Business Segment Information (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Sep. 30, 2024
Segment Reporting Information [Line Items]
Sales		$ 2,931.5	$ 2,997.4
Operating income (loss)		643.6	666.9
Depreciation and amortization		366.8	349.2
Equity affiliates' income		150.6	158.4
Total Assets	[1]	40,017.2		$ 39,574.6
Operating Segments
Segment Reporting Information [Line Items]
Sales		2,931.5	2,997.4
Operating income (loss)		673.5	666.9
Depreciation and amortization		366.8	349.2
Equity affiliates' income		150.6	158.4
Total Assets		40,017.2		39,574.6
Americas | Operating Segments
Segment Reporting Information [Line Items]
Sales		1,287.6	1,252.1
Operating income (loss)		388.2	354.4
Depreciation and amortization		173.4	169.7
Equity affiliates' income		35.1	37.1
Total Assets		12,796.2		12,383.8
Asia | Operating Segments
Segment Reporting Information [Line Items]
Sales		817.1	793.8
Operating income (loss)		216.4	211.2
Depreciation and amortization		122.9	111.8
Equity affiliates' income		10.3	4.2
Total Assets		7,153.1		7,436.5
Europe | Operating Segments
Segment Reporting Information [Line Items]
Sales		697.2	731.2
Operating income (loss)		186.5	197.6
Depreciation and amortization		54.5	48.2
Equity affiliates' income		18.2	20.7
Total Assets		5,760.9		5,849.2
Middle East and India | Operating Segments
Segment Reporting Information [Line Items]
Sales		32.8	35.4
Operating income (loss)		(0.6)	3.9
Depreciation and amortization		6.5	6.6
Equity affiliates' income		85.0	92.9
Total Assets		9,586.0		8,477.4
Corporate and other | Operating Segments
Segment Reporting Information [Line Items]
Sales		96.8	184.9
Operating income (loss)		(117.0)	(100.2)
Depreciation and amortization		9.5	12.9
Equity affiliates' income		2.0	$ 3.5
Total Assets		$ 4,721.0		$ 5,427.7

[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 $5,692.4 and $4,393.9 as of 31 December 2024 and 30 September 2024, 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 $3,994.1 and $3,473.4 as of 31 December 2024 and 30 September 2024, respectively. Refer to Note 3, Variable Interest Entities, for additional information regarding the NEOM Green Hydrogen Company joint venture.