XML 23 R11.htm IDEA: XBRL DOCUMENT v3.8.0.1
Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Central Index Key dei_EntityCentralIndexKey 0000356682
Calvert Moderate Allocation Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading

Calvert Moderate Allocation Fund
Objective [Heading] rr_ObjectiveHeading

Investment Objectives
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation and growth of income, with current income a secondary objective.
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. Investors may also pay commissions or other fees to their financial intermediary when they buy and hold shares of the Fund which are not reflected below. You may qualify for sales charge discounts on purchases of Class A shares if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds. Certain financial intermediaries also may offer variations in Fund sales charges to their customers as described in Appendix B – Financial Intermediary Sales Charge Variations in this Prospectus. More information about these and other discounts is available from your financial professional and under “Sales Charges” on page 37 of this Prospectus and page 6 of the Fund’s Statement of Additional Information (“SAI”).
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 may pay transaction costs, such as commissions, when it buys and sells securities (“turns over” its portfolio). These transaction costs are also incurred by the underlying Calvert funds in which the Fund invests. 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 45% of its portfolio’s average value.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 45.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts on purchases of Class A shares if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds. Certain financial intermediaries also may offer variations in Fund sales charges to their customers as described in Appendix B – Financial Intermediary Sales Charge Variations in this Prospectus. More information about these and other discounts is available from your financial professional and under “Sales Charges” on page 37 of this Prospectus and page 6 of the Fund’s Statement of Additional Information (“SAI”).
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expenses Restated to Reflect Current [Text] rr_ExpensesRestatedToReflectCurrent

Management fees are restated to reflect current contractual fees paid during the previous fiscal year.
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 and that any expense reimbursement arrangement remains in place for the contractual period. 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 is a “fund of funds” that seeks to achieve its investment objectives by primarily allocating its assets among underlying Calvert fixed-income and equity funds meeting its investment criteria, including the responsible investing criteria described below. The Fund typically invests 50%-80% of its net assets in funds that invest primarily in equity securities and 20% to 50% of its net assets in funds that invest primarily in fixed-income securities. The Fund may also invest up to 20% of its net assets in cash and short-term money market instruments. The Fund will invest in accordance with a target asset allocation determined by the Adviser. The Fund’s asset allocation strategy incorporates both historical and forward-looking risk and return characteristics of various asset classes and correlations between asset classes to establish allocations intended to provide an optimal level of return for a given level of risk. Historical returns-based analysis and actual holdings data of the target underlying Calvert funds are then integrated to blend the styles of the underlying Calvert funds with the asset allocation policy.

Incidental to its main investment strategy, the Fund may also invest in (1) derivative instruments, including, but not limited to, futures, options and swaps and (2) exchange-traded funds (“ETFs”). The Fund will use these instruments to facilitate the periodic rebalancing of the Fund’s portfolio to maintain its target asset allocation, to make tactical asset allocations (including to gain or limit exposure to certain asset classes and/or sectors, and/or to manage duration) and to assist in managing cash.

The above asset allocation percentages are allocation targets. The Adviser has discretion to reallocate the Fund’s assets among underlying Calvert funds. The Adviser monitors the Fund’s allocation and may rebalance or reallocate the Fund’s assets (1) based on its view of economic and market factors and events or (2) to adjust for shifts in the style biases of the underlying funds. The Adviser also evaluates any necessary rebalancing to reflect different target asset class allocations based on changed economic and market conditions.

Responsible Investing. In accordance with its asset allocation strategy, the Fund will invest in Calvert fixed-income and equity funds that consider environmental, social and governance (“ESG”) factors in selecting their investments.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration

The Fund is a “fund of funds” that seeks to achieve its investment objectives by primarily allocating its assets among underlying Calvert fixed-income and equity funds meeting its investment criteria, including the responsible investing criteria described below. The Fund typically invests 50%-80% of its net assets in funds that invest primarily in equity securities and 20% to 50% of its net assets in funds that invest primarily in fixed-income securities. The Fund may also invest up to 20% of its net assets in cash and short-term money market instruments. The Fund will invest in accordance with a target asset allocation determined by the Adviser. The Fund’s asset allocation strategy incorporates both historical and forward-looking risk and return characteristics of various asset classes and correlations between asset classes to establish allocations intended to provide an optimal level of return for a given level of risk. Historical returns-based analysis and actual holdings data of the target underlying Calvert funds are then integrated to blend the styles of the underlying Calvert funds with the asset allocation policy.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

Market Risk. The value of investments held by the Fund may increase or decrease in response to economic, political and financial events (whether real, expected or perceived) in the U.S. and global markets. The frequency and magnitude of such changes in value cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Actions taken by the U.S. Federal Reserve or foreign central banks to stimulate or stabilize economic growth, such as decreases or increases in short-term interest rates, could cause high volatility in markets.

Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions.

Derivatives Risk. The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. 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 leverage in the Fund, which represents a non-cash exposure to the underlying asset, index, rate or instrument. Leverage can increase both the risk and return potential of the Fund. 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. Use of 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. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying asset, rate, index or instrument. 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, particularly when there is no stated limit on the Fund’s use of derivatives. A derivative investment also involves the risks relating to the asset, index, rate or instrument underlying the investment.

