| Form N-CSR Cover | 12 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | EATON VANCE SERIES TRUST II |
| Entity Central Index Key | 0000074663 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| Shareholder Report | 12 Months Ended |
| Oct. 31, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | EATON VANCE SERIES TRUST II |
| Entity Central Index Key | 0000074663 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| C000013484 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Income Fund of Boston |
| Class Name | Class A |
| Trading Symbol | EVIBX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Eaton Vance Income Fund of Boston for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B19"><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: 12.8px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $105 0.98% |
| Expenses Paid, Amount | $ 105 |
| Expense Ratio, Percent | 0.98% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year and what affected its performance? Key contributors to (↑) and detractors from (↓) performance, relative to the ICE BofA U.S. High Yield Index (the Index): ↓ The Fund’s security selections by sector ― especially in the health care, gaming, and retail sectors ― detracted from Index-relative returns during the period ↓ Fund allocations by credit quality ― particularly a broad underweight exposure to distressed CCC-rated and lower-rated securities ― detracted from returns ↓ Security selections by credit quality ― especially selections in B-rated and CCC-rated securities ― detracted from Index-relative returns during the period ↓ Security selections by duration segment ― particularly selections in securities with durations of less than 5 years ― hampered returns relative to the Index ↑ An overweight exposure to the health care sector and an underweight allocation to the energy sector contributed to Index-relative returns during the period ↑ The Fund’s selections in lower-rated fixed-income investments contributed to performance relative to the Index during the period ↑ The Fund’s underweight exposure to BB-rated securities contributed to performance relative to the Index during the period ↑ The Fund’s overweight exposure to securities with durations between 5-10 years contributed to performance relative to the Index during the period |
| Performance Past Does Not Indicate Future [Text] | THE FUND'S PAST PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS. |
| Line Graph [Table Text Block] | Class A with Maximum Sales Charge Bloomberg U.S. Universal Index ICE BofA U.S. High Yield Constrained Index ICE BofA U.S. High Yield Index 10/14 $10,000 $10,000 $10,000 $10,000 11/14 $9,625 $10,054 $9,929 $9,929 12/14 $9,513 $10,036 $9,783 $9,782 1/15 $9,594 $10,227 $9,850 $9,850 2/15 $9,785 $10,167 $10,085 $10,085 3/15 $9,753 $10,209 $10,032 $10,031 4/15 $9,850 $10,197 $10,152 $10,151 5/15 $9,900 $10,180 $10,182 $10,181 6/15 $9,799 $10,066 $10,027 $10,026 7/15 $9,799 $10,125 $9,966 $9,964 8/15 $9,665 $10,095 $9,789 $9,789 9/15 $9,427 $10,134 $9,538 $9,535 10/15 $9,665 $10,167 $9,797 $9,795 11/15 $9,491 $10,130 $9,579 $9,575 12/15 $9,318 $10,079 $9,332 $9,328 1/16 $9,230 $10,190 $9,184 $9,180 2/16 $9,329 $10,263 $9,227 $9,223 3/16 $9,624 $10,388 $9,635 $9,631 4/16 $9,830 $10,459 $10,020 $10,016 5/16 $9,881 $10,467 $10,092 $10,088 6/16 $9,931 $10,652 $10,202 $10,197 7/16 $10,125 $10,739 $10,459 $10,455 8/16 $10,281 $10,751 $10,692 $10,688 9/16 $10,348 $10,753 $10,761 $10,757 10/16 $10,343 $10,682 $10,795 $10,790 11/16 $10,319 $10,442 $10,752 $10,748 12/16 $10,497 $10,473 $10,964 $10,959 1/17 $10,603 $10,510 $11,111 $11,106 2/17 $10,721 $10,591 $11,284 $11,280 3/17 $10,716 $10,588 $11,260 $11,256 4/17 $10,839 $10,675 $11,388 $11,384 5/17 $10,907 $10,758 $11,489 $11,485 6/17 $10,919 $10,749 $11,501 $11,497 7/17 $11,026 $10,802 $11,634 $11,630 8/17 $11,020 $10,895 $11,631 $11,627 9/17 $11,108 $10,857 $11,736 $11,732 10/17 $11,121 $10,870 $11,781 $11,777 11/17 $11,095 $10,854 $11,750 $11,745 12/17 $11,127 $10,901 $11,784 $11,779 1/18 $11,179 $10,797 $11,860 $11,855 2/18 $11,091 $10,694 $11,749 $11,744 3/18 $11,026 $10,748 $11,677 $11,672 4/18 $11,077 $10,676 $11,754 $11,750 5/18 $11,071 $10,735 $11,753 $11,748 6/18 $11,083 $10,719 $11,793 $11,788 7/18 $11,197 $10,741 $11,925 $11,920 8/18 $11,251 $10,794 $12,011 $12,006 9/18 $11,303 $10,748 $12,081 $12,076 10/18 $11,136 $10,658 $11,883 $11,878 11/18 $11,046 $10,706 $11,775 $11,771 12/18 $10,816 $10,874 $11,517 $11,513 1/19 $11,281 $11,024 $12,046 $12,041 2/19 $11,434 $11,036 $12,249 $12,245 3/19 $11,531 $11,235 $12,370 $12,365 4/19 $11,669 $11,251 $12,543 $12,538 5/19 $11,579 $11,423 $12,383 $12,378 6/19 $11,801 $11,585 $12,687 $12,682 7/19 $11,858 $11,619 $12,752 $12,747 8/19 $11,915 $11,882 $12,802 $12,797 9/19 $11,971 $11,830 $12,842 $12,837 10/19 $11,985 $11,869 $12,872 $12,867 11/19 $12,041 $11,866 $12,907 $12,902 12/19 $12,251 $11,884 $13,177 $13,172 1/20 $12,222 $12,097 $13,177 $13,172 2/20 $12,038 $12,278 $12,973 $12,968 3/20 $10,762 $12,039 $11,446 $11,443 4/20 $11,193 $12,280 $11,882 $11,878 5/20 $11,629 $12,394 $12,421 $12,421 6/20 $11,665 $12,498 $12,539 $12,542 7/20 $12,172 $12,717 $13,134 $13,142 8/20 $12,255 $12,644 $13,265 $13,271 9/20 $12,133 $12,621 $13,127 $13,133 10/20 $12,172 $12,576 $13,187 $13,194 11/20 $12,642 $12,740 $13,715 $13,722 12/20 $12,841 $12,784 $13,977 $13,984 1/21 $12,857 $12,704 $14,031 $14,037 2/21 $12,913 $12,540 $14,079 $14,086 3/21 $12,944 $12,394 $14,104 $14,110 4/21 $13,067 $12,498 $14,259 $14,265 5/21 $13,121 $12,546 $14,300 $14,306 6/21 $13,315 $12,637 $14,495 $14,502 7/21 $13,347 $12,764 $14,545 $14,553 8/21 $13,402 $12,756 $14,626 $14,633 9/21 $13,409 $12,647 $14,632 $14,638 10/21 $13,417 $12,636 $14,604 $14,612 11/21 $13,303 $12,652 $14,453 $14,462 12/21 $13,552 $12,643 $14,725 $14,734 1/22 $13,197 $12,366 $14,321 $14,329 2/22 $13,248 $12,197 $14,193 $14,200 3/22 $13,135 $11,870 $14,063 $14,069 4/22 $12,749 $11,427 $13,552 $13,557 5/22 $12,757 $11,490 $13,584 $13,591 6/22 $11,972 $11,261 $12,659 $12,666 7/22 $12,651 $11,544 $13,421 $13,429 8/22 $12,385 $11,244 $13,100 $13,107 9/22 $11,941 $10,759 $12,574 $12,580 10/22 $12,226 $10,641 $12,932 $12,938 11/22 $12,536 $11,038 $13,172 $13,180 12/22 $12,443 $11,001 $13,074 $13,081 1/23 $12,937 $11,342 $13,585 $13,593 2/23 $12,735 $11,063 $13,411 $13,417 3/23 $12,924 $11,323 $13,560 $13,568 4/23 $13,007 $11,392 $13,692 $13,699 5/23 $12,862 $11,274 $13,561 $13,569 6/23 $13,056 $11,256 $13,782 $13,789 7/23 $13,223 $11,267 $13,979 $13,986 8/23 $13,261 $11,200 $14,020 $14,026 9/23 $13,115 $10,932 $13,856 $13,863 10/23 $12,941 $10,768 $13,683 $13,691 11/23 $13,462 $11,253 $14,307 $14,314 12/23 $13,907 $11,680 $14,835 $14,842 1/24 $13,944 $11,652 $14,838 $14,844 2/24 $13,956 $11,512 $14,882 $14,888 3/24 $14,135 $11,625 $15,059 $15,066 4/24 $14,011 $11,353 $14,909 $14,915 5/24 $14,191 $11,542 $15,078 $15,084 6/24 $14,319 $11,647 $15,223 $15,230 7/24 $14,529 $11,911 $15,522 $15,529 8/24 $14,741 $12,087 $15,769 $15,776 9/24 $14,869 $12,253 $16,027 $16,034 10/24 $14,808 $11,974 $15,939 $15,945 |
| Average Annual Return [Table Text Block] | Fund 1 Year 5 Years 10 Years Class A 14.38% 4.31% 4.34% Class A with 3.25% Maximum Sales Charge 10.71% 3.61% 4.00% Bloomberg U.S. Universal Index Footnote Reference 11.20% 0.18% 1.82% ICE BofA U.S. High Yield Index 16.47% 4.38% 4.77% ICE BofA U.S. High Yield Constrained Index 16.49% 4.36% 4.77% |
| AssetsNet | $ 5,663,132,601 |
| Holdings Count | Holding | 432 |
| Advisory Fees Paid, Amount | $ 30,275,138 |
| InvestmentCompanyPortfolioTurnover | 45% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Total Net Assets $5,663,132,601 # of Portfolio Holdings 432 Portfolio Turnover Rate 45% Total Advisory Fees Paid $30,275,138 |
