Cost Reduction Plan (Charge As It Relates To Businesses At Segment Level) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Cost Reduction Plan [Line Items]
Severance and Other Benefits					$ 80.8
Asset Impairments					6.0
Total	0	[1]	0	[1]	86.8	[1]	0	[1]
Merchant Gases [Member]
Cost Reduction Plan [Line Items]
Severance and Other Benefits					71.3
Asset Impairments					6.0
Total					77.3
Tonnage Gases [Member]
Cost Reduction Plan [Line Items]
Severance and Other Benefits					3.8
Asset Impairments					0
Total					3.8
Electronics and Performance Materials [Member]
Cost Reduction Plan [Line Items]
Severance and Other Benefits					5.7
Asset Impairments					0
Total					$ 5.7

[1] Information about how this charge related to the businesses at the segment level is discussed in Note 4, Cost Reduction Plan.