Financial Instruments (Schedule of Outstanding Currency Price Risk Management Instruments) (Details) (Forward Exchange Contracts [Member], USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2014	Sep. 30, 2013
Derivative [Line Items]
US$ Notional	$ 3,618.7	$ 4,637.1
Years Average Maturity	1 year 1 month	1 year
Cash Flow Hedges [Member]
Derivative [Line Items]
US$ Notional	2,532.2	2,653.4
Years Average Maturity	6 months	7 months
Net Investment Hedges [Member]
Derivative [Line Items]
US$ Notional	746.8	1,231.8
Years Average Maturity	3 years 5 months	2 years 5 months
Hedges Not Designated [Member]
Derivative [Line Items]
US$ Notional	$ 339.7	$ 751.9
Years Average Maturity	1 month	1 month