| Holdings [Text Block] | Asset Allocation (% of total investments) Value Value Other Footnote Reference 1.9% Short-Term Investments 3.6% Senior Floating-Rate Loans 7.9% Corporate Bonds 86.6% Footnote Description Footnote † Investment types less than 1% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 3.3% CCC or Lower 12.4% B 37.3% BB 44.3% BBB 2.7% Footnote Description Footnote a Excludes Short-Term Investments. Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). This breakdown assigns a numeric equivalent to the ratings from the aforementioned agencies and the mean is rounded to the nearest integer and converted to an equivalent S&P rating ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013486 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Income Fund of Boston |
| Class Name | Class C |
| Trading Symbol | ECIBX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Eaton Vance Income Fund of Boston for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B44"><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: 12.8px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $184 1.73% |
| Expenses Paid, Amount | $ 184 |
| Expense Ratio, Percent | 1.73% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year and what affected its performance? Key contributors to (↑) and detractors from (↓) performance, relative to the ICE BofA U.S. High Yield Index (the Index): ↓ The Fund’s security selections by sector ― especially in the health care, gaming, and retail sectors ― detracted from Index-relative returns during the period ↓ Fund allocations by credit quality ― particularly a broad underweight exposure to distressed CCC-rated and lower-rated securities ― detracted from returns ↓ Security selections by credit quality ― especially selections in B-rated and CCC-rated securities ― detracted from Index-relative returns during the period ↓ Security selections by duration segment ― particularly selections in securities with durations of less than 5 years ― hampered returns relative to the Index ↑ An overweight exposure to the health care sector and an underweight allocation to the energy sector contributed to Index-relative returns during the period ↑ The Fund’s selections in lower-rated fixed-income investments contributed to performance relative to the Index during the period ↑ The Fund’s underweight exposure to BB-rated securities contributed to performance relative to the Index during the period ↑ The Fund’s overweight exposure to securities with durations between 5-10 years contributed to performance relative to the Index during the period |
| Performance Past Does Not Indicate Future [Text] | THE FUND'S PAST PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS. |
| Line Graph [Table Text Block] | Class C Bloomberg U.S. Universal Index ICE BofA U.S. High Yield Constrained Index ICE BofA U.S. High Yield Index 10/14 $10,000 $10,000 $10,000 $10,000 11/14 $9,943 $10,054 $9,929 $9,929 12/14 $9,820 $10,036 $9,783 $9,782 1/15 $9,898 $10,227 $9,850 $9,850 2/15 $10,072 $10,167 $10,085 $10,085 3/15 $10,049 $10,209 $10,032 $10,031 4/15 $10,143 $10,197 $10,152 $10,151 5/15 $10,188 $10,180 $10,182 $10,181 6/15 $10,077 $10,066 $10,027 $10,026 7/15 $10,071 $10,125 $9,966 $9,964 8/15 $9,927 $10,095 $9,789 $9,789 9/15 $9,659 $10,134 $9,538 $9,535 10/15 $9,896 $10,167 $9,797 $9,795 11/15 $9,712 $10,130 $9,579 $9,575 12/15 $9,529 $10,079 $9,332 $9,328 1/16 $9,450 $10,190 $9,184 $9,180 2/16 $9,545 $10,263 $9,227 $9,223 3/16 $9,839 $10,388 $9,635 $9,631 4/16 $10,044 $10,459 $10,020 $10,016 5/16 $10,090 $10,467 $10,092 $10,088 6/16 $10,116 $10,652 $10,202 $10,197 7/16 $10,307 $10,739 $10,459 $10,455 8/16 $10,478 $10,751 $10,692 $10,688 9/16 $10,539 $10,753 $10,761 $10,757 10/16 $10,528 $10,682 $10,795 $10,790 11/16 $10,497 $10,442 $10,752 $10,748 12/16 $10,671 $10,473 $10,964 $10,959 1/17 $10,772 $10,510 $11,111 $11,106 2/17 $10,886 $10,591 $11,284 $11,280 3/17 $10,874 $10,588 $11,260 $11,256 4/17 $10,972 $10,675 $11,388 $11,384 5/17 $11,054 $10,758 $11,489 $11,485 6/17 $11,059 $10,749 $11,501 $11,497 7/17 $11,160 $10,802 $11,634 $11,630 8/17 $11,148 $10,895 $11,631 $11,627 9/17 $11,210 $10,857 $11,736 $11,732 10/17 $11,236 $10,870 $11,781 $11,777 11/17 $11,202 $10,854 $11,750 $11,745 12/17 $11,228 $10,901 $11,784 $11,779 1/18 $11,273 $10,797 $11,860 $11,855 2/18 $11,158 $10,694 $11,749 $11,744 3/18 $11,106 $10,748 $11,677 $11,672 4/18 $11,150 $10,676 $11,754 $11,750 5/18 $11,117 $10,735 $11,753 $11,748 6/18 $11,122 $10,719 $11,793 $11,788 7/18 $11,229 $10,741 $11,925 $11,920 8/18 $11,295 $10,794 $12,011 $12,006 9/18 $11,341 $10,748 $12,081 $12,076 10/18 $11,166 $10,658 $11,883 $11,878 11/18 $11,069 $10,706 $11,775 $11,771 12/18 $10,831 $10,874 $11,517 $11,513 1/19 $11,289 $11,024 $12,046 $12,041 2/19 $11,435 $11,036 $12,249 $12,245 3/19 $11,524 $11,235 $12,370 $12,365 4/19 $11,654 $11,251 $12,543 $12,538 5/19 $11,536 $11,423 $12,383 $12,378 6/19 $11,771 $11,585 $12,687 $12,682 7/19 $11,820 $11,619 $12,752 $12,747 8/19 $11,869 $11,882 $12,802 $12,797 9/19 $11,917 $11,830 $12,842 $12,837 10/19 $11,924 $11,869 $12,872 $12,867 11/19 $11,972 $11,866 $12,907 $12,902 12/19 $12,172 $11,884 $13,177 $13,172 1/20 $12,136 $12,097 $13,177 $13,172 2/20 $11,945 $12,278 $12,973 $12,968 3/20 $10,673 $12,039 $11,446 $11,443 4/20 $11,093 $12,280 $11,882 $11,878 5/20 $11,516 $12,394 $12,421 $12,421 6/20 $11,544 $12,498 $12,539 $12,542 7/20 $12,036 $12,717 $13,134 $13,142 8/20 $12,110 $12,644 $13,265 $13,271 9/20 $11,982 $12,621 $13,127 $13,133 10/20 $12,012 $12,576 $13,187 $13,194 11/20 $12,467 $12,740 $13,715 $13,722 12/20 $12,655 $12,784 $13,977 $13,984 1/21 $12,685 $12,704 $14,031 $14,037 2/21 $12,733 $12,540 $14,079 $14,086 3/21 $12,733 $12,394 $14,104 $14,110 4/21 $12,868 $12,498 $14,259 $14,265 5/21 $12,891 $12,546 $14,300 $14,306 6/21 $13,074 $12,637 $14,495 $14,502 7/21 $13,096 $12,764 $14,545 $14,553 8/21 $13,143 $12,756 $14,626 $14,633 9/21 $13,164 $12,647 $14,632 $14,638 10/21 $13,140 $12,636 $14,604 $14,612 11/21 $13,021 $12,652 $14,453 $14,462 12/21 $13,257 $12,643 $14,725 $14,734 1/22 $12,902 $12,366 $14,321 $14,329 2/22 $12,944 $12,197 $14,193 $14,200 3/22 $12,849 $11,870 $14,063 $14,069 4/22 $12,441 $11,427 $13,552 $13,557 5/22 $12,441 $11,490 $13,584 $13,591 6/22 $11,669 $11,261 $12,659 $12,666 7/22 $12,321 $11,544 $13,421 $13,429 8/22 $12,054 $11,244 $13,100 $13,107 9/22 $11,614 $10,759 $12,574 $12,580 10/22 $11,907 $10,641 $12,932 $12,938 11/22 $12,199 $11,038 $13,172 $13,180 12/22 $12,100 $11,001 $13,074 $13,081 1/23 $12,546 $11,342 $13,585 $13,593 2/23 $12,342 $11,063 $13,411 $13,417 3/23 $12,541 $11,323 $13,560 $13,568 4/23 $12,614 $11,392 $13,692 $13,699 5/23 $12,466 $11,274 $13,561 $13,569 6/23 $12,646 $11,256 $13,782 $13,789 7/23 $12,799 $11,267 $13,979 $13,986 8/23 $12,802 $11,200 $14,020 $14,026 9/23 $12,654 $10,932 $13,856 $13,863 10/23 $12,504 $10,768 $13,683 $13,691 11/23 $12,998 $11,253 $14,307 $14,314 12/23 $13,418 $11,680 $14,835 $14,842 1/24 $13,419 $11,652 $14,838 $14,844 2/24 $13,423 $11,512 $14,882 $14,888 3/24 $13,585 $11,625 $15,059 $15,066 4/24 $13,486 $11,353 $14,909 $14,915 5/24 $13,623 $11,542 $15,078 $15,084 6/24 $13,764 $11,647 $15,223 $15,230 7/24 $13,930 $11,911 $15,522 $15,529 8/24 $14,124 $12,087 $15,769 $15,776 9/24 $14,238 $12,253 $16,027 $16,034 10/24 $14,416 $11,974 $15,939 $15,945 |
| Average Annual Return [Table Text Block] | Fund 1 Year 5 Years 10 Years Class C, with conversion to Class A after 8 years 13.28% 3.50% 3.72% Class C, with 1% Maximum Deferred Sales Charge and conversion to Class A after 8 years 12.28% 3.50% 3.72% Bloomberg U.S. Universal Index Footnote Reference 11.20% 0.18% 1.82% ICE BofA U.S. High Yield Index 16.47% 4.38% 4.77% ICE BofA U.S. High Yield Constrained Index 16.49% 4.36% 4.77% |
| AssetsNet | $ 5,663,132,601 |
| Holdings Count | Holding | 432 |
| Advisory Fees Paid, Amount | $ 30,275,138 |
| InvestmentCompanyPortfolioTurnover | 45% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Total Net Assets $5,663,132,601 # of Portfolio Holdings 432 Portfolio Turnover Rate 45% Total Advisory Fees Paid $30,275,138 |
