Business Segment Information (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Segment Reporting Information [Line Items]
Sales		$ 2,997.4	$ 3,174.7
Operating income (loss)		666.9	652.0
Depreciation and amortization		349.2	321.5
Equity affiliates' income		158.4	110.0
Total Assets	[1]	34,118.2		$ 32,002.5
Operating Segments
Segment Reporting Information [Line Items]
Sales		2,997.4	3,174.7
Operating income (loss)		666.9	652.0
Depreciation and amortization		349.2	321.5
Equity affiliates' income		158.4	110.0
Total Assets		34,118.2		32,002.5
Americas | Operating Segments
Segment Reporting Information [Line Items]
Sales		1,252.1	1,384.2
Operating income (loss)		354.4	343.0
Depreciation and amortization		169.7	156.0
Equity affiliates' income		37.1	16.4
Total Assets		10,666.2		9,927.5
Asia | Operating Segments
Segment Reporting Information [Line Items]
Sales		793.8	777.8
Operating income (loss)		211.2	235.9
Depreciation and amortization		111.8	101.9
Equity affiliates' income		4.2	7.4
Total Assets		7,318.0		7,009.6
Europe | Operating Segments
Segment Reporting Information [Line Items]
Sales		731.2	791.9
Operating income (loss)		197.6	145.8
Depreciation and amortization		48.2	44.3
Equity affiliates' income		20.7	17.7
Total Assets		5,120.9		4,649.8
Middle East and India | Operating Segments
Segment Reporting Information [Line Items]
Sales		35.4	41.4
Operating income (loss)		3.9	6.7
Depreciation and amortization		6.6	6.6
Equity affiliates' income		92.9	64.1
Total Assets		6,214.1		5,708.4
Corporate and other | Operating Segments
Segment Reporting Information [Line Items]
Sales		184.9	179.4
Operating income (loss)		(100.2)	(79.4)
Depreciation and amortization		12.9	12.7
Equity affiliates' income		3.5	$ 4.4
Total Assets		$ 4,799.0		$ 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 $2,751.8 and $2,256.8 as of 31 December 2023 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 $2,166.1 and $1,461.1 as of 31 December 2023 and 30 September 2023, respectively. Refer to Note 3, Variable Interest Entities, for additional information regarding the NEOM Green Hydrogen Company joint venture.