v3.8.0.1
Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Millions
Mar. 31, 2018
Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities $ 648  
Total trading investments   $ 835
Available-for-sale   103
Separate account assets 142,871 149,937
Total separate account collateral held under securities lending agreements 27,247 24,190
Equity Securities/Multi-Asset Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total trading investments   493
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 62 70
Fair Value, Measurements, Recurring [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity securities 648  
Total debt securities 576  
Total trading investments   835
Held-to-maturity securities 132 102
Available-for-sale   103
Total equity method 703 816
Federal Reserve Bank Stock 91  
Cost method investments   93
Carried interest 32 32
Total investments 2,050 1,981
Total investments of consolidated VIEs 1,637 1,493
Other assets 35  
Separate account assets 142,871 149,937
Total separate account collateral held under securities lending agreements 27,247 24,190
Total 173,840 177,601
Separate account collateral liabilities under securities lending agreements 27,247 24,190
Other liabilities 249 243
Total liabilities measured at fair value 27,496 24,433
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Equity securities 34 56
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 614  
Total trading investments   493
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]    
Total trading investments 293 286
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 131 195
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 572 621
Total investments of consolidated VIEs 50 53
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 250 259
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 investments of consolidated VIEs 295 440
Total separate account collateral held under securities lending agreements 18,543 18,778
Fair Value, Measurements, Recurring [Member] | Carried Interest [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 273 266
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 769 475
Total separate account collateral held under securities lending agreements 8,704 5,412
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 648  
Total trading investments   551
Available-for-sale   7
Total equity method 116 183
Total investments 764 741
Total investments of consolidated VIEs 298 446
Separate account assets 107,095 114,422
Total separate account collateral held under securities lending agreements 18,543 18,778
Total 126,700 134,387
Separate account collateral liabilities under securities lending agreements 18,543 18,778
Total liabilities measured at fair value 18,543 18,778
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]    
Equity securities 34 56
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 614  
Total trading investments   493
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total trading investments   2
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 116 183
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 3 6
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 investments of consolidated VIEs 295 440
Total separate account collateral held under securities lending agreements 18,543 18,778
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 413  
Total trading investments   284
Available-for-sale   96
Total investments 413 380
Total investments of consolidated VIEs 772 477
Other assets 35  
Separate account assets 35,063 34,582
Total separate account collateral held under securities lending agreements 8,704 5,412
Total 44,987 40,851
Separate account collateral liabilities under securities lending agreements 8,704 5,412
Other liabilities 7 7
Total liabilities measured at fair value 8,711 5,419
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]    
Total trading investments 288 284
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 3 2
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 769 475
Total separate account collateral held under securities lending agreements 8,704 5,412
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 31  
Total investments 31  
Total investments of consolidated VIEs 116 116
Total 147 116
Other liabilities 242 236
Total liabilities measured at fair value 242 236
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]    
Total trading investments 5  
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 116 116
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 151  
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member] | Significant Other Observable Inputs (Level 2) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 125  
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member] | Significant Unobservable Inputs (Level 3) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 26  
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 584 621
Total investments 584 621
Total investments of consolidated VIEs 106 112
Total 690 733
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Equity And Fixed Income Mutual Funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 15 12
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Other Types Of Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 569 609
Total investments of consolidated VIEs 50 53
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 56 59
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total debt securities 132  
Held-to-maturity securities 132 102
Total equity method 3 12
Federal Reserve Bank Stock 91  
Cost method investments   93
Carried interest 32 32
Total investments 258 239
Total investments of consolidated VIEs 345 342
Separate account assets 712 933
Total 1,315 1,514
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Other Types Of Investments [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total equity method 3 12
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Private/ Public Equity [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs 72 76
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Carried Interest [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total investments of consolidated VIEs $ 273 $ 266