Income taxes - Other (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 53 | $ 30 |
| Deferred tax liability (asset) | 0 | |
| Benefits recognized for non-capital losses | 2 | 4 |
| Deferred tax assets | 14 | $ 23 |
| Unused Tax Losses Dependent on Future Earnings | ||
| Temporary differences | ||
| Deferred tax assets | 4 | |
| Indefinite | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | 8 | |
| 20 Years | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 37 | |
| Carryforward period | 20 years | |
| 5 Years | ||
| Temporary differences | ||
| Tax losses incurred for which no deferred tax asset is recognized | $ 8 | |
| Carryforward period | 5 years | |