Financial assets and liabilities - Financing activity (Details) - USD ($) |
3 Months Ended | 6 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
Jan. 29, 2026 |
|
| Financial assets and liabilities | ||||||
| Lease obligations | $ 325,000,000 | $ 325,000,000 | $ 368,000,000 | |||
| Principal repayments of leases. | 29,000,000 | $ 26,000,000 | 74,000,000 | $ 51,000,000 | ||
| New lease liabilities incurred during the year | 38,000,000 | |||||
| Proceeds from borrowings | 145,000,000 | |||||
| Reduction In Lease Liabilities due to Disposal Of Lease | 5,000,000 | |||||
| Reduction In Lease Liabilities due to Repayment. | 74,000,000 | |||||
| Reduction In Lease Liabilities due to Foreign Currency Movements. | 2,000,000 | |||||
| Global Asset Based Loan Facility | ||||||
| Financial assets and liabilities | ||||||
| Proceeds from borrowings | 28,000,000 | $ 0 | ||||
| Maximum Cash Capacity | 361,000,000 | 361,000,000 | ||||
| Notional amount | $ 450,000,000 | $ 450,000,000 | $ 450,000,000 | |||