v3.26.1
Shareholder Report
 6 Months Ended
Mar. 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Calvert Responsible Index Series, Inc.
Entity Central Index Key 0001105446
Entity Investment Company Type N-1A
Document Period End Date Mar. 31, 2026
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
C000161548  
Shareholder Report [Line Items]  
Fund Name Calvert International Responsible Index Fund
Class Name Class A
Trading Symbol CDHAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert International Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$28
0.54%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 28
Expense Ratio, Percent 0.54% [1]
AssetsNet $ 1,329,408,199
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,329,408,199
# of Portfolio Holdings
818
Portfolio Turnover Rate
8%
Holdings [Text Block]

Country Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Other
17.0%
Netherlands
4.7%
Australia
5.0%
South Korea
5.5%
Germany
6.8%
France
7.2%
Taiwan
7.6%
Switzerland
8.4%
Canada
10.4%
United Kingdom
11.2%
Japan
16.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.
5.1%
Samsung Electronics Co. Ltd.
2.3%
ASML Holding NV
1.9%
AstraZeneca PLC
1.2%
SK Hynix, Inc.
1.2%
Roche Holding AG
1.2%
Novartis AG
1.1%
Nestle SA
1.1%
HSBC Holdings PLC
1.0%
Royal Bank of Canada
0.9%
Total
17.0%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000161551  
Shareholder Report [Line Items]  
Fund Name Calvert International Responsible Index Fund
Class Name Class I
Trading Symbol CDHIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert International Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class I
$15
0.29%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 15
Expense Ratio, Percent 0.29% [2]
AssetsNet $ 1,329,408,199
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,329,408,199
# of Portfolio Holdings
818
Portfolio Turnover Rate
8%
Holdings [Text Block]

Country Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Other
17.0%
Netherlands
4.7%
Australia
5.0%
South Korea
5.5%
Germany
6.8%
France
7.2%
Taiwan
7.6%
Switzerland
8.4%
Canada
10.4%
United Kingdom
11.2%
Japan
16.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.
5.1%
Samsung Electronics Co. Ltd.
2.3%
ASML Holding NV
1.9%
AstraZeneca PLC
1.2%
SK Hynix, Inc.
1.2%
Roche Holding AG
1.2%
Novartis AG
1.1%
Nestle SA
1.1%
HSBC Holdings PLC
1.0%
Royal Bank of Canada
0.9%
Total
17.0%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000211122  
Shareholder Report [Line Items]  
Fund Name Calvert International Responsible Index Fund
Class Name Class R6
Trading Symbol CDHRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert International Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$13
0.26%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 13
Expense Ratio, Percent 0.26% [3]
AssetsNet $ 1,329,408,199
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,329,408,199
# of Portfolio Holdings
818
Portfolio Turnover Rate
8%
Holdings [Text Block]

