XML 125 R82.htm IDEA: XBRL DOCUMENT v3.25.3

Loans and Allowance for Credit Losses - Summary of Credit Risk Exposures for Loans Carried at Amortized Cost, FVOCI or FVTPL (Parenthetical) (Detail) - CAD ($) $ in Millions	12 Months Ended
	Oct. 31, 2025	Oct. 31, 2024
Stage 3 [member]
Disclosure of credit risk exposure [line items]
Percentage of collateralized loan	94.00%	92.00%
Credit Card Loans [member] | Principal [member] | Bottom of range [member]
Disclosure of credit risk exposure [line items]
Number of days for which the loan receivable is overdue for the loans to be written off	180 days	180 days
Credit Card Loans [member] | Interest [member] | Bottom of range [member]
Disclosure of credit risk exposure [line items]
Number of days for which the loan receivable is overdue for the loans to be written off	180 days	180 days
Residential mortgages [member] | FVTPL loans [member] | Stage 1 [member]
Disclosure of credit risk exposure [line items]
FVTPL loans	$ 79	$ 163
Business and government loans [member] | FVTPL loans [member] | Stage 1 [member]
Disclosure of credit risk exposure [line items]
FVTPL loans	$ 13,231	$ 12,431

X

- Definition

Loans and receivables carried at fair value through profit or loss.

+ References

No definition available.

+ Details

Name:	bmo_LoansAndReceivablesCarriedAtFairValueThroughProfitOrLoss
Namespace Prefix:	bmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Number of days for which the loan receivable is overdue for the loans to be written off.

+ References

No definition available.

+ Details

Name:	bmo_NumberOfDaysForWhichTheLoanReceivableIsOverdueForTheLoansToBeWrittenOff
Namespace Prefix:	bmo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of collateralized loan.

+ References

No definition available.

+ Details

Name:	bmo_PercentageOfCollateralizedLoan
Namespace Prefix:	bmo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

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_ImpairmentOfFinancialAssetsAxis=bmo_StageThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=bmo_CreditCardLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	bmo_ComponentOfLoanReceivableAxis=bmo_PrincipalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	bmo_ComponentOfLoanReceivableAxis=bmo_InterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=bmo_ResidentialMortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis=bmo_FairValueThroughProfitOrLossLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ImpairmentOfFinancialAssetsAxis=bmo_StageOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=bmo_BusinessAndGovernmentLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: