Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (3,174.7)	$ (2,994.2)
Cost of sales	2,272.3	2,223.6
Interest expense	41.2	30.5
Other non-operating income (expense), net	0.6	(22.6)
Net Income Attributable to Air Products	(572.2)	(560.4)
Reclassification out of Accumulated Other Comprehensive Income | (Gain) Loss on Cash Flow Hedges, net of tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	0.0	0.3
Cost of sales	1.0	(0.1)
Interest expense	1.0	0.9
Other non-operating income (expense), net	(70.7)	17.6
Net Income Attributable to Air Products	(68.7)	18.7
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	$ 11.9	$ 16.0