Loans and Allowance for Credit Losses - Summary of Credit Risk Exposures for Loans Carried at Amortized Cost, FVOCI or FVTPL (Detail) - CAD ($) $ in Millions	Oct. 31, 2025	Oct. 31, 2024
Disclosure of credit risk exposure [line items]
ACL	$ 5,739	$ 4,936
Residential mortgages [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	195,787	190,829
Residential mortgages [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	196,033	191,080
ACL	246	251
Residential mortgages [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	903	657
Residential mortgages [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1	1
Residential mortgages [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	111,143	92,361
Residential mortgages [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	53,199	67,191
Residential mortgages [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	13,761	12,731
Residential mortgages [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	3,272	2,890
Residential mortgages [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	13,754	15,249
Consumer installment and other personal loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	91,867	91,889
Consumer installment and other personal loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	92,741	92,687
ACL	874	798
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	627	577
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	9,985	9,307
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	21,997	21,369
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	28,920	30,700
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	12,557	12,931
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,834	2,806
Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	15,821	14,997
Credit Card Loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	11,997	13,030
Credit Card Loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	12,649	13,612
ACL	652	582
Credit Card Loans [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,643	1,660
Credit Card Loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,133	2,167
Credit Card Loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,926	2,170
Credit Card Loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	4,741	5,368
Credit Card Loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,824	1,668
Credit Card Loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	382	579
Business and government loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	378,221	382,627
Business and government loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	381,499	385,352
ACL	3,278	2,725
Business and government loans [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	5,561	4,609
Business and government loans [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	192,580	195,179
Business and government loans [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	161,769	162,791
Business and government loans [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	21,589	22,773
Loan commitments and financial guarantee contracts issued [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	293,646	283,360
Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
ACL	689	580
Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	1,660	1,373
Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	204,457	198,919
Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	79,126	74,824
Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	9,092	8,824
Gross Total Loans And Acceptances [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	682,922	682,731
Net Total Loans And Acceptances [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	677,872	678,375
Gross commitments and financial guarantee contracts [Member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	294,335	283,940
Stage One [member] \| Residential mortgages [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	180,482	160,663
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	180,538	160,719
ACL	56	56
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1	1
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	110,299	86,730
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	50,148	52,111
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	7,048	7,402
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	240	268
Stage One [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	12,802	14,207
Stage One [member] \| Consumer installment and other personal loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	80,475	78,286
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	80,657	78,469
ACL	182	183
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	9,984	9,162
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	21,962	20,466
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	26,238	26,125
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	6,991	7,405
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	670	789
Stage One [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	14,812	14,522
Stage One [member] \| Credit Card Loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	9,895	11,495
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	10,020	11,656
ACL	125	161
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,643	1,660
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,129	2,166
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,846	2,110
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	3,550	4,544
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	592	746
Stage One [member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	260	430
Stage One [member] \| Business and government loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	327,143	338,950
Stage One [member] \| Business and government loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	327,899	339,693
ACL	756	743
Stage One [member] \| Business and government loans [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	188,707	191,742
Stage One [member] \| Business and government loans [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	139,069	147,713
Stage One [member] \| Business and government loans [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	123	238
Stage One [member] \| Loan commitments and financial guarantee contracts issued [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	268,056	266,133
Stage One [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
ACL	256	235
Stage One [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	202,913	198,132
Stage One [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	65,393	68,177
Stage One [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	6	59
Stage One [member] \| Gross Total Loans And Acceptances [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	599,114	590,537
Stage One [member] \| Net Total Loans And Acceptances [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	597,995	589,394
Stage One [member] \| Gross commitments and financial guarantee contracts [Member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	268,312	266,368
Stage Two [Member] \| Residential mortgages [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	14,414	29,519
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	14,592	29,704
ACL	178	185
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	844	5,631
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	3,051	15,080
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	6,713	5,329
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	3,032	2,622
Stage Two [Member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	952	1,042
Stage Two [Member] \| Consumer installment and other personal loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	10,925	13,194
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	11,457	13,641
ACL	532	447
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Exceptionally low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1	145
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	35	903
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,682	4,575
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	5,566	5,526
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,164	2,017
Stage Two [Member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,009	475
Stage Two [Member] \| Credit Card Loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,102	1,535
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	2,629	1,956
ACL	527	421
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Very low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	4	1
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Low probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	80	60
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Medium probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,191	824
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| High probability of default [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	1,232	922
Stage Two [Member] \| Credit Card Loans [member] \| Gross carrying amount [member] \| Not Rated [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	122	149
Stage Two [Member] \| Business and government loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	46,319	39,543
Stage Two [Member] \| Business and government loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	48,039	41,050
ACL	1,720	1,507
Stage Two [Member] \| Business and government loans [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	3,873	3,437
Stage Two [Member] \| Business and government loans [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	22,700	15,078
Stage Two [Member] \| Business and government loans [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	21,466	22,535
Stage Two [Member] \| Loan commitments and financial guarantee contracts issued [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	23,986	15,932
Stage Two [Member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
ACL	377	267
Stage Two [Member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	1,544	787
Stage Two [Member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Sub investment grade [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	13,733	6,647
Stage Two [Member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Watch list [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	9,086	8,765
Stage Two [Member] \| Gross Total Loans And Acceptances [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	76,717	86,351
Stage Two [Member] \| Net Total Loans And Acceptances [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	73,760	83,791
Stage Two [Member] \| Gross commitments and financial guarantee contracts [Member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	24,363	16,199
Stage three [member] \| Residential mortgages [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	891	647
Stage three [member] \| Residential mortgages [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	903	657
ACL	12	10
Stage three [member] \| Residential mortgages [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	903	657
Stage three [member] \| Consumer installment and other personal loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	467	409
Stage three [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	627	577
ACL	160	168
Stage three [member] \| Consumer installment and other personal loans [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	627	577
Stage three [member] \| Business and government loans [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	4,759	4,134
Stage three [member] \| Business and government loans [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	5,561	4,609
ACL	802	475
Stage three [member] \| Business and government loans [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	5,561	4,609
Stage three [member] \| Loan commitments and financial guarantee contracts issued [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	1,604	1,295
Stage three [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
ACL	56	78
Stage three [member] \| Loan commitments and financial guarantee contracts issued [member] \| Gross carrying amount [member] \| Default and impaired [member]
Disclosure of credit risk exposure [line items]
Commitments and financial guarantee contracts	1,660	1,373
Stage three [member] \| Gross Total Loans And Acceptances [member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	7,091	5,843
Stage three [member] \| Net Total Loans And Acceptances [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	6,117	5,190
Stage three [member] \| Gross commitments and financial guarantee contracts [Member] \| Gross carrying amount [member]
Disclosure of credit risk exposure [line items]
Credit risk exposure for loans	$ 1,660	$ 1,373

Loans and Allowance for Credit Losses - Summary of Credit Risk Exposures for Loans Carried at Amortized Cost, FVOCI or FVTPL (Detail) - CAD ($)
$ in Millions