Business Segment Information (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2025
Segment Reporting Information [Line Items]
Sales		$ 3,102.5	$ 2,931.5
Cost of sales		(2,107.5)	(2,016.5)
Selling and administrative expense		(228.7)	(242.4)
Operating income (loss)		734.5	643.6
Depreciation and amortization		370.7	366.8
Equity affiliates' income		172.2	150.6
Investment in net assets of and advances to equity affiliates		5,440.1		$ 5,366.1
Total assets	[1]	41,240.7		41,059.5
Operating Segments
Segment Reporting Information [Line Items]
Sales		3,102.5	2,931.5
Cost of sales		(2,107.5)	(2,016.5)
Selling and administrative expense		(228.7)	(242.4)
Other segment items		(9.8)	0.9
Operating income (loss)		756.5	673.5
Depreciation and amortization		370.7	366.8
Equity affiliates' income		172.2	150.6
Expenditures for long-lived assets		1,251.2	2,117.6
Investment in net assets of and advances to equity affiliates		5,440.1		5,366.1
Total assets		41,240.7		41,059.5
Americas | Operating Segments
Segment Reporting Information [Line Items]
Sales		1,341.7	1,287.6
Cost of sales		(886.6)	(855.1)
Selling and administrative expense		(55.2)	(54.4)
Other segment items		3.9	10.1
Operating income (loss)		403.8	388.2
Depreciation and amortization		171.9	173.4
Equity affiliates' income		51.7	35.1
Expenditures for long-lived assets		503.7	690.7
Investment in net assets of and advances to equity affiliates		600.3		555.2
Total assets		12,447.2		12,058.7
Asia | Operating Segments
Segment Reporting Information [Line Items]
Sales		831.5	817.1
Cost of sales		(573.2)	(572.1)
Selling and administrative expense		(28.0)	(31.5)
Other segment items		2.0	2.9
Operating income (loss)		232.3	216.4
Depreciation and amortization		112.7	122.9
Equity affiliates' income		13.8	10.3
Expenditures for long-lived assets		103.6	99.9
Investment in net assets of and advances to equity affiliates		338.8		331.3
Total assets		6,766.2		6,712.2
Europe | Operating Segments
Segment Reporting Information [Line Items]
Sales		782.0	697.2
Cost of sales		(491.7)	(449.4)
Selling and administrative expense		(67.0)	(61.9)
Other segment items		0.2	0.6
Operating income (loss)		223.5	186.5
Depreciation and amortization		69.8	54.5
Equity affiliates' income		23.4	18.2
Expenditures for long-lived assets		209.1	230.6
Investment in net assets of and advances to equity affiliates		671.6		649.9
Total assets		7,086.5		6,916.8
Middle East and India | Operating Segments
Segment Reporting Information [Line Items]
Sales		30.3	32.8
Cost of sales		(19.9)	(25.7)
Selling and administrative expense		(5.0)	(7.8)
Other segment items		0.4	0.1
Operating income (loss)		5.8	(0.6)
Depreciation and amortization		6.2	6.5
Equity affiliates' income		84.5	85.0
Expenditures for long-lived assets		405.3	1,040.4
Investment in net assets of and advances to equity affiliates		3,714.6		3,713.2
Total assets		11,313.5		10,919.4
Corporate and other | Operating Segments
Segment Reporting Information [Line Items]
Sales		117.0	96.8
Cost of sales		(136.1)	(114.2)
Selling and administrative expense		(73.5)	(86.8)
Other segment items		(16.3)	(12.8)
Operating income (loss)		(108.9)	(117.0)
Depreciation and amortization		10.1	9.5
Equity affiliates' income		(1.2)	2.0
Expenditures for long-lived assets		29.5	$ 56.0
Investment in net assets of and advances to equity affiliates		114.8		116.5
Total assets		$ 3,627.3		$ 4,452.4

[1] Includes balances associated with a consolidated variable interest entity ("VIE"), including amounts reflected in "Total Assets" that can only be used to settle obligations of the VIE of $7,684.6 and $7,134.7 as of 31 December 2025 and 30 September 2025, respectively, as well as liabilities of the VIE reflected within "Total Liabilities" for which creditors do not have recourse to the general credit of Air Products of $5,304.8 and $4,937.7 as of 31 December 2025 and 30 September 2025, respectively. Refer to Note 3, Variable Interest Entities, for additional information regarding the NEOM Green Hydrogen Company joint venture.