Consolidated Income Statements - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2016
Income Statement [Abstract]
Sales	$ 8,930.2		$ 8,187.6		$ 7,503.7
Cost of sales	6,189.5		5,751.5		5,177.3
Selling and administrative	760.8		713.5		683.8
Research and development	64.5		57.6		71.8
Business separation costs	0.0		32.5	[1]	50.6
Cost reduction and asset actions	0.0		151.4	[2]	34.5
Goodwill and intangible asset impairment charge	0.0		162.1	[3]	0.0
Other income (expense), net	50.2		121.0		49.4
Operating Income	1,965.6		1,440.0		1,535.1
Equity affiliates' income	174.8	[4]	80.1	[5]	147.0
Interest expense	130.5		120.6		115.2
Other non-operating income (expense), net	5.1		16.6		(5.4)
Loss on extinguishment of debt	0.0		0.0		6.9
Income From Continuing Operations Before Taxes	2,015.0		1,416.1		1,554.6
Income tax provision	524.3	[4],[6]	260.9	[7]	432.6
Income From Continuing Operations	1,490.7		1,155.2		1,122.0
Income (Loss) From Discontinued Operations, net of tax	42.2		1,866.0		(460.5)
Net Income	1,532.9		3,021.2	[8]	661.5
Net Income Attributable to Noncontrolling Interests of Continuing Operations	35.1		20.8		22.5
Net Income Attributable to Noncontrolling Interests of Discontinued Operations	0.0		0.0		7.9
Net Income Attributable to Air Products	1,497.8		3,000.4		631.1
Net Income Attributable to Air Products
Income from continuing operations	1,455.6		1,134.4		1,099.5
Income (Loss) from discontinued operations	42.2	[9]	1,866.0	[8]	(468.4)
Net Income Attributable to Air Products	$ 1,497.8		$ 3,000.4		$ 631.1
Basic Earnings Per Common Share Attributable to Air Products
Income from continuing operations (in dollars per share)	$ 6.64		$ 5.20		$ 5.08
Income (Loss) from discontinued operations (in dollars per share)	0.19		8.56		(2.16)
Net Income Attributable to Air Products (in dollars per share)	6.83		13.76		2.92
Diluted Earnings Per Common Share Attributable to Air Products
Income from continuing operations (in dollars per share)	6.59		5.16		5.04
Income (Loss) from discontinued operations (in dollars per share)	0.19		8.49		(2.15)
Net Income Attributable to Air Products (in dollars per share)	$ 6.78		$ 13.65		$ 2.89
Weighted Average Common Shares - Basic (in millions)	219.3		218.0		216.4
Weighted Average Common Shares - Diluted (in millions)	220.8		219.8		218.3

[1] For additional information, refer to Note 4, Materials Technologies Separation.

[2] For additional information, refer to Note 5, Cost Reduction and Asset Actions.

[3] For additional information, refer to Note 10, Goodwill, and Note 11, Intangible Assets.

[4] Includes the impacts of the Tax Act. For additional information, refer to Note 22, Income Taxes.

[5] Includes the impact of an other-than-temporary impairment of an investment in an equity affiliate. For additional information, refer to Note 8, Summarized Financial Information of Equity Affiliates.

[6] Includes the impacts of the restructuring of several foreign subsidiaries. For additional information, refer to Note 22, Income Taxes.

[7] Includes the impact of a tax election benefit related to a non-U.S. subsidiary. For additional information, see Note 22, Income Taxes.

[8] Includes the after-tax gain on the sale of PMD. For additional information, see Note 3, Discontinued Operations.

[9] Primarily includes benefits resulting from the resolution of uncertain tax positions related to the disposition of our former European Homecare business and post-closing adjustments associated with the sale of PMD. For additional information, refer to Note 3, Discontinued Operations.