Derivative Instruments and Fair Value Measurement (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments and Fair Value Measurement (Textual) [Abstract]
Notional values of forward exchange contracts	$ 867.7
Foreign currency denominated debt designated as net investment hedges	14.7	14.4
Net unrealized gains on cash flow hedges to be reclassified into earnings during the next 12 months	9.0
Net unrealized gains on cash flow hedges to be reclassified into earnings during the next 12 months, net of tax	9.2
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	13.7	(4.9)
Net derivative asset / (liability) not designated as hedging instruments	1.7	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	13.1	4.8
Derivative assets not designated as hedging instruments	3.5	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	5.0	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	(4.1)	(8.3)
Derivative liabilities not designated as hedging instruments	(1.8)	(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	(0.3)	(1.6)
Cash Flow Hedging [Member]
Derivative Instruments and Fair Value Measurement (Textual) [Abstract]
Notional values of forward exchange contracts	$ 641.2