Investments - Summary of Carrying Value of Total Investments (Detail) - USD ($) $ in Millions |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Investments [Line Items] | ||
| Held-to-maturity investments | $ 213 | $ 188 |
| Trading securities (debt securities of consolidated sponsored investment funds of $143 and $233 at June 30, 2019 and December 31, 2018, respectively) | 180 | 265 |
| Total debt securities | 393 | 453 |
| Equity securities at FVTNI(1) (equity securities of consolidated sponsored investment funds of $309 and $291 at June 30, 2019 and December 31, 2018, respectively) | 537 | 452 |
| Total investments | 1,989 | 1,796 |
| Other Investments [Member] | ||
| Investments [Line Items] | ||
| Total investments | 108 | |
| Equity Method Investments [Member] | ||
| Investments [Line Items] | ||
| Total investments | 846 | 781 |
| Federal Reserve Bank Stock [Member] | ||
| Investments [Line Items] | ||
| Total investments | 93 | 92 |
| Consolidated Entities [Member] | Carried Interest [Member] | ||
| Investments [Line Items] | ||
| Total investments | $ 12 | $ 18 |