v3.26.1
Class K [Member] Investment Risks - Class K - BlackRock LifePath Dynamic 2060 Fund
Dec. 31, 2025
Allocation Risk [Member]  
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Allocation Risk — The Fund’s ability to achieve its investment objective depends upon BFA’s skill in determining the Fund’s strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA’s evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, the asset allocation or the combination of Underlying Funds determined by BFA could result in underperformance as compared to funds with similar investment objectives and strategies.
Market Risk and Selection Risk [Member]  
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Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. The value of a security or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues like pandemics or epidemics, recessions, or other events could have a significant impact on the Fund and its investments. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.
Investments in Underlying Funds Risk [Member]  
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Investments in Underlying Funds Risk — The Fund’s investments are concentrated in Underlying Funds, so the Fund’s investment performance is directly related to the performance of the Underlying Funds. The Fund’s net asset value will change with changes in the equity and bond markets and the value of the Underlying Funds and other securities in which it invests. An investment in the Fund will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds. For example, the Fund indirectly pays a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds.
Affiliated Fund Risk [Member]  
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Affiliated Fund Risk — In managing the Fund, BFA will have authority to select and substitute underlying funds and ETFs. BFA may be subject to conflicts of interest in selecting underlying funds and ETFs because the fees paid to BFA by some underlying funds and ETFs are higher than the fees paid by other underlying funds and ETFs. However, BFA is a fiduciary to the Fund and is legally obligated to act in the Fund’s best interests when selecting underlying funds and ETFs. If an underlying fund or ETF holds interests in an affiliated fund, the Fund may be prohibited from purchasing shares of that underlying fund or ETF.
Retirement Income Risk [Member]  
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Retirement Income Risk — The Fund does not provide a guarantee that sufficient capital appreciation will be achieved to provide adequate income at and through retirement. The Fund also does not ensure that you will have assets in your account sufficient to cover your retirement expenses or that you will have enough saved to be able to retire in the target year identified in the Fund’s name; this will depend on the amount of money you have invested in the Fund, the length of time you have held your investment, the returns of the markets over time, the amount you spend in retirement, and your other assets and income sources.
Derivatives Risks [Member]  
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Derivatives Risk — The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or increase volatility. Derivatives involve significant risks, including:
Leverage Risk — The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market movements may result in large changes in the value of a derivatives position and can result in losses that greatly exceed the amount originally invested.
Market Risk — Some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s derivatives positions to lose value.
Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated exposure to such a counterparty.
Illiquidity Risk — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately.
Operational Risk — The use of derivatives includes the risk of potential operational issues, including documentation issues, settlement issues, systems failures, inadequate controls and human error.
Legal Risk — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or enforceability of a contract.
Volatility and Correlation Risk — Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate with the overall securities markets.
Valuation Risk — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them.
Hedging Risk — Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging may result in certain adverse tax consequences.
Tax Risk — Certain aspects of the tax treatment of derivative instruments, including swap agreements and commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund realizes from its investments.
Leverage Risk [Member]  
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Leverage Risk — Some transactions may give rise to a form of economic leverage. These transactions may include, among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage.
Operational and Technology Risks [Member]  
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Operational and Technology Risks — The Fund is directly and indirectly susceptible to operational and technology risks, including those related to human errors, processing errors, communication errors, systems failures, cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are required to have appropriate operational, information security and cybersecurity risk management policies and procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and may cause the Fund’s investments in such issuers to lose value.
Authorized Participant Concentration Risk [Member]  
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Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with an ETF. There are a limited number of institutions that may act as authorized participants for an ETF, including on an agency basis on behalf of other market participants. No authorized participant is obligated to engage in creation or redemption transactions. To the extent that authorized participants exit the business or do not place creation or redemption orders for an ETF and no other authorized participant places orders, ETF shares are more likely to trade at a premium or discount to net asset value and possibly face trading halts or delisting.
Commodities Related Investments Risk [Member]  
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Commodities Related Investments Risk — Exposure to the commodities markets may subject the Fund to greater volatility than investments in traditional securities. The value of commodity-linked derivative investments may be affected by changes in overall market movements, commodity index volatility, changes in inflation, interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, embargoes, tariffs and international economic, political and regulatory developments.
Concentration Risk [Member]  
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Concentration Risk — To the extent that the Fund or an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, the Fund or that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.
