Loans and Allowance for Credit Losses - Summary of Gross Carrying Amount of Loans Measured at Amortized Cost (Parenthetical) (Detail) - CAD ($) $ in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Apr. 30, 2026 |
Oct. 31, 2025 |
|
| Financial instruments purchased or originated credit-impaired [member] | ||
| Disclosure of credit risk exposure [line items] | ||
| Purchased Credit Impaired Loan | $ 197 | $ 195 |