v3.26.3
Accumulated Other Comprehensive Loss - Schedule of AOCI Activity (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance at beginning of period     $ (1,117)  
Other comprehensive income before reclassifications     3 $ 14
Amounts reclassified from accumulated other comprehensive loss     47 62
Other comprehensive income $ 13 $ 32 50 76
Balance at end of period (1,722) (1,173) (1,722) (1,173)
Total        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance at beginning of period (564) (679) (601) (723)
Other comprehensive income 13 32 50 76
Balance at end of period (551) (647) (551) (647)
Defined Benefit Plan | Pension Plans        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance at beginning of period     (848) (1,003)
Other comprehensive income before reclassifications     0 0
Amounts reclassified from accumulated other comprehensive loss     70 81
Other comprehensive income     70 81
Balance at end of period (778) (922) (778) (922)
Defined Benefit Plan | Post-Retirement Benefit Plans        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance at beginning of period     271 320
Other comprehensive income before reclassifications     0 0
Amounts reclassified from accumulated other comprehensive loss     (23) (19)
Other comprehensive income     (23) (19)
Balance at end of period 248 301 248 301
Foreign Currency Translation Adjustment and Other        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance at beginning of period     (24) (40)
Other comprehensive income before reclassifications     3 14
Amounts reclassified from accumulated other comprehensive loss     0 0
Other comprehensive income     3 14
Balance at end of period $ (21) $ (26) $ (21) $ (26)