v3.25.2
Retirement Benefits (Components Of Net Periodic Benefit Cost) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Total non-service cost components $ (62) $ (76) $ (128) $ (152)
Pension Plan        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Service Cost 20 23 41 44
Interest cost 59 56 117 111
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (75) (82) (151) (164)
Prior service cost (credit) 0 0 0 0
Actuarial (gain) (7) (16) (17) (33)
Total non-service cost components (23) (42) (51) (86)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total (3) (19) $ (10) (42)
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 6
Interest cost 11 11 22 22
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (24) (23) (47) (46)
Prior service cost (credit) (1) (1) (2) (2)
Actuarial (gain) (9) (10) (18) (20)
Total non-service cost components (23) (23) (45) (46)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total $ (20) $ (20) $ (40) $ (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