Special (Gains) and Charges (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Employee Termination Costs 2011 Restructuring Plan	Sep. 30, 2011 Asset Disposals 2011 Restructuring Plan	Sep. 30, 2011 Other Restructuring Charges 2011 Restructuring Plan	Sep. 30, 2011 2011 Restructuring Plan	Sep. 30, 2011 2011 Restructuring Plan position	Dec. 31, 2010 2009 Restructuring Plan
Restructuring Reserve
Recorded expense and accrual			$ 52.4	$ 0.5	$ 5.2		$ 58.1
Cash payments			(11.7)		(1.7)		(13.4)
Non-cash charges				(0.5)			(0.5)
Effect of foreign currency translation			0.3				0.3
Restructuring liability	44.5	2.8	41.0		3.5	44.5	44.5	2.8
Other Restructuring Information
Number of positions expected to be eliminated							900
Restructuring charge expected to be incurred through 2013, pretax							150
Restructuring charge expected to be incurred through 2013, after tax							125
Restructuring charge expected to occur in 2011, pretax, low end of the range							60
Restructuring charge expected to occur in 2011, pretax, high end of the range							70
Restructuring charge expected to occur in 2011, after tax, low end of the range							50
Restructuring charge expected to occur in 2011, after tax, high end of the range							60
Restructuring charges, expected cash expenditures							125
Restructuring charges, expected asset disposals							25
Restructuring charges						17.1	58.1
Restructuring charges, after tax						14.8	49.0
Restructuring charges, per diluted share (in dollars per share)						$ 0.06	$ 0.21
Nalco merger and integration costs	$ 10.3