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Label Element Value
[RiskReturnAbstract] rr_RiskReturnAbstract  
Document Type dei_DocumentType 485BPOS
Document Period End Date dei_DocumentPeriodEndDate Jan. 31, 2014
Registrant Name dei_EntityRegistrantName Eaton Vance Mutual Funds Trust
Central Index Key dei_EntityCentralIndexKey 0000745463
Amendment Flag dei_AmendmentFlag false
Document Creation Date dei_DocumentCreationDate Jun. 26, 2014
Document Effective Date dei_DocumentEffectiveDate Jul. 01, 2014
Prospectus Date rr_ProspectusDate Jul. 01, 2014
Parametric Emerging Markets Fund
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund’s investment objective is to seek long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
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.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses 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” the portfolio). A higher portfolio turnover rate 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 7% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 7.00%
Expense Example [Heading] rr_ExpenseExampleHeading

Example.
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

This 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 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 Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal market conditions, the Fund invests at least 80% of its net assets in equity securities of companies located in emerging market countries (the “80% Policy”). A company will be considered to be located in an emerging market country if it is domiciled in or derives more than 50% of its revenues or profits from emerging market countries. Emerging market countries are generally countries not considered to be developed market countries, and therefore not included in the MSCI World Index. The Fund intends to invest primarily in securities of companies located in countries included in the MSCI Emerging Markets Index or the MSCI Frontier Markets Index. Securities acquired by the Fund are typically listed on stock exchanges in emerging market countries, but also may include securities traded in markets outside these countries, including securities trading in the form of depositary receipts. For purposes of the Fund’s 80% Policy, depositary receipts are considered as being located in emerging markets if the company is domiciled in or derives more than 50% of its revenues or profits from emerging market countries. The Fund may invest in securities of smaller, less seasoned companies. More than 25% of the Fund’s total assets may be denominated in any single currency. The Fund may also invest in other pooled investment vehicles and may lend its securities.

The Fund may engage in derivative transactions as a substitute for the purchase or sale of securities or currencies or to attempt to mitigate the adverse effects of foreign currency fluctuations during the period between the purchase of a security and its settlement. Such transactions may include forward foreign currency exchange contracts, options and equity-linked securities (such as participation notes, equity swaps and zero strike calls and warrants).

The Fund seeks to employ a top-down, disciplined and systematic investment process that emphasizes broad exposure and diversification among emerging market countries, economic sectors and issuers. This rules-based strategy utilizes targeted allocation and systematic rebalancing to take advantage of certain quantitative and behavioral characteristics of emerging markets identified by the portfolio managers. The portfolio managers select and allocate across countries based on factors such as size, liquidity, level of economic development, local economic diversification, and perceived risk and potential for growth. The Fund maintains a bias to broad inclusion; that is, the Fund intends to allocate its portfolio holdings to more emerging market countries rather than fewer emerging market countries. Relative to capitalization-weighted country indexes, individual country allocation targets emphasize the less represented emerging market countries and attempts to reduce concentration risks relative to a capitalization-weighted index. The Fund’s country allocations are rebalanced to their target weights if they exceed a certain pre-determined overweight. The frequency of rebalancing depends on the volatility and trading costs of the individual country. This has the effect of reducing exposure to countries with strong relative performance and increasing exposure to countries which have underperformed. Within each country, the Fund seeks to maintain exposure across key economic sectors, such as industrial/technology, consumer, utilities, basic industry/resource and financial. Relative to capitalization-weighted country indexes, the portfolio managers target weights to these sectors to emphasize the less represented sectors. The portfolio managers select individual securities as representatives of their economic sectors and generally weight them by their relative capitalization within that sector.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration

Under normal market conditions, the Fund invests at least 80% of its net assets in equity securities of companies located in emerging market countries (the “80% Policy”). A company will be considered to be located in an emerging market country if it is domiciled in or derives more than 50% of its revenues or profits from emerging market countries. Emerging market countries are generally countries not considered to be developed market countries, and therefore not included in the MSCI World Index. The Fund intends to invest primarily in securities of companies located in countries included in the MSCI Emerging Markets Index or the MSCI Frontier Markets Index. Securities acquired by the Fund are typically listed on stock exchanges in emerging market countries, but also may include securities traded in markets outside these countries, including securities trading in the form of depositary receipts. For purposes of the Fund’s 80% Policy, depositary receipts are considered as being located in emerging markets if the company is domiciled in or derives more than 50% of its revenues or profits from emerging market countries. The Fund may invest in securities of smaller, less seasoned companies. More than 25% of the Fund’s total assets may be denominated in any single currency. The Fund may also invest in other pooled investment vehicles and may lend its securities.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

Equity Investing Risk. The Fund’s shares are sensitive to stock market volatility and the stocks in which the Fund invests may be more volatile than the stock market as a whole. The prices of stocks may decline in response to conditions affecting the general economy; overall market changes; local, regional or global political, social or economic instability; and currency, interest rate and commodity price fluctuations, as well as issuer or sector specific events. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines, the value of Fund shares will also likely decline and, although stock values can rebound, there is no assurance that values will return to previous levels.

