v3.26.1
Accumulated Other Comprehensive Loss - Schedule of AOCI Activity (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period $ (1,117)  
Other comprehensive income (loss) before reclassifications 3 $ 3
Amounts reclassified from accumulated other comprehensive loss 17 20
Other comprehensive income 20 23
Balance at end of period (1,317) 289
Total    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance at beginning of period (601) (723)
Other comprehensive income 20 23
Balance at end of period (581) (700)
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 (loss) before reclassifications 0 0
Amounts reclassified from accumulated other comprehensive loss 27 26
Other comprehensive income 27 26
Balance at end of period (821) (977)
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 (loss) before reclassifications 0 0
Amounts reclassified from accumulated other comprehensive loss (10) (6)
Other comprehensive income (10) (6)
Balance at end of period 261 314
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 (loss) before reclassifications 3 3
Amounts reclassified from accumulated other comprehensive loss 0 0
Other comprehensive income 3 3
Balance at end of period $ (21) $ (37)