Consolidated Income Statements (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Sales	$ 2,216.6	$ 1,882.5
Cost of sales	1,571.8	1,316.7
Selling and administrative	191.6	164.7
Research and development	14.6	15.0
Business separation costs	0.0	32.5
Cost reduction and asset actions	0.0	50.0
Other income (expense), net	22.1	24.7
Operating Income	460.7	328.3
Equity affiliates' income	13.8	38.0
Interest expense	29.8	29.5
Other non-operating income (expense), net	9.8	(0.2)
Income From Continuing Operations Before Taxes	454.5	336.6
Income tax provision	291.8	78.4
Income From Continuing Operations	162.7	258.2
Income (Loss) From Discontinued Operations, net of tax	(1.0)	48.2
Net Income	161.7	306.4
Net Income Attributable to Noncontrolling Interests of Continuing Operations	7.1	6.6
Net Income Attributable to Air Products	154.6	299.8
Net Income Attributable to Air Products
Income from continuing operations	155.6	251.6
Income (Loss) from discontinued operations	(1.0)	48.2
Net Income Attributable to Air Products	$ 154.6	$ 299.8
Basic Earnings Per Common Share Attributable to Air Products
Income from continuing operations, basic (in dollars per share)	$ 0.71	$ 1.16
Income (Loss) from discontinued operations, basic (in dollars per share)	0	0.22
Net Income (Loss) Attributable to Air Products (in dollars per share)	0.71	1.38
Diluted Earnings Per Common Share Attributable to Air Products
Income from continuing operations, diluted (in dollars per share)	0.70	1.15
Income (Loss) from discontinued operations, diluted (in dollars per share)	0	0.22
Net Income (Loss) Attributable to Air Products (in dollars per share)	$ 0.70	$ 1.37
Weighted Average Common Shares - Basic (in millions)	218.9	217.7
Weighted Average Common Shares - Diluted (in millions)	220.4	219.7
Dividends Declared Per Common Share - Cash (in dollars per share)	$ 0.95	$ 0.86