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Investor A Institutional [Member] Investment Strategy - Investor A Institutional [Member] - iShares Total U.S. Stock Market Index Fund
Jul. 31, 2025
Prospectus [Line Items]  
Strategy [Heading] Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]
The Fund seeks to track the investment results of the Russell 3000® Index (the “Underlying Index”), which measures the performance of the broad U.S. equity market. As of October 31, 2025, the Underlying Index included issuers representing approximately 98% of the total market capitalization of all publicly-traded U.S.-domiciled equity securities. The Underlying Index is a float-adjusted capitalization-weighted index of the largest public issuers domiciled in the United States and its territories. Total market capitalization reflects all equity shares outstanding, while total market value reflects float-adjusted capitalizations based on equity shares available for general investment. The Underlying Index may include large-, mid- or small-capitalization companies, and components primarily include technology, consumer discretionary and industrials companies. The components of the Underlying Index and the degree to which these components represent certain industries may change over time.
BlackRock uses a representative sampling indexing strategy to manage the Fund. “Representative sampling” is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to that of the Underlying Index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability and yield) and liquidity measures similar to those of the Underlying Index. The Fund may or may not hold all of the securities in the Underlying Index.
The Fund generally invests at least 90% of its assets, plus the amount of any borrowing for investment purposes, in securities of the Underlying Index. The Fund may invest a portion of the remainder of its assets in securities not included in the Underlying Index, but which BlackRock believes will help the Fund track the Underlying Index.
The Underlying Index is sponsored by an organization (the “Index Provider”) that is independent of the Fund and BlackRock. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of the Underlying Index. The Underlying Index’s Index Provider is Frank Russell Company (“Russell”).
The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated.
The Fund intends to be diversified in approximately the same proportion as the Underlying Index is diversified. The Fund may become “non-diversified,” as defined in the Investment Company Act, solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the Underlying Index. Shareholder approval will not be sought if the Fund becomes “non-diversified” due solely to a change in the relative market capitalization or index weighting of one or more constituents of the Underlying Index.
Strategy Portfolio Concentration [Text] The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated.