v3.25.4
Employee Benefits - Benefit (Income) Cost Related to Pension and Postretirement Health Care and Life Insurance Plans (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]      
Remeasurement loss (gain), net $ 453 $ (657) $ 992
Other components 827 (300) 938
Pension      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 160 185 208
Amortization of prior service cost (credit) 112 112 112
Expected return on plan assets (534) (620) (1,013)
Interest cost 405 479 752
Remeasurement loss (gain), net 216 (110) 266
Curtailment and termination benefits 1 0 0
Other components 200 (139) 117
Total 360 46 325
Health Care and Life      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 33 52 54
Amortization of prior service cost (credit) (129) (129) (419)
Expected return on plan assets (28) (28) (31)
Interest cost 547 543 545
Remeasurement loss (gain), net 237 (547) 726
Curtailment and termination benefits 0 0 0
Other components 627 (161) 821
Total 660 (109) 875
Cost of services | Pension      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 137 159 182
Cost of services | Health Care and Life      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 28 44 46
Selling, general and administrative expense | Pension      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 23 26 26
Selling, general and administrative expense | Health Care and Life      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 5 $ 8 $ 8