v3.26.1
FAIR VALUE MEASUREMENTS - Narrative (Details) - Fuel hedge contracts - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Gain (loss) on derivatives recognized $ 166 $ 53 $ (303) $ 33
Mark-to-Market        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Gain (loss) on derivatives recognized     28  
Settlement Losses on Contracts        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Gain (loss) on derivatives recognized     $ (331)