Financial Instruments (Fair Value of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
Derivative [Line Items]
Total Derivatives, Assets	$ 408.7	$ 171.7
Total Derivatives, Liabilities	232.8	85.9
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total Derivatives, Assets	379.5	165.1
Total Derivatives, Liabilities	199.7	84.0
Designated as Hedging Instrument [Member] | Other Receivables [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Assets	29.7	21.1
Designated as Hedging Instrument [Member] | Other Receivables [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Assets	109.3	78.9
Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Assets	143.7	54.6
Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Assets	96.8	10.5
Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	0.1	18.8
Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	194.8	61.8
Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	0	0.3
Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	4.8	3.1
Hedges Not Designated [Member]
Derivative [Line Items]
Total Derivatives, Assets	29.2	6.6
Total Derivatives, Liabilities	33.1	1.9
Hedges Not Designated [Member] | Other Receivables [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Assets	0	2.6
Hedges Not Designated [Member] | Other Receivables [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Assets	29.2	4.0
Hedges Not Designated [Member] | Accrued Liabilities [Member] | Interest rate management contract [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	0	0
Hedges Not Designated [Member] | Accrued Liabilities [Member] | Forward Exchange Contracts [Member]
Derivative [Line Items]
Total Derivatives, Liabilities	$ 33.1	$ 1.9