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Structured Entities - Additional Information (Detail) - CAD ($) $ in Millions | 12 Months Ended
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Oct. 31, 2025 | Oct. 31, 2024
Disclosure of information about structured entities [Line Items] |  |
Fair value of transferred financial assets that are not derecognised in their entirety | $ 17,209 | $ 16,118
Associated liabilities | 16,815 | 15,598
NHA MBS US Agency MBS And CMO [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Fair value of transferred financial assets that are not derecognised in their entirety | 31,264 | 19,903
Trading securities [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Mortgage backed securities at fair value | 784 | 1,582
Other Securitization Vehicles [Member] |  |
Disclosure of information about structured entities [Line Items] |  |
Sale of CMBS to securitization vehicles | 2,111 | 1,730
Gain or loss on sale of mortgage backed securities | 24 | 19
Other Securitization Vehicles [Member] | Financial liabilities at amortised cost, category [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Financial liabilities | 181 | 169
Securities [member] | NHA MBS US Agency MBS And CMO [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Associated liabilities | 27,568 | 15,223
Securities [member] | BMO managed funds [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Assets recognised | 1,196 | 848
Securities [member] | BMO managed funds [member] | Fair Value Through Profit Or Loss [Member] |  |
Disclosure of information about structured entities [Line Items] |  |
Assets recognised | 278 | 250
Securities [member] | BMO managed funds [member] | Trading securities [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Assets recognised | 918 | 598
U.S. customer securitization vehicle [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Sale of MBS to securitization vehicles | 67,264 | 31,832
Canadian customer securitization vehicles [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Undrawn amount under liquidity facilities | 19,679 | 19,296
Funding vehicle [member] |  |
Disclosure of information about structured entities [Line Items] |  |
Commercial papers issued | $ 15,394 | $ 9,682

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- Definition Gain or loss on sale of mortgage backed securities. + References No definition available. + Details
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- Definition Mortgage backed securities at fair value. + References No definition available. + Details
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- Definition Proceeds from sale of commercial mortgaged backed securities. + References No definition available. + Details
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- Definition Proceeds from sale of mortgage backed securities. + References No definition available. + Details
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- Definition The amount of assets recognised in the entity's financial statements relating to its interests in structured entities. [Refer: Assets; Total for all unconsolidated structured entities [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2024-01-01 -Paragraph 29 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_29_a&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The amount of commercial paper issued by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 112 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Classes of financial instruments [domain]; Financial assets; Derivatives [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2024-01-01 -Paragraph 25 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_25&doctype=Standard -URIDate 2024-03-27 + Details
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