Convertible Securities Risk [Member]  
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Convertible Securities Risk — The market value of a convertible security performs like that of a regular debt security; that is, if market interest rates rise, the value of a convertible security usually falls. In addition, convertible securities are subject to the risk that the issuer will not be able to pay interest, principal or dividends when due, and their market value may change based on changes in the issuer’s credit rating or the market’s perception of the issuer’s creditworthiness. Since it derives a portion of its value from the common stock into which it may be converted, a convertible security is also subject to the same types of market and issuer risks that apply to the underlying common stock, including the potential for increased volatility in the price of the convertible security.
Corporate Loans Risk [Member]  
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Corporate Loans Risk — Commercial banks and other financial institutions or institutional investors make corporate loans to companies that need capital to grow or restructure. Borrowers generally pay interest on corporate loans at rates that change in response to changes in market interest rates such as the Secured Overnight Financing Rate (“SOFR”) or the prime rates of U.S. banks. As a result, the value of corporate loan investments is generally less exposed to the adverse effects of shifts in market interest rates than investments that pay a fixed rate of interest. The market for corporate loans may be subject to irregular trading activity and wide bid/ask spreads. In addition, transactions in corporate loans may settle on a delayed basis. As a result, the proceeds from the sale of corporate loans may not be readily available to make additional investments or to meet the Fund’s redemption obligations. To the extent the extended settlement process gives rise to short-term liquidity needs, the Fund may hold additional cash, sell investments or temporarily borrow from banks and other lenders.
Counterparty Risk [Member]  
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Counterparty Risk — The counterparty to an over‑the‑counter derivatives contract or a borrower of the Fund’s securities may be unable or unwilling to make timely principal, interest or settlement payments, or otherwise to honor its obligations. Any such failure to honor its obligations may cause significant losses to the Fund.
Depositary Receipts Risk [Member]  
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Depositary Receipts Risk — Depositary receipts are generally subject to the same risks as the foreign securities that they evidence or into which they may be converted. In addition to investment risks associated with the underlying issuer, depositary receipts expose the Fund to additional risks associated with the non‑uniform terms that apply to depositary receipt programs, credit exposure to the depository bank and to the sponsors and other parties with whom the depository bank establishes the programs, currency risk and the risk of an illiquid market for depositary receipts. The issuers of unsponsored depositary receipts are not obligated to disclose information that is, in the United States, considered material. Therefore, there may be less information available regarding these issuers and there may not be a correlation between such information and the market value of the depositary receipts. While depositary receipts provide an alternative to directly purchasing underlying foreign securities in their respective markets and currencies, they continue to be subject to many of the risks associated with investing directly in foreign securities, including political, economic, and currency risk.
Emerging Markets Risk [Member]  
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Emerging Markets Risk — Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyperinflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging financial markets have far lower trading volumes and less liquidity than developed markets.
Foreign Securities Risk [Member]  
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Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. These risks include:
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The Fund generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.
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Changes in foreign currency exchange rates can affect the value of the Fund’s portfolio.
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The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.
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The governments of certain countries, or the U.S. Government with respect to certain countries, may prohibit or impose substantial restrictions through capital controls and/or sanctions on foreign investments in the capital markets or certain industries in those countries, which may prohibit or restrict the ability to own or transfer currency, securities, derivatives or other assets.
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Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.
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Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.
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The Fund’s claims to recover foreign withholding taxes may not be successful, and if the likelihood of recovery of foreign withholding taxes materially decreases, due to, for example, a change in tax regulation or approach in the foreign country, accruals in the Fund’s net asset value for such refunds may be written down partially or in full, which will adversely affect the Fund’s net asset value.
Geographic Concentration Risk [Member]  
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Geographic Concentration Risk — From time to time the Fund may invest a substantial amount of its assets in issuers located in a single country or a limited number of countries. If the Fund concentrates its investments in this manner, it assumes the risk that economic, political and social conditions in those countries will have a significant impact on its investment performance. The Fund’s investment performance may also be more volatile if it concentrates its investments in certain countries, especially emerging market countries.
High Portfolio Turnover Risk [Member]  
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High Portfolio Turnover Risk — The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (more than 100%) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark‑ups and other transaction costs on the sale of the securities and on reinvestment in other securities. The sale of Fund portfolio securities may result in the realization and/or distribution to shareholders of higher capital gains or losses as compared to a fund with less active trading policies. These effects of higher than normal portfolio turnover may adversely affect Fund performance.
Income Risk [Member]  
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Income Risk — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.
Indexed and Inverse Securities Risk [Member]  
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Indexed and Inverse Securities Risk — Indexed and inverse securities provide a potential return based on a particular index of value or interest rates. The Fund’s return on these securities will be subject to risk with respect to the value of the particular index. These securities are subject to leverage risk and correlation risk. Certain indexed and inverse securities have greater sensitivity to changes in interest rates or index levels than other securities, and the Fund’s investment in such instruments may decline significantly in value if interest rates or index levels move in a way Fund management does not anticipate.
Index Related Risk [Member]  
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Index-Related Risk — The index provider may rely on various sources of information to assess the criteria of components of the Underlying Index, including information that may be based on assumptions and estimates. Neither an Underlying Fund nor BFA can offer assurances that the index provider’s methodology or sources of information will provide an accurate assessment of included components. Errors in index data, index computations or the construction of the Underlying Index in accordance with its methodology may occur, and the index provider may not identify or correct them promptly or at all, which may have an adverse impact on an Underlying Fund and its shareholders. Unusual market conditions or other unforeseen circumstances (such as natural disasters, political unrest or war) may impact the index provider or a third-party data provider and could cause the index provider to postpone a scheduled rebalance. This could cause an underlying index to vary from its normal or expected composition.
Investment Style Risk [Member]  
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Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion and value investments have performed better during periods of economic recovery. Therefore, these investment styles may over time go in and out of favor. At times when an investment style used by the Fund or an Underlying Fund is out of favor, the Fund may underperform other funds that use different investment styles.
Issuer Risk [Member]  
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Issuer Risk — Fund performance depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.
Large Capitalization Companies Risk [Member]  
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Large-Capitalization Companies Risk — Large-capitalization companies may be less able than smaller-capitalization companies to adapt to changing market conditions and competitive challenges. Large-capitalization companies may be more mature and subject to more limited growth potential compared with smaller-capitalization companies. The performance of large-capitalization companies could trail the overall performance of the broader securities markets.
Management Risk [Member]  
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Management Risk — If a passively managed ETF does not fully replicate the underlying index, it is subject to the risk that the manager’s investment management strategy may not produce the intended results.
Mezzanine Securities Risk [Member]  
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Mezzanine Securities Risk — Mezzanine securities carry the risk that the issuer will not be able to meet its obligations and that the equity securities purchased with the mezzanine investments may lose value.
Model Risk [Member]  
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Model Risk — The Fund seeks to pursue its investment objective by using proprietary models that incorporate quantitative analysis. Investments selected using these models may perform differently than as forecasted due to the factors incorporated into the models and the weighting of each factor, changes from historical trends, and issues in the construction and implementation of the models (including, but not limited to, software issues, issues related to the use of AI, and other technological issues). There is no guarantee that BFA’s use of these models will result in effective investment decisions for the Fund.
The information and data used in the models may be supplied by third parties. Inaccurate or incomplete data may limit the effectiveness of the models. In addition, some of the data that BFA uses may be historical data, which may not accurately predict future market movement. There is a risk that the models will not be successful in selecting investments or in determining the weighting of investment positions that will enable the Fund to achieve its investment objective.
New Issues Risk [Member]  
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“New Issues” Risk — “New issues” are initial public offerings (“IPOs”) of equity securities. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the IPO.
Passive Investment Risk [Member]  
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Passive Investment Risk — Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold securities of companies that present risks that an investment adviser researching individual securities might seek to avoid.
Pay in kind Bonds Risk [Member]  
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Pay-in-kind Bonds Risk — Similar to zero coupon obligations, pay-in-kind bonds also carry additional risk as holders of these types of securities realize no cash until the cash payment date unless a portion of such securities is sold and, if the issuer defaults, the Fund may obtain no return at all on its investment. The market price of pay-in-kind bonds is affected by interest rate changes to a greater extent, and therefore tends to be more volatile, than that of securities which pay interest in cash.
Preferred Securities Risk [Member]  
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Preferred Securities Risk — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.
