Equity (Changes in Equity) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2013		Mar. 31, 2012
Schedule of Capitalization [Line Items]
Balance, beginning of period	$ 6,451.2		$ 6,057.1		$ 6,623.3		$ 5,938.7
Net Income	297.5		302.2		582.6		558.5
Other comprehensive income (loss)	(134.5)		150.9		(30.0)		129.4
Dividends on common stock	(147.9)		(135.3)		(280.8)		(257.5)
Dividends to noncontrolling interests	(4.3)		(13.0)		(6.4)		(13.0)
Share-based compensation expense	12.3		15.2		22.4		27.0
Purchase of treasury shares	0		(53.1)		(461.6)		(53.1)
Issuance of treasury shares for stock option and award plans	34.7		64.1		49.5		61.8
Tax benefit of stock option and award plans	9.5		21.2		19.7		25.4
Purchase of noncontrolling interests	(0.3)		0		(0.3)		(6.3)
Other equity transactions	(0.8)		(1.9)		(1.0)		(3.5)
Balance, end of period	6,517.4		6,407.4		6,517.4		6,407.4
Air Products [Member]
Schedule of Capitalization [Line Items]
Balance, beginning of period	6,299.3		5,909.0		6,477.2		5,795.8
Net Income	290.4		296.0		568.7		544.1
Other comprehensive income (loss)	(131.7)		147.5		(28.3)		125.3
Dividends on common stock	(147.9)		(135.3)		(280.8)		(257.5)
Dividends to noncontrolling interests	0		0		0		0
Share-based compensation expense	12.3		15.2		22.4		27.0
Purchase of treasury shares	0		(53.1)		(461.6)		(53.1)
Issuance of treasury shares for stock option and award plans	34.7		64.1		49.5		61.8
Tax benefit of stock option and award plans	9.5		21.2		19.7		25.4
Purchase of noncontrolling interests	(0.3)		0		(0.3)		(4.4)
Other equity transactions	(0.8)		(1.9)		(1.0)		(1.7)
Balance, end of period	6,365.5		6,262.7		6,365.5		6,262.7
Noncontrolling Interests [Member]
Schedule of Capitalization [Line Items]
Balance, beginning of period	151.9		148.1		146.1		142.9
Net Income	7.1	[1]	6.2	[1]	13.9	[1]	14.4	[1]
Other comprehensive income (loss)	(2.8)		3.4		(1.7)		4.1
Dividends on common stock	0		0		0		0
Dividends to noncontrolling interests	(4.3)		(13.0)		(6.4)		(13.0)
Share-based compensation expense	0		0		0		0
Purchase of treasury shares	0		0		0		0
Issuance of treasury shares for stock option and award plans	0		0		0		0
Tax benefit of stock option and award plans	0		0		0		0
Purchase of noncontrolling interests	0		0		0		(1.9)
Other equity transactions	0		0		0		(1.8)
Balance, end of period	$ 151.9		$ 144.7		$ 151.9		$ 144.7

[1] Net income attributable to noncontrolling interests for the three and six months ended 31 March 2013 excludes net income of $2.1 and $4.2, respectively, related to redeemable noncontrolling interests, which are not part of total equity. There were no redeemable noncontrolling interests recorded at 31 March 2012. Refer to Note 14, Noncontrolling Interests, for additional information.