v3.21.2
Regulation and Capital Adequacy - Risk-weighted Assets (Detail) - USD ($)
$ in Millions
Jun. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Standardized [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs $ 531,051 $ 485,438  
Market RWAs 90,284 68,724  
Total RWAs 621,335 554,162 $ 563,575
Standardized [Member] | Derivatives [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 128,830 120,292  
Standardized [Member] | Commitments Guarantees and Loans [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 197,151 176,501  
Standardized [Member] | Securities Financing Transactions [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 77,787 71,427  
Standardized [Member] | Equity Investments [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 55,578 46,944  
Standardized [Member] | Other [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 71,705 70,274  
Standardized [Member] | Regulatory VaR [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 15,771 14,913  
Standardized [Member] | Stressed VaR [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 51,917 31,978  
Standardized [Member] | Incremental Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 7,704 7,882  
Standardized [Member] | Comprehensive Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 2,164 1,758  
Standardized [Member] | Specific Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 12,728 12,193  
Advanced [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 445,646 412,713  
Market RWAs 90,284 68,724  
Total Operational RWAs 131,213 128,313  
Total RWAs 667,143 609,750 $ 544,653
Advanced [Member] | Derivatives [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 110,132 111,691  
Advanced [Member] | Commitments Guarantees and Loans [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 168,796 151,587  
Advanced [Member] | Securities Financing Transactions [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 15,363 16,568  
Advanced [Member] | Equity Investments [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 62,005 49,268  
Advanced [Member] | Other [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Credit RWAs 89,350 83,599  
Advanced [Member] | Regulatory VaR [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 15,771 14,913  
Advanced [Member] | Stressed VaR [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 51,917 31,978  
Advanced [Member] | Incremental Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 7,704 7,882  
Advanced [Member] | Comprehensive Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs 2,164 1,758  
Advanced [Member] | Specific Risk [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Market RWAs $ 12,728 $ 12,193