Financial Instruments (Narrative) (Details) In Millions, unless otherwise specified			6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended		6 Months Ended
	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2015 Foreign Currency Debt [Member] Euro Denominated Member [Member] USD ($)	Mar. 31, 2015 Foreign Currency Debt [Member] Euro Denominated Member [Member] EUR (€)	Sep. 30, 2014 Foreign Currency Debt [Member] Euro Denominated Member [Member] USD ($)	Sep. 30, 2014 Foreign Currency Debt [Member] Euro Denominated Member [Member] EUR (€)	Mar. 31, 2015 Foreign Currency Debt [Member] RMB Denominated Member [Member] USD ($)	Mar. 31, 2015 Foreign Currency Debt [Member] RMB Denominated Member [Member] CNY	Sep. 30, 2014 Foreign Currency Debt [Member] RMB Denominated Member [Member] USD ($)	Sep. 30, 2014 Foreign Currency Debt [Member] RMB Denominated Member [Member] CNY	Mar. 31, 2015 Forward Exchange Contracts [Member]	Mar. 31, 2015 Interest rate management contract [Member]
Derivative [Line Items]
Notional Amount included in designated foreign currency denominated debt			$ 956.2	€ 890.4	$ 1,110.6	€ 879.3	$ 175.1	1,085.8	$ 146.8	900.9
Maximum Remaining Maturity of Foreign Currency Derivatives											3 years 6 months
Maximum length of time of hedged exposures, years												0 years 5 months
Net liability position of derivatives with credit risk-related contingent features	5.0	2.1
Collateral amount that counterparties would be required to post	$ 231.1	$ 107.8