v3.25.2
Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance $ 2,445 $ 2,633 $ 2,641 $ 3,337
Reclassifications into earnings, net of taxes (5) 2 (5) 4
Change in fair value, net of taxes 5 (2) 10 (1)
Ending balance 2,408 2,697 2,408 2,697
Reclassification into earnings, tax 0 1 0 1
Change in fair value, tax 0 0 0 0
Accumulated Other Comprehensive Loss        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance 7 (1) 2 (4)
Ending balance 7 (1) 7 (1)
Aircraft fuel derivatives        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance 0 0 0 (3)
Reclassifications into earnings, net of taxes 0 2 0 4
Change in fair value, net of taxes 0 (2) 0 (1)
Ending balance 0 0 0 0
Available-for-sale securities        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance 7 (1) 2 (1)
Reclassifications into earnings, net of taxes (5) 0 (5) 0
Change in fair value, net of taxes 5 0 10 0
Ending balance $ 7 $ (1) $ 7 $ (1)