Country Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Other
17.0%
Netherlands
4.7%
Australia
5.0%
South Korea
5.5%
Germany
6.8%
France
7.2%
Taiwan
7.6%
Switzerland
8.4%
Canada
10.4%
United Kingdom
11.2%
Japan
16.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.
5.1%
Samsung Electronics Co. Ltd.
2.3%
ASML Holding NV
1.9%
AstraZeneca PLC
1.2%
SK Hynix, Inc.
1.2%
Roche Holding AG
1.2%
Novartis AG
1.1%
Nestle SA
1.1%
HSBC Holdings PLC
1.0%
Royal Bank of Canada
0.9%
Total
17.0%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000014080  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Core Responsible Index Fund
Class Name Class A
Trading Symbol CSXAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$24
0.49%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.49% [4]
AssetsNet $ 5,553,962,380
Holdings Count | Holding 787
InvestmentCompanyPortfolioTurnover 2.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$5,553,962,380
# of Portfolio Holdings
787
Portfolio Turnover Rate
2%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.5%
Utilities
2.0%
Materials
2.5%
Real Estate
3.0%
Consumer Staples
5.5%
Communication Services
8.5%
Consumer Discretionary
8.7%
Health Care
10.3%
Industrials
11.6%
Financials
13.8%
Information Technology
33.5%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
7.0%
Apple, Inc.
6.4%
Alphabet, Inc., Class A
5.4%
Microsoft Corp.
4.7%
Amazon.com, Inc.
3.5%
Broadcom, Inc.
2.6%
JPMorgan Chase & Co.
1.5%
Eli Lilly & Co.
1.4%
Walmart, Inc.
1.0%
Visa, Inc., Class A
1.0%
Total
34.5%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000014082  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Core Responsible Index Fund
Class Name Class C
Trading Symbol CSXCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class C
$61
1.24%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.24% [5]
AssetsNet $ 5,553,962,380
Holdings Count | Holding 787
InvestmentCompanyPortfolioTurnover 2.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$5,553,962,380
# of Portfolio Holdings
787
Portfolio Turnover Rate
2%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.5%
Utilities
2.0%
Materials
2.5%
Real Estate
3.0%
Consumer Staples
5.5%
Communication Services
8.5%
Consumer Discretionary
8.7%
Health Care
10.3%
Industrials
11.6%
Financials
13.8%
Information Technology
33.5%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
7.0%
Apple, Inc.
6.4%
Alphabet, Inc., Class A
5.4%
Microsoft Corp.
4.7%
Amazon.com, Inc.
3.5%
Broadcom, Inc.
2.6%
JPMorgan Chase & Co.
1.5%
Eli Lilly & Co.
1.4%
Walmart, Inc.
1.0%
Visa, Inc., Class A
1.0%
Total
34.5%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000014083  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Core Responsible Index Fund
Class Name Class I
Trading Symbol CISIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class I
$12
0.24%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [6]
AssetsNet $ 5,553,962,380
Holdings Count | Holding 787
InvestmentCompanyPortfolioTurnover 2.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$5,553,962,380
# of Portfolio Holdings
787
Portfolio Turnover Rate
2%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.5%
Utilities
2.0%
Materials
2.5%
Real Estate
3.0%
Consumer Staples
5.5%
Communication Services
8.5%
Consumer Discretionary
8.7%
Health Care
10.3%
Industrials
11.6%
Financials
13.8%
Information Technology
33.5%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
7.0%
Apple, Inc.
6.4%
Alphabet, Inc., Class A
5.4%
Microsoft Corp.
4.7%
Amazon.com, Inc.
3.5%
Broadcom, Inc.
2.6%
JPMorgan Chase & Co.
1.5%
Eli Lilly & Co.
1.4%
Walmart, Inc.
1.0%
Visa, Inc., Class A
1.0%
Total
34.5%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000195939  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Core Responsible Index Fund
Class Name Class R6
Trading Symbol CSXRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$9
0.19%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 9
Expense Ratio, Percent 0.19% [7]
AssetsNet $ 5,553,962,380
Holdings Count | Holding 787
InvestmentCompanyPortfolioTurnover 2.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$5,553,962,380
# of Portfolio Holdings
787
Portfolio Turnover Rate
2%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.5%
Utilities
2.0%
Materials
2.5%
Real Estate
3.0%
Consumer Staples
5.5%
Communication Services
8.5%
Consumer Discretionary
8.7%
Health Care
10.3%
Industrials
11.6%
Financials
13.8%
Information Technology
33.5%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
7.0%
Apple, Inc.
6.4%
Alphabet, Inc., Class A
5.4%
Microsoft Corp.
4.7%
Amazon.com, Inc.
3.5%
Broadcom, Inc.
2.6%
JPMorgan Chase & Co.
1.5%
Eli Lilly & Co.
1.4%
Walmart, Inc.
1.0%
Visa, Inc., Class A
1.0%
Total
34.5%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000154981  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Growth Responsible Index Fund
Class Name Class A
Trading Symbol CGJAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Growth Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$24
0.49%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.49% [8]
AssetsNet $ 908,494,612
Holdings Count | Holding 563
InvestmentCompanyPortfolioTurnover 7.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$908,494,612
# of Portfolio Holdings
563
Portfolio Turnover Rate
7%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Energy
0.1%
Short-Term Investments
0.3%
Utilities
0.7%
Real Estate
2.0%
Materials
2.2%
Consumer Staples
5.1%
Communication Services
6.8%
Financials
8.2%
Health Care
8.5%
Consumer Discretionary
10.3%
Industrials
12.2%
Information Technology
43.6%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
9.6%
Apple, Inc.
8.7%
Microsoft Corp.
6.2%
Amazon.com, Inc.
4.8%
Alphabet, Inc., Class A
4.7%
Broadcom, Inc.
3.7%
Eli Lilly & Co.
2.0%
Visa, Inc., Class A
1.4%
Costco Wholesale Corp.
1.2%
Mastercard, Inc., Class A
1.1%
Total
43.4%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000154983  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Growth Responsible Index Fund
Class Name Class I
Trading Symbol CGJIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Growth Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class I
$12
0.24%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [9]
AssetsNet $ 908,494,612
Holdings Count | Holding 563
InvestmentCompanyPortfolioTurnover 7.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$908,494,612
# of Portfolio Holdings
563
Portfolio Turnover Rate
7%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Energy
0.1%
Short-Term Investments
0.3%
Utilities
0.7%
Real Estate
2.0%
Materials
2.2%
Consumer Staples
5.1%
Communication Services
6.8%
Financials
8.2%
Health Care
8.5%
Consumer Discretionary
10.3%
Industrials
12.2%
Information Technology
43.6%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
9.6%
Apple, Inc.
8.7%
Microsoft Corp.
6.2%
Amazon.com, Inc.
4.8%
Alphabet, Inc., Class A
4.7%
Broadcom, Inc.
3.7%
Eli Lilly & Co.
2.0%
Visa, Inc., Class A
1.4%
Costco Wholesale Corp.
1.2%
Mastercard, Inc., Class A
1.1%
Total
43.4%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000235281  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Growth Responsible Index Fund
Class Name Class R6
Trading Symbol CLGRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Growth Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$10
0.21%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.21% [10]
AssetsNet $ 908,494,612
Holdings Count | Holding 563
