Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 13,702.4	$ 14,088.0
Other comprehensive income before reclassifications	637.3
Amounts reclassified from AOCL	(56.8)
Total Other Comprehensive Income (Loss)	580.5	74.8
Amount attributable to noncontrolling interests	12.7	11.2
Ending balance	14,517.4	14,375.6
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(71.9)
Other comprehensive income before reclassifications	121.0
Amounts reclassified from AOCL	(68.7)
Total Other Comprehensive Income (Loss)	52.3
Amount attributable to noncontrolling interests	(0.6)
Ending balance	(19.0)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,072.4)
Other comprehensive income before reclassifications	509.6
Amounts reclassified from AOCL	0.0
Total Other Comprehensive Income (Loss)	509.6
Amount attributable to noncontrolling interests	13.2
Ending balance	(1,576.0)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(641.8)
Other comprehensive income before reclassifications	6.7
Amounts reclassified from AOCL	11.9
Total Other Comprehensive Income (Loss)	18.6
Amount attributable to noncontrolling interests	0.1
Ending balance	(623.3)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,786.1)	(1,515.9)
Total Other Comprehensive Income (Loss)	567.8	63.6
Ending balance	$ (2,218.3)	$ (1,452.3)