Business Segment And Geographic Information (Segment Identifiable Assets Information) (Details) (USD $) In Millions	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Identifiable Assets	$ 12,380.5	$ 11,568.8	$ 11,067.6
Other	898.6	1,024.3	1,093.4
Consolidated Identifiable Assets Total	13,279.1	12,593.1	12,161.0
Merchant Gases [Member]
Identifiable Assets	5,091.7	5,075.3	4,917.0
Tonnage Gases [Member]
Identifiable Assets	4,464.3	3,876.4	3,597.8
Electronics And Performance Materials [Member]
Identifiable Assets	2,488.9	2,275.8	2,249.5
Equipment And Energy [Member]
Identifiable Assets	$ 335.6	$ 341.3	$ 303.3