Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Mar. 31, 2025		Mar. 31, 2024		Mar. 31, 2025		Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ 18,738.7		$ 16,129.1		$ 18,673.7		$ 15,660.3
Other comprehensive income (loss) before reclassifications		57.3				(501.0)
Amounts reclassified from AOCL		6.5				109.4
Net current period other comprehensive income (loss)		63.8		(93.1)		(391.6)		97.9
Amount attributable to noncontrolling interests		(44.7)		62.5		58.4		(75.6)
Ending balance		16,779.6		16,334.9		16,779.6		16,334.9
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		65.2				27.2
Other comprehensive income (loss) before reclassifications		(45.0)				20.7
Amounts reclassified from AOCL		(7.0)				84.9
Net current period other comprehensive income (loss)		(52.0)				105.6
Amount attributable to noncontrolling interests		(43.9)				75.7
Ending balance		57.1				57.1
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(2,152.8)				(1,545.3)
Other comprehensive income (loss) before reclassifications		102.3				(521.7)
Amounts reclassified from AOCL		2.5				2.5
Net current period other comprehensive income (loss)		104.8				(519.2)
Amount attributable to noncontrolling interests		(0.8)				(17.3)
Ending balance		(2,047.2)				(2,047.2)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(498.6)				(509.6)
Other comprehensive income (loss) before reclassifications		0.0				0.0
Amounts reclassified from AOCL		11.0				22.0
Net current period other comprehensive income (loss)		11.0				22.0
Amount attributable to noncontrolling interests		0.0				0.0
Ending balance		(487.6)				(487.6)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(2,586.2)	[1]	(2,120.3)	[1]	(2,027.7)	[2]	(2,449.4)	[2]
Net current period other comprehensive income (loss)		108.5	[1]	(155.6)	[1]	(450.0)	[2]	173.5	[2]
Ending balance	[1],[2]	$ (2,477.7)		$ (2,275.9)		$ (2,477.7)		$ (2,275.9)

[1] Accumulated other comprehensive loss

[2] (A)Accumulated other comprehensive loss