| Holdings [Text Block] | Asset Allocation (% of total investments) Value Value Other Footnote Reference 1.9% Short-Term Investments 3.6% Senior Floating-Rate Loans 7.9% Corporate Bonds 86.6% Footnote Description Footnote † Investment types less than 1% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 3.3% CCC or Lower 12.4% B 37.3% BB 44.3% BBB 2.7% Footnote Description Footnote a Excludes Short-Term Investments. Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). This breakdown assigns a numeric equivalent to the ratings from the aforementioned agencies and the mean is rounded to the nearest integer and converted to an equivalent S&P rating ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013488 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Income Fund of Boston |
| Class Name | Class I |
| Trading Symbol | EIBIX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Eaton Vance Income Fund of Boston for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B69"><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: 12.8px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I $78 0.73% |
| Expenses Paid, Amount | $ 78 |
| Expense Ratio, Percent | 0.73% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year and what affected its performance? Key contributors to (↑) and detractors from (↓) performance, relative to the ICE BofA U.S. High Yield Index (the Index): ↓ The Fund’s security selections by sector ― especially in the health care, gaming, and retail sectors ― detracted from Index-relative returns during the period ↓ Fund allocations by credit quality ― particularly a broad underweight exposure to distressed CCC-rated and lower-rated securities ― detracted from returns ↓ Security selections by credit quality ― especially selections in B-rated and CCC-rated securities ― detracted from Index-relative returns during the period ↓ Security selections by duration segment ― particularly selections in securities with durations of less than 5 years ― hampered returns relative to the Index ↑ An overweight exposure to the health care sector and an underweight allocation to the energy sector contributed to Index-relative returns during the period ↑ The Fund’s selections in lower-rated fixed-income investments contributed to performance relative to the Index during the period ↑ The Fund’s underweight exposure to BB-rated securities contributed to performance relative to the Index during the period ↑ The Fund’s overweight exposure to securities with durations between 5-10 years contributed to performance relative to the Index during the period |
| Performance Past Does Not Indicate Future [Text] | THE FUND'S PAST PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS. |
| Line Graph [Table Text Block] | Class I Bloomberg U.S. Universal Index ICE BofA U.S. High Yield Constrained Index ICE BofA U.S. High Yield Index 10/14 $1,000,000 $1,000,000 $1,000,000 $1,000,000 11/14 $995,085 $1,005,397 $992,901 $992,852 12/14 $985,305 $1,003,580 $978,297 $978,214 1/15 $992,258 $1,022,684 $985,015 $984,961 2/15 $1,012,236 $1,016,723 $1,008,512 $1,008,460 3/15 $1,009,086 $1,020,920 $1,003,166 $1,003,103 4/15 $1,021,089 $1,019,735 $1,015,225 $1,015,130 5/15 $1,026,474 $1,017,951 $1,018,213 $1,018,137 6/15 $1,016,208 $1,006,590 $1,002,703 $1,002,607 7/15 $1,014,723 $1,012,452 $996,552 $996,434 8/15 $1,001,047 $1,009,468 $978,915 $978,885 9/15 $976,618 $1,013,420 $953,818 $953,492 10/15 $1,001,501 $1,016,659 $979,742 $979,484 11/15 $983,701 $1,012,952 $957,889 $957,494 12/15 $965,948 $1,007,891 $933,190 $932,796 1/16 $958,811 $1,019,017 $918,428 $918,042 2/16 $967,475 $1,026,256 $922,700 $922,312 3/16 $998,237 $1,038,833 $963,487 $963,082 4/16 $1,019,897 $1,045,911 $1,001,986 $1,001,564 5/16 $1,025,397 $1,046,728 $1,009,215 $1,008,791 6/16 $1,030,750 $1,065,155 $1,020,157 $1,019,725 7/16 $1,051,085 $1,073,933 $1,045,923 $1,045,481 8/16 $1,069,436 $1,075,091 $1,069,220 $1,068,768 9/16 $1,074,644 $1,075,347 $1,076,135 $1,075,683 10/16 $1,074,426 $1,068,213 $1,079,498 $1,079,044 11/16 $1,072,149 $1,044,202 $1,075,241 $1,074,789 12/16 $1,090,868 $1,047,304 $1,096,382 $1,095,929 1/17 $1,102,070 $1,050,999 $1,111,096 $1,110,646 2/17 $1,114,587 $1,059,108 $1,128,417 $1,127,977 3/17 $1,114,232 $1,058,753 $1,126,047 $1,125,610 4/17 $1,127,218 $1,067,538 $1,138,792 $1,138,364 5/17 $1,136,559 $1,075,775 $1,148,921 $1,148,532 6/17 $1,137,972 $1,074,863 $1,150,140 $1,149,744 7/17 $1,147,402 $1,080,216 $1,163,435 $1,163,006 8/17 $1,147,044 $1,089,536 $1,163,121 $1,162,704 9/17 $1,156,388 $1,085,702 $1,173,558 $1,173,150 10/17 $1,159,996 $1,087,005 $1,178,137 $1,177,677 11/17 $1,157,451 $1,085,360 $1,174,994 $1,174,517 12/17 $1,159,088 $1,090,145 $1,178,420 $1,177,940 1/18 $1,164,766 $1,079,655 $1,185,976 $1,185,493 2/18 $1,155,739 $1,069,417 $1,174,918 $1,174,441 3/18 $1,149,258 $1,074,811 $1,167,664 $1,167,190 4/18 $1,154,832 $1,067,639 $1,175,432 $1,174,954 5/18 $1,154,452 $1,073,462 $1,175,265 $1,174,777 6/18 $1,155,949 $1,071,905 $1,179,325 $1,178,833 7/18 $1,168,019 $1,074,148 $1,192,502 $1,192,006 8/18 $1,175,973 $1,079,440 $1,201,138 $1,200,639 9/18 $1,179,585 $1,074,815 $1,208,119 $1,207,616 10/18 $1,164,448 $1,065,824 $1,188,326 $1,187,839 11/18 $1,153,278 $1,070,617 $1,177,539 $1,177,060 12/18 $1,129,482 $1,087,367 $1,151,717 $1,151,261 1/19 $1,178,288 $1,102,360 $1,204,609 $1,204,137 2/19 $1,196,661 $1,103,561 $1,224,949 $1,224,469 3/19 $1,204,901 $1,123,489 $1,236,951 $1,236,467 4/19 $1,219,498 $1,125,062 $1,254,258 $1,253,766 5/19 $1,210,367 $1,142,296 $1,238,314 $1,237,830 6/19 $1,233,877 $1,158,453 $1,268,679 $1,268,182 7/19 $1,240,079 $1,161,901 $1,275,177 $1,274,676 8/19 $1,246,312 $1,188,192 $1,280,151 $1,279,650 9/19 $1,254,597 $1,183,044 $1,284,211 $1,283,707 10/19 $1,256,421 $1,186,867 $1,287,194 $1,286,688 11/19 $1,260,302 $1,186,629 $1,290,709 $1,290,201 12/19 $1,282,467 $1,188,398 $1,317,688 $1,317,172 1/20 $1,279,776 $1,209,727 $1,317,745 $1,317,228 2/20 $1,260,692 $1,227,840 $1,297,320 $1,296,813 3/20 $1,127,324 $1,203,856 $1,144,644 $1,144,323 4/20 $1,175,102 $1,227,971 $1,188,162 $1,187,811 5/20 $1,218,715 $1,239,440 $1,242,061 $1,242,137 6/20 $1,222,736 $1,249,782 $1,253,861 $1,254,244 7/20 $1,276,179 $1,271,736 $1,313,363 $1,314,173 8/20 $1,285,166 $1,264,402 $1,326,491 $1,327,105 9/20 $1,272,681 $1,262,124 $1,312,742 $1,313,270 10/20 $1,277,004 $1,257,613 $1,318,664 $1,319,411 11/20 $1,326,563 $1,274,024 $1,371,522 $1,372,224 12/20 $1,347,744 $1,278,423 $1,397,714 $1,398,397 1/21 $1,349,707 $1,270,388 $1,403,106 $1,403,749 2/21 $1,355,882 $1,253,996 $1,407,942 $1,408,640 3/21 $1,359,425 $1,239,403 $1,410,439 $1,411,038 4/21 $1,375,042 $1,249,825 $1,425,870 $1,426,516 5/21 $1,378,622 $1,254,592 $1,429,986 $1,430,634 6/21 $1,399,313 $1,263,738 $1,449,454 $1,450,180 7/21 $1,402,922 $1,276,427 $1,454,542 $1,455,342 8/21 $1,409,038 $1,275,575 $1,462,569 $1,463,280 9/21 $1,412,480 $1,264,683 $1,463,164 $1,463,770 10/21 $1,411,109 $1,263,649 $1,460,410 $1,461,167 11/21 $1,399,435 $1,265,175 $1,445,270 $1,446,193 12/21 $1,425,939 $1,264,322 $1,472,450 $1,473,401 1/22 $1,388,902 $1,236,603 $1,432,083 $1,432,898 2/22 $1,394,573 $1,219,743 $1,419,259 $1,420,032 3/22 $1,385,467 $1,187,019 $1,406,266 $1,406,893 4/22 $1,342,575 $1,142,746 $1,355,183 $1,355,715 5/22 $1,343,753 $1,149,034 $1,358,425 $1,359,110 6/22 $1,261,397 $1,126,073 $1,265,874 $1,266,600 7/22 $1,333,246 $1,154,385 $1,342,055 $1,342,886 8/22 $1,305,514 $1,124,375 $1,309,991 $1,310,727 9/22 $1,258,937 $1,075,933 $1,257,382 $1,258,012 10/22 $1,292,016 $1,064,128 $1,293,158 $1,293,823 11/22 $1,322,382 $1,103,805 $1,317,209 $1,318,043 12/22 $1,312,872 $1,100,056 $1,307,381 $1,308,116 1/23 $1,365,318 $1,134,180 $1,358,481 $1,359,258 2/23 $1,344,234 $1,106,311 $1,341,056 $1,341,668 3/23 $1,367,240 $1,132,265 $1,355,956 $1,356,771 4/23 $1,376,317 $1,139,182 $1,369,169 $1,369,866 5/23 $1,361,261 $1,127,371 $1,356,128 $1,356,860 6/23 $1,379,331 $1,125,619 $1,378,187 $1,378,946 7/23 $1,397,237 $1,126,738 $1,397,883 $1,398,582 8/23 $1,401,496 $1,119,953 $1,402,042 $1,402,573 9/23 $1,386,397 $1,093,247 $1,385,568 $1,386,261 10/23 $1,368,288 $1,076,807 $1,368,266 $1,369,103 11/23 $1,423,714 $1,125,268 $1,430,728 $1,431,373 12/23 $1,471,071 $1,167,966 $1,483,527 $1,484,159 1/24 $1,475,284 $1,165,171 $1,483,812 $1,484,434 2/24 $1,476,835 $1,151,201 $1,488,205 $1,488,830 3/24 $1,496,030 $1,162,504 $1,505,932 $1,506,565 4/24 $1,483,305 $1,135,338 $1,490,874 $1,491,499 5/24 $1,502,682 $1,154,158 $1,507,792 $1,508,423 6/24 $1,516,486 $1,164,708 $1,522,345 $1,522,984 7/24 $1,539,065 $1,191,145 $1,552,219 $1,552,870 8/24 $1,561,896 $1,208,679 $1,576,910 $1,577,571 9/24 $1,575,784 $1,225,257 $1,602,678 $1,603,351 10/24 $1,569,041 $1,197,428 $1,593,858 $1,594,527 |