Real Estate Related Securities Risk [Member]  
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Real Estate-Related Securities Risk — The main risk of real estate-related securities is that the value of the underlying real estate may go down. Many factors may affect real estate values. These factors include both the general and local economies, vacancy rates, changes in rent schedules, tenant bankruptcies, the ability to re‑lease space under expiring leases on attractive terms, the amount of new construction in a particular area, the laws and regulations (including zoning, environmental and tax laws) affecting real estate and the costs of owning, maintaining and improving real estate. The availability of mortgage financing and changes in interest rates may also affect real estate values. If the Fund’s real estate-related investments are concentrated in one geographic area or in one property type, the Fund will be particularly subject to the risks associated with that area or property type. Many issuers of real estate-related securities are highly leveraged, which increases the risk to holders of such securities. The value of the securities the Fund buys will not necessarily track the value of the underlying investments of the issuers of such securities. In addition, certain issuers of real estate-related securities may have developed or commenced development on properties and may develop additional properties in the future. Real estate development involves significant risks in addition to those involved in the ownership and operation of established properties. Real estate securities may have limited diversification and are, therefore, subject to risks inherent in operating and financing a limited number of projects. Real estate securities are also subject to heavy cash flow dependency and defaults by borrowers or tenants.
REIT Investment Risk [Member]  
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REIT Investment Risk — Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume, may engage in dilutive offerings of securities and may be more volatile than other securities. REIT issuers may also fail to maintain their exemptions from investment company registration or fail to qualify for the “dividends paid deduction” under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), which allows REITs to reduce their corporate taxable income for dividends paid to their shareholders.
Representative Sampling Risk [Member]  
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Representative Sampling Risk — Representative sampling is a method of indexing that involves investing in a representative sample of securities that collectively have a similar investment profile to the index and resemble the index in terms of risk factors and other key characteristics. An ETF may or may not hold every security in the index. When an ETF deviates from a full replication indexing strategy to utilize a representative sampling strategy, the ETF is subject to an increased risk of tracking error, in that the securities selected in the aggregate for the ETF may not have an investment profile similar to those of its index.
Reverse Repurchase Agreements Risk [Member]  
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Reverse Repurchase Agreements Risk — Reverse repurchase agreements involve the sale of securities held by the Fund with an agreement to repurchase the securities at an agreed-upon price, date and interest payment. Reverse repurchase agreements involve the risk that the other party may fail to return the securities in a timely manner or at all. The Fund could lose money if it is unable to recover the securities and the value of the collateral held by the Fund, including the value of the investments made with cash collateral, is less than the value of the securities. These events could also trigger adverse tax consequences for the Fund. In addition, reverse repurchase agreements involve the risk that the interest income earned in the investment of the proceeds will be less than the interest expense.
Risk of Investing in the United States [Member]  
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Risk of Investing in the United States — Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.
Shares of an ETF May Trade at Prices Other Than Net Asset Value [Member]  
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Shares of an ETF May Trade at Prices Other Than Net Asset Value — Shares of an ETF trade on exchanges at prices at, above or below their most recent net asset value. The per share net asset value of an ETF is calculated at the end of each business day and fluctuates with changes in the market value of the ETF’s holdings since the most recent calculation. The trading prices of an ETF’s shares fluctuate continuously throughout trading hours based on market supply and demand rather than net asset value. The trading prices of an ETF’s shares may deviate significantly from net asset value during periods of market volatility. Any of these factors may lead to an ETF’s shares trading at a premium or discount to net asset value. However, because shares can be created and redeemed in creation units,
 
which are aggregated blocks of shares that authorized participants who have entered into agreements with the ETF’s distributor can purchase or redeem directly from the ETF, at net asset value (unlike shares of many closed‑end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset values), large discounts or premiums to the net asset value of an ETF are not likely to be sustained over the long-term. While the creation/redemption feature is designed to make it likely that an ETF’s shares normally trade on exchanges at prices close to the ETF’s next calculated net asset value, exchange prices are not expected to correlate exactly with an ETF’s net asset value due to timing reasons as well as market supply and demand factors. In addition, disruptions to creations and redemptions or the existence of extreme market volatility may result in trading prices that differ significantly from net asset value. If a shareholder purchases at a time when the market price is at a premium to the net asset value or sells at a time when the market price is at a discount to the net asset value, the shareholder may sustain losses. The use of cash creations and redemptions may also cause the ETFs’ shares to trade in the market at greater bid-ask spreads or greater premiums or discounts to the ETFs’ net asset value.
Short Sales Risk [Member]  
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Short Sales Risk — Because making short sales in securities that it does not own exposes the Fund to the risks associated with those securities, such short sales involve speculative exposure risk. The Fund will incur a loss as a result of a short sale if the price of the security increases between the date of the short sale and the date on which the Fund replaces the security sold short.
Small and Mid Capitalization Company Risk [Member]  
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Small and Mid‑Capitalization Company Risk — Companies with small or mid‑size market capitalizations will normally have more limited product lines, markets and financial resources and will be dependent upon a more limited management group than larger capitalized companies. In addition, it is more difficult to get information on smaller companies, which tend to be less well known, have shorter operating histories, do not have significant ownership by large investors and are followed by relatively few securities analysts.
Small Cap and Emerging Growth Securities Risk [Member]  
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Small Cap and Emerging Growth Securities Risk — Small cap or emerging growth companies may have limited product lines or markets. They may be less financially secure than larger, more established companies. They may depend on a more limited management group than larger capitalized companies.
Stable Net Asset Value Risk [Member]  
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Stable Net Asset Value Risk — The Fund may not be able to maintain a stable net asset value of $1.00 per share at all times. If the Fund fails to maintain a stable net asset value (or if there is a perceived threat of such a failure), the Fund, along with other money market funds, could be subject to increased redemption activity.
Structured Notes Risk [Member]  
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Structured Notes Risk — Structured notes and other related instruments purchased by the Fund are generally privately negotiated debt obligations where the principal and/or interest is determined by reference to the performance of a specific asset, benchmark asset, market or interest rate (“reference measure”). The purchase of structured notes exposes the Fund to the credit risk of the issuer of the structured product. Structured notes may be leveraged, increasing the volatility of each structured note’s value relative to the change in the reference measure. Structured notes may also be less liquid and more difficult to price accurately than less complex securities and instruments or more traditional debt securities.
Tracking Error Risk [Member]  
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Tracking Error Risk — The Fund may be subject to tracking error, which is the divergence of an Underlying Fund’s performance from that of its underlying index. Tracking error may occur because of differences between the securities (including shares of the Underlying Funds) and other assets held in an Underlying Fund’s portfolio and those included in its underlying index, pricing differences including, as applicable, differences between a security’s price at the local market close and an Underlying Fund’s valuation of a security at the time of calculation of an Underlying Fund’s net asset value, differences in the timing and methodologies used to value securities and other assets, transaction costs and other expenses incurred by an Underlying Fund that the Underlying Index does not incur, an Underlying Fund’s holding of uninvested cash, differences in the timing of the accrual of or the valuation of dividends or interest received by an Underlying Fund or distributions paid to an Underlying Fund shareholders, tax gains or losses, differences between the amount and/or timing of withholding taxes on dividends reflected in the Underlying Index from an Underlying Fund’s obligation, if any, for foreign withholding taxes, the requirements to maintain pass-through tax treatment, portfolio transactions carried out to minimize the distribution of capital gains to shareholders, the acceptance of custom baskets, changes to an underlying index and the cost to an Underlying Fund of complying with various new or existing regulatory requirements, among other reasons. These risks may be heightened during times of increased market volatility or other unusual market conditions. In addition, tracking error may result because a fund incurs fees and expenses, while the Underlying Index does not.
Treasury Obligations Risk [Member]  
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Treasury Obligations Risk — Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. In addition, notwithstanding that U.S. Treasury obligations are backed by the full faith and credit of the United States, circumstances could arise that could prevent the timely payment of interest or principal, such as reaching the legislative “debt ceiling.” Such non-payment could result in losses to the Fund and substantial negative consequences for the U.S. economy and the global financial system.
U S Government Issuer Risk [Member]  
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Risk [Text Block]
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U.S. Government Issuer Risk — Treasury obligations may differ in their interest rates, maturities, times of issuance and other characteristics. Obligations of U.S. Government agencies and authorities are supported by varying degrees
 
of credit but generally are not backed by the full faith and credit of the U.S. Government. No assurance can be given that the U.S. Government will provide financial support to its agencies and authorities if it is not obligated by law to do so.
Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]
∎  
Warrants Risk — If the price of the underlying stock does not rise above the exercise price before the warrant expires, the warrant generally expires without any value and the Fund will lose any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock. Warrants may trade in the same markets as their underlying stock; however, the price of the warrant does not necessarily move with the price of the underlying stock.
When Issued and Delayed Delivery Securities and Forward Commitments Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]
∎  
When-Issued and Delayed Delivery Securities and Forward Commitments Risk — When-issued and delayed delivery securities and forward commitments involve the risk that the security the Fund buys will lose value prior to its delivery. There also is the risk that the security will not be issued or that the other party to the transaction will not meet its obligation. If this occurs, the Fund may lose both the investment opportunity for the assets it set aside to pay for the security and any gain in the security’s price.
Equity Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]
∎  
Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions.
Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments.
Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.