v3.25.4
RETIREMENT BENEFITS - Fair Value of Pension Plan Assets by Asset Category (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset $ 2,136 $ 1,927
Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 69 58
Level 1 | Equity securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 1 1
Level 1 | Equity funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 1 | Fixed income funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 1 | U.S. Treasury and agency securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 1 | Insurance contracts    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 1 | Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 68 57
Level 1 | Other    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 831 754
Level 2 | Equity securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 2 | Equity funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 303 256
Level 2 | Fixed income funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 484 446
Level 2 | U.S. Treasury and agency securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 33 41
Level 2 | Insurance contracts    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 2 | Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 2 | Other    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 11 11
Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 756 708
Level 3 | Equity securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 3 | Equity funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 3 | Fixed income funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 3 | U.S. Treasury and agency securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 3 | Insurance contracts    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 756 708
Level 3 | Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Level 3 | Other    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 0 0
Fair Value, Inputs, Level 1, 2 and 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 1,656 1,520
Fair Value, Inputs, Level 1, 2 and 3 | Equity securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 1 1
Fair Value, Inputs, Level 1, 2 and 3 | Equity funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 303 256
Fair Value, Inputs, Level 1, 2 and 3 | Fixed income funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 484 446
Fair Value, Inputs, Level 1, 2 and 3 | U.S. Treasury and agency securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 33 41
Fair Value, Inputs, Level 1, 2 and 3 | Insurance contracts    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 756 708
Fair Value, Inputs, Level 1, 2 and 3 | Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 68 57
Fair Value, Inputs, Level 1, 2 and 3 | Other    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset 11 11
Plan assets measured at NAV as a practical expedient | Plan assets measured at NAV as a practical expedient    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of pension and postretirement plan asset $ 480 $ 407