v3.26.1
PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Pension and Other Postretirement Benefits (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Net periodic benefit costs (credits) $ (64) $ (43) $ (128) $ (100)
Pension Plan        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Service cost 7 7 14 14
Interest cost 45 52 90 105
Expected return on plan assets (82) (80) (163) (159)
Prior service credits 5 5 9 9
Net actuarial loss (gain) (5) (2) (9) (4)
Net periodic benefit costs (credits) (30) (18) (59) (35)
Defined benefit pension contributions 3 14 16 29
Defined benefit plan        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Service cost 1 2 3 4
Interest cost 15 15 29 29
Expected return on plan assets (11) (10) (22) (21)
Defined Benefit Plan, Other Cost (Credit) 0 15 0 15
Prior service credits (3) (4) (6) (7)
Net actuarial loss (gain) (28) (34) (56) (67)
Net periodic benefit costs (credits) (26) (16) (52) (47)
OPEB contributions $ 0 $ 0 $ 0 $ 0