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Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Central Index Key dei_EntityCentralIndexKey 0000701039
Calvert Income Fund  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks to maximize income, to the extent consistent with preservation of capital, through investment in bonds and income-producing securities.
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 qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds. More information about these and other discounts is available from your financial professional and under “Choosing a Share Class” on page 57 and “Reduced Sales Charges” on page 60 of this Prospectus, and under “Method of Distribution” on page 35 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 that you pay each year as a % 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 (“turns over” its 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 fiscal year ended September 30, 2015, the Fund’s portfolio turnover rate was 236% of its portfolio’s average value.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 236.00%
Expense Breakpoint Discounts [Text] 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 Calvert mutual funds. More information about these and other discounts is available from your financial professional and under “Choosing a Share Class” on page 57 and “Reduced Sales Charges” on page 60 of this Prospectus, and under “Method of Distribution” on page 35 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 ($1,000,000 in the case of Class I shares) in the Fund for the time periods indicated and then either redeem or hold your shares at the end of those periods;
• your investment has a 5% return each year;
• the Fund’s operating expenses remain the same; and
• any expense limitation is in effect for the period indicated in the fee table above.

 

Although your actual costs may be higher or lower, under these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

The Fund typically invests at least 65% of its net assets in investment grade, U.S. dollar-denominated debt securities, as assessed at the time of purchase. A debt security is considered investment grade when assigned a credit quality rating of BBB- or higher by Standard & Poor’s Ratings Services (“Standard & Poor’s”) or an equivalent rating by another nationally recognized statistical rating organization (“NRSRO”), including Moody’s Investors Service or Fitch Ratings, or if unrated, considered to be of comparable credit quality by the Fund’s Adviser.  For purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used.

 

The Fund invests principally in bonds issued by U.S. corporations, the U.S. Government or its agencies, and U.S. government-sponsored enterprises (“GSEs”) such as the Federal National Mortgage Association (“FNMA”) and the Federal Home Loan Mortgage Corporation (“FHLMC”). The Fund also may invest in trust preferred securities, taxable municipal securities, leveraged loans and asset-backed securities (“ABS”), including commercial mortgage-backed securities.

 

The Fund may invest in securities that represent interests in pools of mortgage loans or other assets assembled for sale to investors by various U.S. governmental agencies, government-related organizations and private issuers. These investments may include securities such as collateralized mortgage obligations (“CMOs”) and ABS.

 

The Fund may invest up to 35% of its net assets in below-investment grade, high-yield debt securities (commonly known as “junk bonds”), including distressed securities that are in default.

 

The Fund may also invest up to 25% of its net assets in foreign debt securities. Foreign debt securities include American Depositary Receipts (“ADRs”).

 

Investment decisions for the Fund are made primarily on the basis of fundamental and quantitative research conducted by the investment adviser’s research staff and consideration of the responsible investing criteria described below. Management of the Fund involves consideration of numerous factors (such as quality of business franchises, financial strength, management quality and security structural and collateral considerations). The portfolio managers may sell a security when the investment adviser’s price objective is reached, the fundamentals of the investment change or to pursue more attractive investment options. The portfolio managers intend to focus on risk management and also seek to preserve capital to the extent consistent with the Fund’s investment objectives. The Fund intends to seek to manage investment risk by maintaining broad issuer and industry diversification among its holdings, and by utilizing fundamental analysis of risk/return characteristics in securities selection. The Fund manages duration and any hedging of interest rate risk through the purchase and sale of U.S. Treasury securities and related futures contracts.

 

Responsible Investing. In selecting investments for the Fund, CRM is guided by The Calvert Principles for Responsible Investment, which provide a framework for considering environmental, social and governance factors that may affect investment performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration

The Fund typically invests at least 65% of its net assets in investment grade, U.S. dollar-denominated debt securities, as assessed at the time of purchase. A debt security is considered investment grade when assigned a credit quality rating of BBB- or higher by Standard & Poor’s Ratings Services (“Standard & Poor’s”) or an equivalent rating by another nationally recognized statistical rating organization (“NRSRO”), including Moody’s Investors Service or Fitch Ratings, or if unrated, considered to be of comparable credit quality by the Fund’s Adviser.  For purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

Bond Market Risk. Economic and other events (whether real, perceived or expected) 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 greater price 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 due to rising U.S. treasury yields which reflect the market’s expectations for higher U.S. economic growth and inflation. As a result of the Federal Reserve’s recent decision to raise the target fed funds rate following a similar move last year and the possibility that it may continue with such rate increases and/or unwind its quantitative easing program, fixed income markets could experience continuing high volatility, which could negatively impact the Fund’s performance.