| Average Annual Return [Table Text Block] | Fund 1 Year 5 Years 10 Years Class I 14.67% 4.54% 4.60% Bloomberg U.S. Universal Index Footnote Reference 11.20% 0.18% 1.82% ICE BofA U.S. High Yield Index 16.47% 4.38% 4.77% ICE BofA U.S. High Yield Constrained Index 16.49% 4.36% 4.77% |
| AssetsNet | $ 5,663,132,601 |
| Holdings Count | Holding | 432 |
| Advisory Fees Paid, Amount | $ 30,275,138 |
| InvestmentCompanyPortfolioTurnover | 45% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Total Net Assets $5,663,132,601 # of Portfolio Holdings 432 Portfolio Turnover Rate 45% Total Advisory Fees Paid $30,275,138 |
| Holdings [Text Block] | Asset Allocation (% of total investments) Value Value Other Footnote Reference 1.9% Short-Term Investments 3.6% Senior Floating-Rate Loans 7.9% Corporate Bonds 86.6% Footnote Description Footnote † Investment types less than 1% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 3.3% CCC or Lower 12.4% B 37.3% BB 44.3% BBB 2.7% Footnote Description Footnote a Excludes Short-Term Investments. Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). This breakdown assigns a numeric equivalent to the ratings from the aforementioned agencies and the mean is rounded to the nearest integer and converted to an equivalent S&P rating ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013487 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Income Fund of Boston |
| Class Name | Class R |
| Trading Symbol | ERIBX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Eaton Vance Income Fund of Boston for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B94"><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: 12.8px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R $132 1.23% |
| Expenses Paid, Amount | $ 132 |
| Expense Ratio, Percent | 1.23% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year and what affected its performance? Key contributors to (↑) and detractors from (↓) performance, relative to the ICE BofA U.S. High Yield Index (the Index): ↓ The Fund’s security selections by sector ― especially in the health care, gaming, and retail sectors ― detracted from Index-relative returns during the period ↓ Fund allocations by credit quality ― particularly a broad underweight exposure to distressed CCC-rated and lower-rated securities ― detracted from returns ↓ Security selections by credit quality ― especially selections in B-rated and CCC-rated securities ― detracted from Index-relative returns during the period ↓ Security selections by duration segment ― particularly selections in securities with durations of less than 5 years ― hampered returns relative to the Index ↑ An overweight exposure to the health care sector and an underweight allocation to the energy sector contributed to Index-relative returns during the period ↑ The Fund’s selections in lower-rated fixed-income investments contributed to performance relative to the Index during the period ↑ The Fund’s underweight exposure to BB-rated securities contributed to performance relative to the Index during the period ↑ The Fund’s overweight exposure to securities with durations between 5-10 years contributed to performance relative to the Index during the period |
| Performance Past Does Not Indicate Future [Text] | THE FUND'S PAST PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS. |
| Line Graph [Table Text Block] | Class R Bloomberg U.S. Universal Index ICE BofA U.S. High Yield Constrained Index ICE BofA U.S. High Yield Index 10/14 $10,000 $10,000 $10,000 $10,000 11/14 $9,947 $10,054 $9,929 $9,929 12/14 $9,828 $10,036 $9,783 $9,782 1/15 $9,910 $10,227 $9,850 $9,850 2/15 $10,106 $10,167 $10,085 $10,085 3/15 $10,070 $10,209 $10,032 $10,031 4/15 $10,168 $10,197 $10,152 $10,151 5/15 $10,218 $10,180 $10,182 $10,181 6/15 $10,128 $10,066 $10,027 $10,026 7/15 $10,109 $10,125 $9,966 $9,964 8/15 $9,969 $10,095 $9,789 $9,789 9/15 $9,721 $10,134 $9,538 $9,535 10/15 $9,964 $10,167 $9,797 $9,795 11/15 $9,783 $10,130 $9,579 $9,575 12/15 $9,602 $10,079 $9,332 $9,328 1/16 $9,527 $10,190 $9,184 $9,180 2/16 $9,609 $10,263 $9,227 $9,223 3/16 $9,910 $10,388 $9,635 $9,631 4/16 $10,121 $10,459 $10,020 $10,016 5/16 $10,172 $10,467 $10,092 $10,088 6/16 $10,221 $10,652 $10,202 $10,197 7/16 $10,418 $10,739 $10,459 $10,455 8/16 $10,595 $10,751 $10,692 $10,688 9/16 $10,643 $10,753 $10,761 $10,757 10/16 $10,636 $10,682 $10,795 $10,790 11/16 $10,609 $10,442 $10,752 $10,748 12/16 $10,790 $10,473 $10,964 $10,959 1/17 $10,896 $10,510 $11,111 $11,106 2/17 $11,016 $10,591 $11,284 $11,280 3/17 $11,008 $10,588 $11,260 $11,256 4/17 $11,132 $10,675 $11,388 $11,384 5/17 $11,200 $10,758 $11,489 $11,485 6/17 $11,209 $10,749 $11,501 $11,497 7/17 $11,317 $10,802 $11,634 $11,630 8/17 $11,309 $10,895 $11,631 $11,627 9/17 $11,396 $10,857 $11,736 $11,732 10/17 $11,407 $10,870 $11,781 $11,777 11/17 $11,397 $10,854 $11,750 $11,745 12/17 $11,408 $10,901 $11,784 $11,779 1/18 $11,459 $10,797 $11,860 $11,855 2/18 $11,366 $10,694 $11,749 $11,744 3/18 $11,298 $10,748 $11,677 $11,672 4/18 $11,348 $10,676 $11,754 $11,750 5/18 $11,339 $10,735 $11,753 $11,748 6/18 $11,349 $10,719 $11,793 $11,788 7/18 $11,462 $10,741 $11,925 $11,920 8/18 $11,535 $10,794 $12,011 $12,006 9/18 $11,566 $10,748 $12,081 $12,076 10/18 $11,412 $10,658 $11,883 $11,878 11/18 $11,298 $10,706 $11,775 $11,771 12/18 $11,060 $10,874 $11,517 $11,513 1/19 $11,532 $11,024 $12,046 $12,041 2/19 $11,707 $11,036 $12,249 $12,245 3/19 $11,783 $11,235 $12,370 $12,365 4/19 $11,921 $11,251 $12,543 $12,538 5/19 $11,826 $11,423 $12,383 $12,378 6/19 $12,072 $11,585 $12,687 $12,682 7/19 $12,106 $11,619 $12,752 $12,747 8/19 $12,161 $11,882 $12,802 $12,797 9/19 $12,237 $11,830 $12,842 $12,837 10/19 $12,249 $11,869 $12,872 $12,867 11/19 $12,282 $11,866 $12,907 $12,902 12/19 $12,493 $11,884 $13,177 $13,172 1/20 $12,461 $12,097 $13,177 $13,172 2/20 $12,270 $12,278 $12,973 $12,968 3/20 $10,966 $12,039 $11,446 $11,443 4/20 $11,426 $12,280 $11,882 $11,878 5/20 $11,844 $12,394 $12,421 $12,421 6/20 $11,878 $12,498 $12,539 $12,542 7/20 $12,414 $12,717 $13,134 $13,142 8/20 $12,473 $12,644 $13,265 $13,271 9/20 $12,369 $12,621 $13,127 $13,133 10/20 $12,406 $12,576 $13,187 $13,194 11/20 $12,858 $12,740 $13,715 $13,722 12/20 $13,057 $12,784 $13,977 $13,984 1/21 $13,094 $12,704 $14,031 $14,037 2/21 $13,148 $12,540 $14,079 $14,086 3/21 $13,154 $12,394 $14,104 $14,110 4/21 $13,299 $12,498 $14,259 $14,265 5/21 $13,329 $12,546 $14,300 $14,306 6/21 $13,523 $12,637 $14,495 $14,502 7/21 $13,553 $12,764 $14,545 $14,553 8/21 $13,606 $12,756 $14,626 $14,633 9/21 $13,634 $12,647 $14,632 $14,638 10/21 $13,640 $12,636 $14,604 $14,612 11/21 $13,497 $12,652 $14,453 $14,462 12/21 $13,772 $12,643 $14,725 $14,734 1/22 $13,384 $12,366 $14,321 $14,329 2/22 $13,459 $12,197 $14,193 $14,200 3/22 $13,340 $11,870 $14,063 $14,069 4/22 $12,922 $11,427 $13,552 $13,557 5/22 $12,928 $11,490 $13,584 $13,591 6/22 $12,130 $11,261 $12,659 $12,666 7/22 $12,815 $11,544 $13,421 $13,429 8/22 $12,568 $11,244 $13,100 $13,107 9/22 $12,089 $10,759 $12,574 $12,580 10/22 $12,401 $10,641 $12,932 $12,938 11/22 $12,712 $11,038 $13,172 $13,180 12/22 $12,615 $11,001 $13,074 $13,081 1/23 $13,086 $11,342 $13,585 $13,593 2/23 $12,879 $11,063 $13,411 $13,417 3/23 $13,093 $11,323 $13,560 $13,568 4/23 $13,175 $11,392 $13,692 $13,699 5/23 $13,025 $11,274 $13,561 $13,569 6/23 $13,219 $11,256 $13,782 $13,789 7/23 $13,385 $11,267 $13,979 $13,986 8/23 $13,394 $11,200 $14,020 $14,026 9/23 $13,244 $10,932 $13,856 $13,863 10/23 $13,092 $10,768 $13,683 $13,691 11/23 $13,616 $11,253 $14,307 $14,314 12/23 $14,063 $11,680 $14,835 $14,842 1/24 $14,097 $11,652 $14,838 $14,844 2/24 $14,106 $11,512 $14,882 $14,888 3/24 $14,283 $11,625 $15,059 $15,066 4/24 $14,156 $11,353 $14,909 $14,915 5/24 $14,307 $11,542 $15,078 $15,084 6/24 $14,461 $11,647 $15,223 $15,230 7/24 $14,641 $11,911 $15,522 $15,529 8/24 $14,852 $12,087 $15,769 $15,776 9/24 $14,978 $12,253 $16,027 $16,034 10/24 $14,908 $11,974 $15,939 $15,945 |
