v3.26.1
Share based payments - Restricted Stock Units RSUs (Details)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
shares
Jun. 30, 2025
USD ($)
Dec. 31, 2024
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Number of shares on conversion (in shares) | shares 1    
Total share based payment expense | $ $ 52 $ 55  
Restricted stock units (RSUs)      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Number of shares on conversion (in shares) | shares 1    
Vesting period     4 years
Vesting percentage 0.25    
Total share based payment expense | $ $ 59 $ 56  
Restricted stock units (RSUs) | Non-executive director | Prior To 2024 Grants      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period 4 years    
Restricted stock units (RSUs) | Non-executive director | 2024 & 2025 Grants      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period 1 year    
Holding period 3 years    
Restricted stock units (RSUs) | Non-executive director | January 1, 2026 Grants      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Holding period 4 years