Business and Asset Actions (Project Exit Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Project exit costs	$ 3,623.3	$ 0.0	$ 217.6
Project Exit Costs
Restructuring Cost and Reserve [Line Items]
Project exit costs	3,623.3		$ 217.6
Noncash expense	(3,282.7)
Cash payments	(174.4)
Currency translation adjustment	12.1
Accrued restructuring	178.3	$ 0.0
Impairment of long lived assets to be disposed of	2,500.0
Estimated effect on cash flows	$ 355.0