| N-2 | 6 Months Ended |
| Jun. 30, 2023 shares | |
| Cover [Abstract] | |
| Entity Central Index Key | 0001051003 |
| Amendment Flag | false |
| Document Type | N-CSRS |
| Entity Registrant Name | BlackRock Debt Strategies Fund, Inc. |
| General Description of Registrant [Abstract] | |
| Investment Objectives and Practices [Text Block] | Investment Objective BlackRock Debt Strategies Fund, Inc.’s (DSU) (the “Fund”) No assurance can be given that the Fund’s investment objective will be achieved. |
| Risk Factors [Table Text Block] | 10. PRINCIPAL RISKS In the normal course of business, the Funds invest in securities or other instruments and may enter into certain transactions, and such activities subject each Fund to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, recessions, or other events could have a significant impact on the Funds and their investments. Each Fund may invest without limitation in illiquid or less liquid investments or investments in which no secondary market is readily available or which are otherwise illiquid, including private placement securities. A Fund may not be able to readily dispose of such investments at prices that approximate those at which a Fund could sell such investments if they were more widely traded and, as a result of such illiquidity, a Fund may have to sell other investments or engage in borrowing transactions if necessary to raise funds to meet its obligations. Limited liquidity can also affect the market price of investments, thereby adversely affecting a Fund’s NAV and ability to make dividend distributions. Privately issued debt securities are often of below investment grade quality, frequently are unrated and present many of the same risks as investing in below investment grade public debt securities. Market Risk: Infectious Illness Risk: Valuation Risk: The price a Fund could receive upon the sale of any particular portfolio investment may differ from a Fund’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair valuation technique or a price provided by an independent pricing service. Changes to significant unobservable inputs and assumptions (i.e., publicly traded company multiples, growth rate, time to exit) due to the lack of observable inputs may significantly impact the resulting fair value and therefore a Fund’s results of operations. As a result, the price received upon the sale of an investment may be less than the value ascribed by a Fund, and a Fund could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. A Fund’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third-party service providers. Counterparty Credit Risk: A derivative contract may suffer a mark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract. For OTC options purchased, each Fund bears the risk of loss in the amount of the premiums paid plus the positive change in market values net of any collateral held by the Funds should the counterparty fail to perform under the contracts. Options written by the Funds do not typically give rise to counterparty credit risk, as options written generally obligate the Funds, and not the counterparty, to perform. The Funds may be exposed to counterparty credit risk with respect to options written to the extent each Fund deposits collateral with its counterparty to a written option. With exchange-traded options purchased, exchange-traded futures and centrally cleared swaps, there is less counterparty credit risk to the Funds since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a Fund does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures and centrally cleared swaps with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Funds. Geographic/Asset Class Risk: Certain Funds invest a significant portion of their assets in high yield securities. High yield securities that are rated below investment-grade (commonly referred to as “junk bonds”) or are unrated may be deemed speculative, involve greater levels of risk than higher-rated securities of similar maturity and are more likely to default. High yield securities may be issued by less creditworthy issuers, and issuers of high yield securities may be unable to meet their interest or principal payment obligations. High yield securities are subject to extreme price fluctuations, may be less liquid than higher rated fixed-income securities, even under normal economic conditions, and frequently have redemption features. The Funds invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will decrease as interest rates rise and increase as interest rates fall. The Funds may be subject to a greater risk of rising interest rates due to the period of historically low interest rates that ended in March 2022. The Federal Reserve has recently been raising the federal funds rate as part of its efforts to address inflation. There is a risk that interest rates will continue to rise, which will likely drive down the prices of bonds and other fixed-income securities, and could negatively impact the Funds’ performance. The Funds invest a significant portion of their assets in securities of issuers located in the United States. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the United States may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the United States may also have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the United States will continue to maintain elevated public debt levels for the foreseeable future which may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative “debt ceiling.” Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system. If U.S. relations with certain countries deteriorate, it could adversely affect issuers that rely on the United States for trade. The United States has also experienced increased internal unrest and discord. If these trends were to continue, they may have an adverse impact on the U.S. economy and the issuers in which the Funds invest. Certain Funds invest a significant portion of their assets in securities backed by commercial or residential mortgage loans or in issuers that hold mortgage and other asset-backed securities. When a fund concentrates its investments in this manner, it assumes a greater risk of prepayment or payment extension by securities issuers. Changes in economic conditions, including delinquencies and/or defaults on assets underlying these securities, can affect the value, income and/or liquidity of such positions. Investment percentages in these securities are presented in the Schedules of Investments. LIBOR Transition Risk: |
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |
| Capital Stock [Table Text Block] | 11. CAPITAL SHARE TRANSACTIONS DSU is authorized to issue 400 million shares, all of which were initially classified as Common Shares. FRA and BKT are authorized to issue 200 million shares, all of which were initially classified as Common Shares. BLW is authorized to issue an unlimited number of shares, all of which were initially classified as Common Shares. The par value for DSU’s, FRA’s, BKT’s and BLW’s shares is $0.10, $0.10, $0.010 and $0.001, respectively. The Board for DSU, FRA and BLW are each authorized, however, to reclassify any unissued Common Shares to Preferred Shares without the approval of Common Shareholders. Common Shares For the periods shown, shares issued and outstanding increased by the following amounts as a result of dividend reinvestment: Fund Name Six Months Ended Year Ended 12/31/22 DSU — 3,721 BKT 3,394 3,887 For the six months ended June 30, 2023, shares issued and outstanding remained constant for DSU. For the six months ended June 30, 2023 and the year ended December 31, 2022, shares issued and outstanding remained constant for FRA and BLW. The Funds participate in an open market share repurchase program (the “Repurchase Program”). From December 1, 2022 through November 30, 2023, each Fund may repurchase up to 5% of its outstanding common shares under the Repurchase Program, based on common shares outstanding as of the close of business on November 30, 2022, subject to certain conditions. The Repurchase Program has an accretive effect as shares are purchased at a discount to the Fund’s NAV. There is no assurance that the Funds will purchase shares in any particular amounts. For the six months ended June 30, 2023, the Funds did not repurchase any shares. DSU, BKT and BLW have each filed a prospectus with the SEC allowing them to issue an additional 16,000,000, 8,333,333 and 10,000,000 Common Shares, respectively, through an equity Shelf Offering. Under the Shelf Offering, DSU, BKT and BLW, subject to market conditions, may raise additional equity capital from time to time in varying amounts and utilizing various offering methods at a net price at or above each Fund’s NAV per Common Share (calculated within 48 hours of pricing). As of period end, 16,000,000, 8,333,333 and 10,000,000 Common Shares, respectively, remain available for issuance under the Shelf Offering. For the six months ended June 30, 2023, Common Shares issued and outstanding under the Shelf Offering remained constant for DSU, BKT and BLW. See Additional Information - Shelf Offering Program for additional information. Initial costs incurred by DSU, BKT and BLW in connection with their Shelf Offering are recorded as “Deferred offering costs” in the Statements of Assets and Liabilities. As shares are sold, a portion of the costs attributable to the shares sold will be charged against paid-in-capital. Any remaining deferred charges at the end of the Shelf Offering period will be charged to expense. |
| Outstanding Securities [Table Text Block] | DSU is authorized to issue 400 million shares, all of which were initially classified as Common Shares. |
| Outstanding Security, Authorized [Shares] | 400,000,000 |
| Outstanding Security, Held [Shares] | 46,610,312 |
| Market Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | Market Risk: |
| Infectious Illness Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | Infectious Illness Risk: |
| Valuation Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | Valuation Risk: The price a Fund could receive upon the sale of any particular portfolio investment may differ from a Fund’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair valuation technique or a price provided by an independent pricing service. Changes to significant unobservable inputs and assumptions (i.e., publicly traded company multiples, growth rate, time to exit) due to the lack of observable inputs may significantly impact the resulting fair value and therefore a Fund’s results of operations. As a result, the price received upon the sale of an investment may be less than the value ascribed by a Fund, and a Fund could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. A Fund’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third-party service providers. |
| Counterparty Credit Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | Counterparty Credit Risk: A derivative contract may suffer a mark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract. For OTC options purchased, each Fund bears the risk of loss in the amount of the premiums paid plus the positive change in market values net of any collateral held by the Funds should the counterparty fail to perform under the contracts. Options written by the Funds do not typically give rise to counterparty credit risk, as options written generally obligate the Funds, and not the counterparty, to perform. The Funds may be exposed to counterparty credit risk with respect to options written to the extent each Fund deposits collateral with its counterparty to a written option. With exchange-traded options purchased, exchange-traded futures and centrally cleared swaps, there is less counterparty credit risk to the Funds since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a Fund does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures and centrally cleared swaps with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Funds. |
| Geographic Asset Class Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | Geographic/Asset Class Risk: Certain Funds invest a significant portion of their assets in high yield securities. High yield securities that are rated below investment-grade (commonly referred to as “junk bonds”) or are unrated may be deemed speculative, involve greater levels of risk than higher-rated securities of similar maturity and are more likely to default. High yield securities may be issued by less creditworthy issuers, and issuers of high yield securities may be unable to meet their interest or principal payment obligations. High yield securities are subject to extreme price fluctuations, may be less liquid than higher rated fixed-income securities, even under normal economic conditions, and frequently have redemption features. The Funds invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will decrease as interest rates rise and increase as interest rates fall. The Funds may be subject to a greater risk of rising interest rates due to the period of historically low interest rates that ended in March 2022. The Federal Reserve has recently been raising the federal funds rate as part of its efforts to address inflation. There is a risk that interest rates will continue to rise, which will likely drive down the prices of bonds and other fixed-income securities, and could negatively impact the Funds’ performance. The Funds invest a significant portion of their assets in securities of issuers located in the United States. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the United States may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the United States may also have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the United States will continue to maintain elevated public debt levels for the foreseeable future which may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative “debt ceiling.” Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system. If U.S. relations with certain countries deteriorate, it could adversely affect issuers that rely on the United States for trade. The United States has also experienced increased internal unrest and discord. If these trends were to continue, they may have an adverse impact on the U.S. economy and the issuers in which the Funds invest. Certain Funds invest a significant portion of their assets in securities backed by commercial or residential mortgage loans or in issuers that hold mortgage and other asset-backed securities. When a fund concentrates its investments in this manner, it assumes a greater risk of prepayment or payment extension by securities issuers. Changes in economic conditions, including delinquencies and/or defaults on assets underlying these securities, can affect the value, income and/or liquidity of such positions. Investment percentages in these securities are presented in the Schedules of Investments. |
| LIBOR Transition Risk [Member] | |
| General Description of Registrant [Abstract] | |
| Risk [Text Block] | LIBOR Transition Risk: |
