CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 197.7	$ 89.0	$ 78.2
Other comprehensive income (loss), net of tax:
Currency translation	(6.8)	12.5	(1.8)
Defined benefit pension plans	45.3	(10.4)	(17.3)
Other	(0.3)	(0.7)	(0.8)
Total other comprehensive income (loss), net	38.2	1.4	(19.9)
Comprehensive income	235.9	90.4	58.3
Comprehensive income attributable to noncontrolling interest	80.6	33.9	23.5
Comprehensive income attributable to Valhi stockholders	$ 155.3	$ 56.5	$ 34.8