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Equity - Summary of Classes of Preferred and Common Shares Outstanding (Parenthetical) (Detail) $ in Millions, $ in Millions |  | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Nov. 12, 2025 | Oct. 31, 2025 USD ($) shares | Oct. 31, 2025 CAD ($) shares | Jul. 29, 2025 USD ($) | Oct. 31, 2024 shares
4.300% LRCNs, Series 1 [member] |  |  |  |  |
Disclosure of classes of share capital [line items] |  |  |  |  |
Interest Rate | 4.30% |  |  |  |
Other Equity Instruments [member] | 4.300% LRCNs, Series 1 [member] |  |  |  |  |
Disclosure of classes of share capital [line items] |  |  |  |  |
Note issued face value |  |  | $ 1,250 |  |
Interest Rate |  | 4.30% |  |  |
Other Equity Instruments [member] | 6.875% LRCNs, Series 6 [member] |  |  |  |  |
Disclosure of classes of share capital [line items] |  |  |  |  |
Note issued face value |  | $ 1,000 |  | $ 1,000 |
Interest Rate |  | 6.875% |  |  |
Treasury shares [member] |  |  |  |  |
Disclosure of classes of share capital [line items] |  |  |  |  |
Number of shares | shares |  | 0 | 0 |  | 55,172

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