InvestmentCompanyPortfolioTurnover 7.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$908,494,612
# of Portfolio Holdings
563
Portfolio Turnover Rate
7%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Energy
0.1%
Short-Term Investments
0.3%
Utilities
0.7%
Real Estate
2.0%
Materials
2.2%
Consumer Staples
5.1%
Communication Services
6.8%
Financials
8.2%
Health Care
8.5%
Consumer Discretionary
10.3%
Industrials
12.2%
Information Technology
43.6%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
NVIDIA Corp.
9.6%
Apple, Inc.
8.7%
Microsoft Corp.
6.2%
Amazon.com, Inc.
4.8%
Alphabet, Inc., Class A
4.7%
Broadcom, Inc.
3.7%
Eli Lilly & Co.
2.0%
Visa, Inc., Class A
1.4%
Costco Wholesale Corp.
1.2%
Mastercard, Inc., Class A
1.1%
Total
43.4%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000154985  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Value Responsible Index Fund
Class Name Class A
Trading Symbol CFJAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Value Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$25
0.49%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.49% [11]
AssetsNet $ 1,819,623,514
Holdings Count | Holding 548
InvestmentCompanyPortfolioTurnover 6.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,819,623,514
# of Portfolio Holdings
548
Portfolio Turnover Rate
6%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.9%
Materials
3.9%
Communication Services
5.6%
Consumer Discretionary
5.7%
Utilities
6.3%
Real Estate
6.5%
Consumer Staples
7.7%
Information Technology
10.0%
Industrials
11.2%
Health Care
15.1%
Financials
27.0%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
JPMorgan Chase & Co.
3.5%
Bank of America Corp.
2.0%
Merck & Co., Inc.
1.7%
Wells Fargo & Co.
1.5%
UnitedHealth Group, Inc.
1.5%
Goldman Sachs Group, Inc.
1.5%
Micron Technology, Inc.
1.3%
Verizon Communications, Inc.
1.3%
AT&T, Inc.
1.2%
Citigroup, Inc.
1.2%
Total
16.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000154987  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Value Responsible Index Fund
Class Name Class I
Trading Symbol CFJIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Value Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class I
$12
0.24%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [12]
AssetsNet $ 1,819,623,514
Holdings Count | Holding 548
InvestmentCompanyPortfolioTurnover 6.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,819,623,514
# of Portfolio Holdings
548
Portfolio Turnover Rate
6%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.9%
Materials
3.9%
Communication Services
5.6%
Consumer Discretionary
5.7%
Utilities
6.3%
Real Estate
6.5%
Consumer Staples
7.7%
Information Technology
10.0%
Industrials
11.2%
Health Care
15.1%
Financials
27.0%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
JPMorgan Chase & Co.
3.5%
Bank of America Corp.
2.0%
Merck & Co., Inc.
1.7%
Wells Fargo & Co.
1.5%
UnitedHealth Group, Inc.
1.5%
Goldman Sachs Group, Inc.
1.5%
Micron Technology, Inc.
1.3%
Verizon Communications, Inc.
1.3%
AT&T, Inc.
1.2%
Citigroup, Inc.
1.2%
Total
16.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000235282  
Shareholder Report [Line Items]  
Fund Name Calvert US Large-Cap Value Responsible Index Fund
Class Name Class R6
Trading Symbol CLVRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Large-Cap Value Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$10
0.19%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.19% [13]
AssetsNet $ 1,819,623,514
Holdings Count | Holding 548
InvestmentCompanyPortfolioTurnover 6.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$1,819,623,514
# of Portfolio Holdings
548
Portfolio Turnover Rate
6%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.1%
Energy
0.9%
Materials
3.9%
Communication Services
5.6%
Consumer Discretionary
5.7%
Utilities
6.3%
Real Estate
6.5%
Consumer Staples
7.7%
Information Technology
10.0%
Industrials
11.2%
Health Care
15.1%
Financials
27.0%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
JPMorgan Chase & Co.
3.5%
Bank of America Corp.
2.0%
Merck & Co., Inc.
1.7%
Wells Fargo & Co.
1.5%
UnitedHealth Group, Inc.
1.5%
Goldman Sachs Group, Inc.
1.5%
Micron Technology, Inc.
1.3%
Verizon Communications, Inc.
1.3%
AT&T, Inc.
1.2%
Citigroup, Inc.
1.2%
Total
16.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000161544  
Shareholder Report [Line Items]  
Fund Name Calvert US Mid-Cap Core Responsible Index Fund
Class Name Class A
Trading Symbol CMJAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Mid-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$25
0.49%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.49% [14]
AssetsNet $ 425,427,867
Holdings Count | Holding 625
InvestmentCompanyPortfolioTurnover 5.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$425,427,867
# of Portfolio Holdings
625
Portfolio Turnover Rate
5%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.2%
Energy
1.2%
Communication Services
3.0%
Materials
4.0%
Consumer Staples
6.1%
Utilities
6.4%
Real Estate
6.8%
Consumer Discretionary
9.2%
Health Care
11.0%
Financials
14.3%
Information Technology
16.6%
Industrials
21.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Corning, Inc.
0.9%
Vertiv Holdings Co., Class A
0.9%
Western Digital Corp.
0.8%
Marvell Technology, Inc.
0.8%
Sandisk Corp.
0.8%
Seagate Technology Holdings PLC
0.8%
Quanta Services, Inc.
0.7%
Cummins, Inc.
0.7%
Ross Stores, Inc.
0.7%
Warner Bros Discovery, Inc.
0.6%
Total
7.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000161547  
Shareholder Report [Line Items]  
Fund Name Calvert US Mid-Cap Core Responsible Index Fund
Class Name Class I
Trading Symbol CMJIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Mid-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class I
$12
0.24%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [15]
AssetsNet $ 425,427,867
Holdings Count | Holding 625
InvestmentCompanyPortfolioTurnover 5.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$425,427,867
# of Portfolio Holdings
625
Portfolio Turnover Rate
5%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.2%
Energy
1.2%
Communication Services
3.0%
Materials
4.0%
Consumer Staples
6.1%
Utilities
6.4%
Real Estate
6.8%
Consumer Discretionary
9.2%
Health Care
11.0%
Financials
14.3%
Information Technology
16.6%
Industrials
21.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Corning, Inc.
0.9%
Vertiv Holdings Co., Class A
0.9%
Western Digital Corp.
0.8%
Marvell Technology, Inc.
0.8%
Sandisk Corp.
0.8%
Seagate Technology Holdings PLC
0.8%
Quanta Services, Inc.
0.7%
Cummins, Inc.
0.7%
Ross Stores, Inc.
0.7%
Warner Bros Discovery, Inc.
0.6%
Total
7.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
C000235283  
Shareholder Report [Line Items]  
Fund Name Calvert US Mid-Cap Core Responsible Index Fund
Class Name Class R6
Trading Symbol CMCRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Calvert US Mid-Cap Core Responsible Index Fund for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.
Additional Information Phone Number 1-800-368-2745
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">www.eatonvance.com/calvert-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class R6
$10
0.20%Footnote Reference1
Footnote Description
Footnote1
 Annualized
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20% [16]
AssetsNet $ 425,427,867
Holdings Count | Holding 625
InvestmentCompanyPortfolioTurnover 5.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets
$425,427,867
# of Portfolio Holdings
625
Portfolio Turnover Rate
5%
Holdings [Text Block]

Sector Allocation (% of total investments)

Group By Asset Type Chart
Table Summary
Value
Value
Short-Term Investments
0.2%
Energy
1.2%
Communication Services
3.0%
Materials
4.0%
Consumer Staples
6.1%
Utilities
6.4%
Real Estate
6.8%
Consumer Discretionary
9.2%
Health Care
11.0%
Financials
14.3%
Information Technology
16.6%
Industrials
21.2%
Largest Holdings [Text Block]

Top Ten Holdings (% of total investments)Footnote Referencea

Table Summary
Corning, Inc.
0.9%
Vertiv Holdings Co., Class A
0.9%
Western Digital Corp.
0.8%
Marvell Technology, Inc.
0.8%
Sandisk Corp.
0.8%
Seagate Technology Holdings PLC
0.8%
Quanta Services, Inc.
0.7%
Cummins, Inc.
0.7%
Ross Stores, Inc.
0.7%
Warner Bros Discovery, Inc.
0.6%
Total
7.7%
Footnote Description
Footnotea
 Excluding cash equivalents
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-368-2745
[1] Annualized
[2] Annualized
[3] Annualized
[4] Annualized
[5] Annualized
[6] Annualized
[7] Annualized
[8] Annualized
[9] Annualized
[10] Annualized
[11] Annualized
[12] Annualized
[13] Annualized
[14] Annualized
[15] Annualized
[16] Annualized