v3.26.1
Acquisitions - Additional Information (Detail)
$ / shares in Units, $ in Millions, £ in Billions
 3 Months Ended 6 Months Ended 12 Months Ended
Jul. 01, 2025
USD ($)
$ / shares
shares
Mar. 03, 2025
USD ($)
Mar. 03, 2025
GBP (£)
Sep. 30, 2026
USD ($)
shares
Jun. 30, 2026
USD ($)
$ / shares
shares
Dec. 31, 2025
USD ($)
shares
Business Acquisition [Line Items]            
Contingent consideration liabilities | $         $ 7,875 $ 8,429
Common stock, shares issued         156,276,289 156,276,289
Restricted Stock Units (RSUs) [Member]            
Business Acquisition [Line Items]            
Stock price | $ / shares         $ 962  
Cliff Vesting RSU [Member]            
Business Acquisition [Line Items]            
RSUs to employees that cliff vest, percentage           100.00%
Subco Units [Member]            
Business Acquisition [Line Items]            
Number of shares issued 8,500,000          
Maximum [Member] | Subco Units [Member]            
Business Acquisition [Line Items]            
Contingent payments 4,400,000          
Minimum [Member] | Subco Units [Member]            
Business Acquisition [Line Items]            
Contingent payments 2,800,000          
Hps Investment Partners [Member]            
Business Acquisition [Line Items]            
Asset under management | $ $ 165,000          
Fee-paying AUM | $ $ 118,000          
Date of acquisition Jul. 01, 2025          
Business acquisition, percentage of equity interest acquired 100.00%          
Contingent consideration liabilities | $ $ 3,400          
Restricted Stock Units, Granted 680,000          
Hps Investment Partners [Member] | Restricted Stock Units (RSUs) [Member]            
Business Acquisition [Line Items]            
Award vesting period 5 years          
Granted incentive retention awards | $ $ 675          
Hps Investment Partners [Member] | Cliff Vesting RSU [Member]            
Business Acquisition [Line Items]            
Restricted Stock Units, Granted 270,000          
Granted incentive retention awards | $ $ 260          
Hps Investment Partners [Member] | Common Stock [Member]            
Business Acquisition [Line Items]            
Stock price | $ / shares $ 1,049          
Hps Investment Partners [Member] | Subco Units [Member]            
Business Acquisition [Line Items]            
Number of shares issued 8,500,000          
Issuance of common share in connection with acquisition | $ $ 8,500          
Hps Investment Partners [Member] | Subco Units [Member] | Scenario Forecast [Member]            
Business Acquisition [Line Items]            
Contingent payments       2,800,000    
Contingent consideration liability fair value | $       $ 2,600    
Hps Investment Partners [Member] | Maximum [Member]            
Business Acquisition [Line Items]            
Common stock, shares issued 13,800,000          
Hps Investment Partners [Member] | Maximum [Member] | Subco Units [Member]            
Business Acquisition [Line Items]            
Contingent payments 4,400,000       4,400,000  
Hps Investment Partners [Member] | Minimum [Member] | Subco Units [Member]            
Business Acquisition [Line Items]            
Contingent payments 2,800,000       2,800,000  
Preqin Holding Limited [Member]            
Business Acquisition [Line Items]            
Cash paid   $ 3,219 £ 2.5      
Description of acquisition   On March 3, 2025, BlackRock completed the acquisition of 100% of the shares of Preqin Holding Limited (the "Preqin Transaction" or "Preqin"), a leading provider of private markets data, for £2.5 billion (or approximately $3.2 billion) in cash. On March 3, 2025, BlackRock completed the acquisition of 100% of the shares of Preqin Holding Limited (the "Preqin Transaction" or "Preqin"), a leading provider of private markets data, for £2.5 billion (or approximately $3.2 billion) in cash.      
Business acquisition, percentage of equity interest acquired   100.00% 100.00%