| Label | Element | Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Investor A, C and Institutional | BlackRock Income Fund | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk/Return [Heading] | rr_RiskReturnHeading | Fund Overview Key Facts About BlackRock Income Fund | ||||||||||
| Objective [Heading] | rr_ObjectiveHeading | Investment Objective | ||||||||||
| Objective, Primary [Text Block] | rr_ObjectivePrimaryTextBlock | The investment objective of the BlackRock Income Fund (formerly known as BlackRock Credit Strategies Income Fund) (the “Fund”) is to seek to provide high current income, | ||||||||||
| Objective, Secondary [Text Block] | rr_ObjectiveSecondaryTextBlock | with a secondary objective of long-term capital appreciation. | ||||||||||
| Expense [Heading] | rr_ExpenseHeading | Fees and Expenses of the Fund | ||||||||||
| Expense Narrative [Text Block] | rr_ExpenseNarrativeTextBlock | This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to your financial professional or your selected securities dealer, broker, investment adviser, service provider or industry professional (including BlackRock Advisors, LLC (“BlackRock”) and its affiliates) (each, a “Financial Intermediary”), which are not reflected in the table and example below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the fund complex advised by BlackRock or its affiliates. More information about these and other discounts is available from your Financial Intermediary and in the “Details About the Share Classes” and the “Intermediary-Defined Sales Charge Waiver Policies” sections on pages 33 and A-1, respectively, of the Fund’s prospectus and in the “Purchase of Shares” section on page II-90 of Part II of the Fund’s Statement of Additional Information.
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| Shareholder Fees Caption [Text] | rr_ShareholderFeesCaption | Shareholder Fees (fees paid directly from your investment) | ||||||||||
| Operating Expenses Caption [Text] | rr_OperatingExpensesCaption | Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) | ||||||||||
| Fee Waiver or Reimbursement over Assets, Date of Termination | rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination | June 30, 2025 | ||||||||||
| Portfolio Turnover [Heading] | rr_PortfolioTurnoverHeading | Portfolio Turnover: | ||||||||||
| Portfolio Turnover [Text Block] | rr_PortfolioTurnoverTextBlock | The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 571% of the average value of its portfolio.
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| Portfolio Turnover, Rate | rr_PortfolioTurnoverRate | 571.00% | ||||||||||
| Expenses Deferred Charges [Text Block] | rr_ExpensesDeferredChargesTextBlock | A contingent deferred sales charge (“CDSC”) of 0.75% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $500,000 or more. | ||||||||||
| Expense Breakpoint Discounts [Text] | rr_ExpenseBreakpointDiscounts | You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the fund complex advised by BlackRock or its affiliates. | ||||||||||
| Expense Breakpoint, Minimum Investment Required [Amount] | rr_ExpenseBreakpointMinimumInvestmentRequiredAmount | $ 50,000 | ||||||||||
| Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text] | rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees | The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent annual report, which do not include Acquired Fund Fees and Expenses. | ||||||||||
| Expense Example [Heading] | rr_ExpenseExampleHeading | Example: | ||||||||||
| Expense Example Narrative [Text Block] | rr_ExpenseExampleNarrativeTextBlock | This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
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| Expense Example, No Redemption, By Year, Caption [Text] | rr_ExpenseExampleNoRedemptionByYearCaption | You would pay the following expenses if you did not redeem your shares: | ||||||||||
| Strategy [Heading] | rr_StrategyHeading | Principal Investment Strategies of the Fund | ||||||||||