Foreign and Emerging Market Investment Risk. Because the Fund invests a significant portion of its assets in foreign instruments, the value of Fund shares can be adversely affected by changes in currency exchange rates and political, economic and market developments abroad. In emerging or less developed countries, these risks can be more significant. Investment markets in emerging market countries are typically substantially smaller, less liquid and more volatile than the major markets in developed countries. As a result, Fund share values may be more volatile than if the Fund invested only in developed markets. Emerging market countries may have relatively unstable governments and economies. Emerging market investments often are subject to speculative trading, which typically contributes to volatility. Trading in foreign and emerging markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. The value of investments denominated in foreign currencies can be adversely affected by changes in foreign currency exchange rates. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities including political, economic and market risks.

Smaller Company Equity Risk. The stocks of smaller, less seasoned companies are generally subject to greater price fluctuations, limited liquidity, higher transaction costs and higher investment risk than the stocks of larger, more established companies. Smaller, less seasoned companies may have limited product lines, markets or financial resources, may be dependent on a limited management group, and may lack substantial capital reserves or an established performance record. There may be generally less publicly available information about such companies than for larger, more established companies.

Derivatives Risk. The use of derivatives can lead to losses because of adverse movements in the price or value of the asset, index, rate or instrument underlying a derivative, due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create economic leverage in the Fund, which magnifies the Fund’s exposure to the underlying investment. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. When derivatives are used to gain or limit exposure to a particular market or market segment, their performance may not correlate as expected to the performance of such market, thereby causing the Fund to fail to achieve its original purpose for using such derivatives. A decision as to whether, when and how to use derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment.

Securities Lending Risk. Securities lending involves possible delay in recovery of the securities or possible loss of rights in the collateral should the borrower fail financially. As a result, the value of Fund shares may fall and there may be a delay in recovering the loaned securities. The value of Fund shares could also fall if a loan is called and the Fund is required to liquidate reinvested collateral at a loss or if the sub-adviser is unable to reinvest cash collateral at rates that exceed the costs involved.

Rules-Based Management Risks. The sub-adviser uses proprietary investment techniques and analyses in making investment decisions for the Fund, seeking to achieve its investment objective while minimizing exposure to market risk. The strategy seeks to take advantage of certain quantitative and behavioral market characteristics identified by the sub-adviser, utilizing a rules-based country weighting process, a systematic sector allocation methodology and a disciplined rebalancing model. The Fund’s strategy has not been independently tested or validated, and there can be no assurance that it will achieve the desired results.

General Fund Investing Risks. The Fund is not a complete investment program and you may lose money by investing in the Fund. All investments carry a certain amount of risk and there is no guarantee that the Fund will be able to achieve its investment objective. Annual Fund Operating Expenses expressed as a percentage of the Fund’s average daily net assets may change as Fund assets increase and decrease, and Annual Fund Operating Expenses may differ in the future. Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective. In addition, the redemption by one or more large shareholders or groups of shareholders of their holdings in the Fund could have an adverse impact on the remaining shareholders in the Fund. Investors in the Fund should have a long-term investment perspective and be able to tolerate potentially sharp declines in value. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, entity or person. Mutual funds, investment advisers, other market participants and many securities markets are subject to rules and regulations and the jurisdiction of one or more regulators. Changes to applicable rules and regulations could have an adverse effect on securities markets and market participants, as well as on the Fund’s ability to execute its investment strategy.
Risk Lose Money [Text] rr_RiskLoseMoney

The Fund is not a complete investment program and you may lose money by investing in the Fund.

Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, entity or person.

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 by showing changes in the Fund’s performance from year to year and how the Fund’s average annual returns over time compare with those of a broad-based securities market index. The returns in the bar chart are for Investor Class shares. Past performance (both before and after taxes) is no guarantee of future results. The Fund’s performance for certain periods reflects the effects of expense reductions. Absent these reductions, performance would have been lower. Updated Fund performance information can be obtained by visiting www.eatonvance.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 by showing changes in the Fund’s performance from year to year and how the Fund’s average annual returns over time compare with those of a broad-based securities market index.

Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress

www.eatonvance.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture

Past performance (both before and after taxes) is no guarantee of future results.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

During the period from December 31, 2006 through December 31, 2013, the highest quarterly total return for Investor Class was 37.04% for the quarter ended June 30, 2009, and the lowest quarterly return was -30.11% for the quarter ended December 31, 2008. The year-to-date return through the end of the most recent calendar quarter (December 31, 2013 to March 31, 2014) was 0.94%.
Year to Date Return, Label rr_YearToDateReturnLabel

The year-to-date return through the end of the most recent calendar quarter (December 31, 2013 to March 31, 2014 ) was
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 0.94%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel

During the period from December 31, 2006 through December 31, 2013 , the highest quarterly total return for Investor Class was

Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 37.04%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel

and the lowest quarterly return was
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2008
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (30.11%)
Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads

These returns reflect any applicable contingent deferred sales charge (“CDSC”) for Class C.

