Other long-term obligations - Summary of Other Long-Term Obligations (Detail) - CAD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Other Liabilities Disclosure [Abstract] | ||
| Employee retirement benefits | $ 828 | $ 846 |
| Asset retirement obligations and other environmental liabilities | 2,607 | 2,641 |
| Share-based incentive compensation liabilities | 197 | 119 |
| Operating lease liability | 147 | 144 |
| Other obligations | 122 | 120 |
| Total other long-term obligations | $ 3,901 | $ 3,870 |
| X | ||||||||||
- Definition Asset retirement obligation and other environmental liabilities, noncurrent. No definition available.
|
| X | ||||||||||
- Definition Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable after one year (or the operating cycle, if longer). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Obligations not otherwise itemized or categorized in the footnotes to the financial statements that are expected to be paid after one year (or the normal operating cycle, if longer), from the balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|