v3.26.1
Comprehensive Income - Schedule of AOCI Components (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period $ 6,875 $ 7,981
Deferred tax impact, beginning balance 1 8
Reclassification to earnings 23 46
Reclassification to earnings, deferred tax impact (7) (14)
Balance at end of period 7,082 7,082
Deferred tax impact, ending balance (6) (6)
Accumulated other comprehensive income (loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period (1) (24)
Balance at end of period 22 22
Fuel derivatives    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period (108) (137)
Reclassification to earnings 29 58
Balance at end of period (79) (79)
Defined benefit plan items    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period 106 106
Reclassification to earnings 0 0
Balance at end of period 106 106
Other    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period 0 (1)
Reclassification to earnings 1 2
Balance at end of period $ 1 $ 1