Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ 18,673.7	$ 15,660.3
Other comprehensive income (loss) before reclassifications		(558.3)
Amounts reclassified from AOCL		102.9
Net current period other comprehensive income (loss)		(455.4)	191.0
Amount attributable to noncontrolling interests		103.1	(138.1)
Ending balance		18,738.7	16,129.1
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		27.2
Other comprehensive income (loss) before reclassifications		65.7
Amounts reclassified from AOCL		91.9
Net current period other comprehensive income (loss)		157.6
Amount attributable to noncontrolling interests		119.6
Ending balance		65.2
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(1,545.3)
Other comprehensive income (loss) before reclassifications		(624.0)
Amounts reclassified from AOCL		0.0
Net current period other comprehensive income (loss)		(624.0)
Amount attributable to noncontrolling interests		(16.5)
Ending balance		(2,152.8)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(509.6)
Other comprehensive income (loss) before reclassifications		0.0
Amounts reclassified from AOCL		11.0
Net current period other comprehensive income (loss)		11.0
Amount attributable to noncontrolling interests		0.0
Ending balance		(498.6)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	[1]	(2,027.7)	(2,449.4)
Net current period other comprehensive income (loss)	[1]	(558.5)	329.1
Ending balance	[1]	$ (2,586.2)	$ (2,120.3)

[1] (A)Accumulated other comprehensive loss