Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Taxes
Effective income tax rate (as a percent)	35.70%	35.10%	35.40%	36.20%
Effective income tax rates as compared to the U.S. Federal income tax rate
U.S. Federal income tax rate (as a percent)			35.00%
Reasonably possible increase in the reserve for uncertain tax positions, low range	$ 7.0		$ 7.0
Reasonably possible increase in the reserve for uncertain tax positions, high range	$ 10.6		$ 10.6