Financial Instruments (Schedule of Gain/Loss Related to Derivative Instruments) (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Net gain (loss) recognized in OCI (effective portion)		$ (44.1)	$ 45.9	$ (12.6)
Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI (effective portion)		(44.1)	45.9
Designated as Hedging Instrument | Cash Flow Hedges | Sales/Cost of Sales
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		0.6	7.1
Designated as Hedging Instrument | Cash Flow Hedges | Other Income (Expense)
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		(2.9)	(41.6)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)		(0.1)	(1.0)
Designated as Hedging Instrument | Cash Flow Hedges | Interest Expense
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		14.7	5.1
Designated as Hedging Instrument | Fair Value Hedges | Interest Expense
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[1]	4.3	(10.1)
Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI		98.5	20.6
Not Designated as Hedging Instrument | Other Income (Expense)
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[2]	0.7	(4.8)
Forward Exchange Contracts | Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI (effective portion)		(35.7)	2.4
Forward Exchange Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Sales/Cost of Sales
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		0.6	7.1
Forward Exchange Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Other Income (Expense)
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		21.8	(7.8)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)		0.0	(0.5)
Forward Exchange Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Interest Expense
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)		12.1	1.2
Forward Exchange Contracts | Designated as Hedging Instrument | Fair Value Hedges | Interest Expense
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[1]	0.0	0.0
Forward Exchange Contracts | Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI		39.1	(0.6)
Forward Exchange Contracts | Not Designated as Hedging Instrument | Other Income (Expense)
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[2]	(1.3)	(4.0)
Foreign Currency Debt | Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI		49.6	10.2
Other Contracts | Designated as Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI (effective portion)	[3]	(8.4)	43.5
Other Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Sales/Cost of Sales
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)	[3]	0.0	0.0
Other Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Other Income (Expense)
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)	[3]	(24.7)	(33.8)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)	[3]	(0.1)	(0.5)
Other Contracts | Designated as Hedging Instrument | Cash Flow Hedges | Interest Expense
Derivative [Line Items]
Net (gain) loss reclassified from OCI (effective portion)	[3]	2.6	3.9
Other Contracts | Designated as Hedging Instrument | Fair Value Hedges | Interest Expense
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[1],[3]	4.3	(10.1)
Other Contracts | Designated as Hedging Instrument | Net Investment Hedges
Derivative [Line Items]
Net gain (loss) recognized in OCI	[3]	9.8	11.0
Other Contracts | Not Designated as Hedging Instrument | Other Income (Expense)
Derivative [Line Items]
Net gain (loss) recognized in other income (expense)	[2],[3]	$ 2.0	$ (0.8)

[1] The impact of fair value hedges was largely offset by recognized gains and losses resulting from the impact of changes in related interest rates on outstanding debt.

[2] The impact of the non-designated hedges was largely offset by recognized gains and losses resulting from the impact of changes in exchange rates on assets and liabilities denominated in non-functional currencies.

[3] Includes the impact on other comprehensive income (OCI) and earnings primarily related to interest rate and cross currency interest rate swaps.