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Financial Instruments and Risk Management - Summary of Credit Exposure (Detail) - Credit Risk [Member] | 12 Months Ended
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Dec. 31, 2017 BRL (R$)
A1 [Member] |
Disclosure of credit risk exposure [line items] |
Bank equity | R$ 3,500,000,000
Concentration | Minimum of 80%
A2 Rating [Member] |
Disclosure of credit risk exposure [line items] |
Concentration | Maximum 20%
B [Member] |
Disclosure of credit risk exposure [line items] |
Concentration | Maximum 20%
Bottom of range [member] | A1 [Member] |
Disclosure of credit risk exposure [line items] |
Percentage of limit per bank entity | 6.00%
Bottom of range [member] | A2 Rating [Member] |
Disclosure of credit risk exposure [line items] |
Bank equity | R$ 1,000,000,000
Percentage of limit per bank entity | 5.00%
Bottom of range [member] | B [Member] |
Disclosure of credit risk exposure [line items] |
Bank equity | R$ 400,000,000,000
Percentage of limit per bank entity | 5.00%
Top of range [member] | A1 [Member] |
Disclosure of credit risk exposure [line items] |
Percentage of limit per bank entity | 9.00%
Top of range [member] | A2 Rating [Member] |
Disclosure of credit risk exposure [line items] |
Bank equity | R$ 3,500,000,000
Percentage of limit per bank entity | 8.00%
Top of range [member] | B [Member] |
Disclosure of credit risk exposure [line items] |
Bank equity | R$ 1,000,000,000
Percentage of limit per bank entity | 7.00%

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- Definition The description of a shared characteristic for the concentration of risks arising from financial instruments (for example, counterparty, geographical area, currency or market). [Refer: Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph B8 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_B8_b&doctype=Appendix&seq=2 -URIDate 2017-03-09 + Details
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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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- Definition Percentage of limit per bank entity. + References No definition available. + Details
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- Details
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- Details
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