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DREYFUS BASIC MONEY MARKET FUND, INC  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Fund Summary
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The fund seeks as high a level of current income as is consistent with the preservation of capital and the maintenance of liquidity.

Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment if your account balance is less than $50,000)
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 Jul. 01, 2017
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The 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. The one-year example and the first year of the three-, five- and ten-years examples are based on net operating expenses, which reflect the expense limitation by The Dreyfus Corporation. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategy
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

As a money market fund, the fund is subject to the maturity, quality, liquidity and diversification requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended, which are designed to help money market funds maintain a stable share price of $1.00. To pursue its goal, the fund invests in a diversified portfolio of high quality, short-term dollar-denominated debt securities, including: securities issued or guaranteed as to principal and interest by the U.S. government or its agencies or instrumentalities; certificates of deposit, time deposits, bankers' acceptances and other short-term securities issued by domestic or foreign banks or thrifts or their subsidiaries or branches; repurchase agreements, including tri-party repurchase agreements; asset-backed securities; domestic and dollar-denominated foreign commercial paper and other short-term corporate obligations, including those with floating or variable rates of interest; and dollar-denominated obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions or agencies. Normally, the fund invests at least 25% of its net assets in domestic or dollar-denominated foreign bank obligations.

Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

An investment in the fund is not a bank deposit. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. Neither The Dreyfus Corporation nor its affiliates have a legal obligation to provide financial support to the fund, and you should not expect that The Dreyfus Corporation or its affiliates will provide financial support to the fund at any time. The fund's yield will fluctuate as the short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. The following are the principal risks that could reduce the fund's income level and/or share price:


· Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. A sharp and unexpected rise in interest rates could cause a money market fund's share price to drop below a dollar. A low interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of fund assets and could impair the fund's ability to maintain a stable net asset value.


· Liquidity risk. When there is little or no active trading market for specific types of securities, it can become more difficult to sell the securities in a timely manner at or near their perceived value. In such a market, the value of such securities may fall dramatically, potentially impairing the fund's ability to maintain a stable net asset value, even during periods of declining interest rates.


·  Credit risk. Failure of an issuer of a security to make timely interest or principal payments when due, or a decline or perception of a decline in the credit quality of a security, can cause the security's price to fall. Although the fund invests only in high quality debt securities, the credit quality and prices of the securities held by the fund can change rapidly in certain market environments, and the default or a significant price decline of a single holding could impair the fund's ability to maintain a stable net asset value.


· Regulatory risk. The Securities and Exchange Commission has adopted amendments to the rules governing money market funds that will change the way that the fund, and similar money market funds, operate. The amended rules permit, and in some cases will require, the fund to impose a "liquidity fee" of up to 2% of the amount redeemed or temporarily restrict shareholder redemptions from the fund. The liquidity fee or redemption restrictions could be applied (subject to board determination) when the fund's "weekly liquid assets"—including cash, certain U.S. government securities and securities maturing in five business days—fall below 30% of the fund's total assets. These changes are anticipated to take effect on October 14, 2016. The changes to the rules may affect fund investment strategies and the cost of operating the fund.


· Banking industry risk. The risks generally associated with concentrating investments in the banking industry include interest rate risk, credit risk, and regulatory developments relating to the banking industry.


· Foreign investment risk. The risks generally associated with dollar-denominated foreign investments include economic and political developments, seizure or nationalization of deposits, imposition of taxes or other restrictions on payment of principal and interest.


· Government securities risk. Not all obligations of the U.S. government, its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Some obligations are backed only by the credit of the issuing agency or instrumentality, and in some cases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agencies or instrumentalities, of a security held by the fund does not apply to the market value of such security or to shares of the fund itself. A security backed by the U.S. Treasury or the full faith and credit of the United States, is guaranteed only as to the timely payment of interest and principal when held to maturity.


· Repurchase agreement counterparty risk. The fund is subject to the risk that a counterparty in a repurchase agreement and/or for a tri-party repurchase agreement, the third party bank priority payment administration, collateral custody and management services for the transaction could fail to honor the terms of the agreement.

Risk Money Market Fund [Text] rr_RiskMoneyMarketFund Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the fund is not a bank deposit. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the performance of the fund's shares from year to year. The table shows the average annual total returns of the fund's shares over time. The fund's past performance is not necessarily an indication of how the fund will perform in the future. More recent performance information may be available at www.dreyfus.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following bar chart and table provide some indication of the risks of investing in the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.dreyfus.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The fund's past performance is not necessarily an indication of how the fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Year-by-Year Total Returns as of 12/31 each year (%)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Best Quarter
Q4, 2006: 1.24%


Worst Quarter
Q3, 2015: 0.00%


The year-to-date total return of the fund’s shares as of 3/31/16 was 0.01%.

Year to Date Return, Label rr_YearToDateReturnLabel year-to-date total return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Mar. 31, 2016
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 0.01%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2006
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 1.24%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn none
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

For the fund's current yield, call toll free 1-800-DREYFUS (inside the U.S. only).
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of 12/31/15
Money Market Seven Day Yield Phone rr_MoneyMarketSevenDayYieldPhone 1-800-DREYFUS
DREYFUS BASIC MONEY MARKET FUND, INC | DREYFUS BASIC MONEY MARKET FUND, INC  
Risk/Return: rr_RiskReturnAbstract  
Redemption Fee rr_RedemptionFee $ (5.00)
Exchange fee rr_ExchangeFee 5.00
Account closeout fee rr_MaximumAccountFee 5.00
Checkwriting charge rr_ShareholderFeeOther $ 2.00
Management fees rr_ManagementFeesOverAssets 0.50%
Other expenses (including shareholder services fees) rr_OtherExpensesOverAssets 0.27%
Total annual fund operating expenses rr_ExpensesOverAssets 0.77%
Fee waiver and/or expense reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.32%) [1]
Total annual fund operating expenses (after fee waiver and/or expense reimbursement) rr_NetExpensesOverAssets 0.45%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 46
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 214
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 396
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 924
Annual Return 2006 rr_AnnualReturn2006 4.71%
Annual Return 2007 rr_AnnualReturn2007 4.99%
Annual Return 2008 rr_AnnualReturn2008 2.76%
Annual Return 2009 rr_AnnualReturn2009 0.32%
Annual Return 2010 rr_AnnualReturn2010 none
Annual Return 2011 rr_AnnualReturn2011 none
Annual Return 2012 rr_AnnualReturn2012 none
Annual Return 2013 rr_AnnualReturn2013 none
Annual Return 2014 rr_AnnualReturn2014 none
Annual Return 2015 rr_AnnualReturn2015 none
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 none
Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 none
Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 1.26%
[1] The fund's investment adviser, The Dreyfus Corporation, has contractually agreed to waive receipt of its fees and/or assume the expenses of the fund so that total annual fund operating expenses do not exceed 0.45%. The Dreyfus Corporation may terminate the agreement upon at least 90 days' prior notice to investors, but has committed not to do so until at least July 1, 2017.