Derivatives And Risk Management (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
Derivatives And Risk Management [Abstract]
Increase in the carrying value of debt through fair value hedge accounting for interest rate swaps			$ 55.1
Reductions in interest expense related to interest rate swaps	4.4	3.5	8.6	6.8
Notional Amount of Foreign Currency Derivatives	280		280
Notional amount of interest rate swap transactions	$ 800		$ 800