Income Taxes (Details 4) (USD $) In Millions	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Unrecognized tax benefits, excluding interest and penalties
Gross unrecognized tax benefits balance at beginning of year	$ 66.3	$ 116.7	$ 125.8
Additions based on tax positions related to the current year	22.3	6.3	15.3
Additions based on tax positions related to prior years	9.3	1.0	2.2
Reductions based on tax positions related to prior years	(0.6)	(12.0)	(8.1)
Reductions related to settlements with taxing authorities	(18.5)	(44.0)	(13.3)
Reductions related to lapses of statute of limitations	(3.0)	(3.7)	(3.9)
Effect of foreign currency translation	(0.7)	2.0	(1.3)
Gross unrecognized tax benefits balance at end of year	75.1	66.3	116.7
Offsetting tax benefits	(44.9)	(51.1)	(49.1)
Net unrecognized tax benefits	$ 30.2	$ 15.2	$ 67.6

Increases / (reductions) in unrecognized tax benefits resulting from fluctuations in foreign currency exchange rates.

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