v3.25.2
Retirement Benefits - Calculation of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Amortization of:        
Non-service net periodic benefit cost $ (13) $ (11) $ (26) $ (17)
Pension Plan, Defined Benefit [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 39 40 77 82
Interest cost 147 141 293 282
Expected return on assets (178) (184) (356) (368)
Amortization of:        
Prior service credit 0 0 1 1
Actuarial loss (gain) 53 54 106 107
Non-service net periodic benefit cost 61 51 121 104
Other Postretirement Benefit Plan, Defined Benefit [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 6 7 12 14
Interest cost 25 24 50 48
Expected return on assets (21) (21) (42) (42)
Amortization of:        
Prior service credit (2) (2) (4) (4)
Actuarial loss (gain) (1) 0 (1) 0
Non-service net periodic benefit cost $ 7 $ 8 $ 15 $ 16