Earnings per share (Details) - CAD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Earnings per share [abstract] | ||||
| Net earnings attributable to common shareholders - basic | $ 558 | $ 579 | $ 1,174 | $ 1,209 |
| Dividends declared per common share (in dollars) (CAD per share) | $ 0.4375 | $ 0.4375 | $ 0.8750 | $ 1.4350 |
| Weighted average number of common shares outstanding (in millions) | ||||
| Weighted average number of common shares outstanding - basic (in shares) | 932,500,000 | 930,900,000 | 932,500,000 | 925,600,000 |
| Assumed exercise of stock options (in shares) | 0 | 0 | 0 | 0 |
| Weighted average number of common shares outstanding - diluted (in millions) (in shares) | 932,500,000 | 930,900,000 | 932,500,000 | 925,600,000 |
| Shares excluded from calculation of earnings per share (in shares) | 8,762,229 | 5,503,174 | 8,762,229 | 5,503,174 |