0001111178 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member ck0001111178:C000004623Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member ck0001111178:C000004625Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member ck0001111178:C000004626Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member rr:AfterTaxesOnDistributionsMember ck0001111178:C000004623Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member rr:AfterTaxesOnDistributionsAndSalesMember ck0001111178:C000004623Member 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member ck0001111178:index_SP_500Index_reflects_no_deduction_for_fees_expenses_or_taxesMember 2012-12-31 2012-12-31 0001111178 ck0001111178:S000001720Member ck0001111178:S000001720Member ck0001111178:index_SP_North_American_Natural_Resources_Sector_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember 2012-12-31 2012-12-31 xbrli:pure iso4217:USD Class A shares bought without an initial sales charge as part of an investment of $1 million or more may be charged a deferred sales charge of 1.00% if redeemed within one year. The Dreyfus Corporation has contractually agreed, until February 1, 2014, to waive receipt of its fees and/or assume the expenses of the fund so that the expenses of none of the fund's share classes (excluding Rule 12b-1 fees, shareholder services fees, taxes, interest, brokerage commissions, commitment fees on borrowings and extraordinary expenses) exceed 1.10%. On or after February 1, 2014, The Dreyfus Corporation may terminate this expense waiver at any time. DREYFUS OPPORTUNITY FUNDS 485BPOS false 0001111178 2012-09-30 2013-01-25 2013-02-01 2013-02-01 Fund Summary DNLAX DLDCX DLDRX Portfolio Turnover The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when fund 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 64.59% of the average value of its portfolio. 0.6459 Performance 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 Class A shares from year to year. The table compares the average annual total returns of the fund's shares to those of a broad measure of market performance. The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. Sales charges, if any, are not reflected in the bar chart, and if those charges were included, returns would have been less than those shown. More recent performance information may be available at www.dreyfus.com. Year-by-Year Total Returnsas of 12/31 each year (%) Class A Shares 0.2800 0.3479 0.1208 0.4375 -0.4989 0.4235 0.2049 -0.0946 0.0425 ~ http://dreyfus.com/20130125/role/ScheduleAnnualTotalReturnsBarChart20005 column dei_LegalEntityAxis compact ck0001111178_S000001720Member row primary compact * ~ Best Quarter 0.2743 2008-06-30 Worst Quarter -0.3826 2008-09-30 Best Quarter Q2, 2008: 27.43% Worst Quarter Q3, 2008: -38.26% After-tax performance is shown only for Class A shares. After-tax performance of the fund's other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal 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. -0.0175 -0.0523 0.1027 -0.0178 -0.0524 0.0972 -0.0109 -0.0437 0.0895 0.0242 -0.0481 0.1016 0.0449 -0.0383 0.1129 0.1599 0.0166 0.0553 0.0220 -0.0151 0.1212 2003-10-31 2003-10-31 2003-10-31 2003-10-31 2003-10-31 ~ http://dreyfus.com/20130125/role/ScheduleAverageAnnualReturnsTransposed20006 column dei_LegalEntityAxis compact ck0001111178_S000001720Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal tax rates, and do not reflect the impact of state and local taxes. The following bar chart and table provide some indication of the risks of investing in the fund. The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. After-tax performance is shown only for Class A shares. After-tax performance of the fund's other share classes will vary. reflects no deduction for fees, expenses or taxes Sales charges, if any, are not reflected in the bar chart, and if those charges were included, returns would have been less than those shown. www.dreyfus.com Average Annual Total Returns (as of 12/31/12) 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. Investment Objective The fund seeks long-term capital appreciation. Example 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 waiver/reimbursement by The Dreyfus Corporation. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 705 1129 1578 2819 313 822 1458 3166 112 515 944 2137 705 1129 1578 2819 213 822 1458 3166 112 515 944 2137 ~ http://dreyfus.com/20130125/role/ScheduleExpenseExampleTransposed20003 column dei_LegalEntityAxis compact ck0001111178_S000001720Member row primary compact * ~ ~ http://dreyfus.com/20130125/role/ScheduleExpenseExampleNoRedemptionTransposed20004 column dei_LegalEntityAxis compact ck0001111178_S000001720Member row primary compact * ~ You would pay the following expenses if you did not redeem your shares: Principal Investment Strategy To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in stocks of companies in the natural resources and natural resources related sectors. Generally, these are companies principally engaged in owning or developing natural resources, or supplying goods, technology and services relating to natural resources. The fund invests in growth and value stocks and typically will maintain exposure to the major natural resources sectors. Using fundamental research and direct management contact, the portfolio managers seek stocks of companies with strong positions in their natural resources sector, sustained achievement records and strong financial condition. There are no prescribed limits on the weightings of securities in any particular natural resources sector or in any individual company, and the fund may invest in companies of any market capitalization. The fund typically will invest in equity securities of U.S.-based companies, but may invest up to 45% of its total assets in foreign securities, including emerging market securities. Fees and Expenses This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. 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 certain funds in the Dreyfus Family of Funds. More information about these and other discounts is available from your financial professional and in the Shareholder Guide section on page 9 of the Prospectus and in the How to Buy Shares section and the Additional Information About How to Buy Shares section on page II-1 and page III-1, respectively, of the fund's Statement of Additional Information. 0.0575 0.0000 0.0000 0.0000 0.0100 0.0000 0.0075 0.0075 0.0075 0.0000 0.0075 0.0000 0.0136 0.0140 0.0113 0.0211 0.0290 0.0188 -0.0076 -0.0080 -0.0078 0.0135 0.0210 0.0110 ~ http://dreyfus.com/20130125/role/ScheduleShareholderFees20001 column dei_LegalEntityAxis compact ck0001111178_S000001720Member row primary compact * ~ ~ http://dreyfus.com/20130125/role/ScheduleAnnualFundOperatingExpenses20002 column dei_LegalEntityAxis compact ck0001111178_S000001720Member row primary compact * ~ 2014-02-01 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 certain funds in the Dreyfus Family of Funds. Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 50000 Class A shares bought without an initial sales charge as part of an investment of $1 million or more may be charged a deferred sales charge of 1.00% if redeemed within one year. Shareholder Fees (fees paid directly from your investment) Principal Risks 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. It is not a complete investment program. The fund's share price fluctuates, sometimes dramatically, which means you could lose money. · Natural resources sector risk. Investments in the natural resources and related sectors may be affected by numerous factors, including events occurring in nature, inflationary pressures and domestic and international politics. For example, events occurring in nature (such as earthquakes or fires in prime natural resource areas) and political events (such as coups or military confrontations) can affect the overall supply of a natural resource and the value of companies involved in such natural resource. Political risks and other risks to which foreign securities are subject also may affect domestic companies in which the fund invests if they have significant operations or investments in foreign countries. In addition, interest rates, prices of raw materials and other commodities, international economic developments, energy conservation, tax and other government regulations (both domestic and foreign) may affect the supply of and demand for natural resources, which can affect the profitability and value of securities issued by companies in the natural resources sectors. Securities of companies within specific natural resources sectors can perform differently than the overall market. This may be due to changes in such things as the regulatory or competitive environment or to changes in investor perceptions regarding a sector. Because the fund may allocate relatively more assets to certain natural resources sectors than others, the fund's performance may be more sensitive to developments which affect those sectors emphasized by the fund. · Risks of stock investing. Stocks generally fluctuate more in value than bonds and may decline significantly over short time periods. There is the chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising prices and falling prices. The market value of a stock may decline due to general weakness in the stock market or because of factors that affect the company or its particular industry. · Growth and value stock risk. By investing in a mix of growth and value companies, the fund assumes the risks of both. Investors often expect growth companies to increase their earnings at a certain rate. If these expectations are not met, investors can punish the stocks inordinately, even if earnings do increase. In addition, growth stocks typically lack the dividend yield that can cushion stock prices in market downturns. Value stocks involve the risk that they may never reach their expected full market value, either because the market fails to recognize the stock's intrinsic worth, or the expected value was misgauged. They also may decline in price even though in theory they are already undervalued. · Foreign investment risk. The fund's performance will be influenced by political, social and economic factors affecting investments in foreign companies. Special risks associated with investments in foreign issuers include exposure to currency fluctuations, less liquidity, less developed or less efficient trading markets, lack of comprehensive company information, political and economic instability and differing auditing and legal standards. Investments denominated in foreign currencies are subject to the risk that such currencies will decline in value relative to the U.S. dollar and affect the value of these investments held by the fund. Emerging markets tend to be more volatile and less liquid than the markets of more mature economies, and generally have less diverse and less mature economic structures and less stable political systems than those of developed countries. · Small and midsize company risk. Small and midsize companies carry additional risks because the operating histories of these companies tend to be more limited, their earnings and revenues less predictable (and some companies may be experiencing significant losses), and their share prices more volatile than those of larger, more established companies. The shares of smaller companies tend to trade less frequently than those of larger, more established companies, which can adversely affect the pricing of these securities and the fund's ability to sell these securities. · 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 at or near their perceived value. In such a market, the value of such securities and the fund's share price may fall dramatically. Investments in foreign securities, particularly those of issuers located in emerging markets, tend to have greater exposure to liquidity risk than domestic securities. · 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. The fund's share price fluctuates, sometimes dramatically, which means you could lose money. 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. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.