ETF Risk. ETFs are subject to the risks of investing in the underlying securities or other investments. ETF shares may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Fund will bear a pro rata portion of the operating expenses of an ETF in which it invests. Other pooled investment vehicles generally are subject to risks similar to those of ETFs.

Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; and other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund’s equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels.

Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States, and as a result, Fund share values may be more volatile. Trading in foreign 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. Depositary receipts are subject to many of the risks associated with investing directly in foreign instruments.

Convertible Securities Risk. Convertible securities generally possess characteristics common to both equity and debt securities. In addition to risks associated with investing in income securities, such as interest rate and credit risks, convertible securities may be subject to issuer-specific and market risks generally applicable to equity securities. Convertible securities may also react to changes in the value of the common stock into which they convert, and are thus subject to equity investing and market risks. A convertible security may be converted at an inopportune time, which may decrease the Fund’s return.

Emerging Markets Investment Risk. Investment markets in emerging market countries are typically smaller, less liquid and more volatile than developed markets, and emerging market securities often involve greater risks than developed market securities.

Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks.

U.S. Government Securities Risk. Although certain U.S. Government-sponsored agencies (such as the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association) may be chartered or sponsored by acts of Congress, their securities are neither issued nor guaranteed by the U.S. Treasury. U.S. Treasury securities generally have a lower return than other obligations because of their higher credit quality and market liquidity.

Mortgage- and Asset-Backed Securities Risk. Mortgage- and asset-backed securities represent interests in “pools” of commercial or residential mortgages or other assets, including consumer loans or receivables. Movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain types of mortgage- and asset-backed securities. Although certain mortgage- and asset-backed securities are guaranteed as to timely payment of interest and principal by a government entity, the market price for such securities is not guaranteed and will fluctuate. The purchase of mortgage- and asset-backed securities issued by non-government entities may entail greater risk than such securities that are issued or guaranteed by a government entity. Mortgage- and asset-backed securities issued by non-government entities may offer higher yields than those issued by government entities, but may also be subject to greater volatility than government issues and can also be subject to greater credit risk and the risk of default on the underlying mortgages or other assets. Investments in mortgage- and asset-backed securities are subject to both extension risk, where borrowers pay off their debt obligations more slowly in times of rising interest rates, and prepayment risk, where borrowers pay off their debt obligations sooner than expected in times of declining interest rates.

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, causing them to be more volatile. Conversely, fixed income securities with shorter durations will be less volatile but generally provide lower returns than fixed income securities with longer durations. In a rising interest rate environment, the durations of income securities that have the ability to be prepaid or called by the issuer may be extended. 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 instruments 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 debt instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make payments with respect to such instruments deteriorates. In the event of bankruptcy of the issuer of debt instrument, 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, which may increase the Fund’s operating expenses and adversely affect net asset value.

Money Market Instrument Risk. Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty.

Additional Risks of Loans. Loans are traded in a private, unregulated inter-dealer or inter-bank resale market and are generally subject to contractual restrictions that must be satisfied before a loan can be bought or sold. These restrictions may impede the Fund’s ability to buy or sell loans (thus affecting their liquidity) and may negatively impact the transaction price. See also “Market Risk” above. It also may take longer than seven days for transactions in loans to settle. Due to the possibility of an extended loan settlement process, the Fund may hold cash, sell investments or temporarily borrow from banks or other lenders to meet short-term liquidity needs, such as to satisfy redemption requests from Fund shareholders. Loans may be structured such that they are not securities under securities law, and in the event of fraud or misrepresentation by a borrower, lenders may not have the protection of the anti-fraud provisions of the federal securities laws. Loans are also subject to risks associated with other types of income investments as described herein.

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 securities 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 adversely affect the analysis of 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.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. 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. 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. 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.
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 objectives. It is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text] rr_RiskMoneyMarketFund

Money Market Instrument Risk. Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty.
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.
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 a broad-based market index and a composite benchmark. 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 not necessarily an indication how the Fund will perform in the future.

Effective December 31, 2016, CRM became the investment adviser to the Fund and performance reflected prior to such date is that of the Fund’s former investment adviser, Calvert Investment Management, Inc. Performance for all periods has been calculated by CRM, the Fund’s current administrator, in accordance with applicable requirements. The Fund’s performance reflects the effects of expense reductions. Absent these reductions, performance would have been lower. Updated Fund performance information can be obtained by visiting www.calvert.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 a broad-based market index and a composite benchmark.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress

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

Past performance (both before and after taxes) is not necessarily an indication how the Fund will perform in the future.
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, 2017, the highest quarterly total return for Class A was 13.24% for the quarter ended June 30, 2009 and the lowest quarterly return was -16.48% for the quarter ended December 31, 2008.
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel

