v3.26.1
TiO2 segment information - Reconciliation of segment profit (loss) and Consolidated net income (loss) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
TiO2 segment and geographic information [Line Items]    
Net sales $ 509.8 $ 489.8
Segment profit (2.0) 25.7
Corporate interest and dividend income 0.2 0.4
Marketable equity securities 0.3 (1.0)
Other components of net periodic pension and OPEB cost (0.8) (0.5)
Interest expense (14.3) (11.6)
Income tax expense 2.8 7.6
Net income (loss) $ (4.8) 18.1
Number of reportable segments not disclosed true  
Corporate non segment    
TiO2 segment and geographic information [Line Items]    
Corporate expenses $ (2.4) (3.0)
Corporate interest and dividend income 0.1 0.2
Single reportable segment | Operating segment    
TiO2 segment and geographic information [Line Items]    
Net sales 509.8 489.8
Segment profit 15.1 41.6
Marketable equity securities 0.3 (1.0)
Other components of net periodic pension and OPEB cost (0.8) (0.5)
Interest expense (14.3) (11.6)
Income tax expense $ (2.8) $ (7.6)