Plant And Equipment (Schedule Of Major Classes Of Plant And Equipment At Cost) (Details) (USD $) In Millions, unless otherwise specified							12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended						12 Months Ended						12 Months Ended				12 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2009		Sep. 30, 2011 Merchant Gases [Member] Production Facilities [Member] years		Sep. 30, 2010 Merchant Gases [Member] Production Facilities [Member]		Sep. 30, 2011 Tonnage Gases [Member] Production Facilities [Member] years		Sep. 30, 2010 Tonnage Gases [Member] Production Facilities [Member]		Sep. 30, 2011 Electronics And Performance Materials [Member] Production Facilities [Member] years		Sep. 30, 2010 Electronics And Performance Materials [Member] Production Facilities [Member]		Sep. 30, 2011 Equipment And Energy [Member] Production Facilities [Member] years		Sep. 30, 2010 Equipment And Energy [Member] Production Facilities [Member]		Sep. 30, 2011 Cylinders [Member] Distribution Equipment [Member]	Sep. 30, 2011 Tanks [Member] Distribution Equipment [Member]	Sep. 30, 2011 Customer Stations [Member] Distribution Equipment [Member]	Sep. 30, 2011 Tractors And Trailers [Member] Distribution Equipment [Member]	Sep. 30, 2011 Land [Member]	Sep. 30, 2010 Land [Member]	Sep. 30, 2011 Buildings [Member] years	Sep. 30, 2010 Buildings [Member]	Sep. 30, 2011 Production Facilities [Member]		Sep. 30, 2010 Production Facilities [Member]		Sep. 30, 2011 Distribution Equipment [Member] years		Sep. 30, 2010 Distribution Equipment [Member]		Sep. 30, 2011 Other Machinery And Equipment [Member] years	Sep. 30, 2010 Other Machinery And Equipment [Member]	Sep. 30, 2011 Construction In Progress [Member]	Sep. 30, 2010 Construction In Progress [Member]
Plant and equipment, at cost	$ 17,227.1		$ 16,309.7				$ 3,256.4	[1]	$ 3,346.3	[1]	$ 6,266.5	[1]	$ 5,691.4	[1]	$ 1,862.3	[1]	$ 2,061.2	[1]	$ 165.9	[1]	$ 296.5	[1]					$ 173.2	$ 172.3	$ 919.5	$ 886.2	$ 11,551.1	[1]	$ 11,395.4	[1]	$ 3,092.4	[2]	$ 2,918.6	[2]	$ 252.3	$ 248.0	$ 1,238.6	$ 689.2
Less accumulated depreciation	9,815.1		9,258.4
Plant and equipment, net	$ 7,412.0	[3]	$ 7,051.3	[3]	$ 6,859.6	[3]
Average Useful Life (years)							15																	20	7.5				30
Minimum Useful Life (years)											15				10				5				10			5									5	[2]			10
Maximum Useful Life (years)											20				15				20				25			15									25	[2]			25

[1] Depreciable lives of production facilities related to long-term customer supply contracts are matched to the contract lives.

[2] The depreciable lives for various types of distribution equipment are 10 to 25 years for cylinders, depending on the nature and properties of the product; 20 years for tanks; 7.5 years for customer stations; and 5 to 15 years for tractors and trailers.

[3] Long lived assets include plant and equipment, net.