Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net income from continuing operations		$ 471.7	$ 475.6
Net income from discontinued operations		10.3	0.0
Net Income Attributable to Air Products		$ 482.0	$ 475.6
Weighted average common shares — Basic		221.5	220.9
Employee stock option and other award plans		1.1	1.3
Weighted average common shares — Diluted		222.6	222.2
Per Share Data
Basic EPS from continuing operations (in dollars per share)	[1]	$ 2.13	$ 2.15
Basic EPS from discontinued operations (in dollars per share)	[1]	0.05	0
Basic EPS Attributable to Air Products (in dollars per share)	[1]	2.18	2.15
Diluted EPS from continuing operations (in dollars per share)	[1]	2.12	2.14
Diluted EPS from discontinued operations (in dollars per share)	[1]	0.05	0
Diluted EPS Attributable to Air Products (in dollars per share)	[1]	$ 2.17	$ 2.14

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