Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (2,916.2)	$ (2,930.2)	$ (5,847.7)	$ (5,927.6)
Cost of sales	2,053.9	1,991.5	4,070.4	4,058.7
Other non-operating income (expense), net	18.6	9.2	(20.3)	24.0
Currency translation adjustment associated with business and asset actions	2,927.9	57.0	2,927.9	57.0
Net Income attributable to Air Products	1,730.6	(572.4)	1,113.2	(1,181.7)
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	0.1	(0.3)	0.3	(0.1)
Cost of sales	5.2	0.4	6.0	1.4
Interest expense	0.0	0.7	0.3	1.5
Other non-operating income (expense), net	(12.3)	34.0	78.3	(10.2)
Net Income attributable to Air Products	(7.0)	34.8	84.9	(7.4)
Reclassification out of Accumulated Other Comprehensive Income | Foreign currency translation adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Currency translation adjustment associated with business and asset actions	2.5	0.0	2.5	0.0
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	$ 11.0	$ 13.6	$ 22.0	$ 27.3