| Strategy Narrative [Text Block] | rr_StrategyNarrativeTextBlock | Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in fixed-income securities. The Fund may invest without limit in fixed-income securities across several investment sectors, including, but not limited to: fixed-income securities rated below investment grade, investment grade corporate bonds, fixed-income securities issued by governmental entities (including supranational entities), their agencies and instrumentalities, mezzanine investments, collateralized loan obligations (“CLOs”), bank loans, mortgage-related securities (including, but not limited to, “to be announced” or “TBA” securities), asset-backed securities and other fixed and floating or variable rate obligations. The Fund may invest in such fixed-income securities of issuers located in the United States and non-U.S. countries, including emerging market countries. The Fund is not required to invest in each investment sector at all times, and its investment in each investment sector may vary over time. The Fund may invest in instruments of any credit quality without limitation, including instruments rated below investment grade, which are commonly referred to as “junk bonds.” The Fund may invest in fixed-income securities of any duration or maturity. The Fund may also invest in companies whose financial condition is uncertain, where the borrower has defaulted in the payment of interest or principal or in the performance of its covenants or agreements, or that may be involved in bankruptcy proceedings, reorganizations or financial restructurings. The Fund may use a variety of portfolio strategies to hedge its portfolio against interest rate and currency risk, or to seek to enhance its return. These strategies include the use of derivatives, such as options on portfolio positions or currencies, financial and currency futures and options on these futures, forward foreign currency transactions, interest rate swaps, credit default swaps and total return swaps. Derivatives are financial instruments whose value is derived from another security or an index. The Fund may invest in indexed and inverse securities (which are securities that provide a potential return based on a particular index of value or interest rates). The Fund may engage in active and frequent trading of portfolio securities to achieve its primary investment strategies.
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| Risk [Heading] | rr_RiskHeading | Principal Risks of Investing in the Fund | ||||||||||
| Bar Chart and Performance Table [Heading] | rr_BarChartAndPerformanceTableHeading | Performance Information | ||||||||||
| Performance Narrative [Text Block] | rr_PerformanceNarrativeTextBlock | The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. The Fund acquired all of the assets, subject to the liabilities, of BlackRock Credit Strategies Income Fund, a series of BlackRock Funds II (the “Predecessor Fund”), in a reorganization on September 17, 2018 (the “Reorganization”). The Fund adopted the performance of the Predecessor Fund as a result of the Reorganization. The performance information below is based on the performance of the Predecessor Fund for periods prior to the date of the Reorganization. The Predecessor Fund had the same investment objectives, strategies and policies, portfolio management team and contractual arrangements, including the same contractual fees and expenses, as the Fund as of the date of the Reorganization. The Predecessor Fund’s returns prior to July 1, 2016 as reflected in the bar chart and the table are the returns of the Predecessor Fund when it followed different investment strategies under the name “BlackRock Secured Credit Portfolio.” The table compares the Fund’s performance to that of the Morningstar LSTA Leveraged Loan Index (formerly S&P/LSTA Leveraged Loan Index), the Bloomberg Global High Yield 100% Hedged USD Index, the Bloomberg U.S. CMBS Investment Grade Index, the JPMorgan Corporate Emerging Markets Bond Index Broad Diversified (CEMBI Broad Diversified) and a customized performance benchmark comprised of the returns of the Bloomberg Global High Yield 100% Hedged USD Index (25%), Morningstar LSTA Leveraged Loan Index (25%), Bloomberg U.S. CMBS Investment Grade Index (25%) and JPMorgan Corporate Emerging Markets Bond Index Broad Diversified (CEMBI Broad Diversified) (25%) (the “Customized Reference Benchmark”). To the extent that dividends and distributions have been paid by the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If the Fund’s investment manager and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s performance, including its current net asset value, can be obtained by visiting http://www.blackrock.com or can be obtained by phone at (800) 882-0052.
