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N-2 - $ / shares
Sep. 01, 2022
Jun. 30, 2022
Dec. 31, 2021
Cover [Abstract]      
Entity Central Index Key 0000832327    
Amendment Flag false    
Document Type N-CSRS    
Entity Registrant Name BLACKROCK INCOME TRUST, INC.    
General Description of Registrant [Abstract]      
Investment Objectives and Practices [Text Block]
BlackRock Income Trust, Inc.’s (BKT) (the “Fund”)
investment objective is to manage a portfolio of high-quality securities to achieve both preservation of capital and high monthly income. The Fund seeks to achieve its investment objective by investing at least 65% of its assets in mortgage-backed securities. The Fund invests at least 80% of its assets in securities that are (i) issued or guaranteed by the U.S. government or one of its agencies or instrumentalities or (ii) rated at the time of investment either AAA by S&P Global Ratings or Aaa by Moody’s Investors Service, Inc. The Fund may invest directly in such securities or synthetically through the use of derivatives. 		   
Share Price [Table Text Block]
Market Price and Net Asset Value Per Share Summary
 
    
06/30/22
     
12/31/21
     
Change
    
High
     
Low
  
Closing Market Price
   $ 4.54      $ 5.65        (19.65 )%     $  5.65      $  4.34  
Net Asset Value
     4.85        5.65        (14.16 )      5.65        4.66  
    
Lowest Price or Bid   $ 4.34  
Highest Price or Bid   5.65  
Lowest Price or Bid, NAV   4.66  
Highest Price or Bid, NAV   5.65  
Latest Share Price   4.54 $ 5.65
Latest NAV   $ 4.85 $ 5.65
Capital Stock, Long-Term Debt, and Other Securities [Abstract]      
Outstanding Security, Authorized [Shares]   200,000,000  
Outstanding Security, Held [Shares]   63,912,834