Business Segment Information (Schedule of Income Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating income	$ 385.6	$ 372.4
Merchant Gases [Member]
Segment Reporting Information [Line Items]
Operating income	169.2	171.0
Tonnage Gases [Member]
Segment Reporting Information [Line Items]
Operating income	117.6	138.1
Electronics and Performance Materials [Member]
Segment Reporting Information [Line Items]
Operating income	83.5	61.3
Equipment and Energy [Member]
Segment Reporting Information [Line Items]
Operating income	20.5	8.4
Segment Total [Member]
Segment Reporting Information [Line Items]
Operating income	390.8	378.8
All Other Segments [Member]
Segment Reporting Information [Line Items]
Operating income	$ (5.2)	$ (6.4)