Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income from continuing operations		$ 473.1	$ 492.1	$ 944.8	$ 967.7
Net income (loss) from discontinued operations		0.0	(14.3)	10.3	(14.3)
Net Income Attributable to Air Products		$ 473.1	$ 477.8	$ 955.1	$ 953.4
Weighted average common shares — Basic		221.6	221.2	221.6	221.0
Employee stock option and other award plans		0.9	1.1	0.9	1.2
Weighted average common shares — Diluted		222.5	222.3	222.5	222.2
Per Share Data
Basic EPS from continuing operations (in dollars per share)	[1]	$ 2.13	$ 2.22	$ 4.26	$ 4.38
Basic EPS from discontinued operations (in dollars per share)	[1]	0	(0.06)	0.05	(0.06)
Basic EPS Attributable to Air Products (in dollars per share)	[1]	2.13	2.16	4.31	4.31
Diluted EPS from continuing operations (in dollars per share)	[1]	2.13	2.21	4.25	4.36
Diluted EPS from discontinued operations (in dollars per share)	[1]	0	(0.06)	0.05	(0.06)
Diluted EPS Attributable to Air Products (in dollars per share)	[1]	$ 2.13	$ 2.15	$ 4.29	$ 4.29

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