Significant capital and funding transactions - Summary of Common Shares Issued (Detail) - CAD ($) shares in Thousands, $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jul. 31, 2026 |
Jul. 31, 2025 |
Jul. 31, 2026 |
Jul. 31, 2025 |
|
| Disclosure of classes of share capital [line items] | ||||
| Issued in connection with share-based compensation plans | $ (19) | $ 4 | $ (88) | $ 23 |
| Purchased for cancellation | $ (1,603) | $ (955) | $ (4,236) | $ (1,781) |
| Ordinary shares [member] | ||||
| Disclosure of classes of share capital [line items] | ||||
| Issued in connection with share-based compensation plans, shares | 741 | 227 | 1,393 | 601 |
| Purchased for cancellation, shares | (5,620) | (5,445) | (17,231) | (10,400) |
| Increase (decrease) in number of ordinary shares issued, shares | (4,879) | (5,218) | (15,838) | (9,799) |
| Issued in connection with share-based compensation plans | $ 78 | $ 22 | $ 148 | $ 58 |
| Purchased for cancellation | (84) | (81) | (257) | (155) |
| Increase (decrease) in equity | $ (6) | $ (59) | $ (109) | $ (97) |