Property,Plant,and Equipment - Balances and changes in property, plant, and equipment beginning and ending (Parenthetical) (Detail) - Oxiteno Andina [member] R$ in Millions	12 Months Ended
Dec. 31, 2018 BRL (R$)
Land [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss recognised in property, plant and equipment	R$ 680
Machinery [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss recognised in property, plant and equipment	R$ 1,334

The amount of impairment loss recognised in profit or loss for property, plant and equipment. [Refer: Impairment loss recognised in profit or loss; Property, plant and equipment]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2018-01-01
-Paragraph 73
-Subparagraph e
-Clause v
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=16&date=2018-03-01&anchor=para_73_e_v&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 98
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_98_a&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration