Employee Future Benefits - Weighted Average Duration of the Defined Benefit Obligations (Detail) - yr |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Pension plans | U.S. plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration (in years) of the defined benefit obligations | 8.0 | 8.0 |
| Pension plans | Canadian plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration (in years) of the defined benefit obligations | 9.9 | 10.1 |
| Retiree welfare plans | U.S. plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration (in years) of the defined benefit obligations | 7.5 | 7.7 |
| Retiree welfare plans | Canadian plans | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration (in years) of the defined benefit obligations | 10.5 | 10.9 |