Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary - DREYFUS NEW YORK AMT-Free Municipal MONEY MARKET FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The fund seeks as high a level of current income exempt from federal, New York state and New York city income taxes 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.
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)
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. 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 normally invests substantially all of its net assets in short-term, high quality municipal obligations that provide income exempt from federal, New York state and New York city income taxes. The fund also seeks to provide income exempt from the federal alternative minimum tax. The fund also may invest in high quality short-term structured notes, which are derivative instruments whose value is tied to underlying municipal obligations. Although the fund seeks to provide income exempt from federal, New York state and New York city income taxes, the fund may invest temporarily in high quality, taxable money market instruments and/or municipal obligations that pay income exempt only from federal income tax, including when the portfolio manager believes acceptable New York state or New York city municipal obligations are not available for investment. During such periods, the fund may not reach its investment objective.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. 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. Additionally, while the fund has maintained a constant share price since inception, and will continue to try to do so, neither The Dreyfus Corporation nor its affiliates are required to make a capital infusion, enter into a capital support agreement or take other actions to prevent the fund's share price from falling below $1.00. 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. · Credit risk. Failure of an issuer to make timely interest or principal payments, 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, any of the fund's holdings could have its credit rating downgraded or could default. 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. · 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. Also, during such periods, redemptions by a few large investors in the fund may impair the fund's ability to maintain a stable net asset value and remaining fund shareholders. · Regulatory risk. The Securities and Exchange Commission has adopted amendments to the rules governing money market funds that may change the way that the fund, and similar money market funds, operate. Under the amended rules, as of October 14, 2016, the share price of money market funds that will be designated as "institutional prime" or "institutional municipal" type money funds would fluctuate and, as a result, shares of those funds when sold may be worth more or less than their original purchase price. In addition, as of October 14, 2016, all prime and all municipal money market funds become subject to a regime of liquidity fees imposed upon the sale of their shares or the temporary suspension of redemptions, in each case triggered (and subject to board determination) by the percentage of a fund's Weekly Liquid Assets falling below certain minimums as defined in amended Rule 2a-7. The amendments impose additional regulatory and reporting requirements on all money market funds, which generally are expected to be implemented by the funds by April 14, 2016. As a result of the amendments, additional expenses may be incurred by the fund. · State-specific risk. The fund is subject to the risk that New York's economy, and the revenues underlying its municipal obligations, may decline. Investing primarily in a single state makes the fund more sensitive to risks specific to the state and may magnify other risks. · Tax risk. To be tax-exempt, municipal obligations generally must meet certain regulatory requirements. If any such municipal obligation fails to meet these regulatory requirements, the interest received by the fund from its investment in such obligations and distributed to fund shareholders will be taxable. · Structured notes risk. Structured notes, a type of derivative instrument, can be volatile, and the possibility of default by the financial institution or counterparty may be greater for these instruments than for other types of money market instruments. Structured notes typically are purchased in privately negotiated transactions from financial institutions and, thus, an active trading market for such instruments may not exist. · Non-diversification risk. The fund is non-diversified, which means that the fund may invest a relatively high percentage of its assets in a limited number of issuers. Therefore, the fund's performance may be more vulnerable to changes in the market value of a single issuer or group of issuers and more susceptible to risks associated with a single economic, political or regulatory occurrence than a diversified fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	The fund is non-diversified, which means that the fund may invest a relatively high percentage of its assets in a limited number of issuers. Therefore, the fund's performance may be more vulnerable to changes in the market value of a single issuer or group of issuers and more susceptible to risks associated with a single economic, political or regulatory occurrence than a diversified fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit. It 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 Q2, 2007: 0.78% Worst Quarter Q4, 2013: 0.00% The fund's year-to-date total return as of June 30, 2014 was 0.00%.
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date total return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2014
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.78%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2013
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
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 12/31/13
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	1-800-DREYFUS
DREYFUS NEW YORK AMT-FREE MUNICIPAL MONEY MARKET FUND
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.50%
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.24%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.74%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 76
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	237
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	411
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 918
Annual Return 2004	rr_AnnualReturn2004	0.59%
Annual Return 2005	rr_AnnualReturn2005	1.79%
Annual Return 2006	rr_AnnualReturn2006	2.85%
Annual Return 2007	rr_AnnualReturn2007	3.06%
Annual Return 2008	rr_AnnualReturn2008	1.80%
Annual Return 2009	rr_AnnualReturn2009	0.24%
Annual Return 2010	rr_AnnualReturn2010	0.00%
Annual Return 2011	rr_AnnualReturn2011	0.01%
Annual Return 2012	rr_AnnualReturn2012	0.00%
Annual Return 2013	rr_AnnualReturn2013	0.00%
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	none
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	0.05%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	1.03%

If the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Form

-Number N-1A

-Chapter A

-Section 4

-Subsection b

-Paragraph 2

-Subparagraph instructions

-Clause 3

-Exhibit a