Financial Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016
Derivative [Line Items]
Total derivatives, asset	$ 464.3	$ 373.7
Total derivatives, liabilities	209.1	95.3
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total derivatives, asset	370.9	296.6
Total derivatives, liabilities	160.9	65.1
Hedges Not Designated [Member]
Derivative [Line Items]
Total derivatives, asset	93.4	77.1
Total derivatives, liabilities	48.2	30.2
Forward Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Receivables [Member]
Derivative [Line Items]
Total derivatives, asset	62.4	72.3
Forward Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivative [Line Items]
Total derivatives, asset	73.6	44.4
Forward Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	144.2	44.0
Forward Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	1.9	9.1
Forward Exchange Contracts [Member] | Hedges Not Designated [Member] | Other Receivables [Member]
Derivative [Line Items]
Total derivatives, asset	93.4	77.1
Forward Exchange Contracts [Member] | Hedges Not Designated [Member] | Other Noncurrent Assets [Member]
Derivative [Line Items]
Total derivatives, asset	0.0	0.0
Forward Exchange Contracts [Member] | Hedges Not Designated [Member] | Accrued Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	47.7	29.5
Forward Exchange Contracts [Member] | Hedges Not Designated [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	0.2	0.0
Interest Rate Management Contract [Member] | Designated as Hedging Instrument [Member] | Other Receivables [Member]
Derivative [Line Items]
Total derivatives, asset	32.3	19.9
Interest Rate Management Contract [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivative [Line Items]
Total derivatives, asset	202.6	160.0
Interest Rate Management Contract [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	0.0	0.0
Interest Rate Management Contract [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	14.8	12.0
Interest Rate Management Contract [Member] | Hedges Not Designated [Member] | Other Noncurrent Assets [Member]
Derivative [Line Items]
Total derivatives, asset	0.0	0.0
Interest Rate Management Contract [Member] | Hedges Not Designated [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Total derivatives, liabilities	$ 0.3	$ 0.7