v3.26.1
Fair value of financial instruments - Changes in Fair Value Measurement for Instruments Measured on a Recurring Basis and Categorized in Level 3 (Detail) - CAD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jul. 31, 2026
Jul. 31, 2025
Jul. 31, 2026
Jul. 31, 2025
Disclosure of fair value measurement of assets and liabilities [line Items]        
Transfers into Level 3 $ 0 $ 0    
Recurring [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance     $ 931,102  
Fair value assets, ending balance 1,017,413   1,017,413  
Fair value liabilities, beginning balance     712,835  
Fair value liabilities, ending balance 758,222   758,222  
Recurring [member] | Level 3 [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 4,569 3,692 4,033 $ 4,183
Gains (losses) included in earnings (12) (276) (299) (217)
Gains (losses) included in OCI 127 7 80 38
Purchases (issuances) 1,166 195 1,967 658
Settlement (sales) and other (98) (96) (138) (1,054)
Transfers into Level 3 (50) (3) (15) (228)
Transfers out of Level 3 (130) 162 (56) 301
Fair value assets, ending balance 5,572 3,681 5,572 3,681
Gains (losses) included in earnings for positions still held 16 (251) (226) (228)
Fair value liabilities, beginning balance (188) (542) (301) (478)
Gains (losses) included in earnings (11) (51) (26) (42)
Gains (losses) included in OCI (1) (1) 2  
Purchases (issuances) (67) (208) (180) (609)
Settlement (sales) and other 38 27 95 115
Transfers into Level 3 (80) (61) (297) (271)
Transfers out of Level 3 81 267 479 716
Fair value liabilities, ending balance (228) (569) (228) (569)
Gains (losses) included in earnings for positions still held (9) (32) (13) 14
Recurring [member] | Level 3 [member] | Investment [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 741 735 745 680
Gains (losses) included in earnings 22   24  
Gains (losses) included in OCI 74 6 77 43
Purchases (issuances) 13   15 32
Settlement (sales) and other (25) (4) (36) (18)
Fair value assets, ending balance 825 737 825 737
Gains (losses) included in earnings for positions still held 22   20  
Recurring [member] | Level 3 [member] | Mortgage-backed securities [member] | Investment [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 29 31 29 31
Gains (losses) included in OCI 2 (2)   (2)
Fair value assets, ending balance 31 29 31 29
Recurring [member] | Level 3 [member] | Corporate debt and other debt [member] | Investment [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 123 134 134 143
Gains (losses) included in earnings 1   3  
Gains (losses) included in OCI 2 3 (3) 5
Settlement (sales) and other (4) (3) (12) (14)
Fair value assets, ending balance 122 134 122 134
Gains (losses) included in earnings for positions still held     2  
Recurring [member] | Level 3 [member] | Equities [member] | Investment [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 589 570 582 506
Gains (losses) included in OCI 70 5 78 40
Purchases (issuances) 13   15 32
Settlement (sales) and other (21) (1) (24) (4)
Fair value assets, ending balance 672 574 672 574
Gains (losses) included in earnings for positions still held 21      
Recurring [member] | Level 3 [member] | Interest rate contracts [member] | Net derivative balances, category [Member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance (649) (522) (608) (493)
Gains (losses) included in earnings (36) (68) (69) (103)
Gains (losses) included in OCI   1   3
Purchases (issuances) (4) 34 9 (5)
Settlement (sales) and other (23) (42) (20) (37)
Transfers into Level 3 2 (28) 2 (19)
Transfers out of Level 3 (4) (21) (28) 8
Fair value assets, ending balance (714) (646) (714) (646)
Gains (losses) included in earnings for positions still held (35) (81) (62) (115)
Recurring [member] | Level 3 [member] | Foreign exchange contracts [member] | Net derivative balances, category [Member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance (42) (53) 56 (51)
Gains (losses) included in earnings 60 7 (65) (4)
Gains (losses) included in OCI (2) (1) (2) 2
Purchases (issuances) 9 1 (40) 2
Settlement (sales) and other     32 (1)
Transfers into Level 3 0   10  
Transfers out of Level 3 14   33 6
Fair value assets, ending balance 24 (46) 24 (46)
