Goodwill And Intangible Assets (Schedule Of Goodwill By Segment) (Details) (USD $) In Millions	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Goodwill, Beginning Balance	$ 914.6	$ 916.0
Goodwill, Acquisitions and Adjustments	4.9	18.5
Goodwill, Currency Translation and Other	(27.1)	(19.9)
Goodwill, Ending Balance	892.4	914.6
Merchant Gases [Member]
Goodwill, Beginning Balance	595.7	601.3
Goodwill, Acquisitions and Adjustments	4.9	19.1
Goodwill, Currency Translation and Other	(25.2)	(24.7)
Goodwill, Ending Balance	575.4	595.7
Tonnage Gases [Member]
Goodwill, Beginning Balance	15.5	16.3
Goodwill, Acquisitions and Adjustments		(0.9)
Goodwill, Currency Translation and Other	(1.4)	0.1
Goodwill, Ending Balance	14.1	15.5
Electronics And Performance Materials [Member]
Goodwill, Beginning Balance	303.4	298.4
Goodwill, Acquisitions and Adjustments		0.3
Goodwill, Currency Translation and Other	(0.5)	4.7
Goodwill, Ending Balance	$ 302.9	$ 303.4

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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