Income Taxes (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2.7	$ 11.8
Unrecognized tax benefits
Unrecognized tax benefits, beginning of year	14.1	16.3	65.0
Reductions attributable to tax positions taken in prior years	(2.4)	(1.6)	(48.7)
Reductions attributable to lapse of statue of limitations	(7.5)	(0.6)	0
Unrecognized tax benefits, end of year	$ 4.2	$ 14.1	$ 16.3