Investments - Summary of Carrying Value of Total Investments (Detail) - USD ($) $ in Millions |
Jun. 30, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Investment [Line Items] | ||
| Available-for-sale investments | $ 103 | $ 80 |
| Held-to-maturity investments | 74 | 51 |
| Total trading investments | 719 | 625 |
| Total Other Investments, Carrying Value | 1,046 | 839 |
| Total investments | 1,942 | 1,595 |
| Consolidated Sponsored Investment Funds [Member] | ||
| Investment [Line Items] | ||
| Total trading investments | 503 | 465 |
| Other Equity and Debt Securities [Member] | ||
| Investment [Line Items] | ||
| Total trading investments | 164 | 101 |
| Deferred Compensation Plan Fund [Member] | ||
| Investment [Line Items] | ||
| Total trading investments | 52 | 59 |
| Consolidated Entities [Member] | Carried Interest [Member] | ||
| Investment [Line Items] | ||
| Total Other Investments, Carrying Value | 19 | 18 |
| Equity Method Investments [Member] | ||
| Investment [Line Items] | ||
| Total Other Investments, Carrying Value | 935 | 730 |
| Cost Method Investments [Member] | ||
| Investment [Line Items] | ||
| Total Other Investments, Carrying Value | $ 92 | $ 91 |