Investments in joint ventures - Narrative (Details) - CHS AGRO S.A.	1 Months Ended	12 Months Ended
Jan. 31, 2019	Dec. 31, 2020	Dec. 31, 2018
Disclosure of joint ventures [line items]
Proportion of ownership interest in joint venture (as a percent)		100.00%	50.00%
Proportion of ownership interest in joint venture acquired (as a percent)	50.00%

The proportion of ownership interest in a joint venture attributable to the entity. [Refer: Joint ventures [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2020-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
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-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2020-01-01
-Paragraph 16
-Subparagraph b
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2020-01-01
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-Subparagraph a
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