Financial Instruments (Gains and Losses Recognized In Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Net Investment Hedging Relationships
Tax effects	$ (46.2)	$ 29.8
Net Amount Recognized in OCI	(624.0)	380.6
Derivatives in Cash Flow Hedging Relationships
Tax effects	22.0	(5.5)
Net Amount Recognized in OCI	65.7	(161.1)
Net investment hedges
Net Investment Hedging Relationships
Total Amount Recognized in OCI	194.7	(123.6)
Tax effects	(47.5)	30.1
Net Amount Recognized in OCI	147.2	(93.5)
Net investment hedges \| Forward exchange contracts
Net Investment Hedging Relationships
Total Amount Recognized in OCI	53.9	(31.8)
Net investment hedges \| Foreign currency debt
Net Investment Hedging Relationships
Total Amount Recognized in OCI	140.4	(89.9)
Net investment hedges \| Cross currency interest rate swaps
Net Investment Hedging Relationships
Total Amount Recognized in OCI	0.4	(1.9)
Cash flow hedges
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	43.7	(155.6)
Tax effects	22.0	(5.5)
Net Amount Recognized in OCI	65.7	(161.1)
Cash flow hedges \| Forward exchange contracts
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(177.8)	115.1
Cash flow hedges \| Forward exchange contracts, excluded components
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	(1.5)	(9.0)
Cash flow hedges \| Other
Derivatives in Cash Flow Hedging Relationships
Total Amount Recognized in OCI	$ 223.0	$ (261.7)

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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