Long-term debt - Table Narrative (Detail) - CAD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Debt Disclosure [Abstract] | ||
| Maximum long-term borrowing from affiliate | $ 7,750,000,000 | |
| Cancellation period long-term borrowing from affiliate, days | 370 days | |
| Average effective rate for affiliate long-term borrowing | 2.70% | 3.90% |
| Finance lease obligations for marine services, average imputed rate | 5.80% | 4.80% |
| Finance lease, liability current | $ 19,000,000 | $ 18,000,000 |
| Principal payments on finance lease, year two | 17,000,000 | |
| Principal payments on finance lease, year three | 17,000,000 | |
| Principal payments on finance lease, year four | 17,000,000 | |
| Principal payments on finance lease, year five | $ 17,000,000 | |
| X | ||||||||||
- Definition Cancelation period long term borrowing from affiliate. No definition available.
|
| X | ||||||||||
- Definition Finance lease obligation average imputed rate. No definition available.
|
| X | ||||||||||
- Definition Maximum long term borrowing from affiliate. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Present value of lessee's discounted obligation for lease payments from finance lease, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fourth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in third rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of lessee's undiscounted obligation for lease payments for finance lease, due in second rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|