Summary of Significant Accounting Policies - Pretax Gains (Losses) On Derivatives Not Accounted For As Hedging Instruments (Details) (Not Designated as Hedging Instrument, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	$ (35,991)	$ 150,450	$ (449,937)	$ (128,835)
Commodity and freight derivatives | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	(22,457)	149,464	(452,747)	(125,437)
Foreign exchange derivatives | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	(13,648)	950	2,570	(3,434)
Interest rate derivatives | Interest, net
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	$ 114	$ 36	$ 240	$ 36