Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales		$ (12,698.6)	$ (10,323.0)	$ (8,856.3)
Cost of sales		(9,338.5)	(7,186.1)	(5,858.1)
Interest expense		(128.0)	(141.8)	(109.3)
Other non-operating income (expense), net		(62.4)	(73.7)	(30.7)
Business and asset actions	$ (73.7)	(73.7)	0.0	0.0
Income from discontinued operations, net of tax		(12.6)	(70.3)	14.3
Net income (loss) attributable to Air Products		(2,256.1)	(2,099.1)	(1,886.7)
Reclassification out of Accumulated Other Comprehensive Income | (Gain) Loss on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales		0.5	(0.6)	(0.2)
Cost of sales		(0.4)	(0.3)	(0.8)
Interest expense		3.6	3.5	2.8
Other non-operating income (expense), net		87.7	40.9	(59.5)
Net income (loss) attributable to Air Products		91.4	43.5	(57.7)
Reclassification out of Accumulated Other Comprehensive Income | Currency Translation Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Business and asset actions		5.1	0.0	0.0
Income from discontinued operations, net of tax		2.2	0.0	0.0
Net income (loss) attributable to Air Products		7.3	0.0	0.0
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss) attributable to Air Products		$ 64.8	$ 74.6	$ 82.5