Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	$ (3,189.3)	$ (2,604.7)	$ (9,128.6)	$ (7,481.9)
Cost of sales	(2,342.1)	(1,801.9)	(6,717.3)	(5,179.8)
Interest expense	(32.7)	(35.6)	(95.5)	(108.4)
Other non-operating income (expense), net	(10.5)	(21.1)	(42.2)	(56.5)
Net Income Attributable to Air Products	(582.1)	(533.6)	(1,673.0)	(1,488.7)
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	0.0	0.5	0.2
Cost of sales	1.3	0.2	1.5	(1.1)
Interest expense	1.0	0.9	2.8	2.7
Other non-operating income (expense), net	9.1	(13.1)	51.3	20.9
Net Income Attributable to Air Products	11.4	(12.0)	56.1	22.7
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	$ 17.5	$ 18.7	$ 49.4	$ 55.3