v3.8.0.1
Goodwill - Goodwill Activity (Parenthetical) (Detail) - USD ($)
$ in Millions
Mar. 31, 2018
Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Excess of tax goodwill over book goodwill
$ 161
$ 168
X
- Definition
The balance of tax-deductible goodwill in excess of book goodwill.
+ References
No definition available.
+ Details
Name:
blk_ExcessOfTaxGoodwillOverBookGoodwill
Namespace Prefix:
blk_
Data Type:
xbrli:monetaryItemType
Balance Type:
debit
Period Type:
instant
X
- References
No definition available.
+ Details
Name:
us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration