v3.20.4
Fair Value Disclosures - Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance $ 194 $ 156
Purchases, Assets 86 117
Sales and Maturities, Assets (42)  
Transfers into Level 3, Assets 20  
Transfers out of Level 3, Assets (6) (79)
Assets measured at fair value, ending balance 252 194
Liabilities measured at fair value, beginning balance 388 371
Realized and Unrealized Gains (Losses), Liabilities (23) (53)
Issuances and Other Settlements, Liabilities (139) (36)
Liabilities measured at fair value, ending balance 272 388
Total Net Unrealized Gains (Losses) Included in Earnings (5) (53)
Other Liabilities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Liabilities measured at fair value, beginning balance 388 371
Realized and Unrealized Gains (Losses), Liabilities (23) (53)
Issuances and Other Settlements, Liabilities (139) (36)
Liabilities measured at fair value, ending balance 272 388
Total Net Unrealized Gains (Losses) Included in Earnings (5) (53)
Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance 194 156
Purchases, Assets 86 117
Sales and Maturities, Assets (42)  
Transfers into Level 3, Assets 20  
Transfers out of Level 3, Assets (6) (79)
Assets measured at fair value, ending balance 252 194
Debt securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance 8 4
Purchases, Assets 3 10
Transfers out of Level 3, Assets   (6)
Assets measured at fair value, ending balance 11 8
Debt securities [Member] | Trading [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance 8 4
Purchases, Assets 3 10
Transfers out of Level 3, Assets   (6)
Assets measured at fair value, ending balance 11 8
Consolidated Variable Interest Entities [Member] | Bank Loans [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance 177 70
Purchases, Assets 75 107
Sales and Maturities, Assets (34)  
Transfers into Level 3, Assets 20  
Transfers out of Level 3, Assets (6)  
Assets measured at fair value, ending balance 232 177
Consolidated Variable Interest Entities [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets measured at fair value, beginning balance 9 82
Purchases, Assets 8  
Sales and Maturities, Assets (8)  
Transfers out of Level 3, Assets   (73)
Assets measured at fair value, ending balance $ 9 $ 9