v3.26.1
Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Total non-service cost components $ (49) $ (62) $ (98) $ (128)
Pension Plan        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Service Cost 20 20 40 41
Interest cost 57 59 113 117
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (68) (75) (134) (151)
Prior service cost (credit) 0 0 0 0
Actuarial (gain) loss 3 (7) 5 (17)
Total non-service cost components (8) (23) (16) (51)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total 12 (3) $ 24 (10)
Defined Benefit Plan, Amortization Period of Actuarial Gain (Loss)     10 years  
Defined Benefit Plan, Difference Between Actual and Expected Return (Loss) on Plan Assets Amortization Period     4 years  
Other Postretirement Benefit Plan, Defined Benefit        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Service Cost 3 3 $ 5 5
Interest cost 12 11 23 22
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (24) (24) (47) (47)
Prior service cost (credit) (1) (1) (2) (2)
Actuarial (gain) loss (8) (9) (16) (18)
Total non-service cost components (21) (23) (42) (45)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total $ (18) $ (20) $ (37) $ (40)
Defined Benefit Plan, Amortization Period of Actuarial Gain (Loss)     10 years  
Defined Benefit Plan, Difference Between Actual and Expected Return (Loss) on Plan Assets Amortization Period     4 years