Income taxes - Other (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 56 | $ 53 |
| Deferred tax liability (asset) | 0 | |
| Benefits recognized for non-capital losses | 1 | 2 |
| Deferred tax assets | 29 | $ 14 |
| Unused Tax Losses Dependent on Future Earnings | ||
| Temporary differences | ||
| Deferred tax assets | 15 | |
| Indefinite | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | 6 | |
| 20 Years | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 38 | |
| Carryforward period | 20 years | |
| 5 Years | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 12 | |
| Carryforward period | 5 years | |