| Average Annual Return [Table Text Block] | Fund 1 Year 5 Years 10 Years Class R 13.86% 4.00% 4.07% Bloomberg U.S. Universal Index Footnote Reference 11.20% 0.18% 1.82% ICE BofA U.S. High Yield Index 16.47% 4.38% 4.77% ICE BofA U.S. High Yield Constrained Index 16.49% 4.36% 4.77% |
| AssetsNet | $ 5,663,132,601 |
| Holdings Count | Holding | 432 |
| Advisory Fees Paid, Amount | $ 30,275,138 |
| InvestmentCompanyPortfolioTurnover | 45% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Total Net Assets $5,663,132,601 # of Portfolio Holdings 432 Portfolio Turnover Rate 45% Total Advisory Fees Paid $30,275,138 |
| Holdings [Text Block] | Asset Allocation (% of total investments) Value Value Other Footnote Reference 1.9% Short-Term Investments 3.6% Senior Floating-Rate Loans 7.9% Corporate Bonds 86.6% Footnote Description Footnote † Investment types less than 1% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 3.3% CCC or Lower 12.4% B 37.3% BB 44.3% BBB 2.7% Footnote Description Footnote a Excludes Short-Term Investments. Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). This breakdown assigns a numeric equivalent to the ratings from the aforementioned agencies and the mean is rounded to the nearest integer and converted to an equivalent S&P rating ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000142452 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Income Fund of Boston |
| Class Name | Class R6 |
| Trading Symbol | EIBRX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Eaton Vance Income Fund of Boston for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B119"><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: 12.8px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R6 $69 0.64% |
| Expenses Paid, Amount | $ 69 |
| Expense Ratio, Percent | 0.64% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year and what affected its performance? Key contributors to (↑) and detractors from (↓) performance, relative to the ICE BofA U.S. High Yield Index (the Index): ↓ The Fund’s security selections by sector ― especially in the health care, gaming, and retail sectors ― detracted from Index-relative returns during the period ↓ Fund allocations by credit quality ― particularly a broad underweight exposure to distressed CCC-rated and lower-rated securities ― detracted from returns ↓ Security selections by credit quality ― especially selections in B-rated and CCC-rated securities ― detracted from Index-relative returns during the period ↓ Security selections by duration segment ― particularly selections in securities with durations of less than 5 years ― hampered returns relative to the Index ↑ An overweight exposure to the health care sector and an underweight allocation to the energy sector contributed to Index-relative returns during the period ↑ The Fund’s selections in lower-rated fixed-income investments contributed to performance relative to the Index during the period ↑ The Fund’s underweight exposure to BB-rated securities contributed to performance relative to the Index during the period ↑ The Fund’s overweight exposure to securities with durations between 5-10 years contributed to performance relative to the Index during the period |
| Performance Past Does Not Indicate Future [Text] | THE FUND'S PAST PERFORMANCE IS NO GUARANTEE OF FUTURE RESULTS. |
| Line Graph [Table Text Block] | Class R6 Bloomberg U.S. Universal Index ICE BofA U.S. High Yield Constrained Index ICE BofA U.S. High Yield Index 10/14 $5,000,000 $5,000,000 $5,000,000 $5,000,000 11/14 $4,984,071 $5,026,983 $4,964,506 $4,964,261 12/14 $4,927,176 $5,017,901 $4,891,486 $4,891,071 1/15 $4,962,303 $5,113,418 $4,925,075 $4,924,804 2/15 $5,062,534 $5,083,617 $5,042,562 $5,042,299 3/15 $5,047,143 $5,104,598 $5,015,829 $5,015,515 4/15 $5,107,538 $5,098,676 $5,076,124 $5,075,649 5/15 $5,134,836 $5,089,756 $5,091,064 $5,090,684 6/15 $5,083,845 $5,032,951 $5,013,515 $5,013,033 7/15 $5,076,803 $5,062,258 $4,982,761 $4,982,170 8/15 $5,008,759 $5,047,342 $4,894,575 $4,894,426 9/15 $4,886,884 $5,067,099 $4,769,089 $4,767,458 10/15 $5,011,784 $5,083,296 $4,898,709 $4,897,418 11/15 $4,923,072 $5,064,759 $4,789,447 $4,787,472 12/15 $4,834,594 $5,039,457 $4,665,950 $4,663,980 1/16 $4,799,259 $5,095,087 $4,592,140 $4,590,211 2/16 $4,842,988 $5,131,280 $4,613,499 $4,611,559 3/16 $5,006,424 $5,194,166 $4,817,436 $4,815,408 4/16 $5,115,237 $5,229,555 $5,009,932 $5,007,821 5/16 $5,134,033 $5,233,640 $5,046,075 $5,043,956 6/16 $5,161,207 $5,325,777 $5,100,784 $5,098,626 7/16 $5,263,437 $5,369,663 $5,229,613 $5,227,404 8/16 $5,355,723 $5,375,456 $5,346,098 $5,343,841 9/16 $5,382,205 $5,376,733 $5,380,675 $5,378,413 10/16 $5,381,512 $5,341,063 $5,397,491 $5,395,221 11/16 $5,370,502 $5,221,011 $5,376,203 $5,373,943 12/16 $5,464,665 $5,236,520 $5,481,910 $5,479,647 1/17 $5,521,194 $5,254,995 $5,555,480 $5,553,229 2/17 $5,584,286 $5,295,541 $5,642,086 $5,639,885 3/17 $5,582,925 $5,293,767 $5,630,236 $5,628,052 4/17 $5,648,381 $5,337,691 $5,693,959 $5,691,820 5/17 $5,695,616 $5,378,873 $5,744,605 $5,742,659 6/17 $5,703,127 $5,374,313 $5,750,699 $5,748,721 7/17 $5,750,820 $5,401,082 $5,817,173 $5,815,028 8/17 $5,749,426 $5,447,680 $5,815,607 $5,813,521 9/17 $5,796,664 $5,428,508 $5,867,791 $5,865,750 10/17 $5,815,152 $5,435,026 $5,890,687 $5,888,386 11/17 $5,802,797 $5,426,801 $5,874,971 $5,872,586 12/17 $5,811,404 $5,450,725 $5,892,098 $5,889,701 1/18 $5,840,273 $5,398,274 $5,929,878 $5,927,465 2/18 $5,795,379 $5,347,087 $5,874,591 $5,872,203 3/18 $5,763,300 $5,374,056 $5,838,320 $5,835,951 4/18 $5,791,675 $5,338,197 $5,877,158 $5,874,769 5/18 $5,790,222 $5,367,309 $5,876,326 $5,873,883 6/18 $5,798,149 $5,359,525 $5,896,626 $5,894,167 7/18 $5,859,113 $5,370,741 $5,962,508 $5,960,031 8/18 $5,899,473 $5,397,201 $6,005,691 $6,003,194 9/18 $5,918,026 $5,374,074 $6,040,593 $6,038,078 10/18 $5,842,538 $5,329,118 $5,941,629 $5,939,196 11/18 $5,786,937 $5,353,085 $5,887,696 $5,885,301 12/18 $5,667,988 $5,436,837 $5,758,585 $5,756,303 1/19 $5,913,374 $5,511,800 $6,023,043 $6,020,687 2/19 $6,005,973 $5,517,807 $6,124,744 $6,122,346 3/19 $6,047,800 $5,617,446 $6,184,757 $6,182,335 4/19 $6,121,504 $5,625,309 $6,271,292 $6,268,828 5/19 $6,076,143 $5,711,481 $6,191,571 $6,189,148 6/19 $6,205,636 $5,792,265 $6,343,395 $6,340,912 7/19 $6,226,194 $5,809,507 $6,375,884 $6,373,380 8/19 $6,257,943 $5,940,961 $6,400,756 $6,398,251 9/19 $6,299,997 $5,915,222 $6,421,056 $6,418,535 10/19 $6,309,615 $5,934,333 $6,435,968 $6,433,439 11/19 $6,329,562 $5,933,147 $6,453,546 $6,451,007 12/19 $6,441,384 $5,941,988 $6,588,441 $6,585,862 1/20 $6,428,371 $6,048,634 $6,588,723 $6,586,141 2/20 $6,332,938 $6,139,202 $6,486,599 $6,484,063 3/20 $5,663,471 $6,019,281 $5,723,218 $5,721,614 4/20 $5,903,988 $6,139,856 $5,940,811 $5,939,056 5/20 $6,123,604 $6,197,201 $6,210,305 $6,210,687 6/20 $6,144,289 $6,248,911 $6,269,303 $6,271,222 7/20 $6,413,342 $6,358,678 $6,566,814 $6,570,864 8/20 $6,458,994 $6,322,012 $6,632,456 $6,635,524 9/20 $6,408,616 $6,310,618 $6,563,711 $6,566,352 10/20 $6,430,837 $6,288,063 $6,593,322 $6,597,056 11/20 $6,668,448 $6,370,118 $6,857,611 $6,861,118 12/20 $6,775,446 $6,392,115 $6,988,570 $6,991,982 1/21 $6,798,006 $6,351,938 $7,015,529 $7,018,743 2/21 $6,829,501 $6,269,979 $7,039,710 $7,043,199 3/21 $6,835,597 $6,197,013 $7,052,195 $7,055,191 4/21 $6,914,622 $6,249,123 $7,129,348 $7,132,581 5/21 $6,933,163 $6,272,959 $7,149,931 $7,153,168 6/21 $7,037,726 $6,318,690 $7,247,272 $7,250,902 7/21 $7,056,392 $6,382,137 $7,272,708 $7,276,711 8/21 $7,087,688 $6,377,877 $7,312,844 $7,316,398 9/21 $7,105,520 $6,323,413 $7,315,820 $7,318,852 10/21 $7,099,160 $6,318,245 $7,302,052 $7,305,833 11/21 $7,040,950 $6,325,877 $7,226,351 $7,230,964 12/21 $7,174,843 $6,321,611 $7,362,248 $7,367,003 1/22 $6,989,027 $6,183,015 $7,160,413 $7,164,488 2/22 $7,030,927 $6,098,716 $7,096,295 $7,100,160 3/22 $6,972,728 $5,935,095 $7,031,330 $7,034,464 4/22 $6,757,397 $5,713,731 $6,775,915 $6,778,577 5/22 $6,763,880 $5,745,169 $6,792,124 $6,795,548 6/22 $6,349,873 $5,630,366 $6,329,372 $6,332,998 7/22 $6,712,119 $5,771,925 $6,710,273 $6,714,430 8/22 $6,573,071 $5,621,876 $6,549,956 $6,553,636 9/22 $6,339,107 $5,379,665 $6,286,909 $6,290,060 10/22 $6,506,237 $5,320,638 $6,465,791 $6,469,117 11/22 $6,673,147 $5,519,025 $6,586,043 $6,590,215 12/22 $6,612,318 $5,500,280 $6,536,906 $6,540,580 1/23 $6,877,042 $5,670,901 $6,792,406 $6,796,290 2/23 $6,771,366 $5,531,557 $6,705,279 $6,708,341 3/23 $6,887,837 $5,661,324 $6,779,780 $6,783,854 4/23 $6,934,095 $5,695,908 $6,845,845 $6,849,331 5/23 $6,858,776 $5,636,854 $6,780,641 $6,784,298 6/23 $6,950,343 $5,628,094 $6,890,933 $6,894,729 7/23 $7,041,117 $5,633,689 $6,989,417 $6,992,911 8/23 $7,063,119 $5,599,763 $7,010,211 $7,012,864 9/23 $6,987,548 $5,466,236 $6,927,838 $6,931,303 10/23 $6,896,821 $5,384,034 $6,841,331 $6,845,514 11/23 $7,176,725 $5,626,342 $7,153,641 $7,156,864 12/23 $7,416,009 $5,839,829 $7,417,634 $7,420,795 1/24 $7,437,831 $5,825,853 $7,419,059 $7,422,172 2/24 $7,446,188 $5,756,004 $7,441,024 $7,444,150 3/24 $7,543,548 $5,812,519 $7,529,661 $7,532,827 4/24 $7,480,007 $5,676,689 $7,454,370 $7,457,495 5/24 $7,578,300 $5,770,788 $7,538,958 $7,542,113 6/24 $7,648,491 $5,823,542 $7,611,724 $7,614,920 7/24 $7,762,961 $5,955,723 $7,761,093 $7,764,351 8/24 $7,878,576 $6,043,397 $7,884,548 $7,887,853 9/24 $7,949,157 $6,126,285 $8,013,391 $8,016,753 10/24 $7,915,498 $5,987,140 $7,969,291 $7,972,633 |
| Average Annual Return [Table Text Block] | Fund 1 Year 5 Years 10 Years Class R6 14.77% 4.63% 4.70% Bloomberg U.S. Universal Index Footnote Reference 11.20% 0.18% 1.82% ICE BofA U.S. High Yield Index 16.47% 4.38% 4.77% ICE BofA U.S. High Yield Constrained Index 16.49% 4.36% 4.77% |
| AssetsNet | $ 5,663,132,601 |
| Holdings Count | Holding | 432 |
| Advisory Fees Paid, Amount | $ 30,275,138 |
| InvestmentCompanyPortfolioTurnover | 45% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Total Net Assets $5,663,132,601 # of Portfolio Holdings 432 Portfolio Turnover Rate 45% Total Advisory Fees Paid $30,275,138 |
| Holdings [Text Block] | Asset Allocation (% of total investments) Value Value Other Footnote Reference 1.9% Short-Term Investments 3.6% Senior Floating-Rate Loans 7.9% Corporate Bonds 86.6% Footnote Description Footnote † Investment types less than 1% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 3.3% CCC or Lower 12.4% B 37.3% BB 44.3% BBB 2.7% Footnote Description Footnote a Excludes Short-Term Investments. Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). This breakdown assigns a numeric equivalent to the ratings from the aforementioned agencies and the mean is rounded to the nearest integer and converted to an equivalent S&P rating ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Oct. 31, 2024 | Sep. 30, 2024 | Aug. 31, 2024 | Jul. 31, 2024 | Jun. 30, 2024 | May 31, 2024 | Apr. 30, 2024 | Mar. 31, 2024 | Feb. 29, 2024 | Jan. 31, 2024 | Dec. 31, 2023 | Nov. 30, 2023 | Oct. 31, 2023 | Sep. 30, 2023 | Aug. 31, 2023 | Jul. 31, 2023 | Jun. 30, 2023 | May 31, 2023 | Apr. 30, 2023 | Mar. 31, 2023 | Feb. 28, 2023 | Jan. 31, 2023 | Dec. 31, 2022 | Nov. 30, 2022 | Oct. 31, 2022 | Sep. 30, 2022 | Aug. 31, 2022 | Jul. 31, 2022 | Jun. 30, 2022 | May 31, 2022 | Apr. 30, 2022 | Mar. 31, 2022 | Feb. 28, 2022 | Jan. 31, 2022 | Dec. 31, 2021 | Nov. 30, 2021 | Oct. 31, 2021 | Sep. 30, 2021 | Aug. 31, 2021 | Jul. 31, 2021 | Jun. 30, 2021 | May 31, 2021 | Apr. 30, 2021 | Mar. 31, 2021 | Feb. 28, 2021 | Jan. 31, 2021 | Dec. 31, 2020 | Nov. 30, 2020 | Oct. 31, 2020 | Sep. 30, 2020 | Aug. 31, 2020 | Jul. 31, 2020 | Jun. 30, 2020 | May 31, 2020 | Apr. 30, 2020 | Mar. 31, 2020 | Feb. 29, 2020 | Jan. 31, 2020 | Dec. 31, 2019 | Nov. 30, 2019 | Oct. 31, 2019 | Sep. 30, 2019 | Aug. 31, 2019 | Jul. 31, 2019 | Jun. 30, 2019 | May 31, 2019 | Apr. 30, 2019 | Mar. 31, 2019 | Feb. 28, 2019 | Jan. 31, 2019 | Dec. 31, 2018 | Nov. 30, 2018 | Oct. 31, 2018 | Sep. 30, 2018 | Aug. 31, 2018 | Jul. 31, 2018 | Jun. 30, 2018 | May 31, 2018 | Apr. 30, 2018 | Mar. 31, 2018 | Feb. 28, 2018 | Jan. 31, 2018 | Dec. 31, 2017 | Nov. 30, 2017 | Oct. 31, 2017 | Sep. 30, 2017 | Aug. 31, 2017 | Jul. 31, 2017 | Jun. 30, 2017 | May 31, 2017 | Apr. 30, 2017 | Mar. 31, 2017 | Feb. 28, 2017 | Jan. 31, 2017 | Dec. 31, 2016 | Nov. 30, 2016 | Oct. 31, 2016 | Sep. 30, 2016 | Aug. 31, 2016 | Jul. 31, 2016 | Jun. 30, 2016 | May 31, 2016 | Apr. 30, 2016 | Mar. 31, 2016 | Feb. 29, 2016 | Jan. 31, 2016 | Dec. 31, 2015 | Nov. 30, 2015 | Oct. 31, 2015 | Sep. 30, 2015 | Aug. 31, 2015 | Jul. 31, 2015 | Jun. 30, 2015 | May 31, 2015 | Apr. 30, 2015 | Mar. 31, 2015 | Feb. 28, 2015 | Jan. 31, 2015 | Dec. 31, 2014 | Nov. 30, 2014 | Oct. 31, 2014 | |
| C000013484 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Class A with Maximum Sales Charge | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 14,808 | $ 14,869 | $ 14,741 | $ 14,529 | $ 14,319 | $ 14,191 | $ 14,011 | $ 14,135 | $ 13,956 | $ 13,944 | $ 13,907 | $ 13,462 | $ 12,941 | $ 13,115 | $ 13,261 | $ 13,223 | $ 13,056 | $ 12,862 | $ 13,007 | $ 12,924 | $ 12,735 | $ 12,937 | $ 12,443 | $ 12,536 | $ 12,226 | $ 11,941 | $ 12,385 | $ 12,651 | $ 11,972 | $ 12,757 | $ 12,749 | $ 13,135 | $ 13,248 | $ 13,197 | $ 13,552 | $ 13,303 | $ 13,417 | $ 13,409 | $ 13,402 | $ 13,347 | $ 13,315 | $ 13,121 | $ 13,067 | $ 12,944 | $ 12,913 | $ 12,857 | $ 12,841 | $ 12,642 | $ 12,172 | $ 12,133 | $ 12,255 | $ 12,172 | $ 11,665 | $ 11,629 | $ 11,193 | $ 10,762 | $ 12,038 | $ 12,222 | $ 12,251 | $ 12,041 | $ 11,985 | $ 11,971 | $ 11,915 | $ 11,858 | $ 11,801 | $ 11,579 | $ 11,669 | $ 11,531 | $ 11,434 | $ 11,281 | $ 10,816 | $ 11,046 | $ 11,136 | $ 11,303 | $ 11,251 | $ 11,197 | $ 11,083 | $ 11,071 | $ 11,077 | $ 11,026 | $ 11,091 | $ 11,179 | $ 11,127 | $ 11,095 | $ 11,121 | $ 11,108 | $ 11,020 | $ 11,026 | $ 10,919 | $ 10,907 | $ 10,839 | $ 10,716 | $ 10,721 | $ 10,603 | $ 10,497 | $ 10,319 | $ 10,343 | $ 10,348 | $ 10,281 | $ 10,125 | $ 9,931 | $ 9,881 | $ 9,830 | $ 9,624 | $ 9,329 | $ 9,230 | $ 9,318 | $ 9,491 | $ 9,665 | $ 9,427 | $ 9,665 | $ 9,799 | $ 9,799 | $ 9,900 | $ 9,850 | $ 9,753 | $ 9,785 | $ 9,594 | $ 9,513 | $ 9,625 | $ 10,000 |
| C000013486 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Class C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 14,416 | 14,238 | 14,124 | 13,930 | 13,764 | 13,623 | 13,486 | 13,585 | 13,423 | 13,419 | 13,418 | 12,998 | 12,504 | 12,654 | 12,802 | 12,799 | 12,646 | 12,466 | 12,614 | 12,541 | 12,342 | 12,546 | 12,100 | 12,199 | 11,907 | 11,614 | 12,054 | 12,321 | 11,669 | 12,441 | 12,441 | 12,849 | 12,944 | 12,902 | 13,257 | 13,021 | 13,140 | 13,164 | 13,143 | 13,096 | 13,074 | 12,891 | 12,868 | 12,733 | 12,733 | 12,685 | 12,655 | 12,467 | 12,012 | 11,982 | 12,110 | 12,036 | 11,544 | 11,516 | 11,093 | 10,673 | 11,945 | 12,136 | 12,172 | 11,972 | 11,924 | 11,917 | 11,869 | 11,820 | 11,771 | 11,536 | 11,654 | 11,524 | 11,435 | 11,289 | 10,831 | 11,069 | 11,166 | 11,341 | 11,295 | 11,229 | 11,122 | 11,117 | 11,150 | 11,106 | 11,158 | 11,273 | 11,228 | 11,202 | 11,236 | 11,210 | 11,148 | 11,160 | 11,059 | 11,054 | 10,972 | 10,874 | 10,886 | 10,772 | 10,671 | 10,497 | 10,528 | 10,539 | 10,478 | 10,307 | 10,116 | 10,090 | 10,044 | 9,839 | 9,545 | 9,450 | 9,529 | 9,712 | 9,896 | 9,659 | 9,927 | 10,071 | 10,077 | 10,188 | 10,143 | 10,049 | 10,072 | 9,898 | 9,820 | 9,943 | 10,000 |
