Business Segment Information (Schedule of Revenue from External Customers Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Sales to External Customers	$ 2,581.9	$ 2,484.2	$ 5,127.4	$ 5,046.6
Merchant Gases [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	1,040.1	1,003.2	2,087.8	2,012.3
Tonnage Gases [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	839.9	808.5	1,648.0	1,706.9
Electronics and Performance Materials [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	591.7	548.8	1,170.8	1,097.8
Equipment and Energy [Member]
Segment Reporting Information [Line Items]
Sales to External Customers	$ 110.2	$ 123.7	$ 220.8	$ 229.6