v3.25.4
Postemployment benefit plans - Schedule of changes in projected benefit obligations (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Change in benefit obligation:      
Actuarial loss (gain) $ (294) $ (154) $ (97)
Pension Plan | U.S. Pension Benefits      
Defined Benefit Plan Disclosure      
Accumulated benefit obligation, end of year 12,066 12,171  
Change in benefit obligation:      
Benefit obligation, beginning of year 12,171 13,137  
Service cost 0 0 0
Interest cost 612 625 656
Plan amendments 0 0  
Actuarial loss (gain) 276 (603)  
Foreign currency exchange rates 0 0  
Participant contributions 0 0  
Benefits paid - gross (993) (988)  
Less: federal subsidy on benefits paid 0 0  
Curtailments, settlements and termination benefits 0 0  
Benefit obligation, end of year 12,066 12,171 13,137
Change in plan assets:      
Fair value of plan assets, beginning of year 11,898 12,738  
Actual return on plan assets 1,158 96  
Foreign currency exchange rates 0 0  
Company contributions 50 52  
Participant contributions 0 0  
Benefits paid (993) (988)  
Settlements and termination benefits 0 0  
Fair value of plan assets, ending of year 12,113 11,898 12,738
Over (under) funded status 47 (273)  
Amounts recognized in Statement 3:      
Other assets (non-current asset) 670 354  
Accrued wages, salaries and employee benefits (current liability) (50) (50)  
Liability for postemployment benefits (non-current liability) (573) (577)  
Net (liability) asset recognized 47 (273)  
Amounts recognized in AOCI (pre-tax):      
Prior service cost (credit) $ 0 $ 0  
Weighted-average assumptions used to determine benefit obligation, end of year:      
Discount rate 5.30% 5.60%  
Rate of compensation increase 0.00% 0.00%  
Pension Plan | Non-U.S.  Pension Benefits      
Defined Benefit Plan Disclosure      
Accumulated benefit obligation, end of year $ 3,011 $ 2,880  
Change in benefit obligation:      
Benefit obligation, beginning of year 2,989 3,265  
Service cost 49 43 40
Interest cost 118 118 124
Plan amendments 6 0  
Actuarial loss (gain) (93) (31)  
Foreign currency exchange rates 291 (203)  
Participant contributions 5 5  
Benefits paid - gross (189) (193)  
Less: federal subsidy on benefits paid 0 0  
Curtailments, settlements and termination benefits (45) (15)  
Benefit obligation, end of year 3,131 2,989 3,265
Change in plan assets:      
Fair value of plan assets, beginning of year 3,203 3,467  
Actual return on plan assets 103 74  
Foreign currency exchange rates 307 (194)  
Company contributions 70 59  
Participant contributions 5 5  
Benefits paid (189) (193)  
Settlements and termination benefits (45) (15)  
Fair value of plan assets, ending of year 3,454 3,203 3,467
Over (under) funded status 323 214  
Amounts recognized in Statement 3:      
Other assets (non-current asset) 681 541  
Accrued wages, salaries and employee benefits (current liability) (22) (21)  
Liability for postemployment benefits (non-current liability) (336) (306)  
Net (liability) asset recognized 323 214  
Amounts recognized in AOCI (pre-tax):      
Prior service cost (credit) $ 27 $ 21  
Weighted-average assumptions used to determine benefit obligation, end of year:      
Discount rate 4.30% 4.10%  
Rate of compensation increase 2.20% 2.20%  
Other Postretirement  Benefits      
Change in benefit obligation:      
Benefit obligation, beginning of year $ 2,469 $ 2,741  
Service cost 63 67 67
Interest cost 125 131 144
Plan amendments 0 0  
Actuarial loss (gain) (96) (202)  
Foreign currency exchange rates 21 (33)  
Participant contributions 41 45  
Benefits paid - gross (287) (286)  
Less: federal subsidy on benefits paid 6 6  
Curtailments, settlements and termination benefits 0 0  
Benefit obligation, end of year 2,342 2,469 2,741
Change in plan assets:      
Fair value of plan assets, beginning of year 88 144  
Actual return on plan assets 25 25  
Foreign currency exchange rates 0 0  
Company contributions 261 160  
Participant contributions 41 45  
Benefits paid (287) (286)  
Settlements and termination benefits 0 0  
Fair value of plan assets, ending of year 128 88 $ 144
Over (under) funded status (2,214) (2,381)  
Amounts recognized in Statement 3:      
Other assets (non-current asset) 0 0  
Accrued wages, salaries and employee benefits (current liability) (146) (204)  
Liability for postemployment benefits (non-current liability) (2,068) (2,177)  
Net (liability) asset recognized (2,214) (2,381)  
Amounts recognized in AOCI (pre-tax):      
Prior service cost (credit) $ 0 $ (5)  
Weighted-average assumptions used to determine benefit obligation, end of year:      
Discount rate 5.30% 5.60%  
Rate of compensation increase 4.00% 4.00%