Consolidated Comprehensive Income Statements (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Tax effect on translation adjustments	$ 16.7	$ (10.6)	$ (13.1)	$ (48.6)
Tax effect on net gain (loss) on derivatives	0.2	(0.6)	5.7	37.6
Tax effect on pension and postretirement benefits			0.0	2.4
Tax effect on derivatives reclassification adjustments	10.6	1.9	(2.2)	(19.8)
Tax effect on pension and postretirement benefits reclassification adjustments	$ 4.5	$ 4.7	$ 8.7	$ 8.4

Amount of tax expense (benefit), 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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