Receivables - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
CHS Capital long-term notes receivable	$ 101.5	$ 180.0
Percentage of commercial notes to CHS Capital long-term notes receivable	33.00%	41.00%
Percentage of producer notes to CHS Capital long-term notes receivable	67.00%	59.00%
Interest income accrual, discontinued, term	90 days
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
CHS Capital short-term notes receivable, term	12 months
Long-term notes receivable, term	10 years
CHS Capital
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additional available credit	$ 714.5
CHS Capital Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan loss reserves	0.0
Note receivables sold under loan participations	$ 70.6	$ 92.3