Business Segment Information (Schedule of Revenue from External Customers Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Sales to External Customers	$ 2,634.6	$ 2,547.3	$ 7,762.0	$ 7,593.9
Merchant Gases [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	1,077.3	1,032.5	3,165.1	3,044.8
Tonnage Gases [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	835.3	845.5	2,483.3	2,552.4
Electronics and Performance Materials [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	617.8	565.7	1,788.6	1,663.5
Equipment and Energy [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	$ 104.2	$ 103.6	$ 325.0	$ 333.2