v3.20.4
Loans - Summary of Loans (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Loans Receivable [Line Items]      
Subtotal $ 119,989 $ 110,345  
Allowance for loan losses (3,874) (1,441) $ (1,066)
Total loans receivable 116,115 108,904  
Subtotal 13,625 14,386  
Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 103,565 90,636  
Allowance for loan losses (3,874) (1,441)  
Total loans receivable 99,691 89,195  
Subtotal 101,305 89,186  
Fair Value [Member]      
Loans Receivable [Line Items]      
Total loans receivable 13,625 14,386  
Subtotal 13,625 14,386  
Held for sale [Member]      
Loans Receivable [Line Items]      
Total loans receivable 2,799 5,323  
Subtotal 2,812 5,409  
Subtotal 2,799 5,323  
Corporate [Member]      
Loans Receivable [Line Items]      
Subtotal 48,659 46,307  
Subtotal 2,751 3,224  
Corporate [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 44,778 41,129  
Corporate [Member] | Fair Value [Member]      
Loans Receivable [Line Items]      
Subtotal 2,751 3,224  
Corporate [Member] | Held for sale [Member]      
Loans Receivable [Line Items]      
Subtotal 1,130 1,954  
Wealth management [Member]      
Loans Receivable [Line Items]      
Subtotal 33,023 27,940  
Subtotal 7,872 7,824  
Wealth management [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 25,151 20,116  
Wealth management [Member] | Fair Value [Member]      
Loans Receivable [Line Items]      
Subtotal 7,872 7,824  
Commercial real estate [Member]      
Loans Receivable [Line Items]      
Subtotal 20,290 17,743  
Subtotal 1,961 1,876  
Commercial real estate [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 17,096 13,258  
Commercial real estate [Member] | Fair Value [Member]      
Loans Receivable [Line Items]      
Subtotal 1,961 1,876  
Commercial real estate [Member] | Held for sale [Member]      
Loans Receivable [Line Items]      
Subtotal 1,233 2,609  
Residential real estate [Member]      
Loans Receivable [Line Items]      
Subtotal 5,750 6,958  
Subtotal 494 792  
Residential real estate [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 5,236 6,132  
Residential real estate [Member] | Fair Value [Member]      
Loans Receivable [Line Items]      
Subtotal 494 792  
Residential real estate [Member] | Held for sale [Member]      
Loans Receivable [Line Items]      
Subtotal 20 34  
Installment [Member]      
Loans Receivable [Line Items]      
Subtotal 3,823 4,747  
Installment [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 3,823 4,747  
Credit card [Member]      
Loans Receivable [Line Items]      
Subtotal 4,270 1,858  
Credit card [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 4,270 1,858  
Other Loans [Member]      
Loans Receivable [Line Items]      
Subtotal 4,174 4,792  
Subtotal 547 670  
Other Loans [Member] | Amortized cost [Member]      
Loans Receivable [Line Items]      
Subtotal 3,211 3,396  
Other Loans [Member] | Fair Value [Member]      
Loans Receivable [Line Items]      
Subtotal 547 670  
Other Loans [Member] | Held for sale [Member]      
Loans Receivable [Line Items]      
Subtotal $ 416 $ 726