 

Credit Risk. The credit quality of fixed-income securities may deteriorate, which could lead to default or bankruptcy of the issuer where the issuer becomes unable to pay its obligations when due. Such defaults may reduce the value of Fund shares and income distributions.  Changes in economic conditions or other circumstances may reduce the capacity of issuers of a municipal obligation to make principal and interest payments. The value of a municipal obligation also may decline because of real or perceived concerns about the issuer’s ability to make principal and interest payments.

 

Mortgage-Backed and Asset-Backed Securities Risk. The value of investments in mortgage-backed and asset-backed securities is subject to interest rate risk and credit risk. These securities are also subject to the risk that borrowers will prepay the principal on their loans more quickly than expected (prepayment risk) or more slowly than expected (extension risk), which will affect the yield, average life and price of the securities. In addition, faster than expected prepayments may cause the Fund to invest the prepaid principal in lower yielding securities and slower than expected prepayments may reduce the potential for the Fund to invest in higher yielding securities.

 

Mortgage-Backed Security Risk (Government-Sponsored Enterprises).  Debt and mortgage-backed securities issued by GSEs such as FNMA and FHLMC are neither insured nor guaranteed by the U.S. Treasury and are not backed by the full faith and credit of the U.S. government. Such securities are only supported by the credit of the applicable GSE. The U.S. government has provided financial support to FNMA and FHLMC, but there can be no assurance that it will support these or other GSEs in the future.

 

Leveraged Loan Risk. Leveraged loans are subject to the risks typically associated with debt securities, such as credit risk discussed above. The loans in which the Fund will invest are expected to be below-investment-grade quality and to bear interest at a floating rate that resets periodically. In addition, leveraged loans, which typically hold a senior position in the capital structure of a borrower, are subject to the risk that a court could subordinate such loans to presently existing or future indebtedness or take other action detrimental to the holders of leveraged loans. Leveraged loans are also subject to the risk that the value of the collateral, if any, securing a loan may decline, be insufficient to meet the obligations of the borrower, or be difficult to liquidate. Some leveraged loans are not as easily purchased or sold as publicly-traded securities and others are illiquid, which may make it more difficult for the Fund to value them or dispose of them at an acceptable price. Leveraged loans are usually more credit sensitive than investment-grade securities.

 

Management Risk. The success of the Fund’s investment program depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions. Individual investments of the Fund may not perform as expected, and the Fund’s portfolio management practices may not achieve the desired result.

 

Interest Rate Risk. A change in interest rates may adversely affect the value of fixed-income securities. When interest rates rise, the value of fixed-income securities will generally fall. Longer-term securities are subject to greater interest rate risk.

 

Portfolio Duration Risk. Duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates.

 

Liquidity Risk. Liquidity risk exists when particular investments are difficult to sell. The Fund may be unable to sell illiquid securities at an advantageous time or price or achieve its desired level of exposure to a certain sector. Liquidity risk may result from the lack of an active market, reduced number and capacity of traditional market participants to make a market in fixed-income securities, and may be magnified in a rising interest rate environment or other circumstances where investor redemptions from fixed-income mutual funds may be higher than normal, causing increased supply in the market due to selling activity. The secondary market for municipal obligations 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 obligations at attractive prices. Illiquid securities also may be difficult to value.

 

Lower Rated Investment Risk. Investments rated below investment grade and comparable unrated investments (“junk bonds”) can involve a substantial risk of loss. Junk bonds are considered to be speculative with respect to the issuer’s ability to pay interest and principal. These investments also have a higher risk of issuer default, are subject to greater price volatility than investment grade securities and may be illiquid.

