Inventories - Narrative (Details) (USD $) In Millions, unless otherwise specified	Nov. 30, 2012	Aug. 31, 2012	Nov. 30, 2011
Inventory Disclosure [Abstract]
Percentage of LIFO inventory	10.00%	11.00%	13.00%
LIFO inventory, difference amount had FIFO inventory valuation method been used	$ 518.5	$ 566.6	$ 577.9

The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

No definition available.

Name:	us-gaap_PercentageOfLIFOInventory
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant