v3.20.4
Unsecured Borrowings - Unsecured Long-Term Borrowings (Detail) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]    
Total $ 213,481 $ 207,076
Group Inc. [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 134,472 124,887
Floating-rate obligations 37,450 43,701
Total 171,922 168,588
Subsidiaries [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 4,845 4,144
Floating-rate obligations 36,714 34,344
Total 41,559 38,488
U.S. Dollar [Member]    
Debt Instrument [Line Items]    
Total 142,577 140,696
U.S. Dollar [Member] | Group Inc. [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 98,858 91,256
Floating-rate obligations 18,579 25,318
U.S. Dollar [Member] | Subsidiaries [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 1,700 1,590
Floating-rate obligations 23,440 22,532
Non-U.S. Dollar [Member]    
Debt Instrument [Line Items]    
Total 70,904 66,380
Non-U.S. Dollar [Member] | Group Inc. [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 35,614 33,631
Floating-rate obligations 18,871 18,383
Non-U.S. Dollar [Member] | Subsidiaries [Member]    
Debt Instrument [Line Items]    
Fixed-rate obligations 3,145 2,554
Floating-rate obligations $ 13,274 $ 11,812