Equity (Changes in Equity) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Schedule of Capitalization, Equity [Line Items]
Balance, beginning of period	$ 6,407.4	$ 5,999.2	$ 5,938.7	$ 5,697.6
Net Income	492.5	335.0	1,051.0	922.4
Translation adjustments	(150.6)	103.0	(54.9)	267.4
Net gain (loss) on derivatives	(3.7)	5.3	(14.1)	7.7
Unrealized holding gain (loss) on available-for-sale securities	0	0	0	(4.6)
Pension and postretirement benefits	0	0	0	0
Reclassification Adjustments [Abstract]
Currency translation adjustment	13.3	0	13.3	0
Derivatives	(2.2)	(4.9)	9.8	0.5
Available-for-sale securities	0	0	0	(16.1)
Pension and postretirement benefits	16.1	16.8	48.2	50.4
Total Other Comprehensive Income (Loss)	(127.1)	120.2	2.3	305.3
Comprehensive Income	365.4	455.2	1,053.3	1,227.7
Dividends on common stock	(135.5)	(123.5)	(393.0)	(351.7)
Dividends to noncontrolling interests	(3.1)	(2.2)	(16.1)	(2.7)
Share-based compensation expense	8.8	11.2	35.8	33.1
Purchase of treasury shares	0	0	(53.1)	(350.0)
Issuance of treasury shares for stock option and award plans	15.1	52.1	76.9	117.1
Tax benefit of stock option and award plans	2.6	24.5	28.0	52.3
Purchase of noncontrolling interests	0	0	(6.3)	(6.1)
Contribution from noncontrolling interests	0	0	0	1.4
Other equity transactions	(13.3)	(19.5)	(16.8)	(21.7)
Balance, end of period	6,647.4	6,397.0	6,647.4	6,397.0
Air Products [Member]
Schedule of Capitalization, Equity [Line Items]
Balance, beginning of period	6,262.7	5,825.2	5,795.8	5,546.9
Net Income	484.5	326.5	1,028.6	899.4
Translation adjustments	(149.0)	99.3	(57.6)	255.7
Net gain (loss) on derivatives	(3.9)	5.6	(14.1)	8.1
Unrealized holding gain (loss) on available-for-sale securities	0	0	0	(4.6)
Pension and postretirement benefits	0	0	0	0
Reclassification Adjustments [Abstract]
Currency translation adjustment	13.3	0	13.3	0
Derivatives	(2.2)	(4.9)	9.8	0.5
Available-for-sale securities	0	0	0	(16.1)
Pension and postretirement benefits	16.1	16.8	48.2	50.4
Total Other Comprehensive Income (Loss)	(125.7)	116.8	(0.4)	294.0
Comprehensive Income	358.8	443.3	1,028.2	1,193.4
Dividends on common stock	(135.5)	(123.5)	(393.0)	(351.7)
Dividends to noncontrolling interests	0	0	0	0
Share-based compensation expense	8.8	11.2	35.8	33.1
Purchase of treasury shares	0	0	(53.1)	(350.0)
Issuance of treasury shares for stock option and award plans	15.1	52.1	76.9	117.1
Tax benefit of stock option and award plans	2.6	24.5	28.0	52.3
Purchase of noncontrolling interests	0	0	(4.4)	(6.1)
Contribution from noncontrolling interests	0	0	0	0
Other equity transactions	1.1	(0.6)	(0.6)	(2.8)
Balance, end of period	6,513.6	6,232.2	6,513.6	6,232.2
Noncontrolling Interests [Member]
Schedule of Capitalization, Equity [Line Items]
Balance, beginning of period	144.7	174.0	142.9	150.7
Net Income	8.0	8.5	22.4	23.0
Translation adjustments	(1.6)	3.7	2.7	11.7
Net gain (loss) on derivatives	0.2	(0.3)	0	(0.4)
Unrealized holding gain (loss) on available-for-sale securities	0	0	0	0
Pension and postretirement benefits	0	0	0	0
Reclassification Adjustments [Abstract]
Currency translation adjustment	0	0	0	0
Derivatives	0	0	0	0
Available-for-sale securities	0	0	0	0
Pension and postretirement benefits	0	0	0	0
Total Other Comprehensive Income (Loss)	(1.4)	3.4	2.7	11.3
Comprehensive Income	6.6	11.9	25.1	34.3
Dividends on common stock	0	0	0	0
Dividends to noncontrolling interests	(3.1)	(2.2)	(16.1)	(2.7)
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	(1.9)	0
Contribution from noncontrolling interests	0	0	0	1.4
Other equity transactions	(14.4)	(18.9)	(16.2)	(18.9)
Balance, end of period	$ 133.8	$ 164.8	$ 133.8	$ 164.8