v3.25.2
Variable Interest Entities Reflects adoption of ASU 2015-12 - Balances Relating to Variable Interest Entities in which BlackRock is Not Primary Beneficiary (Detail) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Investments [Member]    
Variable Interest Entity [Line Items]    
Sponsored investment products $ 1,769 $ 2,330
Advisory Fee Receivables [Member]    
Variable Interest Entity [Line Items]    
Sponsored investment products 214 158
Other Net Assets (Liabilities) [Member]    
Variable Interest Entity [Line Items]    
Sponsored investment products (11) (11)
Maximum Risk of Loss [Member]    
Variable Interest Entity [Line Items]    
Sponsored investment products $ 2,001 $ 2,505