v3.25.2
Retirement benefits - Summary of Defined Benefit Plan Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 $ 2,904    
Return on plan assets in excess of interest income (1,243) $ 20,612 $ (8,185)
Other movements (44) 349 (5)
At December 31 1,602 2,904  
Defined benefit plan assets      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 76,756 104,495  
Return on plan assets in excess of interest income 1,243 (20,612)  
Interest income 3,417 1,732  
Employer contributions 704 731  
Plan participants' contributions 34 32  
Benefit payments (3,706) (3,889)  
Other movements (18) (58)  
Currency translation differences 1,531 (5,675)  
At December 31 79,961 76,756 104,495
Defined benefit plan assets | The Netherlands      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 27,986 37,096  
Return on plan assets in excess of interest income 833 (6,576)  
Interest income 1,035 314  
Employer contributions 419 228  
Plan participants' contributions 11 11  
Benefit payments (1,032) (942)  
Other movements (6) (9)  
Currency translation differences 1,020 (2,136)  
At December 31 30,266 27,986 37,096
Defined benefit plan assets | UK      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 21,963 33,720  
Return on plan assets in excess of interest income (999) (8,682)  
Interest income 1,094 552  
Employer contributions 34 54  
Plan participants' contributions 16 16  
Benefit payments (1,014) (1,124)  
Other movements (16) 150  
Currency translation differences 1,242 (2,723)  
At December 31 22,320 21,963 33,720
Defined benefit plan assets | USA      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 14,243 18,055  
Return on plan assets in excess of interest income 609 (3,523)  
Interest income 679 406  
Employer contributions 274 408  
Plan participants' contributions 0 0  
Benefit payments (957) (1,088)  
Other movements (13) (15)  
Currency translation differences 0 0  
At December 31 14,835 14,243 18,055
Defined benefit plan assets | Rest of the world      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 12,564 15,624  
Return on plan assets in excess of interest income 800 (1,831)  
Interest income 609 460  
Employer contributions (23) 41  
Plan participants' contributions 7 5  
Benefit payments (703) (735)  
Other movements 17 (184)  
Currency translation differences (731) (816)  
At December 31 12,540 12,564 $ 15,624
Contributions received from the captive structure in relation to the pension plans reinsurred 225    
Defined benefit plan assets | Germany      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 2,538    
At December 31 2,730 2,538  
Defined benefit plan assets | Canada (Federal)      
Disclosure of net defined benefit liability (asset) [line items]      
At January 1 3,497    
At December 31 $ 3,504 $ 3,497  
Level 1 | Equities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 12.00% 13.00%  
Level 1 | Debt securities      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 71.00% 70.00%  
Level 1 | Real estate      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 1.00% 0.00%  
Level 1 | Other      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 0.00% 1.00%  
Level 2 and 3      
Disclosure of net defined benefit liability (asset) [line items]      
Cash 1.00% 4.00%  
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 4.00% 2.00%  
Level 2 and 3 | Real estate      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 7.00% 7.00%  
Level 2 and 3 | Investment funds      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage 3.00% 4.00%  
Level 2 and 3 | Debt repurchase agreements      
Disclosure of net defined benefit liability (asset) [line items]      
Defined benefit plan asset allocation percentage (11.00%) (14.00%)