Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Net income from continuing operations		$ 560.4	$ 471.7
Net income from discontinued operations		0.0	10.3
Net Income Attributable to Air Products		$ 560.4	$ 482.0
Weighted average common shares — Basic		221.9	221.5
Employee stock option and other award plans		0.7	1.1
Weighted average common shares — Diluted		222.6	222.6
Per Share Data
Basic EPS from continuing operations (in dollars per share)	[1]	$ 2.53	$ 2.13
Basic EPS from discontinued operations (in dollars per share)	[1]	0	0.05
Basic EPS Attributable to Air Products (in dollars per share)	[1]	2.53	2.18
Diluted EPS from continuing operations (in dollars per share)	[1]	2.52	2.12
Diluted EPS from discontinued operations (in dollars per share)	[1]	0	0.05
Diluted EPS Attributable to Air Products (in dollars per share)	[1]	$ 2.52	$ 2.17

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