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Label Element Value
[RiskReturnAbstract] rr_RiskReturnAbstract  
Document Type dei_DocumentType 485BPOS
Document Period End Date dei_DocumentPeriodEndDate Oct. 31, 2013
Registrant Name dei_EntityRegistrantName Eaton Vance Series Trust II
Central Index Key dei_EntityCentralIndexKey 0000074663
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 Mar. 01, 2014
Eaton Vance Income Fund of Boston
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objectives
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund’s investment objective is to provide a high level of current income. The Fund's secondary objectives are to seek growth of income and capital.
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. You may quality for a reduced sales charge if you invest, or agree to invest over a 13-month period, at least $50,000 in Eaton Vance funds. More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 38 of this Prospectus and page 23 of the Fund’s Statement of Additional Information.
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 56% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 56.00%
Expense Footnotes [Text Block] rr_ExpenseFootnotesTextBlock

* Expenses in the table above and the Example below reflect the expenses of the Fund and the Boston Income Portfolio (the “Portfolio”), the Fund’s master Portfolio.
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts

You may quality for a reduced sales charge if you invest, or agree to invest over a 13-month period, at least $50,000 in Eaton Vance funds. More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 38 of this Prospectus and page 23 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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

The Fund currently invests primarily in high yield, high risk corporate bonds (commonly referred to as “junk bonds”) which are rated lower than investment grade (i.e., bonds rated lower than Baa by Moody’s Investors Service, Inc. (“Moody’s”) or lower than BBB by Standard & Poor’s Ratings Services (“S&P”)) or are unrated and of comparable quality as determined by the investment adviser. Bonds rated BBB and Baa have speculative characteristics, while lower rated bonds are predominantly speculative.

The Fund may hold securities that are unrated or in the lowest rating categories (rated C by Moody’s or D by S&P). Bonds rated C by Moody’s are regarded as having extremely poor prospects of ever attaining any real investment standing. Bonds rated D by S&P are in payment default or a bankruptcy petition has been filed and debt service payments are jeopardized.

The Fund invests a substantial portion of its assets in bonds issued in connection with mergers, acquisitions and other highly leveraged transactions. The Fund may invest in a wide variety of other income-producing debt securities (including senior floating rate loans and secured and unsecured subordinated loans, second lien loans and bridge loans) (“bank loans”), as well as preferred stocks that pay dividends. The Fund may invest up to 10% of its net assets in municipal obligations, including shares of affiliated investment companies. Some debt securities acquired by the Fund do not pay current income or do not make regular interest payments, while others may pay interest in the form of additional debt securities. The Fund may invest in zero coupon bonds, deferred interest bonds and bonds or preferred stocks on which the interest is payable-in-kind. The Fund will generally hold well in excess of 100 securities, which may help reduce investment risk.

The Fund may invest up to 25% of total assets in foreign and emerging market securities, which are predominantly U.S. dollar denominated. With respect to non-dollar denominated securities, the Fund may hedge currency fluctuations by entering into forward foreign currency exchange contracts.

The Fund may engage in derivative transactions. Transactions in derivative instruments may include: the purchase or sale of futures contracts on securities, indices or other financial instruments or currencies; options on futures contracts; exchange-traded and over-the-counter options on securities, indices, currencies and other instruments; interest rate, credit default, inflation and total return swaps; forward rate contracts and credit linked notes as well as instruments that have a greater or lesser credit risk than the security underlying that instrument. The Fund may use interest rate swaps for risk management purposes and not as a speculative investment and would typically use interest rate swaps to shorten the average interest rate re-set time of its holdings.

The Fund’s investments are actively managed and securities may be bought and sold on a daily basis. Preservation of capital is considered when consistent with the Fund’s objective. The investment adviser’s staff monitors the credit quality of securities held by the Fund and other securities available to the Fund. Although the investment adviser considers security ratings when making investment decisions, it performs its own credit and investment analysis utilizing various methodologies including “bottom up/top down” analysis and consideration of macroeconomic and technical factors, and does not rely primarily on the ratings assigned by the rating services. The portfolio managers attempt to improve yield and preserve and enhance principal value through timely trading. The portfolio managers also consider the relative value of securities in the marketplace in making investment decisions.