 

Defaulted Bonds Risk. For bonds in default (those rated “D” by Standard & Poor’s or the equivalent by another NRSRO), there is a significant risk that these bonds will not achieve their original value.

 

Unrated Security Risk. Unrated securities may be less liquid than rated securities determined to be of comparable credit quality by the investment adviser. When the Fund purchases unrated securities, it will depend on the investment adviser’s analysis of credit risk without the assessment of a rating agency.  The credit risk of an unrated security will vary depending on its credit quality and whether it is supported by a credit enhancement.

 

Taxable Municipal Bond Risk. Taxable municipal bonds are subject to credit risk, interest rate risk and certain additional risks.  The Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in the bonds of similar projects or industrial development bonds.

 

Trust Preferred Securities Risk. Trust preferred securities are preferred stocks issued by a special purpose trust subsidiary backed by subordinated debt of the corporate parent. Trust preferred securities are subject to unique risks, which include the fact that dividend payments will only be paid if interest payments on the underlying obligations are made, which interest payments are dependent on the financial condition of the parent corporation. There is also the risk that the underlying obligations, and thus the trust preferred securities, may be prepaid after a stated call date or as a result of certain tax or regulatory events, resulting in a lower yield to maturity.

 

Collateralized Mortgage Obligation and Structured Asset-Backed Securities Risk. A CMO is a multiclass bond that is backed by a pool of mortgage loans or mortgage-backed securities. A structured ABS is a multiclass bond that is typically backed by a pool of auto loans, credit card receivables, home equity loans or student loans. A CMO or structured ABS is subject to interest rate risk, credit risk, prepayment risk and extension risk. In addition, if the Fund holds a class of a CMO or a structured ABS that is subordinated to other classes backed by the same pool of collateral, the likelihood that the Fund will receive payments of principal may be substantially limited.

 

Foreign Securities Risk. Investing in foreign securities involves additional risks relating to political, social, and economic developments abroad. Other risks result from the differences between the regulations to which U.S. and foreign issuers and markets are subject, and the potential for foreign markets to be less liquid and more volatile than U.S. markets. Foreign securities include ADRs. Unsponsored ADRs involve additional risks because U.S. reporting requirements do not apply and the issuing bank will recover shareholder distribution costs from movement of share prices and payment of dividends.

 

Foreign Currency Risk. Securities that trade or are denominated in currencies other than the U.S. dollar may be adversely affected by fluctuations in currency exchange rates. When the U.S. dollar strengthens relative to a foreign currency, the U.S. dollar value of an investment denominated in that currency will typically fall. ADRs indirectly bear currency risk because they represent an interest in securities that are not denominated in U.S. dollars.

 

Active Trading Strategy Risk. The Fund employs an active style that seeks to position the Fund with securities that offer the greatest price appreciation while minimizing risk. This style can result in higher turnover (exceeding 100%), may translate to higher transaction costs and may increase your tax liability.

 

Responsible Investing Risk.  Investing primarily in responsible investments carries the risk that, under certain market conditions, the Fund may underperform funds that do not utilize a responsible investment strategy.  The application of responsible investment criteria may affect the Fund’s exposure to certain sectors or types of investments, and may impact the Fund’s relative investment performance depending on whether such sectors or investments are in or out of favor in the market.  An investment’s ESG performance, or the Adviser’s assessment of such performance, may change over time, which could cause the Fund to temporarily hold investments that do not comply with the Fund’s responsible investment criteria.  In evaluating an investment, the Adviser is dependent upon information and data that may be incomplete, inaccurate or unavailable, which could cause the Adviser to misanalyze the ESG factors relevant to a particular investment.  Successful application of the Fund’s responsible investment strategy will depend on the Adviser’s skill in properly identifying and analyzing material ESG issues.

 

Futures Contracts Risk. The value of a futures contract tends to increase and decrease in tandem with the value of the underlying instrument. The price of futures can be highly volatile; using them could lower total return, and the potential loss from futures can exceed the Fund’s initial investment in such contracts. Futures contracts may not provide an effective hedge of the underlying securities or indexes because changes in the prices of futures contracts may not track those of the securities or indexes that they are intended to hedge.

