v3.19.3.a.u2
Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Trading securities $ 1,249 $ 1,660
Total equity securities at FVTNI 1,926 1,021
Separate account assets 102,844 90,285
Total separate account collateral held under securities lending agreements 15,500 20,700
Separate account collateral liabilities under securities lending agreements 15,466 20,655
Investments Measured at NAV [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Other assets 68 18
Equity securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 1,903 987
Fair Value, Measurements, Recurring [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Held-to-maturity investments 249 188
Total debt securities 1,498 1,848
Total equity securities at FVTNI 1,926 1,021
Total equity method 943 781
Bank loans 204 84
Federal Reserve Bank Stock 93 92
Carried interest 528 387
Other investments 297 263
Total investments 5,489 4,476
Other assets 173 122
Separate account assets 102,844 90,285
Total separate account collateral held under securities lending agreements 15,466 20,655
Total 123,972 115,538
Separate account collateral liabilities under securities lending agreements 15,466 20,655
Other liabilities 398 377
Total liabilities measured at fair value 15,864 21,032
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Trading securities 1,249 1,660
Fair Value, Measurements, Recurring [Member] | Equity Securities/Multi-asset Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 1,903 987
Fair Value, Measurements, Recurring [Member] | Equity And Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 157 122
Fair Value, Measurements, Recurring [Member] | Hedge Funds/Funds of Hedge Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 220 173
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 248 116
Fair Value, Measurements, Recurring [Member] | Real Assets Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 296 353
Fair Value, Measurements, Recurring [Member] | Other Types Of Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 22 17
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 23 34
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 1,926 1,021
Total equity method 169 122
Total investments 2,095 1,143
Other assets 173 122
Separate account assets 72,515 63,610
Total separate account collateral held under securities lending agreements 10,209 15,066
Total 84,992 79,941
Separate account collateral liabilities under securities lending agreements 10,209 15,066
Total liabilities measured at fair value 10,209 15,066
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities/Multi-asset Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 1,903 987
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity And Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 157 122
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Types Of Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 12  
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Deferred Compensation Plan Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities at FVTNI 23 34
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 1,241 1,656
Bank loans 27 14
Total investments 1,268 1,670
Separate account assets 29,582 25,810
Total separate account collateral held under securities lending agreements 5,257 5,589
Total 36,107 33,069
Separate account collateral liabilities under securities lending agreements 5,257 5,589
Other liabilities 10 6
Total liabilities measured at fair value 5,267 5,595
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Trading securities 1,241 1,656
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 8 4
Bank loans 177 70
Other investments 9 82
Total investments 194 156
Total 194 156
Other liabilities 388 371
Total liabilities measured at fair value 388 371
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Trading securities 8 4
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Investment in NAV [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 774 656
Other investments 98 106
Total investments 872 762
Total 872 762
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Hedge Funds/Funds of Hedge Funds [Member] | Investment in NAV [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 220 173
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Private/ Public Equity [Member] | Investment in NAV [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 248 116
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Real Assets Funds [Member] | Investment in NAV [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 296 353
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Other Types Of Investments [Member] | Investment in NAV [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 10 14
Fair Value, Measurements, Recurring [Member] | Other [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Held-to-maturity investments 249 188
Total debt securities 249 188
Total equity method   3
Federal Reserve Bank Stock 93 92
Carried interest 528 387
Other investments 190 75
Total investments 1,060 745
Separate account assets 747 865
Total 1,807 1,610
Fair Value, Measurements, Recurring [Member] | Other [Member] | Other Types Of Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method   3
Fair Value, Measurements, Recurring [Member] | Equity securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total separate account collateral held under securities lending agreements 10,209 15,066
Fair Value, Measurements, Recurring [Member] | Equity securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total separate account collateral held under securities lending agreements 10,209 15,066
Fair Value, Measurements, Recurring [Member] | Debt securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total separate account collateral held under securities lending agreements 5,257 5,589
Fair Value, Measurements, Recurring [Member] | Debt securities [Member] | Significant Other Observable Inputs (Level 2) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total separate account collateral held under securities lending agreements $ 5,257 $ 5,589