Securities under guarantee transactions | 5,120 | 3,664 |
Payment to merchants | 60,504 | 53,687 |
Amount of liabilities from transactions related to credit assignments | 3,993 | 4,931 |
Compulsory deposits with the Central Bank of Brazil | 4,689 | (13,137) | R$ (19,144)
Interbank deposits [Member] |  |  |
Disclosure of assets and liabilities according to their remaining contractual maturities [Line Items] |  |  |
Compulsory deposits with the Central Bank of Brazil | R$ 15,886 | R$ 6,689 |

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- Definition The amount of reserve that is kept in deposit at a central bank to fulfil regulatory reserve requirements. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The cash outflow to, and on behalf of, employees. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 14 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_14_d&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition Adjustments for compulsory deposits with the Central Bank + References No definition available. + Details
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- Definition Disclosure of assets and liabilities according to their remaining contractual maturities [Line Items] + References No definition available. + Details
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- Definition Pledged in guarantee of operations. + References No definition available. + Details
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- Details
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