Consolidated VREs Recorded in Condensed Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Consolidated Sponsored Investment Funds [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Investments:
Total trading investments		835
Equity securities	648
Total investments	2,050	1,981
Other assets	2,157	1,636
Other liabilities	(2,130)	(1,626)
Noncontrolling interests ("NCI")	(44)	(50)
Equity Securities/Multi-Asset Mutual Funds [Member]
Investments:
Total trading investments		493
Consolidated Voting Rights Entities [Member]
Consolidated Sponsored Investment Funds [Line Items]
Cash and cash equivalents	44	63
Investments:
Total trading investments	266	267
Total investments	550	512
Other assets	15	13
Other liabilities	(42)	(37)
Noncontrolling interests ("NCI")	(87)	(91)
BlackRock’s net interests in consolidated VREs	480	460
Consolidated Voting Rights Entities [Member] \| Equity Securities/Multi-Asset Mutual Funds [Member]
Investments:
Equity securities	$ 284	$ 245

Consolidated sponsored investment funds.

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Economic interests in consolidated entities.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

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