v3.22.4
Label Element Value
Prospectus [Line Items] rr_ProspectusLineItems  
SEC Form dei_DocumentType 485BPOS
Period end date dei_DocumentPeriodEndDate Sep. 30, 2022
Registrant Name dei_EntityRegistrantName CALVERT RESPONSIBLE INDEX SERIES INC
Registrant CIK dei_EntityCentralIndexKey 0001105446
Amendment Flag dei_AmendmentFlag false
Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CDHAX
Class I  
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Trading Symbol dei_TradingSymbol CDHIX
Class R6  
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Trading Symbol dei_TradingSymbol CDHRX
Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CSXAX
Class C  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CSXCX
Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CISIX
Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CSXRX
Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CGJAX
Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CGJIX
Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CLGRX
Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CFJAX
Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CFJIX
Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CLVRX
Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CMJAX
Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CMJIX
Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol CMCRX
Calvert International Responsible Index Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return rr_RiskReturnHeading Calvert International Responsible Index Fund
Objective rr_ObjectiveHeading Investment Objective
Objective, Primary rr_ObjectivePrimaryTextBlock

The Fund's investment objective is to seek to track the performance of the Calvert International Responsible Index (the “Index”), which measures the investment return of stocks issued by companies that are located in countries (other than the U.S.) with developed markets.

Expense rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Investors may also pay commissions or other fees to their financial intermediary, 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 19 of the Fund’s Statement of Additional Information.

Shareholder Fees Caption rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 31, 2024
Portfolio Turnover rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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  14%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 14.00%
Expense Breakpoint Discounts 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 19 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example rr_ExpenseExampleHeading Example.
Expense Example Narrative 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, 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 rr_StrategyHeading Principal Investment Strategies
Strategy Narrative rr_StrategyNarrativeTextBlock

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.

Calvert International Responsible Index. The Index is composed of common stocks of large companies in developed markets, excluding the U.S. Large companies in developed markets are selected from the 1,000 large publicly traded companies, excluding real estate investments trusts and business development companies, in markets that CRM determines to be developed markets based on a set of criteria including level of economic development, existence of capital controls, openness to foreign direct investment, market trading and liquidity conditions, regulatory environment, treatment of minority shareholders, and investor expectations.  When determining 1,000 large publicly traded companies, CRM generally includes the 500 largest publicly traded companies located in or tied economically to Europe and the 500 largest publicly traded companies located in or tied economically to other non-U.S. and non-European developed markets.  The Calvert Principles for Responsible Investment (the “Calvert Principles”) serve as a framework for considering environmental, social and governance (“ESG”) factors. Stocks are weighted in the Index based on their float-adjusted market capitalization, by country and by sector, subject to certain prescribed limits. The Index is owned by CRM, which also serves as investment adviser to the Fund.  Jade Huang, Director of Applied Responsible Investment Solutions, and Christopher Madden, CFA, Director of Index Management, manage the Index construction process at CRM.

As of December 31, 2022, the Index included 774 companies, and the market capitalization ranged from approximately $925 million to $378.4 billion with a weighted average market capitalization of approximately $78.7 billion. Market capitalizations of companies within the Index are subject to change.  The number of companies in the Index will change over time due to CRM’s evaluation of an issuer relative to the Calvert Principles or corporate actions involving companies in the Index. The Index is reconstituted annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. To track the Index as closely as possible, the Fund attempts to remain fully invested in stocks. The Fund may enter into foreign currency transactions, including foreign forward currency exchange contracts, in the course of purchasing and selling foreign currency denominated securities in order to track, as closely as possible, the performance of the Index.

The Fund uses a replication method of indexing. The replication method involves holding every security in the Index in approximately the same proportion as the Index. Unlike the Index, however, the Fund is subject to certain regulatory requirements that can limit its ability to fully replicate the Index. For example, the Fund is subject to diversification and concentration limitations that can require the Fund's holdings to materially deviate from the Index.

If Fund assets should ever decline to below $5 million, the Fund may use the sampling method. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Strategy Portfolio Concentration rr_StrategyPortfolioConcentration The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.
Risk rr_RiskHeading Principal Risks
Risk Narrative rr_RiskNarrativeTextBlock

Market Risk.  The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments 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.  Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Tracking Error Risk.  Tracking error risk refers to the risk that the Fund’s performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis.  Factors such as Fund expenses, imperfect correlation between the Fund’s investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, limitations on Fund investments imposed by Fund diversification and/or concentration policies, high portfolio turnover rate and the use of leverage all contribute to tracking error.  Tracking error risk may cause the Fund’s performance to be less than expected.

Passive Investment Risk.  The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance.  The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers.  Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund’s return to be lower than if the Fund employed an active strategy.  Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.  

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; unexpected trading activity among retail investors; or 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 against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject.  Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund's investments.  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.

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.

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 security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), 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 reference 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 reference 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 reference 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 (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment.  A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially.  The Fund could also lose money if the value of the collateral decreases.

 

Liquidity Risk.  The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices.  Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

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 investment 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 investment 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 investment 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 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.  Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s).  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.  The Fund relies on various service providers, including the investment adviser, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to 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 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 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 rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative 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 the Index and a broad-based securities market index. 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 of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016.  Performance reflected prior to such date is that of the Fund’s former investment adviser. 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 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 the Index and a broad-based securities market index.
Performance Availability Website Address rr_PerformanceAvailabilityWebSiteAddress www.calvert.com
Performance Past Does Not Indicate Future rr_PerformancePastDoesNotIndicateFuture Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads 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.
Annual Return Caption rr_AnnualReturnCaption Calendar year-by-year total return
Bar Chart Closing rr_BarChartClosingTextBlock

For the period from December 31, 2015 through December 31, 2022, the highest quarterly total return for Class A was 17.67% for the quarter ended June 30, 2020 and the lowest quarterly return was -21.21% for the quarter ended March 31, 2020.

Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads These returns reflect the maximum sales charge for Class A (4.75%).
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 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 that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or 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 rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod The Class R6 performance shown above for the period prior to February 1, 2019 (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 rr_PerformanceTableClosingTextBlock

These returns reflect the maximum sales charge for Class A (4.75%).Class A and Class I commenced operations on October 30, 2015. The Class R6 performance shown above for the period prior to February 1, 2019 (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. (Source for the MSCI World ex USA Index: MSCI.) MSCI data may not be reproduced or used for any other purpose. MSCI provides no warranties, has not prepared or approved this report, and has no liability hereunder. 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 Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of December 31, 2022
Calvert International Responsible Index Fund | MSCI World ex USA Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects net dividends, which reflects the deduction of withholding taxes)
One Year rr_AverageAnnualReturnYear01 (14.29%)
Five Years rr_AverageAnnualReturnYear05 1.79%
Life of Fund rr_AverageAnnualReturnSinceInception 4.25%
Calvert International Responsible Index Fund | Calvert International Responsible Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (19.43%)
Five Years rr_AverageAnnualReturnYear05 2.42%
Life of Fund rr_AverageAnnualReturnSinceInception 4.68%
Calvert International Responsible Index Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none [1]
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.65%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.11%) [2]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.54%
1 Year rr_ExpenseExampleYear01 $ 528
3 Years rr_ExpenseExampleYear03 663
5 Years rr_ExpenseExampleYear05 810
10 Years rr_ExpenseExampleYear10 $ 1,237
2016 rr_AnnualReturn2016 0.11%
2017 rr_AnnualReturn2017 24.89%
2018 rr_AnnualReturn2018 (13.96%)
2019 rr_AnnualReturn2019 24.10%
2020 rr_AnnualReturn2020 15.03%
2021 rr_AnnualReturn2021 12.27%
2022 rr_AnnualReturn2022 (19.41%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly total return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 17.67%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (21.21%)
One Year rr_AverageAnnualReturnYear01 (23.23%)
Five Years rr_AverageAnnualReturnYear05 1.14%
Life of Fund rr_AverageAnnualReturnSinceInception 3.66%
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 30, 2015
Calvert International Responsible Index Fund | Class A | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (23.32%)
Five Years rr_AverageAnnualReturnYear05 0.94%
Life of Fund rr_AverageAnnualReturnSinceInception 3.40%
Calvert International Responsible Index Fund | Class A | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (13.28%)
Five Years rr_AverageAnnualReturnYear05 1.03%
Life of Fund rr_AverageAnnualReturnSinceInception 3.04%
Calvert International Responsible Index Fund | Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.40%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.11%) [2]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.29%
1 Year rr_ExpenseExampleYear01 $ 30
3 Years rr_ExpenseExampleYear03 117
5 Years rr_ExpenseExampleYear05 213
10 Years rr_ExpenseExampleYear10 $ 494
One Year rr_AverageAnnualReturnYear01 (19.20%)
Five Years rr_AverageAnnualReturnYear05 2.40%
Life of Fund rr_AverageAnnualReturnSinceInception 4.67%
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 30, 2015
Calvert International Responsible Index Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.13%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.37%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.11%) [2]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.26%
1 Year rr_ExpenseExampleYear01 $ 27
3 Years rr_ExpenseExampleYear03 108
5 Years rr_ExpenseExampleYear05 197
10 Years rr_ExpenseExampleYear10 $ 457
One Year rr_AverageAnnualReturnYear01 (19.17%)
Five Years rr_AverageAnnualReturnYear05 2.42%
Life of Fund rr_AverageAnnualReturnSinceInception 4.68%
Inception Date rr_AverageAnnualReturnInceptionDate Feb. 01, 2019
Calvert US Large-Cap Core Responsible Index Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return rr_RiskReturnHeading Calvert US Large-Cap Core Responsible Index Fund
Objective rr_ObjectiveHeading Investment Objective
Objective, Primary rr_ObjectivePrimaryTextBlock

The Fund's investment objective is to seek to track the performance of the Calvert US Large-Cap Core Responsible Index (the “Index”), which measures the investment return of large-capitalization stocks.

Expense rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Investors may also pay commissions or other fees to their financial intermediary, 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 19 of the Fund’s Statement of Additional Information.

Shareholder Fees Caption rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 31, 2024
Portfolio Turnover rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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  13%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 13.00%
Expense Breakpoint Discounts 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 19 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example rr_ExpenseExampleHeading Example.
Expense Example Narrative 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, 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 rr_StrategyHeading Principal Investment Strategies
Strategy Narrative rr_StrategyNarrativeTextBlock

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.

Calvert US Large-Cap Core Responsible Index. The Index is composed of the common stocks of large companies that operate their businesses in a manner consistent with The Calvert Principles for Responsible Investment (the “Calvert Principles”). Large companies are selected from the 1,000 largest publicly traded U.S. companies based on market capitalization, excluding real estate investment trusts and business development companies. The Calvert Principles serve as a framework for considering environmental, social and governance (“ESG”) factors. Stocks are weighted in the Index based on their float-adjusted market capitalization within the relevant sector, subject to certain prescribed limits. The Index is owned by CRM, which also serves as investment adviser to the Fund.  Jade Huang, Director of Applied Responsible Investment Solutions, and Christopher Madden, CFA, Director of Index Management, manage the Index construction process at CRM.

As of December 31, 2022, the Index included 752 companies, and the market capitalization ranged from approximately $502 million to $2.1 trillion with a weighted average market capitalization of $377.9 billion. Market capitalizations of companies within the Index are subject to change.  The number of companies in the Index will change over time due to CRM’s evaluation of an issuer relative to the Calvert Principles or corporate actions involving companies in the Index. The Index is reconstituted annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment performance. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. To track the Index as closely as possible, the Fund attempts to remain fully invested in stocks.

The Fund uses a replication method of indexing. The replication method involves holding every security in the Index in approximately the same proportion as the Index. Unlike the Index, however, the Fund is subject to certain regulatory requirements that can limit its ability to fully replicate the Index. For example, the Fund is subject to diversification and concentration limitations that can require the Fund's holdings to materially deviate from the Index.

If Fund assets should ever decline to below $5 million, the Fund may use the sampling method. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Strategy Portfolio Concentration rr_StrategyPortfolioConcentration The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.
Risk rr_RiskHeading Principal Risks
Risk Narrative rr_RiskNarrativeTextBlock

Market Risk.  The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments 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.  Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Tracking Error Risk.  Tracking error risk refers to the risk that the Fund’s performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis.  Factors such as Fund expenses, imperfect correlation between the Fund’s investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, limitations on Fund investments imposed by Fund diversification and/or concentration policies, high portfolio turnover rate and the use of leverage all contribute to tracking error.  Tracking error risk may cause the Fund’s performance to be less than expected.

Passive Investment Risk.  The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance.  The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers.  Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund’s return to be lower than if the Fund employed an active strategy.  Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.  

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; unexpected trading activity among retail investors; or 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.

Liquidity Risk.  The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices.  Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially.  The Fund could also lose money if the value of the collateral decreases.

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 investment 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 investment 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 investment 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 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.  Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s).  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.  The Fund relies on various service providers, including the investment adviser, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to 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 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 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 rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative 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 the Index and a broad-based securities market index. 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 of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016.  Performance reflected prior to such date is that of the Fund’s former investment adviser.  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 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 the Index and a broad-based securities market index.
Performance Availability Website Address rr_PerformanceAvailabilityWebSiteAddress www.calvert.com
Performance Past Does Not Indicate Future rr_PerformancePastDoesNotIndicateFuture Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads 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.
Annual Return Caption rr_AnnualReturnCaption Calendar year-by-year total return
Bar Chart Closing rr_BarChartClosingTextBlock

For the ten years ended December 31, 2022, the highest quarterly total return for Class A was 22.65% for the quarter ended June 30, 2020 and the lowest quarterly return was -18.32% for the quarter ended March 31, 2020.

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 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 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 that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or 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 rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod The Class R6 performance shown above for the period prior to October 3, 2017 (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 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. Effective November 5, 2020, Class C shares automatically convert to Class A shares eight years after purchase. The average annual total returns listed for Class C reflect conversion to Class A shares after eight years. Prior to November 5, 2020, Class C shares automatically converted to Class A shares ten years after purchase.   The Class R6 performance shown above for the period prior to October 3, 2017 (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. 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 Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of December 31, 2022
Calvert US Large-Cap Core Responsible Index Fund | Russell 1000 Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (19.13%)
Five Years rr_AverageAnnualReturnYear05 9.13%
Ten Years rr_AverageAnnualReturnYear10 12.37%
Calvert US Large-Cap Core Responsible Index Fund | Calvert US Large-Cap Core Responsible Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (21.62%)
Five Years rr_AverageAnnualReturnYear05 9.91%
Ten Years rr_AverageAnnualReturnYear10 13.07%
Calvert US Large-Cap Core Responsible Index Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none [3]
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.10%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.59%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.10%) [4]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.49%
1 Year rr_ExpenseExampleYear01 $ 523
3 Years rr_ExpenseExampleYear03 645
5 Years rr_ExpenseExampleYear05 779
10 Years rr_ExpenseExampleYear10 1,169
1 Year rr_ExpenseExampleNoRedemptionYear01 523
3 Years rr_ExpenseExampleNoRedemptionYear03 645
5 Years rr_ExpenseExampleNoRedemptionYear05 779
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,169
2013 rr_AnnualReturn2013 34.30%
2014 rr_AnnualReturn2014 13.75%
2015 rr_AnnualReturn2015 0.76%
2016 rr_AnnualReturn2016 10.34%
2017 rr_AnnualReturn2017 20.74%
2018 rr_AnnualReturn2018 (4.39%)
2019 rr_AnnualReturn2019 32.43%
2020 rr_AnnualReturn2020 25.81%
2021 rr_AnnualReturn2021 25.31%
2022 rr_AnnualReturn2022 (21.85%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly total return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 22.65%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (18.32%)
One Year rr_AverageAnnualReturnYear01 (25.57%)
Five Years rr_AverageAnnualReturnYear05 8.24%
Ten Years rr_AverageAnnualReturnYear10 11.78%
Calvert US Large-Cap Core Responsible Index Fund | Class A | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (25.70%)
Five Years rr_AverageAnnualReturnYear05 7.93%
Ten Years rr_AverageAnnualReturnYear10 11.13%
Calvert US Large-Cap Core Responsible Index Fund | Class A | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (14.99%)
Five Years rr_AverageAnnualReturnYear05 6.74%
Ten Years rr_AverageAnnualReturnYear10 9.89%
Calvert US Large-Cap Core Responsible Index Fund | Class C  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 0.10%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.34%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.10%) [4]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 1.24%
1 Year rr_ExpenseExampleYear01 $ 226
3 Years rr_ExpenseExampleYear03 415
5 Years rr_ExpenseExampleYear05 725
10 Years rr_ExpenseExampleYear10 1,398
1 Year rr_ExpenseExampleNoRedemptionYear01 126
3 Years rr_ExpenseExampleNoRedemptionYear03 415
5 Years rr_ExpenseExampleNoRedemptionYear05 725
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,398
One Year rr_AverageAnnualReturnYear01 (23.21%)
Five Years rr_AverageAnnualReturnYear05 8.48%
Ten Years rr_AverageAnnualReturnYear10 11.63%
Calvert US Large-Cap Core Responsible Index Fund | Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.10%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.34%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.10%) [4]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.24%
1 Year rr_ExpenseExampleYear01 $ 25
3 Years rr_ExpenseExampleYear03 99
5 Years rr_ExpenseExampleYear05 181
10 Years rr_ExpenseExampleYear10 421
1 Year rr_ExpenseExampleNoRedemptionYear01 25
3 Years rr_ExpenseExampleNoRedemptionYear03 99
5 Years rr_ExpenseExampleNoRedemptionYear05 181
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 421
One Year rr_AverageAnnualReturnYear01 (21.66%)
Five Years rr_AverageAnnualReturnYear05 9.59%
Ten Years rr_AverageAnnualReturnYear10 12.72%
Calvert US Large-Cap Core Responsible Index Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.05%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.29%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.10%) [4]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.19%
1 Year rr_ExpenseExampleYear01 $ 19
3 Years rr_ExpenseExampleYear03 83
5 Years rr_ExpenseExampleYear05 153
10 Years rr_ExpenseExampleYear10 358
1 Year rr_ExpenseExampleNoRedemptionYear01 19
3 Years rr_ExpenseExampleNoRedemptionYear03 83
5 Years rr_ExpenseExampleNoRedemptionYear05 153
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 358
One Year rr_AverageAnnualReturnYear01 (21.61%)
Five Years rr_AverageAnnualReturnYear05 9.64%
Ten Years rr_AverageAnnualReturnYear10 12.74%
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 03, 2017
Calvert US Large-Cap Growth Responsible Index Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return rr_RiskReturnHeading Calvert US Large-Cap Growth Responsible Index Fund
Objective rr_ObjectiveHeading Investment Objective
Objective, Primary rr_ObjectivePrimaryTextBlock

