Receivables - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Notes Receivable, Long-Term
CHS Capital long-term notes receivable	$ 322.4	$ 190.4
Percentage of commercial notes to CHS Capital long-term notes receivable	26.00%	34.00%
Percentage of producer notes to CHS Capital long-term notes receivable	74.00%	66.00%
Interest income accrual, discontinue, term	90 days
Minimum
Notes Receivable, Short-Term
CHS Capital short-term notes receivable, term	12 months
Maximum
Notes Receivable, Short-Term
CHS Capital short-term notes receivable, term	14 months
Notes and Loans Receivable, Net, Noncurrent, Term	10 years
CHS Capital [Member]
Notes Receivable, Long-Term
CHS Capital long-term notes receivable additional available credit of counterparty	$ 1,000.0
Customer Concentration Risk [Member] | CHS Capital Notes Receivable [Member]
Notes Receivable, Long-Term
Concentration Risk, Percentage	20.00%
All other third party borrowers [Member] | Customer Concentration Risk [Member] | CHS Capital Notes Receivable [Member]
Notes Receivable, Long-Term
Concentration Risk, Percentage	10.00%