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