Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (2,985.5)	$ (3,033.9)	$ (8,913.1)	$ (9,408.7)
Cost of sales	2,005.6	2,070.7	6,064.3	6,625.8
Other non-operating income (expense), net	1.3	11.7	25.3	26.2
Net Income attributable to Air Products	(696.6)	(595.6)	(1,878.3)	(1,607.6)
Business and asset actions	0.0	59.0	57.0	244.6
Reclassification out of Accumulated Other Comprehensive Income | Loss (Gain) on Cash Flow Hedges, net of tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	0.2	(0.1)	0.1	0.0
Cost of sales	(0.2)	0.3	1.2	3.1
Interest expense	0.5	1.0	2.0	2.7
Other non-operating income (expense), net	15.0	(25.6)	4.8	(93.1)
Net Income attributable to Air Products	15.5	(24.4)	8.1	(87.3)
Reclassification out of Accumulated Other Comprehensive Income | Foreign currency translation adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Business and asset actions	0.0	0.0	0.0	(0.3)
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefits, net of tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income attributable to Air Products	$ 13.8	$ 13.5	$ 41.1	$ 39.8