Gains (losses) included in earnings for positions still held 59 7 57 (16)
Recurring [member] | Level 3 [member] | Credit Derivatives [Member] | Net derivative balances, category [Member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 1   2  
Gains (losses) included in earnings     (2)  
Fair value assets, ending balance 0   0  
Gains (losses) included in earnings for positions still held     (1)  
Recurring [member] | Level 3 [member] | Other contracts [member] | Net derivative balances, category [Member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance (273) (392) (256) (303)
Gains (losses) included in earnings (43) (48) (48) 32
Gains (losses) included in OCI (9) (2) (3) 1
Purchases (issuances) 9 (22) (7) (34)
Settlement (sales) and other 36 (7) 44  
Transfers into Level 3 (62) (27) (171) (301)
Transfers out of Level 3 87 202 186 309
Fair value assets, ending balance (255) (296) (255) (296)
Gains (losses) included in earnings for positions still held (20) (34) (99) 75
Recurring [member] | Level 3 [member] | Valuation adjustments [member] | Net derivative balances, category [Member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance (72) 25 (79) 18
Purchases (issuances) 0 0 (29) 6
Settlement (sales) and other 36 (7) 72 (6)
Fair value assets, ending balance (36) 18 (36) 18
Recurring [member] | Level 3 [member] | Other assets [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 2 5 4 7
Settlement (sales) and other (1) (1) (3) (3)
Fair value assets, ending balance 1 4 1 4
Recurring [member] | Level 3 [member] | Loans [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 1,835 1,207 1,274 1,781
Gains (losses) included in earnings (17) (63) (95) 32
Gains (losses) included in OCI 10 (3) 4 (3)
Purchases (issuances) 646 20 1,194 161
Settlement (sales) and other (58) (1) (60) (815)
Transfers into Level 3 0   106 7
Transfers out of Level 3 (227) (11) (234) (14)
Fair value assets, ending balance 2,189 1,149 2,189 1,149
Gains (losses) included in earnings for positions still held (15) (62) (118) (43)
Recurring [member] | Level 3 [member] | Trading Securities [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 3,026 2,687 2,895 2,544
Gains (losses) included in earnings 3 (104) (44) (174)
Gains (losses) included in OCI 54 6 4 (8)
Purchases (issuances) 493 162 825 496
Settlement (sales) and other (48) (34) (167) (174)
Transfers into Level 3 10 52 38 85
Transfers out of Level 3 0 (8) (13) (8)
Fair value assets, ending balance 3,538 2,761 3,538 2,761
Gains (losses) included in earnings for positions still held 6 (81) (23) (129)
Recurring [member] | Level 3 [member] | Trading Securities [member] | Corporate debt and other debt [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 17 32 32  
Gains (losses) included in earnings     (1)  
Gains (losses) included in OCI     (1)  
Purchases (issuances) 1 3 2 3
Settlement (sales) and other 0 (3) (1) (3)
Transfers into Level 3   51   83
Transfers out of Level 3 0   (13)  
Fair value assets, ending balance 18 83 18 83
Recurring [member] | Level 3 [member] | Trading Securities [member] | Equities [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value assets, beginning balance 3,009 2,655 2,863 2,544
Gains (losses) included in earnings 3 (104) (43) (174)
Gains (losses) included in OCI 54 6 5 (8)
Purchases (issuances) 492 159 823 493
Settlement (sales) and other (48) (31) (166) (171)
Transfers into Level 3 10 1 38 2
Transfers out of Level 3       (8)
Fair value assets, ending balance 3,520 2,678 3,520 2,678
Gains (losses) included in earnings for positions still held 6 (81) (23) (129)
Recurring [member] | Level 3 [member] | Deposits - Personal [member]        
Disclosure of fair value measurement of assets and liabilities [line Items]        
Fair value liabilities, beginning balance (188) (542) (301) (478)
Gains (losses) included in earnings (11) (51) (26) (42)
Gains (losses) included in OCI (1) (1) 2  
Purchases (issuances) (67) (208) (180) (609)
Settlement (sales) and other 38 27 95 115
Transfers into Level 3 (80) (61) (297) (271)
Transfers out of Level 3 81 267 479 716
Fair value liabilities, ending balance (228) (569) (228) (569)
Gains (losses) included in earnings for positions still held $ (9) $ (32) $ (13) $ 14