Business Segment Information (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Segment Reporting Information [Line Items]
Sales		$ 3,033.9	$ 3,189.3	$ 9,408.7	$ 9,128.6
Operating income (loss)		644.2	627.4	1,756.0	1,712.3
Depreciation and amortization				1,001.0	1,005.4
Equity affiliates' income		165.0	116.1	440.9	384.7
Total Assets	[1]	30,929.5		30,929.5		$ 27,192.6
Segment Total
Segment Reporting Information [Line Items]
Sales		3,033.9	3,189.3	9,408.7	9,128.6
Operating income (loss)		703.2	627.4	2,000.6	1,712.3
Depreciation and amortization		339.9	337.2	1,001.0	1,005.4
Equity affiliates' income		165.0	116.1	440.9	384.7
Total Assets		30,929.5		30,929.5		27,192.6
Americas | Segment Total
Segment Reporting Information [Line Items]
Sales		1,260.7	1,416.3	4,018.0	3,827.0
Operating income (loss)		374.8	298.9	1,042.0	841.6
Depreciation and amortization		163.1	160.5	480.8	469.5
Equity affiliates' income		29.9	21.4	74.4	75.7
Total Assets		9,547.9		9,547.9		8,237.7
Asia | Segment Total
Segment Reporting Information [Line Items]
Sales		822.9	751.4	2,414.6	2,283.0
Operating income (loss)		240.8	210.6	709.7	635.3
Depreciation and amortization		108.3	107.6	320.2	330.2
Equity affiliates' income		7.5	5.7	22.2	18.5
Total Assets		7,216.5		7,216.5		6,968.7
Europe | Segment Total
Segment Reporting Information [Line Items]
Sales		706.6	739.6	2,251.4	2,222.4
Operating income (loss)		176.1	137.4	495.1	353.0
Depreciation and amortization		48.6	48.9	141.2	149.0
Equity affiliates' income		28.8	20.6	76.0	57.8
Total Assets		4,597.0		4,597.0		3,645.1
Middle East and India | Segment Total
Segment Reporting Information [Line Items]
Sales		39.7	35.4	125.9	88.0
Operating income (loss)		5.8	6.9	13.8	16.5
Depreciation and amortization		7.0	6.8	20.2	19.8
Equity affiliates' income		95.5	67.2	258.5	230.6
Total Assets		5,182.2		5,182.2		2,980.7
Corporate and other | Segment Total
Segment Reporting Information [Line Items]
Sales		204.0	246.6	598.8	708.2
Operating income (loss)		(94.3)	(26.4)	(260.0)	(134.1)
Depreciation and amortization		12.9	13.4	38.6	36.9
Equity affiliates' income		3.3	$ 1.2	9.8	$ 2.1
Total Assets		$ 4,385.9		$ 4,385.9		$ 5,360.4

[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 $1,621.2 and $519.7 as of 30 June 2023 and 30 September 2022, 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 $496.6 and $506.8 as of 30 June 2023 and 30 September 2022, respectively. Refer to Note 3, Variable Interest Entities, for additional information.