Pension plans and other postretirement benefits - Additional Information (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Retirement Benefits [Abstract] | ||||
| Defined contribution pension and retirement savings plans total expense | $ 40 | $ 40 | $ 90 | $ 85 |