Business Segment And Geographic Information (Segment Expenditures For Long-Lived Assets) (Details) (USD $) In Millions	12 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2009
Expenditures for Long-Lived Assets	$ 1,344.7	[1]	$ 1,030.1	[1]	$ 1,178.1	[1]
Other	7.0	[1]	0.8	[1]	1.0	[1]
Consolidated Expenditures for Long-Lived Assets Total	1,351.7	[1]	1,030.9	[1]	1,179.1	[1]
Merchant Gases [Member]
Expenditures for Long-Lived Assets	432.9	[1]	311.5	[1]	510.8	[1]
Tonnage Gases [Member]
Expenditures for Long-Lived Assets	669.9	[1]	557.2	[1]	532.1	[1]
Electronics And Performance Materials [Member]
Expenditures for Long-Lived Assets	196.0	[1]	139.0	[1]	125.4	[1]
Equipment And Energy [Member]
Expenditures for Long-Lived Assets	$ 45.9	[1]	$ 22.4	[1]	$ 9.8	[1]

[1] Includes plant and equipment