Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income from continuing operations		$ 525.4	$ 446.5	$ 1,470.2	$ 1,414.2
Net income (loss) from discontinued operations		8.2	0.0	18.5	(14.3)
Net Income Attributable to Air Products		$ 533.6	$ 446.5	$ 1,488.7	$ 1,399.9
Weighted average common shares — Basic		221.6	221.2	221.6	221.1
Employee stock option and other award plans		0.9	1.2	0.9	1.2
Weighted average common shares — Diluted		222.5	222.4	222.5	222.3
Per Share Data
Basic EPS from continuing operations (in dollars per share)	[1]	$ 2.37	$ 2.02	$ 6.63	$ 6.40
Basic EPS from discontinued operations (in dollars per share)	[1]	0.04	0	0.08	(0.06)
Basic EPS Attributable to Air Products (in dollars per share)	[1]	2.41	2.02	6.72	6.33
Diluted EPS from continuing operations (in dollars per share)	[1]	2.36	2.01	6.61	6.36
Diluted EPS from discontinued operations (in dollars per share)	[1]	0.04	0	0.08	(0.06)
Diluted EPS Attributable to Air Products (in dollars per share)	[1]	$ 2.40	$ 2.01	$ 6.69	$ 6.30

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