Debt and Interest (Details 2)	3 Months Ended		9 Months Ended																							1 Months Ended									1 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2012 Series A senior euro notes, due 2013 USD ($)	Sep. 30, 2012 Series A senior euro notes, due 2013 EUR (€)	Dec. 31, 2011 Series A senior euro notes, due 2013 USD ($)	Sep. 30, 2012 Series B senior euro notes, due 2016 USD ($)	Sep. 30, 2012 Series B senior euro notes, due 2016 EUR (€)	Dec. 31, 2011 Series B senior euro notes, due 2016 USD ($)	Sep. 30, 2012 Senior notes USD ($)	Dec. 31, 2011 Senior notes USD ($)	Sep. 30, 2012 Series A private placement senior notes due 2018 USD ($)	Dec. 31, 2011 Series A private placement senior notes due 2018 USD ($)	Sep. 30, 2012 Series B private placement senior notes due 2023 USD ($)	Dec. 31, 2011 Series B private placement senior notes due 2023 USD ($)	Sep. 30, 2012 Three year 2011 senior notes USD ($)	Dec. 31, 2011 Three year 2011 senior notes USD ($)	Sep. 30, 2012 Five year 2011 senior notes USD ($)	Dec. 31, 2011 Five year 2011 senior notes USD ($)	Sep. 30, 2012 Ten year 2011 senior notes USD ($)	Dec. 31, 2011 Ten year 2011 senior notes USD ($)	Sep. 30, 2012 Thirty year 2011 senior notes USD ($)	Dec. 31, 2011 Thirty year 2011 senior notes USD ($)	Aug. 31, 2012 Three year 2012 senior notes USD ($)	Sep. 30, 2012 Three year 2012 senior notes USD ($)	Dec. 31, 2011 Nalco senior notes ($750 million) USD ($)	Dec. 31, 2011 Nalco senior euro notes (200 million euro) USD ($)	Dec. 31, 2011 Nalco senior notes ($500 million) USD ($)	Sep. 30, 2012 Capital lease obligations USD ($)	Dec. 31, 2011 Capital lease obligations USD ($)	Sep. 30, 2012 Other USD ($)	Dec. 31, 2011 Other USD ($)	Jan. 31, 2012 Nalco senior notes USD ($)	Sep. 30, 2012 Nalco senior notes USD ($)	Sep. 30, 2012 2011 Public Debt Offering
Debt instrument
CARRYING VALUE	$ 5,392,500,000		$ 5,392,500,000		$ 6,619,800,000	$ 157,200,000		$ 168,100,000	$ 220,100,000		$ 235,300,000	$ 249,300,000	$ 249,100,000	$ 250,000,000	$ 250,000,000	$ 250,000,000	$ 250,000,000	$ 499,800,000	$ 499,700,000	$ 1,247,900,000	$ 1,247,600,000	$ 1,249,300,000	$ 1,249,200,000	$ 742,500,000	$ 742,300,000		$ 499,800,000	$ 838,700,000	$ 300,700,000	$ 558,500,000	$ 14,300,000	$ 18,300,000	$ 12,300,000	$ 12,300,000
Long-term debt, current maturities	(5,800,000)		(5,800,000)		(6,600,000)
Long-term debt	5,386,700,000		5,386,700,000		6,613,200,000
Aggregate principal amount							125,000,000			175,000,000		250,000,000		250,000,000		250,000,000		500,000,000		1,250,000,000		1,250,000,000		750,000,000			500,000,000
Redemption of notes																																			1,700,000,000
Loss on early extinguishment of debt																																			18,200,000	18,200,000
Interest rate (as a percent)																										1.00%
Issuance of Debt securities																										500,000,000
Public Notes repurchase price as percentage of aggregate principal amount																																					101.00%
Interest
Interest expense	66,800,000	15,900,000	221,600,000	45,700,000
Interest income	(2,600,000)	(2,700,000)	(7,400,000)	(5,900,000)
Interest expense, net	$ 64,200,000	$ 13,200,000	$ 214,200,000	$ 39,800,000