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Acquisitions and Divestitures - Additional Information (Detail) $ in Millions, $ in Millions |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Oct. 16, 2025 CAD ($) Branches | Oct. 16, 2025 USD ($) | Oct. 31, 2025 CAD ($) | Nov. 01, 2025 CAD ($) | Oct. 16, 2025 USD ($) Branches
Disclosure of business acquisitions by acquisition assets acquired and liabilities assumed [line items] |  |  |  |  |
Impairment loss recognised in profit or loss, goodwill |  |  | $ 102 |  |
First-Citizens & Trust Company [Member] |  |  |  |  |
Disclosure of business acquisitions by acquisition assets acquired and liabilities assumed [line items] |  |  |  |  |
Impairment loss recognised in profit or loss, goodwill | $ 102 | $ 73 |  |  |
Deposits held for sale | 8,000 |  |  |  | $ 5,700
Loans held for sale | $ 1,500 |  |  |  | $ 1,100
Percentage Of Net Deposit Premium | 5.00% |  |  |  | 5.00%
Number of Branches to be Sold | Branches | 138 |  |  |  | 138
Burgundy Asset Management Ltd [Member] | Major business combination [member] |  |  |  |  |
Disclosure of business acquisitions by acquisition assets acquired and liabilities assumed [line items] |  |  |  |  |
Consideration transferred, acquisition-date fair value |  |  |  | $ 654 |
Equity interests of acquirer |  |  |  | 593 |
Cash transferred |  |  |  | $ 61 |

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