v3.20.4
Loans - Summary of Loans and Lending Commitments Accounted for at Amortized Cost by Portfolio (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans $ 119,989 $ 110,345
Lending commitments 162,513 150,100
Corporate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 48,659 46,307
Wealth management [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 33,023 27,940
Commercial real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 20,290 17,743
Residential real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 5,750 6,958
Other [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 4,174 4,792
Installment [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 3,823 4,747
Credit card [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 4,270 1,858
PCI [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans   1,622
Wholesale Portfolio Segment [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 103,565 90,636
Lending commitments 162,513 150,100
Wholesale Portfolio Segment [Member] | Corporate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 44,778 41,129
Lending commitments 127,756 127,226
Wholesale Portfolio Segment [Member] | Wealth management [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 25,151 20,116
Lending commitments 2,314 2,198
Wholesale Portfolio Segment [Member] | Commercial real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 17,096 12,803
Lending commitments 4,154 3,207
Wholesale Portfolio Segment [Member] | Residential real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 5,236 4,965
Lending commitments 1,804 759
Wholesale Portfolio Segment [Member] | Other [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 3,211 3,396
Lending commitments 4,841 3,029
Consumer Portfolio Segment [Member] | Installment [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 3,823 4,747
Lending commitments 4 12
Consumer Portfolio Segment [Member] | Credit card [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans 4,270 1,858
Lending commitments $ 21,640 $ 13,669