v3.3.1.900
Net Capital Requirements - Additional Information (Detail) - USD ($)
$ in Billions
Dec. 31, 2015
Dec. 31, 2014
Regulatory Capital Requirements [Abstract]
Net capital requirement in certain regulated subsidiaries
$ 1.1
$ 1.1
X
- Definition
Net capital requirements.
+ References
No definition available.
+ Details
Name:
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Namespace Prefix:
blk_
Data Type:
xbrli:monetaryItemType
Balance Type:
credit
Period Type:
instant
X
- References
No definition available.
+ Details
Name:
us-gaap_RegulatoryCapitalRequirementsAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration