v3.26.1
SEGMENT INFORMATION - Schedule of Segment Adjusted EBITDA and reconciliation of Adjusted EBITDA to Net Income (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Segment Adjusted EBITDA $ 262 $ 147
Metal price lag 97 39
Depreciation and amortization (83) (78)
Impairment of assets (4) 0
Share based compensation (11) (6)
Pension and other post-employment benefits - non - operating gains 3 3
Restructuring costs (3) (1)
Unrealized gains / (losses) on derivatives 42 (12)
Unrealized exchange gains / (losses) from the remeasurement of monetary assets and liabilities – net 1 (1)
Other 0 3
Expenses on factoring arrangements (4) (5)
Finance costs - net (28) (27)
Income before tax 272 62
Income tax expense (76) (24)
Net income 196 38
Flooding of facilities, Valais, Switzerland    
Segment Reporting Information [Line Items]    
Insurance proceeds from catastrophes   7
Loss from catastrophes   3
A&T    
Segment Reporting Information [Line Items]    
Segment Adjusted EBITDA 102 82
P&ARP    
Segment Reporting Information [Line Items]    
Segment Adjusted EBITDA 151 60
AS&I    
Segment Reporting Information [Line Items]    
Segment Adjusted EBITDA 24 16
H&C    
Segment Reporting Information [Line Items]    
Segment Adjusted EBITDA $ (15) $ (11)