Consolidated Income Statements - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Sales		$ 8,856.3	$ 8,918.9	$ 8,930.2
Cost of sales		5,858.1	5,975.5	6,189.5
Facility closure		0.0	29.0	0.0
Selling and administrative		775.9	750.0	760.8
Research and development		83.9	72.9	64.5
Cost reduction actions		0.0	25.5	0.0
Gain on exchange of equity affiliate investments		0.0	29.1	0.0
Company headquarters relocation income (expense)		33.8	0.0	0.0
Other income (expense), net		65.4	49.3	50.2
Operating Income		2,237.6	2,144.4	1,965.6
Equity affiliates' income		264.8	215.4	174.8
Interest expense		109.3	137.0	130.5
Other non-operating income (expense), net		30.7	66.7	5.1
Income From Continuing Operations Before Taxes		2,423.8	2,289.5	2,015.0
Income tax provision		478.4	480.1	524.3
Income From Continuing Operations		1,945.4	1,809.4	1,490.7
(Loss) Income from discontinued operations, net of tax		(14.3)	0.0	42.2
Net Income		1,931.1	1,809.4	1,532.9
Net income attributable to noncontrolling interests of continuing operations		44.4	49.4	35.1
Net Income Attributable to Air Products		1,886.7	1,760.0	1,497.8
Net Income Attributable to Air Products
Net income from continuing operations		1,901.0	1,760.0	1,455.6
Net (loss) income from discontinued operations		(14.3)	0.0	42.2
Net Income Attributable to Air Products		$ 1,886.7	$ 1,760.0	$ 1,497.8
Per Share Data
Basic EPS from continuing operations (in dollars per share)	[1]	$ 8.59	$ 7.99	$ 6.64
Basic EPS from discontinued operations (in dollars per share)	[1]	(0.06)	0	0.19
Basic EPS Attributable to Air Products (in dollars per share)	[1]	8.53	7.99	6.83
Diluted EPS from continuing operations (in dollars per share)	[1]	8.55	7.94	6.59
Diluted EPS from discontinued operations (in dollars per share)	[1]	(0.06)	0	0.19
Diluted EPS Attributable to Air Products (in dollars per share)	[1]	$ 8.49	$ 7.94	$ 6.78
Weighted Average Common Shares (in millions)
Basic		221.2	220.3	219.3
Diluted		222.3	221.6	220.8

[1] Earnings per share ("EPS") is calculated independently for each component and may not sum to total EPS due to rounding.