Long-term debt (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Long-term debt
Total debt	$ 662.3	$ 563.4
Less current maturities	0.8	79.0
Total long-term debt	661.5	484.4
VALHI, INC. \| Contran Credit Facility
Long-term debt
Total debt	25.0	44.6
Kronos Worldwide
Long-term debt
Revolving credit facility	70.2	10.0
Kronos Worldwide \| 9.50% Senior Secured Notes due 2029 \| Kronos International, Inc
Long-term debt
Total debt	502.3	365.4
Kronos Worldwide \| 3.75% Senior Secured Notes due 2025 \| Kronos International, Inc
Long-term debt
Total debt		78.3
Kronos Worldwide \| Subordinated, unsecured term loan from Contran
Long-term debt
Subordinated debt	53.7	53.7
LandWell \| Unsecured Debt \| Western Alliance Bank
Long-term debt
Total debt	11.1	11.4
Subsidiary
Long-term debt
Total debt	$ 637.3	$ 518.8

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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