Financial Instruments (Schedule of Outstanding Currency Price Risk Management Instruments) (Details) (Forward Exchange Contracts [Member], USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2015	Sep. 30, 2014
Derivative [Line Items]
US$ Notional	$ 4,715.2	$ 4,032.9
Years Average Maturity	11 months	1 year
Cash Flow Hedges [Member]
Derivative [Line Items]
US$ Notional	3,100.0	2,965.5
Years Average Maturity	6 months	8 months
Net Investment Hedges [Member]
Derivative [Line Items]
US$ Notional	587.6	685.9
Years Average Maturity	4 years	2 years 11 months
Hedges Not Designated [Member]
Derivative [Line Items]
US$ Notional	$ 1,027.6	$ 381.5
Years Average Maturity	5 months	1 month