Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate	27.10%	20.90%	27.30%	22.90%
U.S. statutory rate	35.00%	35.00%	35.00%	35.00%
Net discrete tax benefits		$ 10.0		$ 14.5
Gross unrecognized tax benefits	42.5		42.5		40.8
Accrued interest and penalties related to unrecognized tax benefits	9.9		9.9		12.4
Net reduction of income tax provision related to unrecognized tax benefits, tax penalties, accrued interest and offsetting tax assets	26.7		26.7
Reasonably possible amount of decrease in gross unrecognized tax benefits for the next twelve months	$ 32.5		$ 32.5