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, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net income from continuing operations		$ 492.1	$ 421.3	$ 967.7	$ 768.8
Net loss from discontinued operations		(14.3)	0.0	(14.3)	0.0
Net Income Attributable to Air Products		$ 477.8	$ 421.3	$ 953.4	$ 768.8
Weighted average common shares — Basic		221.2	220.2	221.0	220.0
Employee stock option and other award plans		1.1	1.2	1.2	1.2
Weighted average common shares — Diluted		222.3	221.4	222.2	221.2
Basic earnings per share from continuing operations (in dollars per share)	[1]	$ 2.22	$ 1.91	$ 4.38	$ 3.49
Basic earnings per share from discontinued operations (in dollars per share)	[1]	(0.06)	0	(0.06)	0
Basic Earnings Per Common Share Attributable to Air Products (in dollars per share)	[1]	2.16	1.91	4.31	3.49
Diluted earnings per share from continuing operations (in dollars per share)	[1]	2.21	1.90	4.36	3.48
Diluted earnings per share from discontinued operations (in dollars per share)	[1]	(0.06)	0	(0.06)	0
Diluted Earnings Per Common Share Attributable to Air Products (in dollars per share)	[1]	$ 2.15	$ 1.90	$ 4.29	$ 3.48

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