v3.26.1
SEGMENT INFORMATION - Segment Revenue Segment Cost and Adjusted EBITDA (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
External revenue $ 2,748 $ 2,103 $ 5,209 $ 4,082
Segment Adjusted EBITDA 310 165 572 312
A&T        
Segment Reporting [Line Items]        
External revenue 636 466 1,219 900
Cost of metal (310) (203) (590) (388)
Production costs (162) (151) (335) (296)
Other segment expenses (29) (27) (56) (50)
Segment Adjusted EBITDA 135 84 238 165
A&T | Segment revenue        
Segment Reporting [Line Items]        
External revenue 680 492 1,289 960
A&T | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (44) (26) (70) (60)
P&ARP        
Segment Reporting [Line Items]        
External revenue 1,673 1,232 3,147 2,416
Cost of metal (1,221) (895) (2,260) (1,753)
Production costs (254) (234) (508) (474)
Other segment expenses (33) (29) (62) (54)
Segment Adjusted EBITDA 165 74 317 135
P&ARP | Segment revenue        
Segment Reporting [Line Items]        
External revenue 1,680 1,235 3,157 2,422
P&ARP | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (7) (3) (10) (6)
AS&I        
Segment Reporting [Line Items]        
External revenue 437 404 840 764
Cost of metal (270) (248) (507) (462)
Production costs (114) (114) (231) (221)
Other segment expenses (27) (24) (53) (47)
Segment Adjusted EBITDA 26 18 49 34
AS&I | Segment revenue        
Segment Reporting [Line Items]        
External revenue 458 421 873 802
AS&I | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue (21) (18) (33) (38)
H&C        
Segment Reporting [Line Items]        
External revenue 2 1 3 2
Cost of metal 1 2 3 3
Production costs (2) (2) (3) (4)
Other segment expenses (17) (12) (35) (24)
Segment Adjusted EBITDA (16) (12) (32) (23)
H&C | Segment revenue        
Segment Reporting [Line Items]        
External revenue 2 1 3 2
H&C | Inter-segment elimination        
Segment Reporting [Line Items]        
External revenue $ 0 $ 0 $ 0 $ 0