Business and Asset Actions (Restructuring Charges Related to Business and Asset Actions) (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
Global cost reduction plan	123.7	57.0	27.0
Business and asset actions	3,747.0	57.0	244.6
Project exit-related impairment of equity method investment	6.8	0.0	0.0
Subtotal	3,753.8	57.0	244.6
Income tax benefit	695.2	13.2	34.7
Amount attributable to noncontrolling interests	10.7	0.0	5.0
Business and asset actions attributable to Air Products after-tax	$ 3,047.9	$ 43.8	$ 204.9