Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Oct. 01, 2011
DREYFUS THIRD CENTURY FUND INC (Prospectus Summary) | DREYFUS THIRD CENTURY FUND INC
Risk/Return:	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	Fund Summary
Investment Objective, Heading	rr_ObjectiveHeading	Investment Objective
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The fund seeks to provide capital growth
Investment Objective, Secondary	rr_ObjectiveSecondaryTextBlock	with current income as a secondary goal by investing in stocks that meet certain financial as well as social criteria.
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. 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 8 of the Prospectus and in the How to Buy Shares section on page II-1 of the fund's Statement of Additional Information. 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, Caption	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses, Caption	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as 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 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 50.46% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	50.46%
Expense Breakpoint, Discounts	rr_ExpenseBreakpointDiscounts	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.
Expense Breakpoint, Minimum Investment Required Amount	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 50,000
Expense Example, Heading	rr_ExpenseExampleHeading	Example
Expense Example, Narrative	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:
Expense Example, No Redemption, By Year, Caption	rr_ExpenseExampleNoRedemptionByYearCaption	You would pay the following expenses if you did not redeem your shares:
Investment Strategy, Heading	rr_StrategyHeading	Principal Investment Strategy
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	The fund invests primarily in the common stocks of companies that fund management determines meet traditional standards and conduct their business in a manner that contributes to the enhancement of the quality of life in America. The portfolio manager employs a computer model to identify and rank stocks based on characteristics such as value, growth and financial profile. Through fundamental analysis, the most attractive, higher ranked securities then are evaluated by industry or sector according to the fund's social criteria, which encompass: the protection/improvement of the environment, the proper use of natural resources, occupational health and safety, consumer protection and product purity, and equal employment opportunity. Next, the eligible companies are analyzed for purchase by industry or sector and investments are made in those companies management considers to be the most attractive. The fund normally focuses on large-cap growth stocks, but may invest in value-oriented, mid-cap and small-cap stocks. Portfolio securities no longer meeting the fund's social criteria will be sold as soon as reasonably possible.
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 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. 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 Social investment risk. A socially responsible investment criteria may limit the number of investment opportunities available to the fund, and as a result, at times the fund may produce more modest gains than funds that are not subject to such special investment considerations.
Risk, Lose Money	rr_RiskLoseMoney	The fund's share price fluctuates, sometimes dramatically, which means you could lose money.
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 Federal Deposit Insurance Corporation (FDIC) or any other government agency. It is not a complete investment program.
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 (before and after taxes) is no guarantee of future results. More recent performance information may be available at www.dreyfus.com.
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 (before and after taxes) is no guarantee of future results.
Bar Chart, Heading	rr_BarChartHeading	Year-by-Year Total Returns as of 12/31 each year (%) Class Z
Bar Chart, Narrative	rr_BarChartNarrativeTextBlock	The bar chart shows changes in the performance of the fund's Class Z shares from year to year. 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.
Bar Chart, Does Not Reflect Sales Loads	rr_BarChartDoesNotReflectSalesLoads	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.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Best Quarter Q2, 2009: 17.10% Worst Quarter Q4, 2008: -21.30% The year-to-date total return of the fund's Class Z shares as of June 30, 2011 was 6.53%.
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses or taxes
Performance Table, Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	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.
Performance Table, Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	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.
Performance Table, One Class of after Tax Shown	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax performance is shown only for Class Z shares. After tax performance of the fund's other share classes will vary.
Performance Table, Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax performance is shown only for Class Z 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.
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns (as of 12/31/10)
DREYFUS THIRD CENTURY FUND INC (Prospectus Summary) | DREYFUS THIRD CENTURY FUND INC | Class Z
Risk/Return:	rr_RiskReturnAbstract
Year to Date Return, Label	rr_YearToDateReturnLabel	The year-to-date total return of the fund's Class Z shares
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2011
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	6.53%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	17.10%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(21.30%)
DREYFUS THIRD CENTURY FUND INC | S&P 500 Comp Stock Price Index
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	S&P 500 Comp Stock Price Index reflects no deduction for fees, expenses or taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.08%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.29%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	1.42%
DREYFUS THIRD CENTURY FUND INC | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum contingent deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.64%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.39%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	708
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	990
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,292
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,148
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	708
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	990
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,292
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,148
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A returns before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	7.66%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.81%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(2.15%)
DREYFUS THIRD CENTURY FUND INC | Class B
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	4.00%
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.93%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.43%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	646
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	1,058
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,496
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,271
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	246
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	758
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,296
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,271
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B returns before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	8.91%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.66%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(2.04%)
DREYFUS THIRD CENTURY FUND INC | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.50%
Total annual fund operating expenses	rr_ExpensesOverAssets	2.00%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	303
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	627
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,078
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,327
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	203
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	627
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,078
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,327
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class C returns before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	12.33%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.25%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(2.32%)
DREYFUS THIRD CENTURY FUND INC | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.14%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.89%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	91
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	284
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	493
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,096
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	91
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	284
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	493
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,096
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class I returns before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	14.73%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.53%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.24%)
DREYFUS THIRD CENTURY FUND INC | Class Z
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.28%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.03%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	105
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	328
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	569
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,259
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	105
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	328
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	569
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,259
Annual Return 2001	rr_AnnualReturn2001	(23.72%)
Annual Return 2002	rr_AnnualReturn2002	(29.37%)
Annual Return 2003	rr_AnnualReturn2003	25.87%
Annual Return 2004	rr_AnnualReturn2004	5.93%
Annual Return 2005	rr_AnnualReturn2005	3.47%
Annual Return 2006	rr_AnnualReturn2006	9.01%
Annual Return 2007	rr_AnnualReturn2007	7.56%
Annual Return 2008	rr_AnnualReturn2008	(34.30%)
Annual Return 2009	rr_AnnualReturn2009	33.30%
Annual Return 2010	rr_AnnualReturn2010	14.49%
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Z returns before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	14.49%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.29%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.34%)
DREYFUS THIRD CENTURY FUND INC | Class Z | After Taxes on Distributions
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Z returns after taxes on distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	14.40%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.22%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.40%)
DREYFUS THIRD CENTURY FUND INC | Class Z | After Taxes on Distributions and Sales
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Z returns after taxes on distributions and sale of fund shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	9.55%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.81%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.14%)