v3.26.1
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 28, 2026
Jun. 29, 2025
Jun. 28, 2026
Jun. 29, 2025
Statement of Comprehensive Income [Abstract]        
Net income $ 154.3 $ 104.0 $ 274.8 $ 204.5
Currency translation adjustment        
Unrealized net change arising during the period 2.0 18.3 0.2 25.7
Reclassification adjustment included in net income 0.0 0.0 0.0 5.1
Total 2.0 18.3 0.2 30.8
Derivatives        
Net derivatives (loss) gain on hedge transactions (3.1) (4.4) (0.7) 2.0
Reclassification to net income of net realized (gain) loss (0.4) 1.6 (3.3) 2.6
Less: Income taxes on derivative transactions (0.9) (0.6) (1.0) 1.1
Total (2.6) (2.2) (3.0) 3.5
Actuarial loss        
Amortization of net actuarial loss 1.3 1.3 2.6 2.6
Prior service cost        
Amortization to net income of net prior service (credits) costs 0.0 (0.1) 0.1 (0.2)
Less: Income taxes on postretirement benefit plans 0.2 0.4 0.6 0.7
Total 1.1 0.8 2.1 1.7
Other comprehensive income (loss), net of tax 0.5 16.9 (0.7) 36.0
Comprehensive income 154.8 120.9 274.1 240.5
Less: Comprehensive income attributable to noncontrolling interests 5.7 5.1 9.3 9.8
Comprehensive income attributable to ATI $ 149.1 $ 115.8 $ 264.8 $ 230.7