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| Performance Information Illustrates Variability of Returns [Text] | rr_PerformanceInformationIllustratesVariabilityOfReturns | The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. | ||||||||||
| Performance Availability Phone [Text] | rr_PerformanceAvailabilityPhone | (800) 882-0052 | ||||||||||
| Performance Availability Website Address [Text] | rr_PerformanceAvailabilityWebSiteAddress | http://www.blackrock.com | ||||||||||
| Performance Past Does Not Indicate Future [Text] | rr_PerformancePastDoesNotIndicateFuture | As with all such investments, past performance (before and after taxes) is not an indication of future results. | ||||||||||
| Bar Chart [Heading] | rr_BarChartHeading | Investor A Shares ANNUAL TOTAL RETURNS BlackRock Income Fund As of 12/31 | ||||||||||
| Bar Chart Does Not Reflect Sales Loads [Text] | rr_BarChartDoesNotReflectSalesLoads | Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. | ||||||||||
| Bar Chart Closing [Text Block] | rr_BarChartClosingTextBlock | During the ten-year period shown in the bar chart, the highest return for a quarter was 9.89% (quarter ended June 30, 2020) and the lowest return for a quarter was -10.33% (quarter ended March 31, 2020).
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| Performance Table Heading | rr_PerformanceTableHeading | For the periods ended 12/31/23 Average Annual Total Returns | ||||||||||
| Performance Table Does Reflect Sales Loads | rr_PerformanceTableDoesReflectSalesLoads | However, the table includes all applicable fees and sales charges. | ||||||||||
| Performance Table Uses Highest Federal Rate | rr_PerformanceTableUsesHighestFederalRate | After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. | ||||||||||
| Performance Table Not Relevant to Tax Deferred | rr_PerformanceTableNotRelevantToTaxDeferred | Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. | ||||||||||
| Performance Table One Class of after Tax Shown [Text] | rr_PerformanceTableOneClassOfAfterTaxShown | After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary. | ||||||||||
| Performance Table Narrative | rr_PerformanceTableNarrativeTextBlock | After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary.
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| Investor A, C and Institutional | BlackRock Income Fund | Risk Lose Money [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Debt Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■ Debt Securities Risk — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, extension risk, and prepayment risk, each of which are described in further detail below: Credit Risk — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.Interest Rate Risk — The market value of bonds and other fixed-income securities changes in response to interest rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise.The Fund may be subject to a greater risk of rising interest rates due to the recent period of historically low interest rates. For example, if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund management.To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities.These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in value when interest rates change.A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could hurt the Fund’s performance.Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these obligations to fall.Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Corporate Loans Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■ 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”), the London Interbank Offered Rate (“LIBOR”) 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. The corporate loans in which the Fund invests are usually rated below investment grade. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Collateralized Debt Obligations Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■ Collateralized Debt Obligations Risk — In addition to the typical risks associated with fixed-income securities and asset-backed securities, collateralized debt obligations (“CDOs”), including CLOs, carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the risk that the collateral may default or decline in value or be downgraded, if rated by a nationally recognized statistical rating organization; (iii) the Fund may invest in tranches of CDOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) the risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Derivatives Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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, BlackRock 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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Distressed Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Distressed Securities Risk — Distressed securities are speculative and involve substantial risks in addition to the risks of investing in junk bonds. The Fund will generally not receive interest payments on the distressed securities and may incur costs to protect its investment. In addition, distressed securities involve the substantial risk that principal will not be repaid. These securities may present a substantial risk of default or may be in default at the time of investment. The Fund may incur additional expenses to the extent it is required to seek recovery upon a default in the payment of principal of or interest on its portfolio holdings. In any reorganization or liquidation proceeding relating to a portfolio company, the Fund may lose its entire investment or may be required to accept cash or securities with a value less than its original investment. Distressed securities and any securities received in an exchange for such securities may be subject to restrictions on resale. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Emerging Markets Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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 affectreturns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Foreign Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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:■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.■Changes in foreign currency exchange rates can affect the value of the Fund’s portfolio.■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.■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.■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.■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.■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.■The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries as well as acts of war in the region. These events may spread to other countries in Europe and may affect the value and liquidity of certain of the Fund’s investments. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | High Portfolio Turnover Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | High Yield Bonds Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■High Yield Bonds Risk — Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that are considered speculative and may cause income and principal losses for the Fund. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Illiquid Investments Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Illiquid Investments Risk — The Fund may not acquire any illiquid investment if, immediately after the acquisition, the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time or price. In addition, if the Fund is limited in its ability to sell illiquid investments during periods when shareholders are redeeming their shares, the Fund will need to sell liquid securities to meet redemption requests and illiquid securities will become a larger portion of the Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of traditional market participants to make a market in fixed-income securities or the lack of an active trading market. To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to the risks associated with illiquid investments. Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be magnified in a rising interest rate environment or othercircumstances where investor redemptions from fixed-income mutual funds may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Indexed and Inverse Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Leverage Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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, and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Market Risk and Selection Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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.An outbreak of an infectious coronavirus (COVID-19) that was first detected in December 2019 developed into a global pandemic that has resulted in numerous disruptions in the market and has had significant economic impact leaving general concern and uncertainty. Although vaccines have been developed and approved for use by various governments, the duration of the pandemic and its effects cannot be predicted with certainty. The impact of this coronavirus, and other epidemics and pandemics that may arise in the future, could affect the economies of many nations, individual companies and the market in general ways that cannot necessarily be foreseen at the present time. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Mezzanine Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Mortgage and Asset Backed Securities Risks [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Mortgage- and Asset-Backed Securities Risks — Mortgage- and asset-backed securities represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset-backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. TBA commitments are forward agreements for the purchase or sale of securities, including mortgage-backed securities for a fixed price, with payment and delivery on an agreed upon future settlement date. The specific securities to be delivered are not identified at the trade date. However, delivered securities must meet specified terms, including issuer, rate and mortgage terms. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Risk of Investing in the United States [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Risk of Investing in the United States — Certain changes in the United States 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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Senior Loans Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Senior Loans Risk — There is less readily available, reliable information about most senior loans than is the case for many other types of securities. An economic downturn generally leads to a higher non-payment rate, and a senior loan may lose significant value before a default occurs. Moreover, any specific collateral used to secure a senior loan may decline in value or become illiquid, which would adversely affect the senior loan’s value. No active trading market may exist for certain senior loans, which may impair the ability of the Fund to realize full value in the event of the need to sell a senior loan and which may make it difficult to value senior loans. Although senior loans in which the Fund will invest generally will be secured by specific collateral, there can be no assurance that liquidation of such collateral would satisfy the borrower’s obligation in the event of non-payment of scheduled interest or principal or that such collateral could be readily liquidated. To the extent that a senior loan is collateralized by stock in the borrower or its subsidiaries, such stock may lose all of its value in the event of the bankruptcy of theborrower. Uncollateralized senior loans involve a greater risk of loss. The senior loans in which the Fund invests are usually rated below investment grade. