Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013 U.S. Pension	Sep. 30, 2012 U.S. Pension	Sep. 30, 2013 U.S. Pension	Sep. 30, 2012 U.S. Pension	Dec. 31, 2012 U.S. Pension Nalco	Sep. 30, 2013 U.S. qualified defined benefit plans	Sep. 30, 2013 U.S. non-contributory non-qualified defined benefit plans	Sep. 30, 2013 International Pension	Sep. 30, 2012 International Pension	Sep. 30, 2013 International Pension	Sep. 30, 2012 International Pension	Sep. 30, 2013 U.S. Postretirement Health Care	Sep. 30, 2012 U.S. Postretirement Health Care	Sep. 30, 2013 U.S. Postretirement Health Care	Sep. 30, 2012 U.S. Postretirement Health Care
Net periodic benefit costs
Service cost	$ 17.2	$ 12.6	$ 51.5	$ 37.8				$ 9.0	$ 7.1	$ 27.0	$ 21.8	$ 1.5	$ 1.3	$ 4.5	$ 3.9
Interest cost on benefit obligation	21.2	22.3	63.6	66.9				11.7	11.6	35.2	35.4	2.7	3.2	8.1	9.6
Expected return on plan assets	(32.5)	(31.8)	(97.6)	(95.4)				(11.6)	(10.4)	(34.9)	(31.6)	(0.3)	(0.3)	(0.8)	(0.9)
Recognition of net actuarial loss	15.6	11.3	46.8	33.9				2.8	0.9	8.5	2.9	0.2	0.1	0.5	0.3
Amortization of prior service benefit	(1.7)	(1.0)	(5.2)	(3.0)				(0.1)	(0.1)	(0.1)	(0.2)	(0.1)		(0.3)
Settlements/Curtailments										0.1	0.8
Total expense	19.8	13.4	59.1	40.2				11.8	9.1	35.8	29.1	4.0	4.3	12.0	12.9
Other Pension Plan Information
Required contributions to defined benefit plan in current fiscal year					38
Contributions to plan					180		9			38				15
Contributions anticipated to be made during 2013						$ 0	$ 1			$ 12				$ 5