v3.25.4
Business and geographic segments - Additional Information (Details)
$ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
segment
Dec. 31, 2024
USD ($)
Business and geographic segments    
Number of operating segments | segment 3  
Number of reportable segments | segment 3  
Facility Closing    
Business and geographic segments    
Workforce reduction costs accrued   $ 2
Accelerated depreciation   14
Non-U.S. subsidiaries    
Business and geographic segments    
Net Assets $ 514 $ 532
Kronos | Valhi Incorporation    
Business and geographic segments    
Direct ownership percentage by parent 50.00%  
Kronos | NL Industries    
Business and geographic segments    
Indirect controlling interest in subsidiary 31.00%  
NL Industries | Valhi Incorporation    
Business and geographic segments    
Direct ownership percentage by parent 83.00%  
LandWell | Valhi Incorporation    
Business and geographic segments    
Direct ownership percentage by parent 27.00%  
LandWell | Basic Management Inc    
Business and geographic segments    
Indirect controlling interest in subsidiary 50.00%  
Basic Management Inc | Valhi Incorporation    
Business and geographic segments    
Direct ownership percentage by parent 63.00%