Receivables - Narrative (Details) (USD $) In Millions, unless otherwise specified	May 31, 2013	Aug. 31, 2012	May 31, 2012
Notes Receivable, Long-Term
CHS Capital long-term notes receivable	$ 93.3	$ 164.8	$ 117.6
Percentage of commercial notes to CHS Capital long-term notes receivable	73.00%	74.00%	75.00%
Percentage of producer notes to CHS Capital long-term notes receivable	27.00%	26.00%	25.00%
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 [Member]
Notes Receivable, Long-Term
CHS Capital long-term notes receivable additional available credit of counterparty	$ 903.0