Financial Instruments (Gains and Losses Recognized In Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Net Investment Hedging Relationships
Tax effects	$ (7.6)	$ 24.2
Net Amount Recognized in OCI	40.6	415.7
Derivatives in Cash Flow Hedging Relationships
Tax effects	11.1	(2.7)
Net Amount Recognized in OCI	(0.5)	13.8
Net Investment Hedges
Net Investment Hedging Relationships
Total Amount Recognized in OCI	39.8	(114.3)
Tax effects	(9.8)	28.6
Net Amount Recognized in OCI	30.0	(85.7)
Net Investment Hedges \| Forward exchange contracts
Net Investment Hedging Relationships
Total Amount Recognized in OCI	14.5	(35.9)
Net Investment Hedges \| Foreign currency debt
Net Investment Hedging Relationships
Total Amount Recognized in OCI	27.6	(64.2)
Net Investment Hedges \| Cross currency interest rate swaps
Net Investment Hedging Relationships
Total Amount Recognized in OCI	(2.3)	(14.2)
Cash Flow Hedges
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(11.6)	16.5
Tax effects	11.1	(2.7)
Net Amount Recognized in OCI	(0.5)	13.8
Cash Flow Hedges \| Forward exchange contracts
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(23.4)	64.7
Cash Flow Hedges \| Forward exchange contracts, excluded components
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(2.7)	(2.7)
Cash Flow Hedges \| Other
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	$ 14.5	$ (45.5)

Amount after tax, before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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