Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) (Kronos, USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Kronos
Current assets	$ 886.2	$ 781.2
Property and equipment, net	479.7	536.3
Investment in TiO2 joint venture	89.0	102.3
Other noncurrent assets	187.6	199.3
Total assets	1,642.5	1,619.1
Current liabilities	237.9	278.0
Long-term debt	344.7	180.4
Accrued pension and postretirement benefits	245.2	171.6
Other noncurrent liabilities	33.6	54.0
Stockholders' equity	781.1	935.1
Total liabilities and stockholders' equity	$ 1,642.5	$ 1,619.1