v3.26.3
Comprehensive Income - Schedule of AOCI Components (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2026
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period $ 7,082 $ 7,981
Deferred tax impact, beginning balance (6) 8
Changes in fair value 7 7
Changes in fair value, deferred tax impact (2) (2)
Reclassification to earnings 23 69
Reclassification to earnings, deferred tax impact (7) (21)
Balance at end of period 7,329 7,329
Deferred tax impact, ending balance (15) (15)
Accumulated other comprehensive income (loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period 22 (24)
Balance at end of period 51 51
Fuel derivatives    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period (79) (137)
Changes in fair value 0 0
Reclassification to earnings 29 86
Balance at end of period (50) (50)
Defined benefit plan items    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period 106 106
Changes in fair value 0 0
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 1 (1)
Changes in fair value 9 9
Reclassification to earnings 1 4
Balance at end of period $ 11 $ 11