Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			12 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013 U.S. Pension	Jun. 30, 2012 U.S. Pension	Jun. 30, 2013 U.S. Pension	Jun. 30, 2012 U.S. Pension	Jun. 30, 2012 U.S. Pension Nalco	Dec. 31, 2012 U.S. Pension Nalco	Jun. 30, 2013 U.S. qualified defined benefit plans	Jun. 30, 2013 International Pension	Jun. 30, 2012 International Pension	Jun. 30, 2013 International Pension	Jun. 30, 2012 International Pension	Jun. 30, 2013 U.S. Postretirement Health Care	Jun. 30, 2012 U.S. Postretirement Health Care	Jun. 30, 2013 U.S. Postretirement Health Care	Jun. 30, 2012 U.S. Postretirement Health Care
Net periodic benefit costs
Service cost	$ 17.2	$ 12.6	$ 34.3	$ 25.2				$ 8.9	$ 7.3	$ 18.0	$ 14.7	$ 1.5	$ 1.3	$ 3.0	$ 2.5
Interest cost on benefit obligation	21.2	22.3	42.4	44.7				11.6	12.0	23.5	23.8	2.7	3.2	5.4	6.5
Expected return on plan assets	(32.6)	(31.8)	(65.1)	(63.6)				(11.5)	(10.7)	(23.3)	(21.2)	(0.2)	(0.3)	(0.5)	(0.6)
Recognition of net actuarial loss	15.6	11.3	31.2	22.6				2.8	1.0	5.7	2.0	0.1	0.1	0.3	0.2
Amortization of prior service benefit	(1.8)	(1.0)	(3.5)	(2.1)				0.1			(0.1)	(0.1)		(0.2)
Settlements/Curtailments								0.1	0.8	0.1	0.8
Total expense	19.6	13.4	39.3	26.8				12.0	10.4	24.0	20.0	4.0	4.3	8.0	8.6
Other Pension Plan Information
Required contributions to defined benefit plan in current fiscal year						38
Contributions to plan			2		166	180				25				10
Contributions anticipated to be made during 2013	$ 8		$ 8				$ 0	$ 22		$ 22		$ 10		$ 10