Equity (Changes in Equity) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Balance, beginning of period		$ 7,381.1	$ 7,521.4
Net income		372.0	332.1
Other comprehensive income (loss)		(82.7)	(233.8)
Dividends on common stock		(174.7)	(165.4)
Dividends to noncontrolling interests		(8.5)	(6.2)
Share-based compensation expense		10.2	11.9
Treasury shares for stock option and award plans		(2.0)	30.1
Tax benefit of stock option and award plans		4.9	13.5
Other		(1.3)	(0.3)
Balance, end of period		7,499.0	7,503.3
Net income related to redeemable noncontrolling interests		0.0	5.4
Air Products Shareholders' Equity [Member]
Balance, beginning of period		7,249.0	7,365.8
Net income		363.6	324.6
Other comprehensive income (loss)		(82.7)	(228.7)
Dividends on common stock		(174.7)	(165.4)
Dividends to noncontrolling interests		0.0	0.0
Share-based compensation expense		10.2	11.9
Treasury shares for stock option and award plans		(2.0)	30.1
Tax benefit of stock option and award plans		4.9	13.5
Other		(1.2)	(0.3)
Balance, end of period		7,367.1	7,351.5
Noncontrolling Interests [Member]
Balance, beginning of period		132.1	155.6
Net income	[1]	8.4	7.5
Other comprehensive income (loss)		0.0	(5.1)
Dividends on common stock		0.0	0.0
Dividends to noncontrolling interests		(8.5)	(6.2)
Share-based compensation expense		0.0	0.0
Treasury shares for stock option and award plans		0.0	0.0
Tax benefit of stock option and award plans		0.0	0.0
Other		(0.1)	0.0
Balance, end of period		$ 131.9	$ 151.8

[1] Net income attributable to noncontrolling interests for the three months ended 31 December 2014 excludes net income of $5.4 related to redeemable noncontrolling interests, which were not part of total equity. There was no net income related to redeemable noncontrolling interests for the three months ended 31 December 2015.