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Sovereign Debt Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Sovereign Debt Risk — Sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt position in relation to the economy or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Supranational Entities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Supranational Entities Risk — The Fund may invest in obligations issued or guaranteed by the World Bank. The government members, or “stockholders,” usually make initial capital contributions to the World Bank and in many cases are committed to make additional capital contributions if the World Bank is unable to repay its borrowings. There is no guarantee that one or more stockholders of the World Bank will continue to make any necessary additional capital contributions. If such contributions are not made, the entity may be unable to pay interest or repay principal on its debt securities, and the Fund may lose money on such investments. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | U S Government Issuer Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■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. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | U S Government Mortgage Related Securities Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■U.S. Government Mortgage-Related Securities Risk — There are a number of important differences among the agencies and instrumentalities of the U.S. Government that issue mortgage-related securities and among the securities that they issue. Mortgage-related securities guaranteed by the Government National Mortgage Association (“GNMA” or “Ginnie Mae”) are guaranteed as to the timely payment of principal and interest by GNMA and such guarantee is backed by the full faith and credit of the United States. GNMA securities also are supported by the right of GNMA to borrow funds from the U.S. Treasury to make payments under its guarantee. Mortgage-related securities issued by Fannie Mae or Freddie Mac are solely the obligations of Fannie Mae or Freddie Mac, as the case may be, and are not backed by or entitled to the full faith and credit of the United States but are supported by the right of the issuer to borrow from the Treasury. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Variable and Floating Rate Instrument Risk [Member] | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Risk [Text Block] | rr_RiskTextBlock | ■Variable and Floating Rate Instrument Risk — Variable and floating rate securities provide for periodic adjustment in the interest rate paid on the securities. These securities may be subject to greater illiquidity risk than other fixed income securities, meaning the absence of an active market for these securities could make it difficult for the Fund to dispose of them at any given time. | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Investor A Shares | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 2.50% | ||||||||||
| Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower) | rr_MaximumDeferredSalesChargeOverOfferingPrice | none | [1] | |||||||||
| Management Fee | rr_ManagementFeesOverAssets | 0.49% | [2] | |||||||||
| Distribution and/or Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | 0.25% | ||||||||||
| Other Expenses | rr_OtherExpensesOverAssets | 0.23% | ||||||||||
| Acquired Fund Fees and Expenses | rr_AcquiredFundFeesAndExpensesOverAssets | 0.02% | [3] | |||||||||
| Total Annual Fund Operating Expenses | rr_ExpensesOverAssets | 0.99% | [3] | |||||||||
| Fee Waivers and/or Expense Reimbursements | rr_FeeWaiverOrReimbursementOverAssets | (0.10%) | [2],[4] | |||||||||
| Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements | rr_NetExpensesOverAssets | 0.89% | [2],[4] | |||||||||
| 1 Year | rr_ExpenseExampleYear01 | $ 339 | ||||||||||
| 3 Years | rr_ExpenseExampleYear03 | 548 | ||||||||||
| 5 Years | rr_ExpenseExampleYear05 | 774 | ||||||||||
| 10 Years | rr_ExpenseExampleYear10 | $ 1,424 | ||||||||||
| 2014 | rr_AnnualReturn2014 | 2.21% | ||||||||||
| 2015 | rr_AnnualReturn2015 | 0.03% | ||||||||||
| 2016 | rr_AnnualReturn2016 | 7.46% | ||||||||||
| 2017 | rr_AnnualReturn2017 | 6.35% | ||||||||||
| 2018 | rr_AnnualReturn2018 | (1.23%) | ||||||||||
| 2019 | rr_AnnualReturn2019 | 11.71% | ||||||||||
| 2020 | rr_AnnualReturn2020 | 6.63% | ||||||||||
| 2021 | rr_AnnualReturn2021 | (0.42%) | ||||||||||
| 2022 | rr_AnnualReturn2022 | (9.61%) | ||||||||||
| 2023 | rr_AnnualReturn2023 | 9.07% | ||||||||||
| Highest Quarterly Return, Label | rr_HighestQuarterlyReturnLabel | highest return | ||||||||||
| Highest Quarterly Return, Date | rr_BarChartHighestQuarterlyReturnDate | Jun. 30, 2020 | ||||||||||
| Highest Quarterly Return | rr_BarChartHighestQuarterlyReturn | 9.89% | ||||||||||
| Lowest Quarterly Return, Label | rr_LowestQuarterlyReturnLabel | lowest return | ||||||||||
| Lowest Quarterly Return, Date | rr_BarChartLowestQuarterlyReturnDate | Mar. 31, 2020 | ||||||||||
