Sales Of Accounts Receivable (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012 Domestic Country Sale Of Accounts Receivable [Member]	Aug. 31, 2011 Domestic Country Sale Of Accounts Receivable [Member]	Feb. 29, 2012 International [Member]	Aug. 31, 2011 International [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Accounts receivable sold					$ 502.5	$ 557.0	$ 156.7	$ 132.2
Advance payment received on sale of account receivable					130.0	50.0
Outstanding deferred purchase price of receivables sold					372.5	507.0
Fair value of deferred purchase price					363.2	494.7
Maximum advance limit for receivables sold					200
Proceed from sales of receivables			988.7	499.8
Cash payment to owners of receivables			884.2	464.7
Discount on domestic and international sales of accounts receivables	$ 1.8	$ 0.9	$ 3.5	$ 2.1