v3.26.1
Other Comprehensive (Loss) Income (Changes Net of Tax in the Balances of Each Components of Other Accumulated Comprehensive Income Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]    
Balance, beginning of period $ 15,315  
Other comprehensive (loss) income, net of tax (131) $ 344
Balance, end of period 14,806 14,268
Deferred tax assets, net 1,600 1,600
Total    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]    
Balance, beginning of period (5,429) (6,240)
Other comprehensive (loss) income before reclassifications (148) 337
Amounts reclassified from accumulated other comprehensive income 17 7
Other comprehensive (loss) income, net of tax (131) 344
Balance, end of period (5,560) (5,896)
Pension/Post-Retirement Plans Gains (Losses)    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]    
Balance, beginning of period (3,707) (3,408)
Other comprehensive (loss) income before reclassifications 58 (74)
Amounts reclassified from accumulated other comprehensive income 17 7
Other comprehensive (loss) income, net of tax 75 (67)
Balance, end of period (3,632) (3,475)
Foreign Currency Translation Adjustments    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]    
Balance, beginning of period (1,722) (2,832)
Other comprehensive (loss) income before reclassifications (206) 411
Amounts reclassified from accumulated other comprehensive income 0 0
Other comprehensive (loss) income, net of tax (206) 411
Balance, end of period $ (1,928) $ (2,421)