Derivative Financial Instruments and Hedging Activities Purchase and Sale Contracts (Details) (Not Designated as Hedging Instrument [Member], Forward Contracts [Member])	Feb. 28, 2015 Bushels	Aug. 31, 2014 Bushels
Grain and oilseed - bushels | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	716,952,000	665,690,000
Grain and oilseed - bushels | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	1,380,157,000	938,140,000
Ocean and barge freight - tons | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	5,006,000	5,423,000
Ocean and barge freight - tons | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	3,308,000	4,005,000
Livestock - pounds | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	21,320,000	0
Livestock - pounds | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	200,000	46,280,000
Energy products [Member] | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	57,686,000	27,754,000
Energy products [Member] | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	55,030,000	50,450,000
Soy product contracts [Member] | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	4,192,000	37,000
Soy product contracts [Member] | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	3,660,000	1,212,000
Derivative number of units Crop nutrients contracts [Member] | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	134,000	1,613,000
Derivative number of units Crop nutrients contracts [Member] | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	3,091,000	1,607,000
Derivative number of units cargo and freight rail contracts [Member] | Long [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	202,000	321,000
Derivative number of units cargo and freight rail contracts [Member] | Short [Member]
Purchase and Sales Contracts [Line Items]
Derivative, Nonmonetary Notional Amount	117,000	186,000