v3.26.1
Employee Benefits - Costs by Plans (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Defined Benefit Plan Disclosure [Line Items]          
Remeasurement loss (gain), net   $ (237)      
Pension          
Defined Benefit Plan Disclosure [Line Items]          
Service cost $ 53   $ 41 $ 101 $ 80
Amortization of prior service cost (credit) 49   28 82 56
Expected return on plan assets (184)   (134) (361) (268)
Interest cost 129   101 248 204
Remeasurement loss (gain), net 0   45 (18) 45
Other components (6)   40 (49) 37
Total 47   81 52 117
Pension | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold          
Defined Benefit Plan Disclosure [Line Items]          
Service cost 53   35 101 69
Pension | Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense          
Defined Benefit Plan Disclosure [Line Items]          
Service cost 0   6 0 11
Health Care and Life          
Defined Benefit Plan Disclosure [Line Items]          
Service cost 5   8 11 17
Amortization of prior service cost (credit) (31)   (32) (62) (64)
Expected return on plan assets (7)   (7) (14) (14)
Interest cost 135   137 264 273
Remeasurement loss (gain), net 0   0 (219) 0
Other components 97   98 (31) 195
Total 102   106 (20) 212
Health Care and Life | Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold          
Defined Benefit Plan Disclosure [Line Items]          
Service cost 5   7 11 14
Health Care and Life | Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense          
Defined Benefit Plan Disclosure [Line Items]          
Service cost $ 0   $ 1 $ 0 $ 3