The Fund's investment objective is to seek to track the performance of the Calvert US Large-Cap Growth Responsible Index (the “Index”), which measures the investment return of large-capitalization stocks.

Expense rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Investors may also pay commissions or other fees to their financial intermediary, 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 19 of the Fund’s Statement of Additional Information.

Shareholder Fees Caption rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 31, 2024
Portfolio Turnover rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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  19%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 19.00%
Expense Breakpoint Discounts 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 19 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example rr_ExpenseExampleHeading Example.
Expense Example Narrative 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, 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 rr_StrategyHeading Principal Investment Strategies
Strategy Narrative rr_StrategyNarrativeTextBlock

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.

Calvert US Large-Cap Growth Responsible Index. The Index is composed of the common stocks of large growth companies that operate their businesses in a manner consistent with The Calvert Principles for Responsible Investment (the “Calvert Principles”). Large growth companies are selected from the 1,000 largest publicly traded U.S. companies based on market capitalization and growth style factors, excluding real estate investment trusts and business development companies. The Calvert Principles serve as a framework for considering environmental, social and governance (“ESG”) factors. Stocks are weighted in the Index based on their float-adjusted market capitalization within the relevant sector, subject to certain prescribed limits. The Index is owned by CRM, which also serves as investment adviser to the Fund.  Jade Huang, Director of Applied Responsible Investment Solutions, and Christopher Madden, CFA, Director of Index Management, manage the Index construction process at CRM.

As of December 31, 2022, the Index included 544 companies, and the market capitalization ranged from approximately $502 million to $2.1 trillion with a weighted average market capitalization of $535.8 billion. Market capitalizations of companies within the Index are subject to change.  The number of companies in the Index will change over time due to CRM’s evaluation of an issuer relative to the Calvert Principles or corporate actions involving companies in the Index. The Index is reconstituted annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment performance. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. To track the Index as closely as possible, the Fund attempts to remain fully invested in stocks.

The Fund uses a replication method of indexing. The replication method involves holding every security in the Index in approximately the same proportion as the Index. Unlike the Index, however, the Fund is subject to certain regulatory requirements that can limit its ability to fully replicate the Index. For example, the Fund is subject to diversification and concentration limitations that can require the Fund's holdings to materially deviate from the Index.

If Fund assets should ever decline to below $5 million, the Fund may use the sampling method. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Growth Investing. Growth funds generally focus on stocks of companies believed to have above-average potential for growth in revenue, earnings, cash flow or other similar criteria. These stocks typically have low dividend yields and above-average prices in relation to measures such as earnings and book value.

Strategy Portfolio Concentration rr_StrategyPortfolioConcentration The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.
Risk rr_RiskHeading Principal Risks
Risk Narrative rr_RiskNarrativeTextBlock

Market Risk.  The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments 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.  Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

 

Tracking Error Risk.  Tracking error risk refers to the risk that the Fund’s performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis.  Factors such as Fund expenses, imperfect correlation between the Fund’s investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, limitations on Fund investments imposed by Fund diversification and/or concentration policies, high portfolio turnover rate and the use of leverage all contribute to tracking error.  Tracking error risk may cause the Fund’s performance to be less than expected.

Passive Investment Risk.  The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance.  The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers.  Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund’s return to be lower than if the Fund employed an active strategy.  Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.  

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; unexpected trading activity among retail investors; or 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.

Large-Cap Growth Risk. Because the Fund normally invests primarily in stocks of large-cap growth companies, it is subject to the risk of underperforming the overall stock market during periods in which stocks of such companies are out of favor and generate lower returns than the market as a whole.

Liquidity Risk.  The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices.  Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially.  The Fund could also lose money if the value of the collateral decreases.

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 investment 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 investment 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 investment 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 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.  Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s).  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.  The Fund relies on various service providers, including the investment adviser, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to 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 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 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 rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative 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 the Index and a broad-based securities market index. 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 of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016.  Performance reflected prior to such date is that of the Fund’s former investment adviser. 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 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 the Index and a broad-based securities market index.
Performance Availability Website Address rr_PerformanceAvailabilityWebSiteAddress www.calvert.com
Performance Past Does Not Indicate Future rr_PerformancePastDoesNotIndicateFuture Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads 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.
Annual Return Caption rr_AnnualReturnCaption Calendar year-by-year total return
Bar Chart Closing rr_BarChartClosingTextBlock

For the period from December 31, 2015 through December 31, 2022, the highest quarterly total return for Class A was 27.02% for the quarter ended June 30, 2020 and the lowest quarterly return was -19.70% for the quarter ended June 30, 2022.

Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads These returns reflect the maximum sales charge for Class A (4.75%).
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 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 that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or 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 rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod The Class R6 performance shown for the period prior to February 1, 2022 (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 rr_PerformanceTableClosingTextBlock

These returns reflect the maximum sales charge for Class A (4.75%). Class A and Class I commenced operations on June 19, 2015. The Class R6 performance shown for the period prior to February 1, 2022 (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.  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 Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of December 31, 2022
Calvert US Large-Cap Growth Responsible Index Fund | Russell 1000 Growth Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (29.14%)
Five Years rr_AverageAnnualReturnYear05 10.95%
Life of Fund rr_AverageAnnualReturnSinceInception 11.88%
Calvert US Large-Cap Growth Responsible Index Fund | Calvert US Large-Cap Growth Responsible Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (26.78%)
Five Years rr_AverageAnnualReturnYear05 12.09%
Life of Fund rr_AverageAnnualReturnSinceInception 11.99%
Calvert US Large-Cap Growth Responsible Index Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none [5]
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.65%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.16%) [6]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.49%
1 Year rr_ExpenseExampleYear01 $ 523
3 Years rr_ExpenseExampleYear03 658
5 Years rr_ExpenseExampleYear05 805
10 Years rr_ExpenseExampleYear10 $ 1,232
2016 rr_AnnualReturn2016 4.03%
2017 rr_AnnualReturn2017 26.99%
2018 rr_AnnualReturn2018 35.02%
2019 rr_AnnualReturn2019 35.02%
2020 rr_AnnualReturn2020 38.28%
2021 rr_AnnualReturn2021 25.79%
2022 rr_AnnualReturn2022 (27.02%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly total return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 27.02%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2022
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (19.70%)
One Year rr_AverageAnnualReturnYear01 (30.48%)
Five Years rr_AverageAnnualReturnYear05 10.37%
Life of Fund rr_AverageAnnualReturnSinceInception 10.64%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 19, 2015
Calvert US Large-Cap Growth Responsible Index Fund | Class A | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (30.52%)
Five Years rr_AverageAnnualReturnYear05 9.87%
Life of Fund rr_AverageAnnualReturnSinceInception 10.18%
Calvert US Large-Cap Growth Responsible Index Fund | Class A | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (18.00%)
Five Years rr_AverageAnnualReturnYear05 8.48%
Life of Fund rr_AverageAnnualReturnSinceInception 8.84%
Calvert US Large-Cap Growth Responsible Index Fund | Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.16%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.40%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.16%) [6]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.24%
1 Year rr_ExpenseExampleYear01 $ 25
3 Years rr_ExpenseExampleYear03 112
5 Years rr_ExpenseExampleYear05 208
10 Years rr_ExpenseExampleYear10 $ 490
One Year rr_AverageAnnualReturnYear01 (26.83%)
Five Years rr_AverageAnnualReturnYear05 11.77%
Life of Fund rr_AverageAnnualReturnSinceInception 11.69%
Calvert US Large-Cap Growth Responsible Index Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.13%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.37%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.16%) [6]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.21%
1 Year rr_ExpenseExampleYear01 $ 22
3 Years rr_ExpenseExampleYear03 103
5 Years rr_ExpenseExampleYear05 192
10 Years rr_ExpenseExampleYear10 $ 452
One Year rr_AverageAnnualReturnYear01 (26.82%)
Five Years rr_AverageAnnualReturnYear05 11.77%
Life of Fund rr_AverageAnnualReturnSinceInception 11.69%
Inception Date rr_AverageAnnualReturnInceptionDate Feb. 01, 2022
Calvert US Large-Cap Value Responsible Index Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return rr_RiskReturnHeading Calvert US Large-Cap Value Responsible Index Fund
Objective rr_ObjectiveHeading Investment Objective
Objective, Primary rr_ObjectivePrimaryTextBlock

The Fund's investment objective is to seek to track the performance of the Calvert US Large-Cap Value Responsible Index (the “Index”), which measures the investment return of large-capitalization stocks.

Expense rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Investors may also pay commissions or other fees to their financial intermediary, 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 19 of the Fund’s Statement of Additional Information.

Shareholder Fees Caption rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 31, 2024
Portfolio Turnover rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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  34%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 34.00%
Expense Breakpoint Discounts 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 19 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example rr_ExpenseExampleHeading Example.
Expense Example Narrative 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, 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 rr_StrategyHeading Principal Investment Strategies
Strategy Narrative rr_StrategyNarrativeTextBlock

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.

Calvert US Large-Cap Value Responsible Index. The Index is composed of the common stocks of large value companies that operate their businesses in a manner consistent with The Calvert Principles for Responsible Investment (the “Calvert Principles”). Large value companies are selected from the 1,000 largest publicly traded U.S. companies based on market capitalization and value style factors, excluding real estate investment trusts and business development companies. The Calvert Principles serve as a framework for considering environmental, social and governance (“ESG”) factors. Stocks are weighted in the Index based on their float-adjusted market capitalization within the relevant sector, subject to certain prescribed limits. The Index is owned by CRM, which also serves as investment adviser to the Fund.  Jade Huang, Director of Applied Responsible Investment Solutions, and Christopher Madden, CFA, Director of Index Management, manage the Index construction process at CRM.

As of December 31, 2022, the Index included 509 companies, and the market capitalization ranged from approximately $653 million to $393.3 billion with a weighted average market capitalization of $89.6 billion. Market capitalizations of companies within the Index are subject to change.  The number of companies in the Index will change over time due to CRM’s evaluation of an issuer relative to the Calvert Principles or corporate actions involving companies in the Index. The Index is reconstituted annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment performance. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. To track the Index as closely as possible, the Fund attempts to remain fully invested in stocks.

The Fund uses a replication method of indexing. The replication method involves holding every security in the Index in approximately the same proportion as the Index. Unlike the Index, however, the Fund is subject to certain regulatory requirements that can limit its ability to fully replicate the Index. For example, the Fund is subject to diversification and concentration limitations that can require the Fund's holdings to materially deviate from the Index.

If Fund assets should ever decline to below $5 million, the Fund may use the sampling method. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Value Investing. Value companies tend to have stock prices that are low relative to their earnings, dividends, assets or other financial measures. They may include companies that are temporarily out of favor with the market or that may have experienced adverse business developments but that have the potential for growth.

Strategy Portfolio Concentration rr_StrategyPortfolioConcentration The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.
Risk rr_RiskHeading Principal Risks
Risk Narrative rr_RiskNarrativeTextBlock

Market Risk.  The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments 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.  Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Tracking Error Risk.  Tracking error risk refers to the risk that the Fund’s performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis.  Factors such as Fund expenses, imperfect correlation between the Fund’s investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, limitations on Fund investments imposed by Fund diversification and/or concentration policies, high portfolio turnover rate and the use of leverage all contribute to tracking error.  Tracking error risk may cause the Fund’s performance to be less than expected.

Passive Investment Risk.  The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance.  The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers.  Maintaining investments regardless of market conditions

or the performance of individual investments could cause the Fund’s return to be lower than if the Fund employed an active strategy.  Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.  

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; unexpected trading activity among retail investors; or 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.

Large-Cap Value Risk. Because the Fund normally invests primarily in stocks of large-cap value companies, it is subject to the risk of underperforming the overall stock market during periods in which stocks of such companies are out of favor and generate lower returns than the market as a whole.

Liquidity Risk.  The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices.  Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially.  The Fund could also lose money if the value of the collateral decreases.

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 investment 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 investment 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 investment 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 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.  Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s).  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.  The Fund relies on various service providers, including the investment adviser, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to 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 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 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 rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative 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 the Index and a broad-based securities market index. 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 of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016.  Performance reflected prior to such date is that of the Fund’s former investment adviser. 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 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 the Index and a broad-based securities market index.
Performance Availability Website Address rr_PerformanceAvailabilityWebSiteAddress www.calvert.com
Performance Past Does Not Indicate Future rr_PerformancePastDoesNotIndicateFuture Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads 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.
Annual Return Caption rr_AnnualReturnCaption Calendar year-by-year total return
Bar Chart Closing rr_BarChartClosingTextBlock

For the period from December 31, 2015 through December 31, 2022, the highest quarterly total return for Class A was 17.50% for the quarter ended December 31, 2020 and the lowest quarterly return was -26.04% for the quarter ended March 31, 2020.

Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads These returns reflect the maximum sales charge for Class A (4.75%).
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 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 that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or 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 rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod The Class R6 performance shown above for the period prior to February 1, 2022 (commencement of operations) is the performance for 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 rr_PerformanceTableClosingTextBlock

These returns reflect the maximum sales charge for Class A (4.75%). Class A and Class I commenced operations on June 19, 2015. The Class R6 performance shown above for the period prior to February 1, 2022 (commencement of operations) is the performance for 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.  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 Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of December 31, 2022
Calvert US Large-Cap Value Responsible Index Fund | Russell 1000 Value Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (7.54%)
Five Years rr_AverageAnnualReturnYear05 6.66%
Life of Fund rr_AverageAnnualReturnSinceInception 7.64%
Calvert US Large-Cap Value Responsible Index Fund | Calvert US Large-Cap Value Responsible Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (11.46%)
Five Years rr_AverageAnnualReturnYear05 7.04%
Life of Fund rr_AverageAnnualReturnSinceInception 8.01%
Calvert US Large-Cap Value Responsible Index Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none [7]
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.12%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.61%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.12%) [8]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.49%
1 Year rr_ExpenseExampleYear01 $ 523
3 Years rr_ExpenseExampleYear03 650
5 Years rr_ExpenseExampleYear05 788
10 Years rr_ExpenseExampleYear10 $ 1,190
2016 rr_AnnualReturn2016 16.78%
2017 rr_AnnualReturn2017 14.71%
2018 rr_AnnualReturn2018 (10.36%)
2019 rr_AnnualReturn2019 29.06%
2020 rr_AnnualReturn2020 8.76%
2021 rr_AnnualReturn2021 24.04%
2022 rr_AnnualReturn2022 (11.87%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly total return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 17.50%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (26.04%)
One Year rr_AverageAnnualReturnYear01 (16.06%)
Five Years rr_AverageAnnualReturnYear05 5.55%
Life of Fund rr_AverageAnnualReturnSinceInception 6.72%
Inception Date rr_AverageAnnualReturnInceptionDate Jun. 19, 2015
Calvert US Large-Cap Value Responsible Index Fund | Class A | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (16.36%)
Five Years rr_AverageAnnualReturnYear05 4.87%
Life of Fund rr_AverageAnnualReturnSinceInception 5.93%
Calvert US Large-Cap Value Responsible Index Fund | Class A | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (9.19%)
Five Years rr_AverageAnnualReturnYear05 4.37%
Life of Fund rr_AverageAnnualReturnSinceInception 5.32%
Calvert US Large-Cap Value Responsible Index Fund | Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.12%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.36%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.12%) [8]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.24%
1 Year rr_ExpenseExampleYear01 $ 25
3 Years rr_ExpenseExampleYear03 104
5 Years rr_ExpenseExampleYear05 190
10 Years rr_ExpenseExampleYear10 $ 444
One Year rr_AverageAnnualReturnYear01 (11.66%)
Five Years rr_AverageAnnualReturnYear05 6.86%
Life of Fund rr_AverageAnnualReturnSinceInception 7.73%
Calvert US Large-Cap Value Responsible Index Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.07%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.31%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.12%) [8]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.19%
1 Year rr_ExpenseExampleYear01 $ 19
3 Years rr_ExpenseExampleYear03 88
5 Years rr_ExpenseExampleYear05 162
10 Years rr_ExpenseExampleYear10 $ 381
One Year rr_AverageAnnualReturnYear01 (11.63%)
Five Years rr_AverageAnnualReturnYear05 6.87%
Life of Fund rr_AverageAnnualReturnSinceInception 7.73%
Inception Date rr_AverageAnnualReturnInceptionDate Feb. 01, 2022
Calvert US Mid-Cap Core Responsible Index Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return rr_RiskReturnHeading Calvert US Mid-Cap Core Responsible Index Fund
Objective rr_ObjectiveHeading Investment Objective
Objective, Primary rr_ObjectivePrimaryTextBlock

