Financial risk management activities - Narrative (Details) $ in Millions |
Jun. 30, 2025
USD ($)
|
Dec. 31, 2024
USD ($)
|
Dec. 31, 2023
USD ($)
|
|---|---|---|---|
| Disclosure of detailed information about financial instruments [line items] | |||
| Contingent consideration asset | $ 79 | $ 48 | $ 48 |
| Mponeng | |||
| Disclosure of detailed information about financial instruments [line items] | |||
| Contingent consideration asset | $ 19 | ||
| Discount rates applied to consideration projections | 0.073 | 0.080 | |
| Gramalote | |||
| Disclosure of detailed information about financial instruments [line items] | |||
| Contingent consideration asset | $ 26 | ||
| Discount rates applied to consideration projections | 0.094 | 0.094 | |
| Mansala and ABC | |||
| Disclosure of detailed information about financial instruments [line items] | |||
| Contingent consideration asset | $ 34 | ||
| Discount rates applied to consideration projections | 0.090 | 0.120 |