Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2025	Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ 17,349.8	$ 18,673.7
Other comprehensive income before reclassifications		109.0
Amounts reclassified from AOCL		25.9
Total Other Comprehensive Income (Loss)		134.9	(455.4)
Amount attributable to noncontrolling interests		24.2	103.1
Ending balance		17,837.1	18,738.7
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		49.3
Other comprehensive income before reclassifications		35.5
Amounts reclassified from AOCL		16.6
Total Other Comprehensive Income (Loss)		52.1
Amount attributable to noncontrolling interests		27.3
Ending balance		74.1
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(1,640.7)
Other comprehensive income before reclassifications		73.5
Amounts reclassified from AOCL		0.0
Total Other Comprehensive Income (Loss)		73.5
Amount attributable to noncontrolling interests		(3.0)
Ending balance		(1,564.2)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(496.4)
Other comprehensive income before reclassifications		0.0
Amounts reclassified from AOCL		9.3
Total Other Comprehensive Income (Loss)		9.3
Amount attributable to noncontrolling interests		(0.1)
Ending balance		(487.0)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	[1]	(2,087.8)	(2,027.7)
Total Other Comprehensive Income (Loss)	[1]	110.7	(558.5)
Ending balance	[1]	$ (1,977.1)	$ (2,586.2)

[1] (A)Accumulated other comprehensive loss.