Financial Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Total Derivatives, Assets	$ 137.7	$ 146.1
Total Derivatives, Liabilities	80.5	94.1
Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	106.3	117.7
Total Derivatives, Liabilities	41.0	55.5
Designated as Hedging Instrument | Other Receivables | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	28.3	24.9
Designated as Hedging Instrument | Other Receivables | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	14.0	24.3
Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	27.9	19.8
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	36.1	48.7
Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	32.3	37.0
Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.6	2.3
Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.8	4.6
Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	7.3	11.6
Not Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	31.4	28.4
Total Derivatives, Liabilities	39.5	38.6
Not Designated as Hedging Instrument | Other Receivables | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	7.9	7.9
Not Designated as Hedging Instrument | Other Receivables | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.0	4.0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	22.8	16.2
Not Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Assets	0.7	0.3
Not Designated as Hedging Instrument | Accrued Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	13.4	14.9
Not Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	0.0	0.0
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	26.1	23.7
Not Designated as Hedging Instrument | Other Noncurrent Liabilities | Interest Rate Management Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.0	$ 0.0