v3.26.1
Common shares - Calculation of basic and diluted earnings per common share and the dividend declared by the company on its outstanding common shares (Detail) - CAD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Net income (loss) per common share – basic    
Net income (loss) $ 940 $ 1,288
Weighted-average number of common shares outstanding (millions of shares) 483.6 509.0
Net income (loss) per common share (dollars) $ 1.94 $ 2.53
Net income (loss) per common share – diluted    
Net income (loss) $ 940 $ 1,288
Weighted-average number of common shares outstanding (millions of shares) 483.6 509.0
Effect of employee share-based awards (millions of shares) 1.2 1.2
Weighted-average number of common shares outstanding, assuming dilution (millions of shares) 484.8 510.2
Net income (loss) per common share (dollars) $ 1.94 $ 2.52
Dividends per common share – declared (dollars) $ 0.87 $ 0.72