Hedge Accounting - Summary of Fair Value Hedge Instruments (Detail) - BRL (R$)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Disclosure of Detailed Information about Hedges [Line Items]
Nominal Value	R$ 116,430,000,000	R$ 126,549,000,000
Fair value hedge [Member]
Disclosure of Detailed Information about Hedges [Line Items]
Nominal Value	19,431,000,000	21,591,000,000
Fair value hedge [Member] \| Interest rate risk [Member]
Disclosure of Detailed Information about Hedges [Line Items]
Nominal Value	19,431,000,000	21,591,000,000
Book Value, Assets	766,000,000	86,000,000
Book value, Liabilities	4,636,000,000	1,078,000,000
Variation in the amount used to calculate hedge ineffectiveness	426,000,000	(93,000,000)
Hedge ineffectiveness recognized in income	15,000,000	10,000,000
Fair value hedge [Member] \| Interest rate risk [Member] \| Interest rate swap2 [Member]
Disclosure of Detailed Information about Hedges [Line Items]
Nominal Value	19,431,000,000	21,591,000,000
Book Value, Assets	766,000,000	86,000,000
Book value, Liabilities	4,636,000,000	1,078,000,000
Variation in the amount used to calculate hedge ineffectiveness	426,000,000	(93,000,000)
Hedge ineffectiveness recognized in income	R$ 15,000,000	R$ 10,000,000

The nominal amount of a credit derivative. [Refer: Derivatives [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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.

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No definition available.

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The gain (loss) on the change in fair value of the hedging instrument used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The gain (loss) recognised in profit or loss on hedge ineffectiveness. [Refer: Gain (loss) on hedge ineffectiveness]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The amount of a hedging instrument, recognised as an asset. [Refer: Hedging instruments [member]]

+ References

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The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [member]]

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