Pensions and similar obligations - Summary of Changes in Unrecognized Assets (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure of changes in unrecognized assets of defined benefit plans [abstract] | |||
| Irrecoverable surplus impact at 1 January | $ (63) | $ (38) | $ (43) |
| Interest expense | (7) | (4) | (4) |
| Changes excluding amounts included in interest expense | (25) | (21) | 9 |
| Irrecoverable surplus impact at 31 December | $ (95) | $ (63) | $ (38) |