Equity (Changes in Equity) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended				12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014		Mar. 31, 2013		Sep. 30, 2013
Schedule of Capitalization [Line Items]
Balance, beginning of period	$ 7,422.7		$ 6,451.2		$ 7,198.9		$ 6,623.3		$ 6,623.3
Net Income	290.8		297.5		588.6		582.6
Other comprehensive income (loss)	(71.2)		(134.5)		(18.6)		(30.0)
Dividends on common stock	(163.4)		(147.9)		(313.7)		(280.8)
Dividends to noncontrolling interests	(5.6)		(4.3)		(10.2)		(6.4)
Share-based compensation expense	11.6		12.3		23.4		22.4
Purchase of treasury shares	0		0		0		(461.6)		(461.6)
Issuance of treasury shares for stock option and award plans	34.7		34.7		47.9		49.5
Tax benefit of stock option and award plans	9.2		9.5		14.0		19.7
Purchase of noncontrolling interests	0		(0.3)		(0.5)		(0.3)
Other equity transactions	(1.0)		(0.8)		(2.0)		(1.0)
Balance, end of period	7,527.8		6,517.4		7,527.8		6,517.4		7,198.9
Air Products [Member]
Schedule of Capitalization [Line Items]
Balance, beginning of period	7,264.0		6,299.3		7,042.1		6,477.2		6,477.2
Net Income	283.5		290.4		573.7		568.7
Other comprehensive income (loss)	(67.7)		(131.7)		(14.0)		(28.3)
Dividends on common stock	(163.4)		(147.9)		(313.7)		(280.8)
Dividends to noncontrolling interests	0		0		0		0
Share-based compensation expense	11.6		12.3		23.4		22.4
Purchase of treasury shares	0		0		0		(461.6)
Issuance of treasury shares for stock option and award plans	34.7		34.7		47.9		49.5
Tax benefit of stock option and award plans	9.2		9.5		14.0		19.7
Purchase of noncontrolling interests	0		(0.3)		(0.5)		(0.3)
Other equity transactions	(1.0)		(0.8)		(2.0)		(1.0)
Balance, end of period	7,370.9		6,365.5		7,370.9		6,365.5
Noncontrolling Interests [Member]
Schedule of Capitalization [Line Items]
Balance, beginning of period	158.7		151.9		156.8		146.1		146.1
Net Income	7.3	[1]	7.1	[1]	14.9	[1]	13.9	[1]
Other comprehensive income (loss)	(3.5)		(2.8)		(4.6)		(1.7)
Dividends on common stock	0		0		0		0
Dividends to noncontrolling interests	(5.6)		(4.3)		(10.2)		(6.4)
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		0
Other equity transactions	0		0		0		0
Balance, end of period	$ 156.9		$ 151.9		$ 156.9		$ 151.9

[1] Net income attributable to noncontrolling interests excludes net income related to redeemable noncontrolling interests, which are not part of total equity. Refer to Note 14, Noncontrolling Interests, for additional information.