v3.19.3.a.u2
Leases - Schedule of Maturity of Operating Lease Liabilities (Parenthetical) (Details)
$ in Billions
Dec. 31, 2019
USD ($)
Leases [Abstract]
Minimum lease payments for leases signed but not yet commenced excluded
$ 1.5
X
- Definition
Minimum lease payments for leases signed but not yet commenceD.
+ References
No definition available.
+ Details
Name:
blk_MinimumLeasePaymentsForLeasesSignedButNotYetCommenced
Namespace Prefix:
blk_
Data Type:
xbrli:monetaryItemType
Balance Type:
credit
Period Type:
instant
X
- References
No definition available.
+ Details
Name:
us-gaap_LeasesAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration