v3.25.4
Retirement benefits - Summary of Assumptions for Sensitivity Analysis (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Rate of increase in pensionable remuneration    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 3.80% 3.90%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Rate of increase in pensionable remuneration | of which the Netherlands    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 3.30% 3.30%
Rate of increase in pensionable remuneration | of which the UK    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 3.50% 3.50%
Rate of increase in pensionable remuneration | of which the USA    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 4.60% 4.60%
Rate of increase in pensionable remuneration | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (365) $ (421)
Rate of increase in pensionable remuneration | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 411 $ 469
Rate of increase in pensions in payment    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 1.90% 2.00%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Rate of increase in pensions in payment | of which the Netherlands    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 2.10% 2.10%
Rate of increase in pensions in payment | of which the UK    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 2.60% 2.90%
Rate of increase in pensions in payment | of which the USA    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 0.00% 0.00%
Rate of increase in pensions in payment | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (4,994) $ (4,978)
Rate of increase in pensions in payment | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 6,015 $ 6,045
Discount rate for pension plans    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 4.90% 4.50%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Discount rate for pension plans | of which the Netherlands    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 4.30% 3.50%
Discount rate for pension plans | of which the UK    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 5.50% 5.50%
Discount rate for pension plans | of which the USA    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 5.50% 5.60%
Discount rate for pension plans | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 8,283 $ 8,641
Discount rate for pension plans | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (6,705) $ (6,925)
Inflation rate for defined benefit obligation    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Weighted average inflation rate used in the calculation of the defined benefit obligation 2.00% 2.10%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Inflation rate for defined benefit obligation | of which the Netherlands    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Weighted average inflation rate used in the calculation of the defined benefit obligation 2.10% 2.10%
Inflation rate for defined benefit obligation | of which the UK    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Weighted average inflation rate used in the calculation of the defined benefit obligation 2.70% 3.00%
Inflation rate for defined benefit obligation | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (5,217) $ (5,328)
Inflation rate for defined benefit obligation | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 6,217 $ 6,494
Rate of increase in health-care costs    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 7.60% 8.00%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Rate of increase in health-care costs | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (305) $ (295)
Rate of increase in health-care costs | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 371 $ 359
Discount rate for health-care plans    
Disclosure of sensitivity analysis for actuarial assumptions [line items]    
Percentage assumptions used 6.10% 6.00%
Expected age at death for persons aged 60:    
Range of assumptions, possible decrease 1.00%  
Range of assumptions, possible increase 1.00%  
Discount rate for health-care plans | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 407 $ 390
Discount rate for health-care plans | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (327) $ (314)
Men    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 88 years 88 years
Range of assumptions, expected age at death decrease 1 year  
Range of assumptions, expected age at death increase 1 year  
Men | of which the Netherlands    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 88 years 88 years
Men | of which the UK    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 88 years 87 years
Men | of which the USA    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 88 years 88 years
Men | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (960) $ (970)
Men | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 990 $ 981
Women    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 90 years 89 years
Range of assumptions, expected age at death decrease 1 year  
Range of assumptions, expected age at death increase 1 year  
Women | of which the Netherlands    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 90 years 90 years
Women | of which the UK    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 89 years 89 years
Women | of which the USA    
Expected age at death for persons aged 60:    
Expected age at death assumptions used 89 years 89 years
Women | Bottom of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ (825) $ (850)
Women | Top of range    
Expected age at death for persons aged 60:    
Increase/(decrease) in defined benefit obligations $ 843 $ 874