Pension and other postretirement benefits (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Defined contribution plan, cost | $ 21 | $ 21 | $ 50 | $ 48 |
| Contributions to union-sponsored multiemployer pension plans | 11 | 11 | 17 | 17 |
| Pension Plan | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Net periodic pension benefit costs | 2 | 1 | 5 | 3 |
| Other Postretirement Benefits Plan | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Net periodic pension benefit costs | $ 2 | $ 1 | $ 2 | $ 2 |