Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (3,171.8)	$ (2,916.2)	$ (6,274.3)	$ (5,847.7)
Cost of sales	2,184.4	2,053.9	4,291.9	4,070.4
Interest expense	49.5	42.2	104.0	84.8
Other non-operating income (expense), net	(0.9)	18.6	0.5	(20.3)
Net Income attributable to Air Products	(710.4)	1,730.6	(1,388.6)	1,113.2
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	(1.1)	0.3
Cost of sales	(0.5)	5.2	(0.3)	6.0
Interest expense	(0.3)	0.0	(0.6)	0.3
Other non-operating income (expense), net	17.3	(12.3)	34.9	78.3
Net Income attributable to Air Products	16.3	(7.0)	32.9	84.9
Reclassification out of Accumulated Other Comprehensive Income | Foreign currency translation adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income attributable to Air Products	0.0	2.5	0.0	2.5
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	$ 9.9	$ 11.0	$ 19.2	$ 22.0