v3.26.3
SEGMENT INFORMATION - Segment Revenue Segment Cost and Adjusted EBITDA (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
External revenue $ 2,639 $ 2,166 $ 7,848 $ 6,248
Segment Adjusted EBITDA 280 196 852 507
A&T        
Segment Reporting [Line Items]        
External revenue 624 462 1,843 1,362
Cost of metal (333) (203) (923) (592)
Production costs (162) (142) (498) (438)
Other segment expenses (27) (26) (82) (76)
Segment Adjusted EBITDA 102 90 340 256
A&T | Segment revenue        
Segment Reporting [Line Items]        
External revenue 664 481 1,954 1,441
A&T | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (40) (19) (111) (79)
P&ARP        
Segment Reporting [Line Items]        
External revenue 1,622 1,305 4,769 3,720
Cost of metal (1,175) (946) (3,435) (2,700)
Production costs (254) (246) (762) (720)
Other segment expenses (31) (30) (94) (83)
Segment Adjusted EBITDA 162 82 478 217
P&ARP | Segment revenue        
Segment Reporting [Line Items]        
External revenue 1,625 1,307 4,782 3,729
P&ARP | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (3) (2) (13) (9)
AS&I        
Segment Reporting [Line Items]        
External revenue 390 399 1,230 1,163
Cost of metal (241) (224) (748) (686)
Production costs (105) (119) (335) (341)
Other segment expenses (23) (22) (76) (69)
Segment Adjusted EBITDA 21 33 71 67
AS&I | Segment revenue        
Segment Reporting [Line Items]        
External revenue 402 409 1,275 1,211
AS&I | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (12) (10) (45) (48)
H&C        
Segment Reporting [Line Items]        
External revenue 2 1 6 3
Cost of metal 2 2 5 5
Production costs (1) (1) (5) (5)
Other segment expenses (8) (11) (43) (35)
Segment Adjusted EBITDA (5) (9) (37) (32)
H&C | Segment revenue        
Segment Reporting [Line Items]        
External revenue 2 1 6 3
H&C | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue $ 0 $ 0 $ 0 $ 0