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the highest historical individual federal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder's tax situation and the actual characterization of distributions, and may differ from those shown.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred After-tax returns are not relevant to shareholders who hold shares in tax-deferred accounts or to shares held by non-taxable entities.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns for other Classes of shares will vary from the after-tax returns presented for Investor Class shares.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher Return After Taxes on Distributions for a period may be the same as Return Before Taxes for a period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.
Performance Table Footnotes, Reason Performance Information for Class Different from Immediately Preceding Period [Text] rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod

The Class R6 performance shown above for the period prior to July 1, 2014 (commencement of operations) is the performance of Institutional Class at net asset value without adjustment for any differences in the expenses of the two classes. If adjusted for such differences, returns would be different.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

These returns reflect any applicable contingent deferred sales charge (“CDSC”) for Class C. Investor Class, Class C and Institutional Class commenced operations on June 30, 2006. The Class R6 performance shown above for the period prior to July 1, 2014 (commencement of operations) is the performance of Institutional Class at net asset value without adjustment for any differences in the expenses of the two classes. If adjusted for such differences, returns would be different. Investors cannot invest directly in an Index. (Source for MSCI Emerging Markets Index: MSCI) MSCI data may not be reproduced or used for any other purpose. MSCI provides no warranties, has not prepared or approved this data, and has no liability hereunder.

After-tax returns are calculated using the highest historical individual federal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and the actual characterization of distributions, and may differ from those shown. After-tax returns are not relevant to shareholders who hold shares in tax-deferred accounts or to shares held by nontaxable entities. After-tax returns for other Classes of shares will vary from the after-tax returns presented for Investor Class shares. Return After Taxes on Distributions for a period may be the same as Return Before Taxes for that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.
Parametric Emerging Markets Fund | Investor Class
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EAEMX
Maximum Sales Charge (Load) (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption) rr_MaximumDeferredSalesChargeOverOther none
Management Fees rr_ManagementFeesOverAssets 0.93%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.20%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.38%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 140
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 437
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 755
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,657
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 140
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 437
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 755
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,657
Annual Return 2007 rr_AnnualReturn2007 35.94%
Annual Return 2008 rr_AnnualReturn2008 (51.76%)
Annual Return 2009 rr_AnnualReturn2009 67.38%
Annual Return 2010 rr_AnnualReturn2010 21.80%
Annual Return 2011 rr_AnnualReturn2011 (19.27%)
Annual Return 2012 rr_AnnualReturn2012 19.28%
Annual Return 2013 rr_AnnualReturn2013 0.73%
1 Year rr_AverageAnnualReturnYear01 0.73%
5 Years rr_AverageAnnualReturnYear05 (1.01%)
Since Inception rr_AverageAnnualReturnSinceInception 6.46%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 30, 2006
Parametric Emerging Markets Fund | Class C
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol ECEMX
Maximum Sales Charge (Load) (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption) rr_MaximumDeferredSalesChargeOverOther 1.00%
Management Fees rr_ManagementFeesOverAssets 0.93%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 0.20%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.13%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 316
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 667
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,144
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,462
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 216
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 667
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,144
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,462
1 Year rr_AverageAnnualReturnYear01 (1.04%)
5 Years rr_AverageAnnualReturnYear05 13.75%
Since Inception rr_AverageAnnualReturnSinceInception 5.66%
Parametric Emerging Markets Fund | Institutional Class
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EIEMX
Maximum Sales Charge (Load) (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption) rr_MaximumDeferredSalesChargeOverOther none
Management Fees rr_ManagementFeesOverAssets 0.93%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.20%
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
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 115
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 359
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 622
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,375
1 Year rr_AverageAnnualReturnYear01 1.00%
5 Years rr_AverageAnnualReturnYear05 14.89%
Since Inception rr_AverageAnnualReturnSinceInception 6.71%
Parametric Emerging Markets Fund | Class R6
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EREMX
Maximum Sales Charge (Load) (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption) rr_MaximumDeferredSalesChargeOverOther none
Management Fees rr_ManagementFeesOverAssets 0.93%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.09%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 111
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 347
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 601
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,329
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 111
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 347
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 601
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,329
1 Year rr_AverageAnnualReturnYear01 1.00%
5 Years rr_AverageAnnualReturnYear05 14.89%
Since Inception rr_AverageAnnualReturnSinceInception 6.71%
Parametric Emerging Markets Fund | After Taxes on Distributions | Investor Class
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.60%
5 Years rr_AverageAnnualReturnYear05 14.55%
Since Inception rr_AverageAnnualReturnSinceInception 6.42%
Parametric Emerging Markets Fund | After Taxes on Distributions and Sales | Investor Class
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.83%
5 Years rr_AverageAnnualReturnYear05 12.01%
Since Inception rr_AverageAnnualReturnSinceInception 5.34%
Parametric Emerging Markets Fund | MSCI Emerging Markets Index
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects net dividends, which reflect the deduction of withholding taxes)
1 Year rr_AverageAnnualReturnYear01 (2.60%)
5 Years rr_AverageAnnualReturnYear05 14.78%
Since Inception rr_AverageAnnualReturnSinceInception 6.45%