v3.25.4
Employee Benefits - Narrative (Detail)
$ in Millions
 2 Months Ended 10 Months Ended 12 Months Ended
Mar. 06, 2024
USD ($)
retiree
Feb. 29, 2024
USD ($)
agreement
Dec. 31, 2025
USD ($)
employee
plan
shares
Mar. 31, 2025
employee
Dec. 31, 2025
USD ($)
plan
shares
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]                
Accumulated benefit obligation for all defined benefit pension plans     $ 7,900   $ 7,900 $ 7,900    
Defined benefit plan, number of pension authorization commitment agreements | agreement   2            
Liability, defined benefit plan   $ 5,800            
Defined benefit plan, benefit obligation, actuarial gain (loss) from assumptions used calculating benefit obligation, discount rate         (375) 1,400 $ (503)  
Discount Rate               5.20%
Defined benefit plan, benefit obligation, actuarial gain (loss) from actuarial assumption adjustments         (78)   45  
Defined benefit plan, reclassification adjustment from AOCI         $ 0 0 252  
Defined benefit plan, period used to determine overall expected long term rate of return on assets assumption (in years)         10 years      
Number of leveraged employee stock ownership plans (ESOP) | plan     4   4      
Number of allocated shares of common stock in ESOP (in shares) | shares     38,000,000   38,000,000      
Number of unallocated shares of common stock in ESOP (in shares) | shares     0   0      
Total savings plan cost         $ 666 700 724  
Severance liability charged to expense         1,491 1,494 531  
Restructuring and related cost, number of positions eliminated | employee     13,000 4,800        
Defined benefit plan, actuarial gain (loss), immediate recognition as component in net periodic benefit (cost) credit         $ (453) 657 $ (992)  
Pension and benefit credits (charges) from actual return           $ (1,000)    
Weighted-average healthcare cost trend rate assumed for next year     9.30%   9.30% 8.80% 7.30% 6.60%
Minimum                
Defined Benefit Plan Disclosure [Line Items]                
Selected bonds     $ 300   $ 300      
Minimum | Return Seeking Assets                
Defined Benefit Plan Disclosure [Line Items]                
Target allocation percentage of assets     45.00%   45.00%      
Minimum | Liability Hedging Assets                
Defined Benefit Plan Disclosure [Line Items]                
Target allocation percentage of assets     52.00%   52.00%      
Maximum | Return Seeking Assets                
Defined Benefit Plan Disclosure [Line Items]                
Target allocation percentage of assets     55.00%   55.00%      
Maximum | Liability Hedging Assets                
Defined Benefit Plan Disclosure [Line Items]                
Target allocation percentage of assets     62.00%   62.00%      
Maximum | Cash and cash equivalents                
Defined Benefit Plan Disclosure [Line Items]                
Target allocation percentage of assets     10.00%   10.00%      
Pension                
Defined Benefit Plan Disclosure [Line Items]                
Defined benefit plan, benefit obligation, actuarial gain (loss) from pension annuitization   $ 200       $ 200    
Defined benefit plan, number of retirees receiving benefit payments from pension plan | retiree 56,000              
Annuity contracts transfer $ 5,600       $ 0 (5,611)    
Defined benefit plan, benefit obligation, actuarial gain (loss) from assumptions used calculating benefit obligation, discount rate         $ (106) $ 764 $ (288)  
Discount Rate     5.70%   5.70% 5.80% 5.00%  
Company contributions         $ 1,313 $ 421    
Defined benefit plan, actuarial gain (loss), immediate recognition as component in net periodic benefit (cost) credit         (216) 110 $ (266)  
Defined benefit plan, benefit obligation, actuarial gain (loss) from healthcare cost assumptions used calculating benefit obligation, discount rate             (534)  
Pension | Qualified Plan                
Defined Benefit Plan Disclosure [Line Items]                
Company contributions         1,300      
Pension | Nonqualified Plan                
Defined Benefit Plan Disclosure [Line Items]                
Company contributions         $ 54      
Pension | Bonds and Common Stock                
Defined Benefit Plan Disclosure [Line Items]                
Defined benefit plan, plan assets, investment within plan asset category, percentage     8.00%   8.00%      
Health Care and Life                
Defined Benefit Plan Disclosure [Line Items]                
Annuity contracts transfer         $ 0 0    
Defined benefit plan, benefit obligation, actuarial gain (loss) from assumptions used calculating benefit obligation, discount rate         $ (269) $ 656 $ (215)  
Discount Rate     5.40%   5.40% 5.60% 5.00%  
Company contributions         $ 762 $ 935    
Defined benefit plan contributions by employer in next fiscal year     $ 700   700      
Defined benefit plan, actuarial gain (loss), immediate recognition as component in net periodic benefit (cost) credit         $ (237) $ 547 $ (726)  
Health Care and Life | Bonds and Common Stock                
Defined Benefit Plan Disclosure [Line Items]                
Defined benefit plan, plan assets, investment within plan asset category, percentage     0.00%   0.00%      
Pension and Postretirement Plan                
Defined Benefit Plan Disclosure [Line Items]                
Discount Rate     5.50%   5.50%