Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Jun. 30, 2025		Jun. 30, 2024		Jun. 30, 2025		Jun. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ 16,779.6		$ 16,334.9		$ 18,673.7		$ 15,660.3
Other comprehensive income before reclassifications		569.3				68.3
Amounts reclassified from AOCL		(37.4)				72.0
Net current period other comprehensive income (loss)		531.9		(97.4)		140.3		0.5
Amount attributable to noncontrolling interests		24.0		17.8		82.4		(57.8)
Ending balance		17,768.0		16,687.0		17,768.0		16,687.0
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		57.1				27.2
Other comprehensive income before reclassifications		40.9				61.6
Amounts reclassified from AOCL		(52.2)				32.7
Net current period other comprehensive income (loss)		(11.3)				94.3
Amount attributable to noncontrolling interests		(7.7)				68.0
Ending balance		53.5				53.5
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(2,047.2)				(1,545.3)
Other comprehensive income before reclassifications		528.4				6.7
Amounts reclassified from AOCL		3.3				5.8
Net current period other comprehensive income (loss)		531.7				12.5
Amount attributable to noncontrolling interests		31.7				14.4
Ending balance		(1,547.2)				(1,547.2)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(487.6)				(509.6)
Other comprehensive income before reclassifications		0.0				0.0
Amounts reclassified from AOCL		11.5				33.5
Net current period other comprehensive income (loss)		11.5				33.5
Amount attributable to noncontrolling interests		0.0				0.0
Ending balance		(476.1)				(476.1)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(2,477.7)	[1]	(2,275.9)	[1]	(2,027.7)	[2]	(2,449.4)	[2]
Net current period other comprehensive income (loss)		507.9	[1]	(115.2)	[1]	57.9	[2]	58.3	[2]
Ending balance	[1],[2]	$ (1,969.8)		$ (2,391.1)		$ (1,969.8)		$ (2,391.1)

[1] Accumulated other comprehensive loss

[2] (A)Accumulated other comprehensive loss