Pension and other postretirement benefits - Schedule of Benefit Obligations in Excess of Plan Assets (Details) - Pension Plan - USD ($) $ in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| U.S. | ||
| Defined benefit pension plans with projected benefit obligations in excess of plan assets: | ||
| Projected benefit obligation | $ 77 | $ 79 |
| Fair value of plan assets | 0 | 0 |
| Non-U.S. | ||
| Defined benefit pension plans with projected benefit obligations in excess of plan assets: | ||
| Projected benefit obligation | 60 | 60 |
| Fair value of plan assets | $ 0 | $ 0 |