The Fund's investment objective is to seek to track the performance of the Calvert US Mid-Cap Core Responsible Index (the “Index”), which measures the investment return of mid-capitalization stocks.

Expense rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Investors may also pay commissions or other fees to their financial intermediary, 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 19 of the Fund’s Statement of Additional Information.

Shareholder Fees Caption rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 31, 2024
Portfolio Turnover rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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  26%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 26.00%
Expense Breakpoint Discounts 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 19 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
Expense Example rr_ExpenseExampleHeading Example.
Expense Example Narrative 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, 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 rr_StrategyHeading Principal Investment Strategies
Strategy Narrative rr_StrategyNarrativeTextBlock

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.

Calvert US Mid-Cap Core Responsible Index. The Index is composed of the common stocks of mid-size companies that operate their businesses in a manner consistent with The Calvert Principles for Responsible Investment (the “Calvert Principles”). Mid-size companies are selected from the 1,000 largest publicly traded U.S. companies based on market capitalization, excluding real estate investment trusts, business development companies and approximately the 200 largest publicly traded U.S. companies. The Calvert Principles serve as a framework for considering environmental, social and governance (“ESG”) factors. Stocks are weighted in the Index based on their float-adjusted market capitalization within the relevant sector, subject to certain prescribed limits. The Index is owned by CRM, which also serves as investment adviser to the Fund.  Jade Huang, Director of Applied Responsible Investment Solutions, and Christopher Madden, CFA, Director of Index Management, manage the Index construction process at CRM.

As of December 31, 2022, the Index included 603 companies, and the market capitalization ranged from approximately $502 million to $44.9 billion with a weighted average market capitalization of $18.6 billion. Market capitalizations of companies within the Index are subject to change.  The number of companies in the Index will change over time due to CRM’s evaluation of an issuer relative to the Calvert Principles or corporate actions involving companies in the Index. The Index is reconstituted annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment performance. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. To track the Index as closely as possible, the Fund attempts to remain fully invested in stocks.

The Fund uses a replication method of indexing. The replication method involves holding every security in the Index in approximately the same proportion as the Index. Unlike the Index, however, the Fund is subject to certain regulatory requirements that can limit its ability to fully replicate the Index. For example, the Fund is subject to diversification and concentration limitations that can require the Fund's holdings to materially deviate from the Index.

If Fund assets should ever decline to below $5 million, the Fund may use the sampling method. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Strategy Portfolio Concentration rr_StrategyPortfolioConcentration The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund invests in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index (the “95% Policy”). The Fund may also lend its securities.
Risk rr_RiskHeading Principal Risks
Risk Narrative rr_RiskNarrativeTextBlock

Market Risk.  The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments 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.  Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Tracking Error Risk.  Tracking error risk refers to the risk that the Fund’s performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis.  Factors such as Fund expenses, imperfect correlation between the Fund’s investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, limitations on Fund investments imposed by Fund diversification and/or concentration policies, high portfolio turnover rate and the use of leverage all contribute to tracking error.  Tracking error risk may cause the Fund’s performance to be less than expected.

Passive Investment Risk.  The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance.  The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers.  Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund’s return to be lower than if the Fund employed an active strategy.  Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.  

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; unexpected trading activity among retail investors; or 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.

Mid-Sized Company Risk.  The stocks of mid-sized companies are generally subject to greater price fluctuations, limited liquidity, higher transaction costs and higher investment risk than the stocks of larger, more established companies. Such companies may have limited product lines, markets or financial resources, may be dependent on a limited management group, and may lack substantial capital reserves or an established performance record. There may be generally less publicly available information about such companies than for larger, more established companies.  Stocks of these companies frequently have lower trading volumes making them more volatile and potentially less liquid and more difficult to value.

Liquidity Risk.  The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices.  Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially.  The Fund could also lose money if the value of the collateral decreases.

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 investment 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 investment 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 investment 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 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.  Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s).  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.  The Fund relies on various service providers, including the investment adviser, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to 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 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 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 rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative 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 the Index and a broad-based securities market index. 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 of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016.  Performance reflected prior to such date is that of the Fund’s former investment adviser. 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 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 the Index and a broad-based securities market index.
Performance Availability Website Address rr_PerformanceAvailabilityWebSiteAddress www.calvert.com
Performance Past Does Not Indicate Future rr_PerformancePastDoesNotIndicateFuture Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart Does Not Reflect Sales Loads 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.
Annual Return Caption rr_AnnualReturnCaption Calendar year-by-year total return
Bar Chart Closing rr_BarChartClosingTextBlock

For the period from December 31, 2015 through December 31, 2022, the highest quarterly total return for Class A was 25.75% for the quarter ended June 30, 2020 and the lowest quarterly return was -25.02% for the quarter ended March 31, 2020 .

Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads These returns reflect the maximum sales charge for Class A (4.75%).
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 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 that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or 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 rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod The Class R6 performance shown above for the period prior to February 1, 2022 (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 rr_PerformanceTableClosingTextBlock

These returns reflect the maximum sales charge for Class A (4.75%). Class A and Class I commenced operations on October 30, 2015. The Class R6 performance shown above for the period prior to February 1, 2022 (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.  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 Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Average Annual Return, Caption rr_AverageAnnualReturnCaption Average Annual Total Returns as of December 31, 2022
Calvert US Mid-Cap Core Responsible Index Fund | Russell Midcap Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (17.32%)
Five Years rr_AverageAnnualReturnYear05 7.10%
Life of Fund rr_AverageAnnualReturnSinceInception 8.99%
Calvert US Mid-Cap Core Responsible Index Fund | Calvert US Mid-Cap Core Responsible Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
One Year rr_AverageAnnualReturnYear01 (19.08%)
Five Years rr_AverageAnnualReturnYear05 7.90%
Life of Fund rr_AverageAnnualReturnSinceInception 9.87%
Calvert US Mid-Cap Core Responsible Index Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none [9]
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 0.17%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.66%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.17%) [10]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.49%
1 Year rr_ExpenseExampleYear01 $ 523
3 Years rr_ExpenseExampleYear03 660
5 Years rr_ExpenseExampleYear05 809
10 Years rr_ExpenseExampleYear10 $ 1,243
2016 rr_AnnualReturn2016 14.72%
2017 rr_AnnualReturn2017 18.71%
2018 rr_AnnualReturn2018 (9.49%)
2019 rr_AnnualReturn2019 30.69%
2020 rr_AnnualReturn2020 23.68%
2021 rr_AnnualReturn2021 20.92%
2022 rr_AnnualReturn2022 (19.30%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel highest quarterly total return
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 25.75%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel lowest quarterly return
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (25.02%)
One Year rr_AverageAnnualReturnYear01 (23.13%)
Five Years rr_AverageAnnualReturnYear05 6.33%
Life of Fund rr_AverageAnnualReturnSinceInception 8.51%
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 30, 2015
Calvert US Mid-Cap Core Responsible Index Fund | Class A | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (23.25%)
Five Years rr_AverageAnnualReturnYear05 5.83%
Life of Fund rr_AverageAnnualReturnSinceInception 7.92%
Calvert US Mid-Cap Core Responsible Index Fund | Class A | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
One Year rr_AverageAnnualReturnYear01 (13.57%)
Five Years rr_AverageAnnualReturnYear05 5.08%
Life of Fund rr_AverageAnnualReturnSinceInception 6.91%
Calvert US Mid-Cap Core Responsible Index Fund | Class I  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.17%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.41%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.17%) [10]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.24%
1 Year rr_ExpenseExampleYear01 $ 25
3 Years rr_ExpenseExampleYear03 114
5 Years rr_ExpenseExampleYear05 213
10 Years rr_ExpenseExampleYear10 $ 501
One Year rr_AverageAnnualReturnYear01 (19.07%)
Five Years rr_AverageAnnualReturnYear05 7.67%
Life of Fund rr_AverageAnnualReturnSinceInception 9.58%
Calvert US Mid-Cap Core Responsible Index Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Maximum Sales Charge (load) Imposed on Purchases (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_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees rr_ManagementFeesOverAssets 0.24%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.13%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.37%
Less Fee Waiver and/or Expense Reimbursement (1) rr_FeeWaiverOrReimbursementOverAssets (0.17%) [10]
Total Annual Fund Operating Expenses after Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.20%
1 Year rr_ExpenseExampleYear01 $ 20
3 Years rr_ExpenseExampleYear03 102
5 Years rr_ExpenseExampleYear05 191
10 Years rr_ExpenseExampleYear10 $ 451
One Year rr_AverageAnnualReturnYear01 (19.06%)
Five Years rr_AverageAnnualReturnYear05 7.68%
Life of Fund rr_AverageAnnualReturnSinceInception 9.58%
Inception Date rr_AverageAnnualReturnInceptionDate Feb. 01, 2022
[1] Class A shares purchased at net asset value in amounts of $1 million or more are subject to a 0.25% contingent deferred sales charge if redeemed within 12 months of purchase.
[2] Calvert Research and Management (“CRM”) has agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.54% for Class A shares, 0.29% for Class I shares and 0.26% for Class R6 shares. This expense reimbursement will continue through January 31, 2024. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year.
[3] Class A shares purchased at net asset value in amounts of $1 million or more are subject to a 0.25% contingent deferred sales charge if redeemed within 12 months of purchase.
[4] Calvert Research and Management (“CRM”) has agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.49% for Class A shares, 1.24% for Class C shares, 0.24% for Class I shares and 0.19% for Class R6 shares. This expense reimbursement will continue through January 31, 2024. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year.
[5] Class A shares purchased at net asset value in amounts of $1 million or more are subject to a 0.25% contingent deferred sales charge if redeemed within 12 months of purchase.
[6] Calvert Research and Management (“CRM”) has agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.49% for Class A shares, 0.24% for Class I shares and 0.21% for Class R6 shares. This expense reimbursement will continue through January 31, 2024. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year.
[7] Class A shares purchased at net asset value in amounts of $1 million or more are subject to a 0.25% contingent deferred sales charge if redeemed within 12 months of purchase.
[8] Calvert Research and Management (“CRM”) has agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.49% for Class A shares, 0.24% for Class I shares and 0.19% for Class R6 shares. This expense reimbursement will continue through January 31, 2024. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year.
[9] Class A shares purchased at net asset value in amounts of $1 million or more are subject to a 0.25% contingent deferred sales charge if redeemed within 12 months of purchase.
[10] Calvert Research and Management (“CRM”) has agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.49% for Class A shares, 0.24% for Class I shares and 0.20% for Class R6 shares. This expense reimbursement will continue through January 31, 2024. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year.