Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Income Taxes
Effective income tax rate (as a percent)	36.60%	34.90%	35.40%	35.10%
Effective income tax rates as compared to the U.S. Federal income tax rate
U.S. federal statutory rate (as a percent)			35.00%
Reasonably possible increase in the reserve for uncertain tax positions, low range	$ 8.0		$ 8.0
Reasonably possible increase in the reserve for uncertain tax positions, high range	10.7		10.7
Uncertain tax positions related to discontinued operations	$ 3.1		$ 3.1