| Lowest Quarterly Return | rr_BarChartLowestQuarterlyReturn | (10.33%) | ||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 6.35% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.66% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 2.78% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Investor C Shares | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||
| Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower) | rr_MaximumDeferredSalesChargeOverOfferingPrice | 1.00% | [5] | |||||||||
| Management Fee | rr_ManagementFeesOverAssets | 0.49% | [2] | |||||||||
| Distribution and/or Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | 1.00% | ||||||||||
| Other Expenses | rr_OtherExpensesOverAssets | 0.24% | ||||||||||
| Acquired Fund Fees and Expenses | rr_AcquiredFundFeesAndExpensesOverAssets | 0.02% | [3] | |||||||||
| Total Annual Fund Operating Expenses | rr_ExpensesOverAssets | 1.75% | [3] | |||||||||
| Fee Waivers and/or Expense Reimbursements | rr_FeeWaiverOrReimbursementOverAssets | (0.11%) | [2],[4] | |||||||||
| Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements | rr_NetExpensesOverAssets | 1.64% | [2],[4] | |||||||||
| 1 Year | rr_ExpenseExampleYear01 | $ 267 | ||||||||||
| 3 Years | rr_ExpenseExampleYear03 | 540 | ||||||||||
| 5 Years | rr_ExpenseExampleYear05 | 939 | ||||||||||
| 10 Years | rr_ExpenseExampleYear10 | 1,852 | ||||||||||
| 1 Year | rr_ExpenseExampleNoRedemptionYear01 | 167 | ||||||||||
| 3 Years | rr_ExpenseExampleNoRedemptionYear03 | 540 | ||||||||||
| 5 Years | rr_ExpenseExampleNoRedemptionYear05 | 939 | ||||||||||
| 10 Years | rr_ExpenseExampleNoRedemptionYear10 | $ 1,852 | ||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 7.38% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 2.43% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 2.44% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Institutional Shares | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) | rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | none | ||||||||||
| Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower) | rr_MaximumDeferredSalesChargeOverOfferingPrice | none | ||||||||||
| Management Fee | rr_ManagementFeesOverAssets | 0.49% | [2] | |||||||||
| Distribution and/or Service (12b-1) Fees | rr_DistributionAndService12b1FeesOverAssets | none | ||||||||||
| Other Expenses | rr_OtherExpensesOverAssets | 0.36% | ||||||||||
| Acquired Fund Fees and Expenses | rr_AcquiredFundFeesAndExpensesOverAssets | 0.02% | [3] | |||||||||
| Total Annual Fund Operating Expenses | rr_ExpensesOverAssets | 0.87% | [3] | |||||||||
| Fee Waivers and/or Expense Reimbursements | rr_FeeWaiverOrReimbursementOverAssets | (0.23%) | [2],[4] | |||||||||
| Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements | rr_NetExpensesOverAssets | 0.64% | [2],[4] | |||||||||
| 1 Year | rr_ExpenseExampleYear01 | $ 65 | ||||||||||
| 3 Years | rr_ExpenseExampleYear03 | 255 | ||||||||||
| 5 Years | rr_ExpenseExampleYear05 | 460 | ||||||||||
| 10 Years | rr_ExpenseExampleYear10 | $ 1,051 | ||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 9.35% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 3.44% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 3.30% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Return After Taxes on Distributions | Investor A Shares | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 4.49% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 0.86% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 0.97% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Return After Taxes on Distributions and Sale of Fund Shares | Investor A Shares | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 3.73% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 1.30% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 1.34% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Morningstar LSTA Leveraged Loan Index (Reflects no deduction for fees, expenses or taxes) | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 13.32% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 5.80% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 4.42% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Bloomberg Global High Yield 100% Hedged USD Index (Reflects no deduction for fees, expenses or taxes) | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 13.66% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 4.43% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 4.43% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Bloomberg U.S. CMBS Investment Grade Index (Reflects no deduction for fees, expenses or taxes) | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 5.42% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 1.68% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 2.06% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | JPMorgan Corporate Emerging Markets Bond Index Broad Diversified (CEMBI Broad Diversified) (Reflects no deduction for fees, expenses or taxes) | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 9.08% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 3.19% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 3.77% | ||||||||||
| Investor A, C and Institutional | BlackRock Income Fund | Customized Reference Benchmark (Reflects no deduction for fees, expenses or taxes) | ||||||||||||
| Risk/Return: | rr_RiskReturnAbstract | |||||||||||
| 1 Year | rr_AverageAnnualReturnYear01 | 10.36% | ||||||||||
| 5 Years | rr_AverageAnnualReturnYear05 | 3.84% | ||||||||||
| 10 Years | rr_AverageAnnualReturnYear10 | 3.72% | ||||||||||
| ||||||||||||