 

General Fund Investing Risk. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. The Fund is designed to be a long-term investment vehicle and is not suited for short-term trading. 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.
Risk Lose Money [Text] rr_RiskLoseMoney

The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to 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.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Class A shares has varied from year to year. The table compares the Fund’s performance over time with that of a benchmark index.  The performance reflected in the bar chart and table assumes the reinvestment of dividends and capital gains distributions, if any.  

 

The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. For updated performance information, visit www.calvert.com.

 

The return for each of the Fund’s other Classes of shares will differ from the Class A returns shown in the bar chart, depending upon the expenses of that Class. The bar chart does not reflect any sales charge that you may be required to pay upon purchase or redemption of the Fund’s shares. Any sales charge will reduce your return.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Class A shares has varied from year to year.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress

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

The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads

The bar chart does not reflect any sales charge that you may be required to pay upon purchase or redemption of the Fund’s shares. Any sales charge will reduce your return.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

For the ten years ended December 31, 2015, the highest quarterly total return for Class A was 7.78% for the quarter ended September 30, 2009 and the lowest quarterly return was -7.72% for the quarter ended December 31, 2008.
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Returns as of December 31, 2015
Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads

These returns reflect the maximum sales charge for Class A (3.75%) and 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 historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your tax situation and may differ from those shown.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to you if you hold your Fund shares through a tax-deferred arrangement such as a 401(k) plan or individual retirement account.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown

After-tax returns are shown only for Class A shares; after-tax returns for other Classes will vary.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher

The return after taxes on distributions and sale of Fund shares may be higher than the return before taxes because the calculation assumes that shareholders receive a tax benefit for capital losses incurred on the sale of their shares.
Performance Table Footnotes, Reason Performance Information for Class Different from Immediately Preceding Period [Text] rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod

Performance results for Class Y shares prior to February 29, 2008 (the Class Y shares’ inception date) reflect the performance of Class A shares at net asset value. Actual Class Y share performance would have been higher than Class A share performance because Class Y has lower class-specific expenses than Class A.  Performance results for Class R shares prior to October 31, 2006 (the Class R shares’ inception date) reflect the performance of Class A shares at net asset value.  Actual Class R share performance would have been lower than Class A share performance because Class R has higher class-specific expenses than Class A.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

These returns reflect the maximum sales charge for Class A (3.75%) and any applicable contingent deferred sales charge (“CDSC”) for Class C.  Performance results for Class Y shares prior to February 29, 2008 (the Class Y shares’ inception date) reflect the performance of Class A shares at net asset value. Actual Class Y share performance would have been higher than Class A share performance because Class Y has lower class-specific expenses than Class A.  Performance results for Class R shares prior to October 31, 2006 (the Class R shares’ inception date) reflect the performance of Class A shares at net asset value.  Actual Class R share performance would have been lower than Class A share performance because Class R has higher class-specific expenses than Class A.  Investors cannot invest directly in an Index.

 

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your tax situation and may differ from those shown. The after-tax returns shown are not relevant to you if you hold your Fund shares through a tax-deferred arrangement such as a 401(k) plan or individual retirement account. The return after taxes on distributions and sale of Fund shares may be higher than the return before taxes because the calculation assumes that shareholders receive a tax benefit for capital losses incurred on the sale of their shares. After-tax returns are shown only for Class A shares; after-tax returns for other Classes will vary.
Calvert Income Fund | Bloomberg Barclays U.S. Credit Index (reflects no deduction for fees, expenses or taxes)  
Risk/Return: rr_RiskReturnAbstract  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.77%)
5 Years rr_AverageAnnualReturnYear05 4.38%
10 Years rr_AverageAnnualReturnYear10 5.18%
Calvert Income Fund | Class A  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 3.75%
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none [1]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.52% [2]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.29%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.06%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.06%) [3]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.00%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 473
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 694
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 932
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,615
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 473
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 694
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 932
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,615
Annual Return 2006 rr_AnnualReturn2006 4.82%
Annual Return 2007 rr_AnnualReturn2007 5.08%
Annual Return 2008 rr_AnnualReturn2008 (12.00%)
Annual Return 2009 rr_AnnualReturn2009 16.42%
Annual Return 2010 rr_AnnualReturn2010 6.45%
Annual Return 2011 rr_AnnualReturn2011 2.63%
Annual Return 2012 rr_AnnualReturn2012 8.63%
Annual Return 2013 rr_AnnualReturn2013 (0.75%)
Annual Return 2014 rr_AnnualReturn2014 4.88%
Annual Return 2015 rr_AnnualReturn2015 (1.20%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel

For the ten years ended December 31, 2015, the highest quarterly total return for Class A was
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 7.78%
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 (7.72%)
1 Year rr_AverageAnnualReturnYear01 (4.92%)
5 Years rr_AverageAnnualReturnYear05 1.99%
10 Years rr_AverageAnnualReturnYear10 2.86%
Calvert Income Fund | Class A | After Taxes on Distributions  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (6.07%)
5 Years rr_AverageAnnualReturnYear05 0.78%
10 Years rr_AverageAnnualReturnYear10 1.43%
Calvert Income Fund | Class A | After Taxes on Distributions and Sales  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (2.80%)
5 Years rr_AverageAnnualReturnYear05 0.78%
10 Years rr_AverageAnnualReturnYear10 1.43%
Calvert Income Fund | Class C  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00% [4]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.52% [2]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.23%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.75%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [3]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.75%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2018
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 (2.89%)
5 Years rr_AverageAnnualReturnYear05 2.06%
10 Years rr_AverageAnnualReturnYear10 2.53%
Calvert Income Fund | Class Y  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.52% [2]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.21%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.73%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [3]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.73%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 75
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 233
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 406
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 906
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 75
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 233
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 406
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 906
1 Year rr_AverageAnnualReturnYear01 (0.88%)
5 Years rr_AverageAnnualReturnYear05 3.14%
10 Years rr_AverageAnnualReturnYear10 3.55%
Inception Date rr_AverageAnnualReturnInceptionDate Feb. 29, 2008
Calvert Income Fund | Class I  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.52% [2]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.14%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.66%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.02%) [3],[5]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.64%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 6,540
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 20,919
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 36,575
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 82,059
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 6,540
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 20,919
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 36,575
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 82,059
1 Year rr_AverageAnnualReturnYear01 (0.55%)
5 Years rr_AverageAnnualReturnYear05 3.42%
10 Years rr_AverageAnnualReturnYear10 3.91%
Calvert Income Fund | Class R  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.52% [2]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.74%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.76%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.29%) [3]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.47%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 150
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 526
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 927
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,049
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 150
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 526
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 927
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,049
1 Year rr_AverageAnnualReturnYear01 (1.44%)
5 Years rr_AverageAnnualReturnYear05 2.58%
10 Years rr_AverageAnnualReturnYear10 3.03%
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 31, 2006
[1] Purchases of Class A shares at net asset value for accounts with $1,000,000 or more on which a finder's fee has been paid are subject to a one-year contingent deferred sales charge of 0.80%.
[2] Management fees are restated to reflect current contractual fees rather than the fees paid during the previous fiscal year.
[3] Calvert Research and Management ("CRM") has agreed to reimburse the Fund's expenses to the extent that Total Annual Fund Operating Expenses exceed 1.00% for Class A shares, 1.09% for Class Y shares, 0.84% for Class I shares and 1.47% for Class R shares. This expense reimbursement will continue through January 31, 2018. Any amendment to or termination of this reimbursement would require approval of the Board of Trustees. The expense reimbursement relates to ordinary operating expenses only and does not include expenses such as: brokerage commissions, acquired fund fees and expenses of unaffiliated funds, interest expense, taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than the contractual expense cap during such year.
[4] Applies to redemptions of Class C shares within one year of purchase.
[5] The contractual administrative fee is 0.12%. CRM has agreed to contractually waive 0.02% of the administrative fee on Class I shares through January 31, 2018.