Loans - Summary of Allowance for Credit Losses under IFRS 9 (Parenthetical) (Detail) - CAD ($) $ in Millions	12 Months Ended
Oct. 31, 2020	Oct. 31, 2019
Disclosure of detailed information about borrowings [line items]
Expected credit loss allowance on debt securities classified at amortized cost	$ 16	$ 2
Stage 3 [member] \| Financial assets at amortised cost, class [member]
Disclosure of detailed information about borrowings [line items]
Expected credit loss allowance on debt securities classified at amortized cost	$ 14

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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