v3.25.4
EMPLOYEE BENEFIT PLANS (Changes in Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Qualified Plan      
Change in benefit obligation:      
Benefit obligation at beginning of year $ 489.8 $ 429.7  
Service cost 53.2 53.4 $ 48.1
Interest cost 25.0 20.3 17.7
Benefit payments (32.5) (15.5)  
Actuarial loss (gain) 11.5 1.9  
Projected benefit obligation at end of year 547.0 489.8 429.7
Change in plan assets:      
Fair value of plan assets at beginning of year 394.7 349.3  
Actual return on plan assets 59.8 25.9  
Benefits paid (32.4) (15.5)  
Employer contributions 35.1 35.0  
Fair value of plan assets at end of year 457.2 394.7 349.3
Reconciliation of funded status:      
Fair value of plan assets at end of year 457.2 394.7 349.3
Less projected benefit obligation at end of year 547.0 489.8 429.7
Funded status at end of year (89.8) (95.1)  
Post-Retirement Medical Plan      
Change in benefit obligation:      
Benefit obligation at beginning of year 15.6 19.6  
Service cost 0.7 0.9 0.5
Interest cost 0.8 0.9 0.7
Benefit payments (2.7) (2.4)  
Actuarial loss (gain) 2.0 (3.4)  
Projected benefit obligation at end of year 16.4 15.6 19.6
Change in plan assets:      
Fair value of plan assets at beginning of year 0.0 0.0  
Actual return on plan assets 0.0 0.0  
Benefits paid (2.7) (2.4)  
Employer contributions 2.7 2.4  
Fair value of plan assets at end of year 0.0 0.0 0.0
Reconciliation of funded status:      
Fair value of plan assets at end of year 0.0 0.0 0.0
Less projected benefit obligation at end of year 16.4 15.6 $ 19.6
Funded status at end of year $ (16.4) $ (15.6)