Business Segment And Geographic Information (Segment Reporting Total Assets) (Details) (USD $) In Millions	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Other	$ 898.6	$ 1,024.3	$ 1,093.4
Assets	14,290.7	13,505.9	13,029.1
Merchant Gases [Member]
Assets	5,892.1	5,824.7	5,630.8
Tonnage Gases [Member]
Assets	4,581.8	3,958.1	3,672.0
Electronics And Performance Materials [Member]
Assets	2,560.7	2,336.1	2,299.1
Equipment And Energy [Member]
Assets	357.5	362.7	333.8
Segment Total [Member]
Assets	$ 13,392.1	$ 12,481.6	$ 11,935.7