Business and Asset Actions (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		13 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026
Restructuring Cost and Reserve [Line Items]
Business and asset actions, including equity affiliate income		$ 2,900.0		$ 2,900.0
Business and asset actions, including equity affiliate income, attributable to Air Products after tax		2,300.0		2,300.0
Business and asset actions, attributable to noncontrolling interest		3.5		3.5
Project Exit Costs
Restructuring Cost and Reserve [Line Items]
Project exit costs	$ 0.0		$ 28.3		$ 3,600.0
Business and asset actions, total pre-tax charge			28.3
Business and asset actions, attributable to Air Products after tax			24.6
Project Exit Costs | Operating income
Restructuring Cost and Reserve [Line Items]
Project exit costs			22.0
Project Exit Costs | Other non‑operating income (expense), net
Restructuring Cost and Reserve [Line Items]
Project exit costs			$ 6.3
Project Exit Costs | Income (Loss) from Equity Method Investments
Restructuring Cost and Reserve [Line Items]
Project exit costs		$ 6.8		$ 6.8