XML 234 R191.htm IDEA: XBRL DOCUMENT
v3.25.3

Related Party Transactions - Additional Information (Detail) - Key management personnel directors and their close family members [member] - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Oct. 31, 2025 | Oct. 31, 2024
Disclosure of transactions between related parties [line items] |  |
Loans to related party | $ 23 | $ 19
Allowance for credit losses | $ 0 | $ 0

X
- Definition The cash outflow for loans and advances made to related parties. [Refer: Total for all related parties [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2024-01-01 -Paragraph 16 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_16&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_CashAdvancesAndLoansMadeToRelatedParties
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of provisions for doubtful debts related to the amount of outstanding balances in related party transactions. [Refer: Provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 24 -IssueDate 2024-01-01 -Paragraph 18 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_18_c&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_ProvisionsForDoubtfulDebtsRelatedToOutstandingBalancesOfRelatedPartyTransaction
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_CategoriesOfRelatedPartiesAxis=bmo_KeyManagementPersonnelDirectorsAndTheirCloseFamilyMembersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |