Financial Instruments (Gains and Losses Recognized In Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Summary of Net Investment Hedge Activity [Abstract]
Tax effects	$ (71.2)	$ (2.8)	$ 29.4
Net Amount Recognized in OCI	(1,230.5)	267.3	233.4
Summary of Cash Flow Hedge Activity [Abstract]
Tax effects	63.9	9.0	(23.7)
Net Amount Recognized in OCI	(120.3)	3.3	$ 43.5
Net Investment Hedges
Summary of Net Investment Hedge Activity [Abstract]
Total Amount Recognized in OCI	331.9	21.6
Tax effects	(82.1)	(5.5)
Net Amount Recognized in OCI	249.8	16.1
Net Investment Hedges \| Forward exchange contracts
Summary of Net Investment Hedge Activity [Abstract]
Total Amount Recognized in OCI	89.8	11.4
Net Investment Hedges \| Foreign currency debt
Summary of Net Investment Hedge Activity [Abstract]
Total Amount Recognized in OCI	229.6	18.1
Net Investment Hedges \| Cross currency interest rate swaps
Summary of Net Investment Hedge Activity [Abstract]
Total Amount Recognized in OCI	12.5	(7.9)
Cash Flow Hedges
Summary of Cash Flow Hedge Activity [Abstract]
Total Amount Recognized in OCI	(184.2)	(5.7)
Tax effects	63.9	9.0
Net Amount Recognized in OCI	(120.3)	3.3
Cash Flow Hedges \| Forward exchange contracts
Summary of Cash Flow Hedge Activity [Abstract]
Total Amount Recognized in OCI	(310.2)	12.7
Cash Flow Hedges \| Forward exchange contracts, excluded components
Summary of Cash Flow Hedge Activity [Abstract]
Total Amount Recognized in OCI	2.8	(11.7)
Cash Flow Hedges \| Other
Summary of Cash Flow Hedge Activity [Abstract]
Total Amount Recognized in OCI	$ 123.2	$ (6.7)

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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