v3.25.2
Retirement Benefits - Net Benefit Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Defined Contribution Plan Disclosure [Line Items]        
Service cost $ 26 $ 28 $ 51 $ 54
Interest cost 121 114 242 227
Expected return on assets (131) (134) (261) (269)
Prior service (credit) cost (1) (1) (3) (3)
Actuarial (gain) loss 23 24 47 47
Settlement charges 0 1 0 4
Non-service components of pension benefits & OPEB (credit) cost 12 4 25 6
Net periodic benefit cost 38 32 76 60
Pension Benefits        
Defined Contribution Plan Disclosure [Line Items]        
Service cost 21 23 42 45
Interest cost 101 96 203 191
Expected return on assets (123) (124) (245) (248)
Prior service (credit) cost 0 0 0 0
Actuarial (gain) loss 25 26 51 51
Settlement charges 0 1 0 4
Non-service components of pension benefits & OPEB (credit) cost 3 (1) 9 (2)
Net periodic benefit cost 24 22 51 43
OPEB        
Defined Contribution Plan Disclosure [Line Items]        
Service cost 5 5 9 9
Interest cost 20 18 39 36
Expected return on assets (8) (10) (16) (21)
Prior service (credit) cost (1) (1) (3) (3)
Actuarial (gain) loss (2) (2) (4) (4)
Settlement charges 0 0 0 0
Non-service components of pension benefits & OPEB (credit) cost 9 5 16 8
Net periodic benefit cost $ 14 $ 10 $ 25 $ 17