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Financial Instruments (Gains and Losses Recognized In Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Investment Hedging Relationships
Tax effects	$ 10.2	$ 3.3	$ 9.7	$ (9.6)
Translation adjustments, net of tax	106.9	(48.8)	(27.3)	(65.6)
Derivatives in Cash Flow Hedging Relationships
Tax effects	(8.1)		(16.7)
Net gain (loss) on derivatives, net of tax	23.4		18.1
Tax effects		(4.5)		4.9
Net gain (loss) on derivatives, net of tax		7.5		(38.2)
Net Investment Hedges
Net Investment Hedging Relationships
Total Amount Recognized in OCI	(44.9)		(17.8)
Total Amount Recognized in OCI		(13.4)		43.0
Tax effects	11.0	3.4	4.4	(10.3)
Translation adjustments, net of tax	(33.9)	(10.0)	(13.4)	32.7
Net Investment Hedges \| Forward Exchange Contracts
Net Investment Hedging Relationships
Total Amount Recognized in OCI	(22.1)		9.3
Total Amount Recognized in OCI		(2.7)		21.0
Net Investment Hedges \| Foreign Currency Debt
Net Investment Hedging Relationships
Total Amount Recognized in OCI	(22.8)		(36.0)
Total Amount Recognized in OCI		(14.9)		20.4
Net Investment Hedges \| Cross Currency Interest Rate Swaps
Net Investment Hedging Relationships
Total Amount Recognized in OCI	0.0		8.9
Total Amount Recognized in OCI		4.2		1.6
Cash Flow Hedges
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	31.5		34.8
Tax effects	(8.1)		(16.7)
Net gain (loss) on derivatives, net of tax	23.4		18.1
Total Amount Recognized in OCI		12.0		(43.1)
Tax effects		(4.5)		4.9
Net gain (loss) on derivatives, net of tax		7.5		(38.2)
Cash Flow Hedges \| Forward Exchange Contracts
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	38.7		54.9
Total Amount Recognized in OCI		6.7		(6.6)
Cash Flow Hedges \| Forward Exchange Contracts, Excluded Components
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(4.9)		(12.2)
Total Amount Recognized in OCI		(4.5)		(11.9)
Cash Flow Hedges \| Other
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	$ (2.3)		$ (7.9)
Total Amount Recognized in OCI		$ 9.8		$ (24.6)