The Fund currently invests its assets in the Portfolio, a separate registered investment company with the same investment objectives and policies as the Fund.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration

The Fund currently invests primarily in high yield, high risk corporate bonds (commonly referred to as “junk bonds”) which are rated lower than investment grade (i.e., bonds rated lower than Baa by Moody’s Investors Service, Inc. (“Moody’s”) or lower than BBB by Standard & Poor’s Ratings Services (“S&P”)) or are unrated and of comparable quality as determined by the investment adviser. Bonds rated BBB and Baa have speculative characteristics, while lower rated bonds are predominantly speculative.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

Risk of Lower Rated Investments. Investments rated below investment grade and comparable unrated securities (“junk bonds”) have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments.

Market Risk. Economic and other events (whether real or perceived) can reduce the demand for investments held by the Fund, which may reduce their market prices and cause the value of Fund shares to fall. The frequency and magnitude of such changes cannot be predicted. Certain securities and other investments held by the Fund can experience downturns in trading activity and, at such times, the supply of such instruments in the market may exceed the demand. At other times, the demand for such instruments may exceed the supply in the market. An imbalance in supply and demand in the market may result in valuation uncertainties and greater volatility, less liquidity, wider trading spreads and a lack of price transparency in the market. No active trading market may exist for certain investments, which may impair the ability of the Fund to sell or to realize the full value of such investments in the event of the need to liquidate such assets. Adverse market conditions may impair the liquidity of some actively traded investments. Fixed income markets have recently experienced a period of relatively high volatility. If the Federal Reserve continues to taper or reverse its quantitative easing stimulus program and/or increases interest rates, fixed income markets could experience continuing high volatility, which could negatively impact the Fund’s performance.

Interest Rate Risk. In general, the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Generally, securities with longer durations are more sensitive to changes in interest rates than shorter duration securities. In a rising interest rate environment, the duration of income securities that have the ability to be prepaid or called by the issuer may extend. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate.

Credit Risk. Investments in debt obligations are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Fund shares and income distributions. The value of a debt obligation also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of income securities and bank loans may be lowered if the financial condition of the party obligated to make payments with respect to such instruments changes. Credit ratings assigned by rating agencies are based on a number of factors and do not necessarily reflect the issuer’s current financial condition or the volatility or liquidity of the security. In the event of bankruptcy of the issuer of income securities and bank loans, the Fund could experience delays or limitations with respect to its ability to realize the benefits of any collateral securing the instrument. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel. This may increase the Fund’s operating expenses and adversely affect net asset value.

Risks of Zero-Coupon and Deep Discount Bonds and PIK Securities. Zero-coupon and deep discount bonds may experience greater volatility in market value due to changes in interest rates. The Fund accrues income on the discount amortization of these investments, which it is required to distribute each year. The Fund may be required to sell investments to obtain cash needed for income distributions. Securities purchased on a when-issued or forward commitment basis are subject to the risk that when delivered they will be worth less than the agreed upon payment price. Bonds and preferred stocks that make “in-kind” payments and other securities that do not pay regular income distributions may experience greater volatility in response to interest rate changes and issuer developments.

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.

Risk of Leveraged Transactions. Certain Fund transactions may give rise to leverage. Such transactions may include, among others, certain derivative transactions. The Fund is required to segregate liquid assets or otherwise cover the Fund’s obligation created by a transaction that may give rise to leverage. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leverage may cause the Fund’s share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment.

Municipal Bond Risk. The amount of public information available about municipal bonds is generally less than for corporate equities or bonds, meaning that the investment performance of municipal bond investments may be more dependent on the analytical abilities of the investment adviser than stock or corporate bond investments. The secondary market for municipal bonds also tends to be less well-developed and less liquid than many other securities markets, which may limit an owner’s ability to sell its municipal bonds at attractive prices. The spread between the price at which an obligation can be purchased and the price at which it can be sold may widen during periods of market distress. Less liquid obligations can become more difficult to value and be subject to erratic price movements. The increased presence of non-traditional participants or the absence of traditional participants in the municipal markets may lead to greater volatility in the markets.

