Consolidated Comprehensive Income Statements (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Tax effect on translation adjustments	$ (29.8)	$ (38.0)
Tax effect on net (loss) gain on derivatives	5.5	38.2
Tax effect on pension and postretirement benefits	0.0	2.4
Tax effect on derivatives reclassification adjustments	(12.8)	(21.7)
Tax effect on pension and postretirement benefits reclassification adjustments	$ 4.2	$ 3.7