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Fair Value Measurements and Trading-Related Revenue - Summary of Changes in Level 3 Instruments Carried At Fair Value (Detail) - Valued using models (without observable inputs) [member] - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Oct. 31, 2025 | Oct. 31, 2024
Corporate equity [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | $ 4,899 |
Assets at end of period | 6,016 | $ 4,899
Trading securities [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 4 | 37
Purchases/Issuances | 7 | 45
Sales | (5) | (41)
Transfers out of Level 3 | (6) | (37)
Assets at end of period |  | 4
Trading securities [member] | NHA MBS US Agency MBS And CMO [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Purchases/Issuances | 5 | 41
Sales | (5) | (41)
Trading securities [member] | Corporate equity [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 4 | 37
Purchases/Issuances | 2 | 4
Transfers out of Level 3 | (6) | (37)
Assets at end of period |  | 4
Financial assets at fair value through profit or loss [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 4,934 | 4,235
Change in fair value included in earnings | (95) | (172)
Change in fair value included in other comprehensive income | 17 | 11
Purchases/Issuances | 1,182 | 1,086
Sales | (252) | (240)
Maturities/Settlement |  | (1)
Transfers into Level 3 | 82 | 16
Transfers out of Level 3 | (44) | (1)
Assets at end of period | 5,824 | 4,934
Change in unrealized gains (losses) recorded in income for instruments still held | 37 | 47
Financial assets at fair value through profit or loss [member] | Corporate debt [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 35 | 27
Change in fair value included in earnings | 1 | (10)
Purchases/Issuances | 2 | 18
Transfers out of Level 3 | (38) |
Assets at end of period |  | 35
Change in unrealized gains (losses) recorded in income for instruments still held | 1 | (10)
Financial assets at fair value through profit or loss [member] | Corporate equity [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 4,899 | 4,208
Change in fair value included in earnings | (96) | (162)
Change in fair value included in other comprehensive income | 17 | 11
Purchases/Issuances | 1,180 | 1,068
Sales | (252) | (240)
Maturities/Settlement |  | (1)
Transfers into Level 3 | 82 | 16
Transfers out of Level 3 | (6) | (1)
Assets at end of period | 5,824 | 4,899
Change in unrealized gains (losses) recorded in income for instruments still held | 36 | 57
Financial assets at fair value through other comprehensive income, category [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 177 | 160
Change in fair value included in other comprehensive income | (14) | 13
Purchases/Issuances | 29 | 4
Assets at end of period | 192 | 177
Financial assets at fair value through other comprehensive income, category [member] | Corporate equity [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 177 | 160
Change in fair value included in other comprehensive income | (14) | 13
Purchases/Issuances | 29 | 4
Assets at end of period | 192 | 177
Business and government loans [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 302 | 186
Change in fair value included in earnings | (21) |
Change in fair value included in other comprehensive income | 4 |
Purchases/Issuances | 62 | 89
Maturities/Settlement | (52) | (171)
Transfers into Level 3 | 29 | 198
Assets at end of period | 324 | 302
Change in unrealized gains (losses) recorded in income for instruments still held | (21) |
Other assets [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 1,717 | 1,723
Change in fair value included in earnings | (67) | 30
Purchases/Issuances | 277 | 86
Sales | (7) | (21)
Maturities/Settlement | (437) | (101)
Assets at end of period | 1,483 | 1,717
Change in unrealized gains (losses) recorded in income for instruments still held | (63) | 47
Derivatives Asset [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 12 | 5
Change in fair value included in earnings | (1) | (3)
Purchases/Issuances | 48 | 10
Maturities/Settlement | (43) |
Transfers into Level 3 | 18 | 13
Transfers out of Level 3 | (9) | (13)
Assets at end of period | 25 | 12
Change in unrealized gains (losses) recorded in income for instruments still held | 1 | (3)
Equity contracts [member] | Derivatives Asset [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Change in fair value included in earnings | 2 |
Transfers into Level 3 | 17 | 13
Transfers out of Level 3 | (9) | (13)
Assets at end of period | 10 |
Change in unrealized gains (losses) recorded in income for instruments still held | 2 |
Credit default swaps [member] | Derivatives Asset [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Maturities/Settlement | (1) |
Transfers into Level 3 | 1 |
Commodity contracts [member] | Derivatives Asset [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 2 | 5
Change in fair value included in earnings | 11 | (3)
Assets at end of period | 13 | 2
Change in unrealized gains (losses) recorded in income for instruments still held | 12 | (3)
Foreign exchange contracts [member] | Derivatives Asset [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Assets at beginning of period | 10 |
Change in fair value included in earnings | (14) |
Purchases/Issuances | 48 | 10
Maturities/Settlement | (42) |
Assets at end of period | 2 | 10
Change in unrealized gains (losses) recorded in income for instruments still held | (13) |
Derivatives Liabilities [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Liabilities at beginning of period | 7 | 11
Change in fair value included in earnings | (1) | 2
Maturities/Settlement | (1) |
Transfers into Level 3 | 3 | 3
Transfers out of Level 3 | (3) | (9)
Liabilities at end of period | 5 | 7
Change in unrealized gains (losses) recorded in income for instruments still held | (1) | 3
Derivatives Liabilities [member] | Equity contracts [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Liabilities at beginning of period | 2 | 8
Change in fair value included in earnings | 3 | 1
Transfers into Level 3 | 3 | 2
Transfers out of Level 3 | (3) | (9)
Liabilities at end of period | 5 | 2
Change in unrealized gains (losses) recorded in income for instruments still held | 3 | 1
Derivatives Liabilities [member] | Credit default swaps [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Liabilities at beginning of period | 1 | 2
Change in fair value included in earnings |  | (2)
Maturities/Settlement | (1) |
Transfers into Level 3 |  | 1
Liabilities at end of period |  | 1
Change in unrealized gains (losses) recorded in income for instruments still held |  | (1)
Derivatives Liabilities [member] | Commodity contracts [member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Liabilities at beginning of period | 4 | 1
Change in fair value included in earnings | (4) | 3
Liabilities at end of period |  | 4
Change in unrealized gains (losses) recorded in income for instruments still held | $ (4) | 3
Other Liabilities [Member] |  |
Disclosure of reconciliation of changes in fair value measurement assets liabilities [line items] |  |
Liabilities at beginning of period |  | 5
Purchases/Issuances |  | 8
Maturities/Settlement |  | $ (13)

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