Label	Element	Value
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 capital appreciation.
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. 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 [Text]	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 [Text Block]	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 52.00% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	52.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	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 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 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:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategy
Strategy Narrative [Text Block]	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 growth companies of any size that The Dreyfus Corporation believes to be leading producers or beneficiaries of technological innovation. Up to 25% of the fund's assets may be invested in foreign securities (i.e., securities issued by companies organized under the laws of countries other than the U.S.). In choosing stocks, the fund looks for technology companies with the potential for strong earnings or revenue growth rates, although some of the fund's investments may currently be experiencing losses. The fund's investment process centers on a multi-dimensional approach that looks for opportunities across emerging growth, cyclical or stable growth companies. The fund's investment approach seeks companies that appear to have strong earnings momentum, positive earnings revisions, favorable growth, product or market cycles and/or favorable valuations.
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. It is not a complete investment program. The fund's share price fluctuates, sometimes dramatically, which means you could lose money. · 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 stock risk. 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 may lack the dividend yield that may cushion stock prices in market downturns. · Technology company risk. The technology sector has been among the most volatile sectors of the stock market. Because the fund's investments are concentrated in the technology sector, its performance will be significantly affected by developments in that sector. Technology companies, especially small-cap technology companies, involve greater risk because their revenue and/or earnings tend to be less predictable (and some companies may be experiencing significant losses) and their share prices tend to be more volatile. Certain technology companies may have limited product lines, markets or financial resources, or may depend on a limited management group. In addition, these companies are strongly affected by worldwide technological developments, and their products and services may not be economically successful or may quickly become outdated. Investor perception may play a greater role in determining the day-to-day value of tech stocks than it does in other sectors. Fund investments made in anticipation of future products and services may decline dramatically in value if the anticipated products or services are delayed or cancelled. The risks associated with technology companies are magnified in the case of small-cap technology companies. The shares of smaller technology companies tend to trade less frequently than those of larger, more established companies, which can have an adverse effect on the pricing of these securities and on the fund's ability to sell these securities. · Foreign investment risk. To the extent the fund invests in foreign securities, the fund's performance will be influenced by political, social and economic factors affecting investments in foreign issuers. 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. Securities of issuers located in emerging markets can be more volatile and less liquid than those of issuers in more developed economies. · 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 [Text]	rr_RiskLoseMoney	The fund's share price fluctuates, sometimes dramatically, which means you could lose money.
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 Initial 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 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 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 [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 (%) Initial Shares
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter Q2, 2003: 24.65% Worst Quarter Q3, 2002: -26.70%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2003
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	24.65%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2002
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.70%)
Index No Deduction for Fees, Expenses, Taxes [Text]	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses or taxes
Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns (as of 12/31/12)
S&P 500® Index reflects no deduction for fees, expenses or taxes
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.99%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.66%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	7.10%
Morgan Stanley High Technology 35® Index reflects no deduction for fees, expenses or taxes
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	18.18%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.64%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	2.17%
Technology Growth Portfolio - Initial Shares
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.08%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.83%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	85
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	265
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	460
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	1,025
Annual Return 2003	rr_AnnualReturn2003	50.96%
Annual Return 2004	rr_AnnualReturn2004	0.46%
Annual Return 2005	rr_AnnualReturn2005	3.78%
Annual Return 2006	rr_AnnualReturn2006	4.31%
Annual Return 2007	rr_AnnualReturn2007	14.72%
Annual Return 2008	rr_AnnualReturn2008	(41.18%)
Annual Return 2009	rr_AnnualReturn2009	57.67%
Annual Return 2010	rr_AnnualReturn2010	29.93%
Annual Return 2011	rr_AnnualReturn2011	(7.78%)
Annual Return 2012	rr_AnnualReturn2012	15.62%
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.62%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.14%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	9.24%
Technology Growth Portfolio - Service Shares
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution and/or service (Rule 12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.08%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.08%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	110
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	343
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	595
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	1,317
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.35%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.88%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	8.97%

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