Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 14,517.4	$ 14,375.6	$ 13,702.4	$ 14,088.0
Other comprehensive (loss) income before reclassifications	36.4		673.7
Amounts reclassified from AOCL	19.9		(36.9)
Total Other Comprehensive Income (Loss)	56.3	(56.3)	636.8	18.5
Amount attributable to noncontrolling interests	1.3	(3.0)	14.0	8.2
Ending balance	14,690.2	14,510.7	14,690.2	14,510.7
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(19.0)		(71.9)
Other comprehensive (loss) income before reclassifications	(14.6)		106.4
Amounts reclassified from AOCL	5.8		(62.9)
Total Other Comprehensive Income (Loss)	(8.8)		43.5
Amount attributable to noncontrolling interests	(1.3)		(1.9)
Ending balance	(26.5)		(26.5)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,576.0)		(2,072.4)
Other comprehensive (loss) income before reclassifications	51.0		560.6
Amounts reclassified from AOCL	(0.3)		(0.3)
Total Other Comprehensive Income (Loss)	50.7		560.3
Amount attributable to noncontrolling interests	2.6		15.8
Ending balance	(1,527.9)		(1,527.9)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(623.3)		(641.8)
Other comprehensive (loss) income before reclassifications	0.0		6.7
Amounts reclassified from AOCL	14.4		26.3
Total Other Comprehensive Income (Loss)	14.4		33.0
Amount attributable to noncontrolling interests	0.0		0.1
Ending balance	(608.9)		(608.9)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,218.3)	(1,452.3)	(2,786.1)	(1,515.9)
Total Other Comprehensive Income (Loss)	55.0	(53.3)	622.8	10.3
Ending balance	$ (2,163.3)	$ (1,505.6)	$ (2,163.3)	$ (1,505.6)