XML 123 R80.htm IDEA: XBRL DOCUMENT
v3.25.3

Loans and Allowance for Credit Losses - Summary of Continuity in Loss Allowance by Each Product Type (Parenthetical) (Detail) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Oct. 31, 2025 | Oct. 31, 2024
Other assets [member] |  |
Disclosure of credit risk exposure [line items] |  |
Provision for credit losses | $ (1) | $ 10

X
- Definition Provision for credit losses. + References No definition available. + Details
Name: | bmo_ProvisionForCreditLosses
Namespace Prefix: | bmo_
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_DisclosureOfCreditRiskExposureLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfAssetsAxis=ifrs-full_OtherAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |