Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	May 01, 2012
Opportunistic Small Cap Portfolio (Prospectus Summary) | Opportunistic Small Cap Portfolio
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	Fund Summary
Investment Objective, Heading	rr_ObjectiveHeading	Investment Objective
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The fund seeks capital growth.
Expense, Heading	rr_ExpenseHeading	Fees and Expenses
Expense, Narrative	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. These figures do not reflect any fees or charges imposed by participating insurance companies under their Variable Annuity contracts (VA contracts) or Variable Life Insurance policies (VLI policies).
Operating Expenses, Caption	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover, Heading	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover	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 may indicate higher transaction costs. 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 91.45% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	91.45%
Expense Example, Heading	rr_ExpenseExampleHeading	Example
Expense Example, Narrative	rr_ExpenseExampleNarrativeTextBlock	The Example below 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. The Example also assumes that your investment has a 5% return each year and that the fund's operating expenses remain the same. The Example does not reflect fees and expenses incurred under VA contracts and VLI policies; if they were reflected, the figures in the Example would be higher. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	Principal Investment Strategy
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in the stocks of small-cap companies. The fund considers small cap companies to be those companies with market capitalizations that fall within the range of the companies in the Russell 2000® Index at the time of purchase. Stocks are selected for the fund's portfolio based primarily on bottom-up fundamental analysis. The fund's portfolio managers use a disciplined investment process that relies, in general, on proprietary fundamental research and valuation. Generally, elements of the process include analysis of mid-cycle business prospects, estimation of the intrinsic value of the company and the identification of a revaluation catalyst. In general, the fund seeks exposure to securities and sectors that the fund's portfolio managers perceive to be attractive from a valuation and fundamental standpoint.
Risk, Heading	rr_RiskHeading	Principal Risks
Risk, Narrative	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the 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.    o 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. o 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. o 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. o Market sector risk. The fund may significantly overweight or underweight certain companies, industries or market sectors, which may cause the fund's performance to be more or less sensitive to developments affecting those companies, industries or sectors. o Liquidity risk. When there is little or no active trading market for a security, the fund may not be able to sell the security in a timely manner at its perceived value, which could cause the fund's share price to fall.
Risk, Lose Money	rr_RiskLoseMoney	It is not a complete investment program.
Risk, Not Insured Depository Institution	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the FDIC or any other government agency.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	Performance
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide some indication of the risks of investing in the fund. 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 is no guarantee of future results. More recent performance information may be available at www.dreyfus.com. Performance information reflects the fund's expenses only and does not reflect the fees and charges imposed by participating insurance companies under their VA contracts or VLI policies. Because these fees and charges will reduce total return, policyowners should consider them when evaluating and comparing the fund's performance. Policyowners should consult the prospectus for their contract or policy for more information.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide some indication of the risks of investing in the fund.
Performance, Availability Website Address	rr_PerformanceAvailabilityWebSiteAddress	www.dreyfus.com
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	The fund's past performance is no guarantee of future results.
Bar Chart, Heading	rr_BarChartHeading	Year-by-Year Total Returns as of 12/31 each year (%) -- Initial Shares
Bar Chart, Narrative	rr_BarChartNarrativeTextBlock	The bar chart shows changes in the performance of the fund's Initial shares from year to year.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Best Quarter               Q4, 2010: 21.59%           Worst Quarter              Q3, 2011: -30.07%
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses or taxes
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns (as of 12/31/11)
Opportunistic Small Cap Portfolio (Prospectus Summary) | Opportunistic Small Cap Portfolio | Russell 2000 Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Russell 2000 Index reflects no deduction for fees, expenses or taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(4.18%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	0.15%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	5.62%
Opportunistic Small Cap Portfolio (Prospectus Summary) | Opportunistic Small Cap Portfolio | Initial Shares
Risk Return [Abstract]	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.13%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.88%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	90
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	281
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	488
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,084
Annual Return 2002	rr_AnnualReturn2002	(19.12%)
Annual Return 2003	rr_AnnualReturn2003	31.69%
Annual Return 2004	rr_AnnualReturn2004	11.34%
Annual Return 2005	rr_AnnualReturn2005	5.80%
Annual Return 2006	rr_AnnualReturn2006	3.77%
Annual Return 2007	rr_AnnualReturn2007	(11.06%)
Annual Return 2008	rr_AnnualReturn2008	(37.59%)
Annual Return 2009	rr_AnnualReturn2009	26.04%
Annual Return 2010	rr_AnnualReturn2010	31.11%
Annual Return 2011	rr_AnnualReturn2011	(13.82%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2010
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	21.59%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(30.07%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Initial Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(13.82%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(4.59%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	0.29%
Opportunistic Small Cap Portfolio (Prospectus Summary) | Opportunistic Small Cap Portfolio | Service Shares
Risk Return [Abstract]	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.13%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.13%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	115
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	359
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	622
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,375
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Service Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(14.03%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	(4.83%)
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	0.04%