v3.8.0.1
Net Capital Requirements - Additional Information (Detail)
$ in Billions
Mar. 31, 2018
USD ($)
Regulatory Capital Requirements [Abstract]
Net capital requirement in certain regulated subsidiaries
$ 2.1
X
- Definition
Net capital requirements.
+ References
No definition available.
+ Details
Name:
blk_NetCapitalRequirements
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