Adoption of amended accounting standards (Details) - CAD ($) $ in Millions |
Jun. 30, 2026 |
Mar. 31, 2026 |
Jan. 01, 2026 |
Dec. 31, 2025 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|---|---|---|---|---|
| Adoption Of Amended Accounting Standards [Line Items] | |||||||
| Cash | $ 477 | $ 1,367 | $ 314 | $ 507 | $ 1,049 | $ 1,572 | |
| Trade and other receivables | 4,173 | 4,474 | |||||
| Trade payables and other liabilities | $ 4,167 | $ 4,392 | |||||
| Impact of Amendments to IFRS 9 and IFRS 7 | |||||||
| Adoption Of Amended Accounting Standards [Line Items] | |||||||
| Cash | $ 107 | ||||||
| Trade and other receivables | 2 | ||||||
| Trade payables and other liabilities | 109 | ||||||
| Upon adoption of Amendments to IFRS 9 and IFRS 7 | |||||||
| Adoption Of Amended Accounting Standards [Line Items] | |||||||
| Cash | 421 | ||||||
| Trade and other receivables | 4,476 | ||||||
| Trade payables and other liabilities | $ 4,501 |