Foreign and Emerging Market Investment Risk. Because the Fund can invest a 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.

Risk of Senior Loans. Risks of investments in Senior Loans are similar to the risks of lower rated securities, although interest rate risk may be reduced because Senior Loan rates generally are adjusted for changes in short-term interest rates. Junior Loans are subject to the same general risks. Due to their lower place in the borrower’s capital structure and possible unsecured status, Junior Loans may involve a higher degree of overall risk than Senior Loans of the same borrower.

Risks Associated with Active Management. The Fund is an actively managed portfolio and its success depends upon the investment skills and analytical abilities of the investment adviser to develop and effectively implement strategies to achieve the Fund’s investment objectives. Subjective decisions made by the investment adviser may cause the Fund to incur losses or to miss profit opportunities on which it may otherwise have capitalized.

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 objectives. 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 objectives. 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 two broad-based securities market indices. The returns in the bar chart are for Class A shares and do not reflect a sales charge. If the sales charge was reflected, the returns would be lower. Past performance (both before and after taxes) is no guarantee of future results. 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 two broad-based securities market indices.
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 Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads

The returns in the bar chart are for Class A shares and do not reflect a sales charge.  If the sales charge was reflected, the returns would be lower.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

For the ten years ended December 31, 2013, the highest quarterly total return for Class A was 22.94% for the quarter ended June 30, 2009, and the lowest quarterly return was –23.52% for the quarter ended December 31, 2008. For the 30 days ended October 31, 2013, the SEC yield for Class A shares was 4.33%, for Class B shares was 3.80 %, for Class C shares was 3.80%, for Class I shares was 4.79% and for Class R shares was 4.30%. For current yield information call 1-800-262-1122.
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel

During the ten years ended December 31, 2013 , the highest quarterly total return for Class A was
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 22.94%
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 (23.52%)
Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads

These returns reflect the maximum sales charge for Class A (4.75%) and any applicable contingent deferred sales charge (“CDSC”) for Class B and 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 Class A 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 R performance shown above for the period prior to January 5, 2004 (commencement of operations), is the performance of Class A shares at net asset value without adjustment for any differences in the expenses of the two classes and the Class R6 performance shown above for the period prior to July 1, 2014 (commencement of operations) is the performance of Class I shares 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 the maximum sales charge for Class A (4.75%) and any applicable contingent deferred sales charge (“CDSC”) for Class B and Class C. The Class R performance shown above for the period prior to January 5, 2004 (commencement of operations), is the performance of Class A shares at net asset value without adjustment for any differences in the expenses of the two classes and the Class R6 performance shown above for the period prior to July 1, 2014 (commencement of operations) is the performance of Class I shares 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. BofA Merrill Lynch® indices not for redistribution or other uses; provided “as is”, without warranties, and with no liability. Eaton Vance has prepared this report, BofAML does not endorse it, or guarantee, review, or endorse Eaton Vance’s products. Investors cannot invest directly in an Index.

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 non-taxable entities. After-tax returns for other Classes of shares will vary from the after-tax returns presented for Class A 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 the 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.
Thirty Day Yield Phone rr_ThirtyDayYieldPhone

For current yield information call 1-800-262-1122.
Eaton Vance Income Fund of Boston | Class A
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EVIBX
Maximum Sales Charge (Load) (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.75%
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 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.00%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 572
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 778
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,001
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,641
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 572
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 778
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,001
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,641
Annual Return 2004 rr_AnnualReturn2004 10.71%
Annual Return 2005 rr_AnnualReturn2005 3.61%
Annual Return 2006 rr_AnnualReturn2006 11.29%
Annual Return 2007 rr_AnnualReturn2007 2.25%
Annual Return 2008 rr_AnnualReturn2008 (30.31%)
Annual Return 2009 rr_AnnualReturn2009 57.07%
Annual Return 2010 rr_AnnualReturn2010 14.84%
Annual Return 2011 rr_AnnualReturn2011 4.58%
Annual Return 2012 rr_AnnualReturn2012 13.40%
Annual Return 2013 rr_AnnualReturn2013 7.29%
1 Year rr_AverageAnnualReturnYear01 2.18%
5 Years rr_AverageAnnualReturnYear05 16.90%
10 Years rr_AverageAnnualReturnYear10 7.11%
Thirty Day Yield Column [Text] rr_ThirtyDayYieldColumnName

