Business Segment Information (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Segment Reporting Information [Line Items]
Sales		$ 2,985.5	$ 3,033.9	$ 8,913.1	$ 9,408.7
Operating income (loss)		737.6	644.2	2,041.7	1,756.0
Depreciation and amortization				1,070.3	1,001.0
Equity affiliates' income		168.9	165.0	470.6	440.9
Total Assets	[1]	36,974.3		36,974.3		$ 32,002.5
Operating Segments
Segment Reporting Information [Line Items]
Sales		2,985.5	3,033.9	8,913.1	9,408.7
Operating income (loss)		737.6	703.2	2,098.7	2,000.6
Depreciation and amortization		360.3	339.9	1,070.3	1,001.0
Equity affiliates' income		168.9	165.0	470.6	440.9
Total Assets		36,974.3		36,974.3		32,002.5
Americas | Operating Segments
Segment Reporting Information [Line Items]
Sales		1,234.7	1,260.7	3,732.6	4,018.0
Operating income (loss)		391.1	374.8	1,117.4	1,042.0
Depreciation and amortization		175.6	163.1	519.4	480.8
Equity affiliates' income		37.5	29.9	118.8	74.4
Total Assets		11,889.9		11,889.9		9,927.5
Asia | Operating Segments
Segment Reporting Information [Line Items]
Sales		789.6	822.9	2,363.1	2,414.6
Operating income (loss)		200.1	240.8	614.9	709.7
Depreciation and amortization		115.5	108.3	343.7	320.2
Equity affiliates' income		8.7	7.5	21.2	22.2
Total Assets		7,147.9		7,147.9		7,009.6
Europe | Operating Segments
Segment Reporting Information [Line Items]
Sales		693.4	706.6	2,092.5	2,251.4
Operating income (loss)		204.7	176.1	603.3	495.1
Depreciation and amortization		52.2	48.6	151.2	141.2
Equity affiliates' income		26.3	28.8	58.7	76.0
Total Assets		5,334.3		5,334.3		4,649.8
Middle East and India | Operating Segments
Segment Reporting Information [Line Items]
Sales		32.8	39.7	103.9	125.9
Operating income (loss)		(1.4)	5.8	8.1	13.8
Depreciation and amortization		6.8	7.0	20.1	20.2
Equity affiliates' income		89.2	95.5	256.0	258.5
Total Assets		7,629.9		7,629.9		5,708.4
Corporate and other | Operating Segments
Segment Reporting Information [Line Items]
Sales		235.0	204.0	621.0	598.8
Operating income (loss)		(56.9)	(94.3)	(245.0)	(260.0)
Depreciation and amortization		10.2	12.9	35.9	38.6
Equity affiliates' income		7.2	$ 3.3	15.9	$ 9.8
Total Assets		$ 4,972.3		$ 4,972.3		$ 4,707.2

[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 $3,916.8 and $2,256.8 as of 30 June 2024 and 30 September 2023, 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 $3,293.8 and $1,461.1 as of 30 June 2024 and 30 September 2023, respectively. Refer to Note 3, Variable Interest Entities, for additional information regarding the NEOM Green Hydrogen Company joint venture.