Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate	27.40%	25.70%
Gross unrecognized tax benefits	$ 41.0		$ 40.8
Accrued interest and penalties related to unrecognized tax benefits	9.2		12.4
Net impact on effective tax rate of unrecognized tax benefits, tax penalties, accrued interest and offsetting tax assets	24.9
Reasonably possible amount of increase / (decrease) in gross unrecognized tax benefits for the next twelve months	$ 31.9