For the ten years ended December 31, 2017, the highest quarterly total return for Class A was
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 13.24%
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 (16.48%)
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Returns as of December 31, 2017
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 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 the 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 I shares prior to May 20, 2016 (the Class I shares’ inception date) reflect the performance of Class A shares at net asset value. Actual Class I share performance would have been higher than Class A share performance because Class I has lower class-specific expenses than Class A.
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 C. Performance results for Class I shares prior to May 20, 2016 (the Class I shares’ inception date) reflect the performance of Class A shares at net asset value. Actual Class I share performance would have been higher than Class A share performance because Class I has lower 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 the other Classes will vary.
Calvert Moderate Allocation Fund | Russell 3000® 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)
Label rr_AverageAnnualReturnLabel Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 21.13%
5 Years rr_AverageAnnualReturnYear05 15.57%
10 Years rr_AverageAnnualReturnYear10 8.59%
Calvert Moderate Allocation Fund | Moderate Allocation Composite Benchmark (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)
Label rr_AverageAnnualReturnLabel Moderate Allocation Composite Benchmark (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 15.72% [1]
5 Years rr_AverageAnnualReturnYear05 9.39% [1]
10 Years rr_AverageAnnualReturnYear10 6.03% [1]
Calvert Moderate Allocation Fund | Class A  
Risk/Return: rr_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.75%
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none [2]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.22%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.52%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.99%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.03%) [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.96%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2019
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 568
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 772
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 993
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,628
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 568
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 772
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 993
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,628
Annual Return 2008 rr_AnnualReturn2008 (29.05%)
Annual Return 2009 rr_AnnualReturn2009 21.92%
Annual Return 2010 rr_AnnualReturn2010 10.22%
Annual Return 2011 rr_AnnualReturn2011 (0.28%)
Annual Return 2012 rr_AnnualReturn2012 13.04%
Annual Return 2013 rr_AnnualReturn2013 18.37%
Annual Return 2014 rr_AnnualReturn2014 6.01%
Annual Return 2015 rr_AnnualReturn2015 (0.35%)
Annual Return 2016 rr_AnnualReturn2016 6.73%
Annual Return 2017 rr_AnnualReturn2017 15.07%
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 9.60%
5 Years rr_AverageAnnualReturnYear05 7.90%
10 Years rr_AverageAnnualReturnYear10 4.62%
Calvert Moderate Allocation Fund | Class A | After Taxes on Distributions  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 8.40%
5 Years rr_AverageAnnualReturnYear05 6.26%
10 Years rr_AverageAnnualReturnYear10 3.59%
Calvert Moderate Allocation Fund | Class A | After Taxes on Distributions and Sales  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Class A Shares
1 Year rr_AverageAnnualReturnYear01 6.33%
5 Years rr_AverageAnnualReturnYear05 5.94%
10 Years rr_AverageAnnualReturnYear10 3.45%
Calvert Moderate Allocation 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% [5]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.26%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.52%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.78%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.07%) [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.71%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2019
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 274
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 553
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 958
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,089
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 174
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 553
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 958
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,089
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 13.25%
5 Years rr_AverageAnnualReturnYear05 8.16%
10 Years rr_AverageAnnualReturnYear10 4.34%
Calvert Moderate Allocation 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 none [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.54%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.52%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.06%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.45%) [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.61%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2019
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 62
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 292
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 541
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,253
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 62
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 292
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 541
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,253
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 15.49%
5 Years rr_AverageAnnualReturnYear05 9.09%
10 Years rr_AverageAnnualReturnYear10 5.20%
Inception Date rr_AverageAnnualReturnInceptionDate May 20, 2016
[1] The Moderate Allocation Composite Benchmark is an internally constructed benchmark comprised of a blend of 47% Russell 3000® Index, 15% MSCI EAFE Investable Market Index, 3% MSCI Emerging Markets Index, 30% Bloomberg Barclays U.S. Aggregate Bond Index, and 5% ICE BofAML 3 Month US Treasury Bills-USD Index. On 2/1/18, the cash component was changed from Bloomberg Barclays U.S. 3 Month Treasury Bellwether Index and on 11/1/15, the fixed income component was changed from the Bloomberg Barclays U.S. Credit Index. Prior to 3/3/15, the blend was comprised of: 47% Russell 3000® Index, 18% MSCI EAFE Investable Market Index, 30% Bloomberg Barclays U.S. Credit Index, and 5% Bloomberg Barclays U.S. 3 Month Treasury Bellwether Index.
[2] Purchases of Class A shares of $1,000,000 or more at net asset value in accounts on which a finder's fee has been paid are subject to a one-year contingent deferred sales charge of 0.80%.
[3] Management fees are restated to reflect current contractual fees paid during the previous fiscal year.
[4] Calvert Research and Management ("CRM") has agreed to reimburse the Fund's expenses to the extent that direct annual ordinary expenses exceed 0.44% for Class A shares, 1.19% for Class C shares and 0.09% for Class I shares. This expense reimbursement will continue through January 31, 2019. Any amendment to or termination of this reimbursement would require approval of the Board of Trustees. The expense reimbursement relates to direct annual ordinary operating expenses only and does not include expenses such as: brokerage commissions, acquired fund fees and expenses, 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.
[5] Applies to redemptions of Class C shares within one year of purchase.