v3.22.2.2
Fair value of financial instrument - Summary of Quantitative Information About Fair Value Measurements Using Significant Unobservable Inputs (Level 3 Instruments) (Detail) - CAD ($)
 12 Months Ended
Oct. 31, 2022
Oct. 31, 2021
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Derivative related assets $ 154,439,000,000 $ 95,541,000,000
Loans 819,965,000,000 717,575,000,000
Deposits 1,208,814,000,000 1,100,831,000,000
Derivative related liabilities 153,491,000,000 91,439,000,000
Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Fair value assets 4,553,000,000 3,594,000,000
Fair value liabilities 2,347,000,000 1,548,000,000
Corporate debt and related derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Corporate debt, related derivatives and other debt 7,000,000 27,000,000
Loans 1,692,000,000 1,077,000,000
Derivative related liabilities 130,000,000 9,000,000
Government Debt and Municipal Bonds [Member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Corporate debt, related derivatives and other debt 151,000,000 150,000,000
Private equities hedge fund investments and related equity derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Equities 2,271,000,000 1,864,000,000
Derivative related liabilities 2,000,000 2,000,000
Interest rate derivatives and interest-rate-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Derivative related assets 270,000,000 367,000,000
Derivative related liabilities 1,216,000,000 974,000,000
Equity derivatives and equity-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Derivative related assets 62,000,000 25,000,000
Deposits 241,000,000 151,000,000
Derivative related liabilities 655,000,000 381,000,000
Other [Member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
U.S. state, municipal and agencies debt 4,000,000 25,000,000
Mortgage Backed Securities 28,000,000 20,000,000
Asset-backed securities 2,000,000 2,000,000
Derivative related assets 51,000,000 37,000,000
Other assets 15,000,000 0
Derivative related liabilities $ 103,000,000 24,000,000
Other liabilities   $ 7,000,000
Bottom of range [member] | Corporate debt and related derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit enhancement 11.70% 11.92%
Bottom of range [member] | Corporate debt and related derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit spread 1.67% 1.15%
Bottom of range [member] | Corporate debt and related derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Prices $ 1 $ 29.18
Bottom of range [member] | Government Debt and Municipal Bonds [Member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Yields 7.85% 3.91%
Bottom of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Liquidity discounts 10.00% 10.00%
Discount rate 10.80% 10.65%
Bottom of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/Rev multiples 0.35X 1.14X
Bottom of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
P/E multiples 8.47X 9.40X
Bottom of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Market comparable companies [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/EBITDA multiples 3.97X 8.82X
Bottom of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
IR-IR correlations 19.00% 19.00%
FX-IR correlations 29.00% 29.00%
FX-FX correlations 68.00% 68.00%
Bottom of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Interest rates 1.88% 0.13%
Bottom of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
CPI swap rates 1.98% 1.76%
Bottom of range [member] | Equity derivatives and equity-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EQ-FX correlations (83.15%) (60.60%)
EQ volatilities 7.00% 8.00%
Bottom of range [member] | Equity derivatives and equity-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Dividend yields (0.63%) 0.00%
Bottom of range [member] | Equity derivatives and equity-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Equity (EQ)-EQ correlations 33.00% 32.00%
Top of range [member] | Corporate debt and related derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit enhancement 15.60% 15.90%
Top of range [member] | Corporate debt and related derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit spread 10.73% 6.92%
Top of range [member] | Corporate debt and related derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Prices $ 111.9 $ 127.09
Top of range [member] | Government Debt and Municipal Bonds [Member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Yields 10.72% 8.17%
Top of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Liquidity discounts 40.00% 40.00%
Discount rate 10.80% 10.65%
Top of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/Rev multiples 5.77X 20.80X
Top of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
P/E multiples 24.04X 38.00X
Top of range [member] | Private equities hedge fund investments and related equity derivatives [member] | Market comparable companies [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/EBITDA multiples 14.31X 26.00X
Top of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
IR-IR correlations 67.00% 67.00%
FX-IR correlations 56.00% 56.00%
FX-FX correlations 68.00% 68.00%
Top of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Interest rates 4.49% 2.46%
Top of range [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
CPI swap rates 2.59% 2.42%
Top of range [member] | Equity derivatives and equity-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EQ-FX correlations 38.44% 27.30%
EQ volatilities 129.00% 128.00%
Top of range [member] | Equity derivatives and equity-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Dividend yields 8.28% 6.37%
Top of range [member] | Equity derivatives and equity-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Equity (EQ)-EQ correlations 94.90% 95.00%
Weighted average [member] | Corporate debt and related derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit enhancement 13.00% 13.25%
Weighted average [member] | Corporate debt and related derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Credit spread 6.20% 4.04%
Weighted average [member] | Corporate debt and related derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Prices $ 85.64 $ 96.36
Weighted average [member] | Government Debt and Municipal Bonds [Member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Yields 8.92% 5.91%
Weighted average [member] | Private equities hedge fund investments and related equity derivatives [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Liquidity discounts 17.35% 16.40%
Discount rate 10.80% 10.65%
Weighted average [member] | Private equities hedge fund investments and related equity derivatives [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/Rev multiples 3.88X 5.40X
Weighted average [member] | Private equities hedge fund investments and related equity derivatives [member] | Price Based [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
P/E multiples 12.46X 10.96X
Weighted average [member] | Private equities hedge fund investments and related equity derivatives [member] | Market comparable companies [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EV/EBITDA multiples 8.59X 9.16X
Weighted average [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
IR-IR correlations Even Even
FX-IR correlations Even Even
FX-FX correlations Even Even
Weighted average [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Interest rates High High
Weighted average [member] | Interest rate derivatives and interest-rate-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
CPI swap rates Even Even
Weighted average [member] | Equity derivatives and equity-linked structured notes [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
EQ-FX correlations Middle Middle
EQ volatilities Upper Upper
Weighted average [member] | Equity derivatives and equity-linked structured notes [member] | Discounted cash flow [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Dividend yields Lower Lower
Weighted average [member] | Equity derivatives and equity-linked structured notes [member] | Option pricing model [member] | Level 3 [member]    
Disclosure of significant unobservable inputs used in fair value measurement of assets and liabilities [line items]    
Equity (EQ)-EQ correlations Middle Middle