v3.25.4
Retirement benefits - Summary of Defined Benefit Plan Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 $ 3,251    
Return on plan assets in excess of interest income 2,449 $ 2,319 $ (1,243)
Other movements 10 7 5
At December 31 (2,084) 3,251  
Defined benefit plan assets      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 69,707 79,961  
Return on plan assets in excess of interest income (2,449) (2,319)  
Interest income 3,153 2,999  
Employer contributions 639 409  
Plan participants' contributions 33 36  
Benefit payments (3,905) (3,590)  
Other movements 24 (4,452)  
Currency translation differences 5,711 (3,337)  
At December 31 72,913 69,707 79,961
Defined benefit plan assets | The Netherlands      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 28,330 30,266  
Return on plan assets in excess of interest income (2,098) (34)  
Interest income 983 946  
Employer contributions 218 2  
Plan participants' contributions 11 12  
Benefit payments (1,158) (1,076)  
Other movements (11) (9)  
Currency translation differences 3,428 (1,777)  
At December 31 29,703 28,330 30,266
Defined benefit plan assets | UK      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 19,560 22,320  
Return on plan assets in excess of interest income (479) (2,435)  
Interest income 1,052 995  
Employer contributions 19 36  
Plan participants' contributions 16 17  
Benefit payments (1,151) (1,081)  
Other movements (22) (22)  
Currency translation differences 1,371 (270)  
At December 31 20,366 19,560 22,320
Defined benefit plan assets | USA      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 9,425 14,835  
Return on plan assets in excess of interest income 64 (566)  
Interest income 486 487  
Employer contributions 297 262  
Plan participants' contributions 0 0  
Benefit payments (732) (702)  
Other movements (11) (4,891)  
Currency translation differences 0 0  
At December 31 9,529 9,425 14,835
Defined benefit plan assets | Rest of the world      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 12,392 12,540  
Return on plan assets in excess of interest income 64 716  
Interest income 632 571  
Employer contributions 105 109  
Plan participants' contributions 6 7  
Benefit payments (864) (731)  
Other movements 68 470  
Currency translation differences 912 (1,290)  
At December 31 13,315 12,392 $ 12,540
Contributions received from the captive structure in relation to the pension plans reinsurred   108  
Defined benefit plan assets | Rest of the world | Captive structure      
Disclosure of net defined benefit liability (asset) [line items]      
Employer contributions 124    
Defined benefit plan assets | Germany      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 2,705    
At December 31 3,123 2,705  
Defined benefit plan assets | Canada (Federal)      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 3,179    
At December 31 $ 3,111 $ 3,179  
Level 1 | Equities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 12.00% 12.00%  
Level 1 | Debt securities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 62.00% 68.00%  
Level 1 | Real estate      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 2.00% 2.00%  
Level 2 and 3      
Disclosure of net defined benefit liability (asset) [line items]      
Cash and cash equivalents [D] 11.00% 3.00%  
Level 2 and 3 | Equities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 12.00% 13.00%  
Level 2 and 3 | Debt securities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 1.00% 4.00%  
Level 2 and 3 | Real estate      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 6.00% 6.00%  
Level 2 and 3 | Other      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 2.00% 1.00%  
Level 2 and 3 | Investment funds      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 3.00% 3.00%  
Level 2 and 3 | Debt repurchase agreements      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage (11.00%) (12.00%)