ACCUMULATED OTHER COMPREHENSIVE INCOME: (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			3 Months Ended					3 Months Ended
	Mar. 31, 2013	Feb. 28, 2013 Titanium Dioxide Pigments joint venture Kemira	Feb. 15, 2013 Titanium Dioxide Pigments joint venture Kemira	Mar. 31, 2013 Pension related adjustments, net of tax	Mar. 31, 2013 Foreign currency translation	Mar. 31, 2013 Intercompany foreign currency loans	Mar. 31, 2013 Net investment hedge, net of tax	Dec. 31, 2012 Net investment hedge, net of tax	Mar. 31, 2013 Foreign exchange contracts, net of tax
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ (14.3)			$ (146.0)	$ 204.2	$ 117.4	$ (189.9)	$ (189.9)
Other comprehensive income (loss) before reclassifications				5.2	(32.4)	(22.0)			(0.1)
Other comprehensive income (loss) before reclassifications	(49.3)
Amounts reclassified from accumulated other comprehensive loss to net income				(3.2)
Amounts reclassified from accumulated other comprehensive loss to net income	(3.2)
Amounts reclassified from noncontrolling interest to accumulated other comprehensive loss	27.6			27.6
Balance at the end of the period	$ (88.0)			$ (165.2)	$ 171.8	$ 95.4	$ (189.9)	$ (189.9)	$ (0.1)
LIABILITIES
Interest acquired (as a percent)		39.00%	39.00%