v3.26.1
Fair Value Measurements - MEC - Level 3 (Details) - MEC - Commodity - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Fair Value, Assets (Liabilities), Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance $ (2) $ (2)
Changes in fair value recognized in regulatory assets (1) 1
Settlements 2 2
Ending balance $ (1) $ 1