Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (3,161.0)	$ (3,022.7)	$ (9,435.3)	$ (8,870.4)
Cost of sales	2,125.0	2,040.1	6,416.9	6,110.5
Interest expense	49.4	61.4	153.4	146.2
Other non-operating income (expense), net	(3.6)	6.0	(3.1)	(14.3)
Net Income attributable to Air Products	1,440.8	(713.8)	52.2	399.4
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	(0.6)	(0.1)	(1.7)	0.2
Cost of sales	5.5	(0.2)	5.2	5.8
Interest expense	(0.2)	(0.4)	(0.8)	(0.1)
Other non-operating income (expense), net	(7.4)	(51.5)	27.5	26.8
Net Income attributable to Air Products	(2.7)	(52.2)	30.2	32.7
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	3.3	0.0	5.8
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	$ 8.9	$ 11.5	$ 28.1	$ 33.5