v3.21.2
Credit Concentrations - Credit Concentration, Government and Federal Agency Obligations (Detail) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2020
U.S. Government and Agency Obligations Held By The Firm [Member]    
Concentration Risk [Line Items]    
Concentration risk, Credit risk, Financial instrument, Maximum exposure $ 144,443 $ 187,009
Concentration risk, Credit risk, Financial instrument, Maximum exposure, As a percentage of total Assets 10.40% 16.10%
Non-U.S. Government and Agency Obligations Held By The Firm [Member]    
Concentration Risk [Line Items]    
Concentration risk, Credit risk, Financial instrument, Maximum exposure $ 70,370 $ 59,580
Concentration risk, Credit risk, Financial instrument, Maximum exposure, As a percentage of total Assets 5.10% 5.10%