Risk and Capital Management - Summary of Financial Assets Individually Evaluated Classified by Rating (Parenthetical) (Detail) - BRL (R$) R$ in Millions	Dec. 31, 2019	Dec. 31, 2018
Disclosure of financial assets individually evaluated classified by rating[Abstract]
Derivatives	R$ 41,854	R$ 23,466

The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard
-URIDate 2019-03-27

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant