Valhi Stockholder's Equity - Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of year	$ 2.1	$ 6.4	$ 14.6
Marketable securities, Unrealized gain (loss) arising during the year		4.1	(8.2)
Common stock sale	0.7	(8.4)
Marketable securities, Balance at end of year	2.8	2.1	6.4
Currency translation, Balance at beginning of year	53.3	37.5	59.2
Currency translation, Arising during the year	5.9	23.0	(21.7)
Currency translation, Common stock sale		(7.2)
Currency translation, Balance at end of year	59.2	53.3	37.5
Balance at beginning of year	(42.0)	(23.3)	21.2
Other comprehensive income (loss)	34.0	(18.7)	(44.5)
Balance at end of year	(8.0)	(42.0)	(23.3)
Pension Plan Defined Benefit
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	(101.5)	(72.6)	(59.8)
Amortization of prior service cost and net losses included in net periodic pension cost	8.4	6.1	4.0
Net actuarial gain (loss) arising during year	12.6	(35.0)	(16.8)
Plan amendment	4.0
Balance at end of year	(76.5)	(101.5)	(72.6)
OPEB
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	4.1	5.4	7.2
Amortization of prior service cost and net losses included in net periodic pension cost	(1.4)	(1.0)	(0.5)
Net actuarial gain (loss) arising during year	1.3	(0.3)	(1.3)
Plan amendment	2.5
Balance at end of year	$ 6.5	$ 4.1	$ 5.4