Variable Interest Entities Reflects adoption of ASU 2015-12 - Balances Relating to Variable Interest Entities in which BlackRock is Not Primary Beneficiary (Detail) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) |
Mar. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Investments [Member] | ||
| Variable Interest Entity [Line Items] | ||
| Sponsored investment products | $ 895,000,000 | $ 882,000,000 |
| Advisory Fee Receivables [Member] | ||
| Variable Interest Entity [Line Items] | ||
| Sponsored investment products | 96,000,000 | 62,000,000 |
| Other Net Assets (Liabilities) [Member] | ||
| Variable Interest Entity [Line Items] | ||
| Sponsored investment products | (12,000,000) | (12,000,000) |
| Maximum Risk of Loss [Member] | ||
| Variable Interest Entity [Line Items] | ||
| Sponsored investment products | $ 1,008,000,000 | $ 961,000,000 |