Investment Strategy - iShares Short-Term TIPS Bond Index Fund	Dec. 31, 2025
Investor A, Institutional
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 Bloomberg U.S. Treasury Inflation-Protected Securities (TIPS) 0-5 Years Index (Series-L) (the “Underlying Index”), which measures the performance of inflation-protected public obligations of the U.S. Treasury that have a remaining maturity of less than five years. Inflation-protected public obligations of the U.S. Treasury, commonly known as “TIPS,” are securities issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS are income-generating instruments whose interest and principal payments are adjusted for inflation — a sustained increase in prices that erodes the purchasing power of money. The inflation adjustment, which is typically applied monthly to the principal of the bond, follows a designated inflation index, the consumer price index (“CPI”), and TIPS’ principal payments are adjusted according to changes in the CPI. A fixed coupon rate is applied to the inflation-adjusted principal so that as inflation rises, both the principal value and the interest payments increase. This can provide investors with a hedge against inflation, as it helps preserve the purchasing power of an investment. Because of this inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds. If there is deflation, the principal value of an inflation-linked security will be adjusted downward, and consequently the interest payments (calculated with respect to a smaller principal amount) will be reduced. During periods of deflation, low inflation or no inflation, a conventional bond may perform better than inflation-linked securities. The Underlying Index includes all publicly-issued U.S. Treasury inflation-protected securities that have less than five years remaining to maturity, are rated investment-grade and have $250 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a notional coupon that is fixed-rate or zero. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last calendar day of each month. 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. From time to time when conditions warrant, however, the Fund may invest at least 80% of its assets 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.
Class K
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 Bloomberg U.S. Treasury Inflation-Protected Securities (TIPS) 0-5 Years Index (Series-L) (the “Underlying Index”), which measures the performance of inflation-protected public obligations of the U.S. Treasury that have a remaining maturity of less than five years. Inflation-protected public obligations of the U.S. Treasury, commonly known as “TIPS,” are securities issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS are income-generating instruments whose interest and principal payments are adjusted for inflation — a sustained increase in prices that erodes the purchasing power of money. The inflation adjustment, which is typically applied monthly to the principal of the bond, follows a designated inflation index, the consumer price index (“CPI”), and TIPS’ principal payments are adjusted according to changes in the CPI. A fixed coupon rate is applied to the inflation-adjusted principal so that as inflation rises, both the principal value and the interest payments increase. This can provide investors with a hedge against inflation, as it helps preserve the purchasing power of an investment. Because of this inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds. If there is deflation, the principal value of an inflation-linked security will be adjusted downward, and consequently the interest payments (calculated with respect to a smaller principal amount) will be reduced. During periods of deflation, low inflation or no inflation, a conventional bond may perform better than inflation-linked securities. The Underlying Index includes all publicly-issued U.S. Treasury inflation-protected securities that have less than five years remaining to maturity, are rated investment-grade and have $250 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a notional coupon that is fixed-rate or zero. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last calendar day of each month. 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. From time to time when conditions warrant, however, the Fund may invest at least 80% of its assets 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 Fund seeks to track the investment results of the Bloomberg U.S. Treasury Inflation-Protected Securities (TIPS) 0-5 Years Index (Series-L) (the “Underlying Index”), which measures the performance of inflation-protected public obligations of the U.S. Treasury that have a remaining maturity of less than five years. Inflation-protected public obligations of the U.S. Treasury, commonly known as “TIPS,” are securities issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS are income-generating instruments whose interest and principal payments are adjusted for inflation — a sustained increase in prices that erodes the purchasing power of money. The inflation adjustment, which is typically applied monthly to the principal of the bond, follows a designated inflation index, the consumer price index (“CPI”), and TIPS’ principal payments are adjusted according to changes in the CPI. A fixed coupon rate is applied to the inflation-adjusted principal so that as inflation rises, both the principal value and the interest payments increase. This can provide investors with a hedge against inflation, as it helps preserve the purchasing power of an investment. Because of this inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds. If there is deflation, the principal value of an inflation-linked security will be adjusted downward, and consequently the interest payments (calculated with respect to a smaller principal amount) will be reduced. During periods of deflation, low inflation or no inflation, a conventional bond may perform better than inflation-linked securities.

The Underlying Index includes all publicly-issued U.S. Treasury inflation-protected securities that have less than five years remaining to maturity, are rated investment-grade and have $250 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a notional coupon that is fixed-rate or zero. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last calendar day of each month.

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. From time to time when conditions warrant, however, the Fund may invest at least 80% of its assets 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.

Prospectus [Line Items]

Strategy Narrative [Text Block]

The Fund seeks to track the investment results of the Bloomberg U.S. Treasury Inflation-Protected Securities (TIPS) 0-5 Years Index (Series-L) (the “Underlying Index”), which measures the performance of inflation-protected public obligations of the U.S. Treasury that have a remaining maturity of less than five years. Inflation-protected public obligations of the U.S. Treasury, commonly known as “TIPS,” are securities issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS are income-generating instruments whose interest and principal payments are adjusted for inflation — a sustained increase in prices that erodes the purchasing power of money. The inflation adjustment, which is typically applied monthly to the principal of the bond, follows a designated inflation index, the consumer price index (“CPI”), and TIPS’ principal payments are adjusted according to changes in the CPI. A fixed coupon rate is applied to the inflation-adjusted principal so that as inflation rises, both the principal value and the interest payments increase. This can provide investors with a hedge against inflation, as it helps preserve the purchasing power of an investment. Because of this inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds. If there is deflation, the principal value of an inflation-linked security will be adjusted downward, and consequently the interest payments (calculated with respect to a smaller principal amount) will be reduced. During periods of deflation, low inflation or no inflation, a conventional bond may perform better than inflation-linked securities.

The Underlying Index includes all publicly-issued U.S. Treasury inflation-protected securities that have less than five years remaining to maturity, are rated investment-grade and have $250 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a notional coupon that is fixed-rate or zero. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last calendar day of each month.

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. From time to time when conditions warrant, however, the Fund may invest at least 80% of its assets 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.