Derivative Instruments and Fair Value Measurement (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Derivatives, Fair Value [Line Items]
Notional values of forward exchange contracts	$ 918.6
Foreign currency denominated debt designated as net investment hedges	15.3
Fair Value, Inputs, Level 2 [Member]
Assets and liabilities measured at fair value on a recurring basis
Net derivative asset / (liability) designated as hedging instruments	(3.4)	(4.9)
Net derivative asset / (liability) not designated as hedging instruments	(0.6)	3.8
Fair Value, Inputs, Level 2 [Member] | Other current assets [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative assets designated as hedging instruments	4.3	4.8
Derivative assets not designated as hedging instruments	3.3	4.9
Fair Value, Inputs, Level 2 [Member] | Other assets [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative assets designated as hedging instruments	1.1	0.2
Derivative assets not designated as hedging instruments	0	0.7
Fair Value, Inputs, Level 2 [Member] | Other current liabilities [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative liabilities designated as hedging instruments	(7.9)	(8.3)
Derivative liabilities not designated as hedging instruments	(3.9)	(1.8)
Fair Value, Inputs, Level 2 [Member] | Other liabilities [Member]
Assets and liabilities measured at fair value on a recurring basis
Derivative liabilities designated as hedging instruments	(0.9)	(1.6)
Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Notional values of forward exchange contracts	$ 673.4