For the 30 days ended October 31, 2013 , the SEC yield for Class A shares was

Thirty Day Yield rr_ThirtyDayYield 4.33%
Eaton Vance Income Fund of Boston | Class B
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EBIBX
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 5.00%
Management Fees rr_ManagementFeesOverAssets 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.75%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 678
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 951
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,149
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,864
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 178
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 551
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 949
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,864
1 Year rr_AverageAnnualReturnYear01 1.33%
5 Years rr_AverageAnnualReturnYear05 16.98%
10 Years rr_AverageAnnualReturnYear10 6.84%
Thirty Day Yield Column [Text] rr_ThirtyDayYieldColumnName

for Class B shares was
Thirty Day Yield rr_ThirtyDayYield 3.80%
Eaton Vance Income Fund of Boston | Class C
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol ECIBX
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 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.75%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 278
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 551
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 949
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,062
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 178
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 551
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 949
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,062
1 Year rr_AverageAnnualReturnYear01 5.33%
5 Years rr_AverageAnnualReturnYear05 17.19%
10 Years rr_AverageAnnualReturnYear10 6.84%
Thirty Day Yield Column [Text] rr_ThirtyDayYieldColumnName

for Class C shares was
Thirty Day Yield rr_ThirtyDayYield 3.80%
Eaton Vance Income Fund of Boston | Class I
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EIBIX
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 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.75%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 77
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 240
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 417
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 930
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 77
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 240
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 417
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 930
1 Year rr_AverageAnnualReturnYear01 7.37%
5 Years rr_AverageAnnualReturnYear05 18.37%
10 Years rr_AverageAnnualReturnYear10 7.92%
Thirty Day Yield Column [Text] rr_ThirtyDayYieldColumnName

for Class I shares was

Thirty Day Yield rr_ThirtyDayYield 4.79%
Eaton Vance Income Fund of Boston | Class R
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol ERIBX
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 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 127
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 397
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 686
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,511
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 127
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 397
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 686
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,511
1 Year rr_AverageAnnualReturnYear01 7.03%
5 Years rr_AverageAnnualReturnYear05 17.77%
10 Years rr_AverageAnnualReturnYear10 7.35%
Thirty Day Yield Column [Text] rr_ThirtyDayYieldColumnName

and for Class R shares was
Thirty Day Yield rr_ThirtyDayYield 4.30%
Eaton Vance Income Fund of Boston | Class R6
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Trading Symbol dei_TradingSymbol EIBRX
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 0.59%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.08%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.67%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 68
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 214
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 373
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 835
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 68
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 214
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 373
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 835
1 Year rr_AverageAnnualReturnYear01 7.37%
5 Years rr_AverageAnnualReturnYear05 18.37%
10 Years rr_AverageAnnualReturnYear10 7.92%
Eaton Vance Income Fund of Boston | After Taxes on Distributions | Class A
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (0.45%)
5 Years rr_AverageAnnualReturnYear05 13.60%
10 Years rr_AverageAnnualReturnYear10 4.12%
Eaton Vance Income Fund of Boston | After Taxes on Distributions and Sales | Class A
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 1.19%
5 Years rr_AverageAnnualReturnYear05 12.12%
10 Years rr_AverageAnnualReturnYear10 4.25%
Eaton Vance Income Fund of Boston | BofA Merrill Lynch U.S. High Yield Index
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 7.42%
5 Years rr_AverageAnnualReturnYear05 18.64%
10 Years rr_AverageAnnualReturnYear10 8.45%
Eaton Vance Income Fund of Boston | BofA Merrill Lynch U.S. High Yield Constrained Index
  
[RiskReturnAbstract] rr_RiskReturnAbstract  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 7.41%
5 Years rr_AverageAnnualReturnYear05 18.69%
10 Years rr_AverageAnnualReturnYear10 8.46%