v3.26.3
RETIREMENT BENEFITS AND ASSETS HELD IN TRUST (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Defined Benefit Plan Disclosure [Line Items]        
Defined Contribution Plan, Cost $ 2 $ 1 $ 7 $ 6