Derivative financial instruments - Change in fair value of the derivative instruments (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Derivative financial instruments | ||||
| Change in fair value of derivative instruments | $ 6.7 | $ 1.4 | $ (12.5) | $ 4.5 |
| Embedded options within listed bonds | ||||
| Derivative financial instruments | ||||
| Change in fair value of derivative instruments | 17.6 | $ 1.4 | 11.4 | 4.3 |
| Foreign exchange swaps | ||||
| Derivative financial instruments | ||||
| Change in fair value of derivative instruments | $ 0.2 | |||
| Nondeliverable forwards | ||||
| Derivative financial instruments | ||||
| Change in fair value of derivative instruments | $ (10.9) | $ (23.9) | ||