v3.21.2
Significant Accounting Policies - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jan. 01, 2020
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Summary of Accounting and Financial Policies [Line Items]            
Firm's revenues from contracts with clients subject to ASU 2014-09 as a percentage of firm's total non-interest revenues   40.00% 40.00% 40.00% 45.00%  
Investment Banking revenues from contracts with clients subject to ASU 2014-09 as a percentage of firm's investment banking revenues   85.00% 85.00% 85.00% 85.00%  
Investment management revenues from contracts with clients subject to ASU 2014-09 as a percentage of firm's investment management revenue   95.00% 95.00% 95.00% 95.00%  
Cash and due from banks   $ 17,340   $ 17,340   $ 11,950
Interest-bearing deposits with banks   222,950   222,950   143,890
Cash segregated for regulatory and other purposes   23,380   23,380   24,520
Receivable from customers and counterparties   104,230   104,230   82,390
Receivables from brokers, dealers and clearing organizations   57,860   57,860   38,940
Firm's receivables from contracts with clients   3,080   3,080   2,600
Payables to customers and counterparties   217,740   217,740   183,570
Payables to brokers, dealers and clearing organizations   $ 20,960   20,960   $ 7,090
Maximum [Member]            
Summary of Accounting and Financial Policies [Line Items]            
Annual average revenues associated with known remaining performance obligations       $ 250    
Accounting Standards Update 2016-13 [Member]            
Summary of Accounting and Financial Policies [Line Items]            
New accounting standards impact on retained earnings $ (638)          
Accounting Standards Update 2016-13 [Member] | Maximum [Member]            
Summary of Accounting and Financial Policies [Line Items]            
Allowance for credit losses 848          
Accounting Standards Update 2016-13 [Member] | Minimum [Member]            
Summary of Accounting and Financial Policies [Line Items]            
Allowance for credit losses $ (169)