v3.21.2
Regulation and Capital Adequacy - Risk-weighted Assets (Detail) - USD ($)
$ in Millions
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Dec. 31, 2020
Sep. 30, 2020
Dec. 31, 2019
Standardized [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs $ 582,630     $ 485,438    
Market RWAs 81,306     68,724    
Total RWAs 663,936 $ 621,000 $ 595,000 554,162 $ 535,000 $ 563,575
Standardized [Member] | Derivatives [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 147,590     120,292    
Standardized [Member] | Commitments Guarantees and Loans [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 222,978     176,501    
Standardized [Member] | Securities Financing Transactions [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 88,391     71,427    
Standardized [Member] | Equity Investments [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 49,346     46,944    
Standardized [Member] | Other [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 74,325     70,274    
Standardized [Member] | Regulatory VaR [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 12,733     14,913    
Standardized [Member] | Stressed VaR [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 40,922     31,978    
Standardized [Member] | Incremental Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 8,325     7,882    
Standardized [Member] | Comprehensive Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 3,292     1,758    
Standardized [Member] | Specific Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 16,034     12,193    
Advanced [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 459,692     412,713    
Market RWAs 81,306     68,724    
Total Operational RWAs 131,063     128,313    
Total RWAs 672,061     609,750   $ 544,653
Advanced [Member] | Derivatives [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 116,971     111,691    
Advanced [Member] | Commitments Guarantees and Loans [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 178,086     151,587    
Advanced [Member] | Securities Financing Transactions [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 18,004     16,568    
Advanced [Member] | Equity Investments [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 55,450     49,268    
Advanced [Member] | Other [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Credit RWAs 91,181     83,599    
Advanced [Member] | Regulatory VaR [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 12,733     14,913    
Advanced [Member] | Stressed VaR [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 40,922     31,978    
Advanced [Member] | Incremental Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 8,325     7,882    
Advanced [Member] | Comprehensive Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs 3,292     1,758    
Advanced [Member] | Specific Risk [Member]            
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]            
Market RWAs $ 16,034     $ 12,193