| C000013488 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Class I | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 1,569,041 | 1,575,784 | 1,561,896 | 1,539,065 | 1,516,486 | 1,502,682 | 1,483,305 | 1,496,030 | 1,476,835 | 1,475,284 | 1,471,071 | 1,423,714 | 1,368,288 | 1,386,397 | 1,401,496 | 1,397,237 | 1,379,331 | 1,361,261 | 1,376,317 | 1,367,240 | 1,344,234 | 1,365,318 | 1,312,872 | 1,322,382 | 1,292,016 | 1,258,937 | 1,305,514 | 1,333,246 | 1,261,397 | 1,343,753 | 1,342,575 | 1,385,467 | 1,394,573 | 1,388,902 | 1,425,939 | 1,399,435 | 1,411,109 | 1,412,480 | 1,409,038 | 1,402,922 | 1,399,313 | 1,378,622 | 1,375,042 | 1,359,425 | 1,355,882 | 1,349,707 | 1,347,744 | 1,326,563 | 1,277,004 | 1,272,681 | 1,285,166 | 1,276,179 | 1,222,736 | 1,218,715 | 1,175,102 | 1,127,324 | 1,260,692 | 1,279,776 | 1,282,467 | 1,260,302 | 1,256,421 | 1,254,597 | 1,246,312 | 1,240,079 | 1,233,877 | 1,210,367 | 1,219,498 | 1,204,901 | 1,196,661 | 1,178,288 | 1,129,482 | 1,153,278 | 1,164,448 | 1,179,585 | 1,175,973 | 1,168,019 | 1,155,949 | 1,154,452 | 1,154,832 | 1,149,258 | 1,155,739 | 1,164,766 | 1,159,088 | 1,157,451 | 1,159,996 | 1,156,388 | 1,147,044 | 1,147,402 | 1,137,972 | 1,136,559 | 1,127,218 | 1,114,232 | 1,114,587 | 1,102,070 | 1,090,868 | 1,072,149 | 1,074,426 | 1,074,644 | 1,069,436 | 1,051,085 | 1,030,750 | 1,025,397 | 1,019,897 | 998,237 | 967,475 | 958,811 | 965,948 | 983,701 | 1,001,501 | 976,618 | 1,001,047 | 1,014,723 | 1,016,208 | 1,026,474 | 1,021,089 | 1,009,086 | 1,012,236 | 992,258 | 985,305 | 995,085 | 1,000,000 |
| C000013487 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Class R | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 14,908 | 14,978 | 14,852 | 14,641 | 14,461 | 14,307 | 14,156 | 14,283 | 14,106 | 14,097 | 14,063 | 13,616 | 13,092 | 13,244 | 13,394 | 13,385 | 13,219 | 13,025 | 13,175 | 13,093 | 12,879 | 13,086 | 12,615 | 12,712 | 12,401 | 12,089 | 12,568 | 12,815 | 12,130 | 12,928 | 12,922 | 13,340 | 13,459 | 13,384 | 13,772 | 13,497 | 13,640 | 13,634 | 13,606 | 13,553 | 13,523 | 13,329 | 13,299 | 13,154 | 13,148 | 13,094 | 13,057 | 12,858 | 12,406 | 12,369 | 12,473 | 12,414 | 11,878 | 11,844 | 11,426 | 10,966 | 12,270 | 12,461 | 12,493 | 12,282 | 12,249 | 12,237 | 12,161 | 12,106 | 12,072 | 11,826 | 11,921 | 11,783 | 11,707 | 11,532 | 11,060 | 11,298 | 11,412 | 11,566 | 11,535 | 11,462 | 11,349 | 11,339 | 11,348 | 11,298 | 11,366 | 11,459 | 11,408 | 11,397 | 11,407 | 11,396 | 11,309 | 11,317 | 11,209 | 11,200 | 11,132 | 11,008 | 11,016 | 10,896 | 10,790 | 10,609 | 10,636 | 10,643 | 10,595 | 10,418 | 10,221 | 10,172 | 10,121 | 9,910 | 9,609 | 9,527 | 9,602 | 9,783 | 9,964 | 9,721 | 9,969 | 10,109 | 10,128 | 10,218 | 10,168 | 10,070 | 10,106 | 9,910 | 9,828 | 9,947 | 10,000 |
| C000142452 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Class R6 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 7,915,498 | 7,949,157 | 7,878,576 | 7,762,961 | 7,648,491 | 7,578,300 | 7,480,007 | 7,543,548 | 7,446,188 | 7,437,831 | 7,416,009 | 7,176,725 | 6,896,821 | 6,987,548 | 7,063,119 | 7,041,117 | 6,950,343 | 6,858,776 | 6,934,095 | 6,887,837 | 6,771,366 | 6,877,042 | 6,612,318 | 6,673,147 | 6,506,237 | 6,339,107 | 6,573,071 | 6,712,119 | 6,349,873 | 6,763,880 | 6,757,397 | 6,972,728 | 7,030,927 | 6,989,027 | 7,174,843 | 7,040,950 | 7,099,160 | 7,105,520 | 7,087,688 | 7,056,392 | 7,037,726 | 6,933,163 | 6,914,622 | 6,835,597 | 6,829,501 | 6,798,006 | 6,775,446 | 6,668,448 | 6,430,837 | 6,408,616 | 6,458,994 | 6,413,342 | 6,144,289 | 6,123,604 | 5,903,988 | 5,663,471 | 6,332,938 | 6,428,371 | 6,441,384 | 6,329,562 | 6,309,615 | 6,299,997 | 6,257,943 | 6,226,194 | 6,205,636 | 6,076,143 | 6,121,504 | 6,047,800 | 6,005,973 | 5,913,374 | 5,667,988 | 5,786,937 | 5,842,538 | 5,918,026 | 5,899,473 | 5,859,113 | 5,798,149 | 5,790,222 | 5,791,675 | 5,763,300 | 5,795,379 | 5,840,273 | 5,811,404 | 5,802,797 | 5,815,152 | 5,796,664 | 5,749,426 | 5,750,820 | 5,703,127 | 5,695,616 | 5,648,381 | 5,582,925 | 5,584,286 | 5,521,194 | 5,464,665 | 5,370,502 | 5,381,512 | 5,382,205 | 5,355,723 | 5,263,437 | 5,161,207 | 5,134,033 | 5,115,237 | 5,006,424 | 4,842,988 | 4,799,259 | 4,834,594 | 4,923,072 | 5,011,784 | 4,886,884 | 5,008,759 | 5,076,803 | 5,083,845 | 5,134,836 | 5,107,538 | 5,047,143 | 5,062,534 | 4,962,303 | 4,927,176 | 4,984,071 | 5,000,000 |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 11,974 | 12,253 | 12,087 | 11,911 | 11,647 | 11,542 | 11,353 | 11,625 | 11,512 | 11,652 | 11,680 | 11,253 | 10,768 | 10,932 | 11,200 | 11,267 | 11,256 | 11,274 | 11,392 | 11,323 | 11,063 | 11,342 | 11,001 | 11,038 | 10,641 | 10,759 | 11,244 | 11,544 | 11,261 | 11,490 | 11,427 | 11,870 | 12,197 | 12,366 | 12,643 | 12,652 | 12,636 | 12,647 | 12,756 | 12,764 | 12,637 | 12,546 | 12,498 | 12,394 | 12,540 | 12,704 | 12,784 | 12,740 | 12,576 | 12,621 | 12,644 | 12,717 | 12,498 | 12,394 | 12,280 | 12,039 | 12,278 | 12,097 | 11,884 | 11,866 | 11,869 | 11,830 | 11,882 | 11,619 | 11,585 | 11,423 | 11,251 | 11,235 | 11,036 | 11,024 | 10,874 | 10,706 | 10,658 | 10,748 | 10,794 | 10,741 | 10,719 | 10,735 | 10,676 | 10,748 | 10,694 | 10,797 | 10,901 | 10,854 | 10,870 | 10,857 | 10,895 | 10,802 | 10,749 | 10,758 | 10,675 | 10,588 | 10,591 | 10,510 | 10,473 | 10,442 | 10,682 | 10,753 | 10,751 | 10,739 | 10,652 | 10,467 | 10,459 | 10,388 | 10,263 | 10,190 | 10,079 | 10,130 | 10,167 | 10,134 | 10,095 | 10,125 | 10,066 | 10,180 | 10,197 | 10,209 | 10,167 | 10,227 | 10,036 | 10,054 | 10,000 |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 11,974 | 12,253 | 12,087 | 11,911 | 11,647 | 11,542 | 11,353 | 11,625 | 11,512 | 11,652 | 11,680 | 11,253 | 10,768 | 10,932 | 11,200 | 11,267 | 11,256 | 11,274 | 11,392 | 11,323 | 11,063 | 11,342 | 11,001 | 11,038 | 10,641 | 10,759 | 11,244 | 11,544 | 11,261 | 11,490 | 11,427 | 11,870 | 12,197 | 12,366 | 12,643 | 12,652 | 12,636 | 12,647 | 12,756 | 12,764 | 12,637 | 12,546 | 12,498 | 12,394 | 12,540 | 12,704 | 12,784 | 12,740 | 12,576 | 12,621 | 12,644 | 12,717 | 12,498 | 12,394 | 12,280 | 12,039 | 12,278 | 12,097 | 11,884 | 11,866 | 11,869 | 11,830 | 11,882 | 11,619 | 11,585 | 11,423 | 11,251 | 11,235 | 11,036 | 11,024 | 10,874 | 10,706 | 10,658 | 10,748 | 10,794 | 10,741 | 10,719 | 10,735 | 10,676 | 10,748 | 10,694 | 10,797 | 10,901 | 10,854 | 10,870 | 10,857 | 10,895 | 10,802 | 10,749 | 10,758 | 10,675 | 10,588 | 10,591 | 10,510 | 10,473 | 10,442 | 10,682 | 10,753 | 10,751 | 10,739 | 10,652 | 10,467 | 10,459 | 10,388 | 10,263 | 10,190 | 10,079 | 10,130 | 10,167 | 10,134 | 10,095 | 10,125 | 10,066 | 10,180 | 10,197 | 10,209 | 10,167 | 10,227 | 10,036 | 10,054 | 10,000 |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 1,197,428 | 1,225,257 | 1,208,679 | 1,191,145 | 1,164,708 | 1,154,158 | 1,135,338 | 1,162,504 | 1,151,201 | 1,165,171 | 1,167,966 | 1,125,268 | 1,076,807 | 1,093,247 | 1,119,953 | 1,126,738 | 1,125,619 | 1,127,371 | 1,139,182 | 1,132,265 | 1,106,311 | 1,134,180 | 1,100,056 | 1,103,805 | 1,064,128 | 1,075,933 | 1,124,375 | 1,154,385 | 1,126,073 | 1,149,034 | 1,142,746 | 1,187,019 | 1,219,743 | 1,236,603 | 1,264,322 | 1,265,175 | 1,263,649 | 1,264,683 | 1,275,575 | 1,276,427 | 1,263,738 | 1,254,592 | 1,249,825 | 1,239,403 | 1,253,996 | 1,270,388 | 1,278,423 | 1,274,024 | 1,257,613 | 1,262,124 | 1,264,402 | 1,271,736 | 1,249,782 | 1,239,440 | 1,227,971 | 1,203,856 | 1,227,840 | 1,209,727 | 1,188,398 | 1,186,629 | 1,186,867 | 1,183,044 | 1,188,192 | 1,161,901 | 1,158,453 | 1,142,296 | 1,125,062 | 1,123,489 | 1,103,561 | 1,102,360 | 1,087,367 | 1,070,617 | 1,065,824 | 1,074,815 | 1,079,440 | 1,074,148 | 1,071,905 | 1,073,462 | 1,067,639 | 1,074,811 | 1,069,417 | 1,079,655 | 1,090,145 | 1,085,360 | 1,087,005 | 1,085,702 | 1,089,536 | 1,080,216 | 1,074,863 | 1,075,775 | 1,067,538 | 1,058,753 | 1,059,108 | 1,050,999 | 1,047,304 | 1,044,202 | 1,068,213 | 1,075,347 | 1,075,091 | 1,073,933 | 1,065,155 | 1,046,728 | 1,045,911 | 1,038,833 | 1,026,256 | 1,019,017 | 1,007,891 | 1,012,952 | 1,016,659 | 1,013,420 | 1,009,468 | 1,012,452 | 1,006,590 | 1,017,951 | 1,019,735 | 1,020,920 | 1,016,723 | 1,022,684 | 1,003,580 | 1,005,397 | 1,000,000 |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 11,974 | 12,253 | 12,087 | 11,911 | 11,647 | 11,542 | 11,353 | 11,625 | 11,512 | 11,652 | 11,680 | 11,253 | 10,768 | 10,932 | 11,200 | 11,267 | 11,256 | 11,274 | 11,392 | 11,323 | 11,063 | 11,342 | 11,001 | 11,038 | 10,641 | 10,759 | 11,244 | 11,544 | 11,261 | 11,490 | 11,427 | 11,870 | 12,197 | 12,366 | 12,643 | 12,652 | 12,636 | 12,647 | 12,756 | 12,764 | 12,637 | 12,546 | 12,498 | 12,394 | 12,540 | 12,704 | 12,784 | 12,740 | 12,576 | 12,621 | 12,644 | 12,717 | 12,498 | 12,394 | 12,280 | 12,039 | 12,278 | 12,097 | 11,884 | 11,866 | 11,869 | 11,830 | 11,882 | 11,619 | 11,585 | 11,423 | 11,251 | 11,235 | 11,036 | 11,024 | 10,874 | 10,706 | 10,658 | 10,748 | 10,794 | 10,741 | 10,719 | 10,735 | 10,676 | 10,748 | 10,694 | 10,797 | 10,901 | 10,854 | 10,870 | 10,857 | 10,895 | 10,802 | 10,749 | 10,758 | 10,675 | 10,588 | 10,591 | 10,510 | 10,473 | 10,442 | 10,682 | 10,753 | 10,751 | 10,739 | 10,652 | 10,467 | 10,459 | 10,388 | 10,263 | 10,190 | 10,079 | 10,130 | 10,167 | 10,134 | 10,095 | 10,125 | 10,066 | 10,180 | 10,197 | 10,209 | 10,167 | 10,227 | 10,036 | 10,054 | 10,000 |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 5,987,140 | 6,126,285 | 6,043,397 | 5,955,723 | 5,823,542 | 5,770,788 | 5,676,689 | 5,812,519 | 5,756,004 | 5,825,853 | 5,839,829 | 5,626,342 | 5,384,034 | 5,466,236 | 5,599,763 | 5,633,689 | 5,628,094 | 5,636,854 | 5,695,908 | 5,661,324 | 5,531,557 | 5,670,901 | 5,500,280 | 5,519,025 | 5,320,638 | 5,379,665 | 5,621,876 | 5,771,925 | 5,630,366 | 5,745,169 | 5,713,731 | 5,935,095 | 6,098,716 | 6,183,015 | 6,321,611 | 6,325,877 | 6,318,245 | 6,323,413 | 6,377,877 | 6,382,137 | 6,318,690 | 6,272,959 | 6,249,123 | 6,197,013 | 6,269,979 | 6,351,938 | 6,392,115 | 6,370,118 | 6,288,063 | 6,310,618 | 6,322,012 | 6,358,678 | 6,248,911 | 6,197,201 | 6,139,856 | 6,019,281 | 6,139,202 | 6,048,634 | 5,941,988 | 5,933,147 | 5,934,333 | 5,915,222 | 5,940,961 | 5,809,507 | 5,792,265 | 5,711,481 | 5,625,309 | 5,617,446 | 5,517,807 | 5,511,800 | 5,436,837 | 5,353,085 | 5,329,118 | 5,374,074 | 5,397,201 | 5,370,741 | 5,359,525 | 5,367,309 | 5,338,197 | 5,374,056 | 5,347,087 | 5,398,274 | 5,450,725 | 5,426,801 | 5,435,026 | 5,428,508 | 5,447,680 | 5,401,082 | 5,374,313 | 5,378,873 | 5,337,691 | 5,293,767 | 5,295,541 | 5,254,995 | 5,236,520 | 5,221,011 | 5,341,063 | 5,376,733 | 5,375,456 | 5,369,663 | 5,325,777 | 5,233,640 | 5,229,555 | 5,194,166 | 5,131,280 | 5,095,087 | 5,039,457 | 5,064,759 | 5,083,296 | 5,067,099 | 5,047,342 | 5,062,258 | 5,032,951 | 5,089,756 | 5,098,676 | 5,104,598 | 5,083,617 | 5,113,418 | 5,017,901 | 5,026,983 | 5,000,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,939 | 16,027 | 15,769 | 15,522 | 15,223 | 15,078 | 14,909 | 15,059 | 14,882 | 14,838 | 14,835 | 14,307 | 13,683 | 13,856 | 14,020 | 13,979 | 13,782 | 13,561 | 13,692 | 13,560 | 13,411 | 13,585 | 13,074 | 13,172 | 12,932 | 12,574 | 13,100 | 13,421 | 12,659 | 13,584 | 13,552 | 14,063 | 14,193 | 14,321 | 14,725 | 14,453 | 14,604 | 14,632 | 14,626 | 14,545 | 14,495 | 14,300 | 14,259 | 14,104 | 14,079 | 14,031 | 13,977 | 13,715 | 13,187 | 13,127 | 13,265 | 13,134 | 12,539 | 12,421 | 11,882 | 11,446 | 12,973 | 13,177 | 13,177 | 12,907 | 12,872 | 12,842 | 12,802 | 12,752 | 12,687 | 12,383 | 12,543 | 12,370 | 12,249 | 12,046 | 11,517 | 11,775 | 11,883 | 12,081 | 12,011 | 11,925 | 11,793 | 11,753 | 11,754 | 11,677 | 11,749 | 11,860 | 11,784 | 11,750 | 11,781 | 11,736 | 11,631 | 11,634 | 11,501 | 11,489 | 11,388 | 11,260 | 11,284 | 11,111 | 10,964 | 10,752 | 10,795 | 10,761 | 10,692 | 10,459 | 10,202 | 10,092 | 10,020 | 9,635 | 9,227 | 9,184 | 9,332 | 9,579 | 9,797 | 9,538 | 9,789 | 9,966 | 10,027 | 10,182 | 10,152 | 10,032 | 10,085 | 9,850 | 9,783 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,945 | 16,034 | 15,776 | 15,529 | 15,230 | 15,084 | 14,915 | 15,066 | 14,888 | 14,844 | 14,842 | 14,314 | 13,691 | 13,863 | 14,026 | 13,986 | 13,789 | 13,569 | 13,699 | 13,568 | 13,417 | 13,593 | 13,081 | 13,180 | 12,938 | 12,580 | 13,107 | 13,429 | 12,666 | 13,591 | 13,557 | 14,069 | 14,200 | 14,329 | 14,734 | 14,462 | 14,612 | 14,638 | 14,633 | 14,553 | 14,502 | 14,306 | 14,265 | 14,110 | 14,086 | 14,037 | 13,984 | 13,722 | 13,194 | 13,133 | 13,271 | 13,142 | 12,542 | 12,421 | 11,878 | 11,443 | 12,968 | 13,172 | 13,172 | 12,902 | 12,867 | 12,837 | 12,797 | 12,747 | 12,682 | 12,378 | 12,538 | 12,365 | 12,245 | 12,041 | 11,513 | 11,771 | 11,878 | 12,076 | 12,006 | 11,920 | 11,788 | 11,748 | 11,750 | 11,672 | 11,744 | 11,855 | 11,779 | 11,745 | 11,777 | 11,732 | 11,627 | 11,630 | 11,497 | 11,485 | 11,384 | 11,256 | 11,280 | 11,106 | 10,959 | 10,748 | 10,790 | 10,757 | 10,688 | 10,455 | 10,197 | 10,088 | 10,016 | 9,631 | 9,223 | 9,180 | 9,328 | 9,575 | 9,795 | 9,535 | 9,789 | 9,964 | 10,026 | 10,181 | 10,151 | 10,031 | 10,085 | 9,850 | 9,782 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,939 | 16,027 | 15,769 | 15,522 | 15,223 | 15,078 | 14,909 | 15,059 | 14,882 | 14,838 | 14,835 | 14,307 | 13,683 | 13,856 | 14,020 | 13,979 | 13,782 | 13,561 | 13,692 | 13,560 | 13,411 | 13,585 | 13,074 | 13,172 | 12,932 | 12,574 | 13,100 | 13,421 | 12,659 | 13,584 | 13,552 | 14,063 | 14,193 | 14,321 | 14,725 | 14,453 | 14,604 | 14,632 | 14,626 | 14,545 | 14,495 | 14,300 | 14,259 | 14,104 | 14,079 | 14,031 | 13,977 | 13,715 | 13,187 | 13,127 | 13,265 | 13,134 | 12,539 | 12,421 | 11,882 | 11,446 | 12,973 | 13,177 | 13,177 | 12,907 | 12,872 | 12,842 | 12,802 | 12,752 | 12,687 | 12,383 | 12,543 | 12,370 | 12,249 | 12,046 | 11,517 | 11,775 | 11,883 | 12,081 | 12,011 | 11,925 | 11,793 | 11,753 | 11,754 | 11,677 | 11,749 | 11,860 | 11,784 | 11,750 | 11,781 | 11,736 | 11,631 | 11,634 | 11,501 | 11,489 | 11,388 | 11,260 | 11,284 | 11,111 | 10,964 | 10,752 | 10,795 | 10,761 | 10,692 | 10,459 | 10,202 | 10,092 | 10,020 | 9,635 | 9,227 | 9,184 | 9,332 | 9,579 | 9,797 | 9,538 | 9,789 | 9,966 | 10,027 | 10,182 | 10,152 | 10,032 | 10,085 | 9,850 | 9,783 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,945 | 16,034 | 15,776 | 15,529 | 15,230 | 15,084 | 14,915 | 15,066 | 14,888 | 14,844 | 14,842 | 14,314 | 13,691 | 13,863 | 14,026 | 13,986 | 13,789 | 13,569 | 13,699 | 13,568 | 13,417 | 13,593 | 13,081 | 13,180 | 12,938 | 12,580 | 13,107 | 13,429 | 12,666 | 13,591 | 13,557 | 14,069 | 14,200 | 14,329 | 14,734 | 14,462 | 14,612 | 14,638 | 14,633 | 14,553 | 14,502 | 14,306 | 14,265 | 14,110 | 14,086 | 14,037 | 13,984 | 13,722 | 13,194 | 13,133 | 13,271 | 13,142 | 12,542 | 12,421 | 11,878 | 11,443 | 12,968 | 13,172 | 13,172 | 12,902 | 12,867 | 12,837 | 12,797 | 12,747 | 12,682 | 12,378 | 12,538 | 12,365 | 12,245 | 12,041 | 11,513 | 11,771 | 11,878 | 12,076 | 12,006 | 11,920 | 11,788 | 11,748 | 11,750 | 11,672 | 11,744 | 11,855 | 11,779 | 11,745 | 11,777 | 11,732 | 11,627 | 11,630 | 11,497 | 11,485 | 11,384 | 11,256 | 11,280 | 11,106 | 10,959 | 10,748 | 10,790 | 10,757 | 10,688 | 10,455 | 10,197 | 10,088 | 10,016 | 9,631 | 9,223 | 9,180 | 9,328 | 9,575 | 9,795 | 9,535 | 9,789 | 9,964 | 10,026 | 10,181 | 10,151 | 10,031 | 10,085 | 9,850 | 9,782 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 1,593,858 | 1,602,678 | 1,576,910 | 1,552,219 | 1,522,345 | 1,507,792 | 1,490,874 | 1,505,932 | 1,488,205 | 1,483,812 | 1,483,527 | 1,430,728 | 1,368,266 | 1,385,568 | 1,402,042 | 1,397,883 | 1,378,187 | 1,356,128 | 1,369,169 | 1,355,956 | 1,341,056 | 1,358,481 | 1,307,381 | 1,317,209 | 1,293,158 | 1,257,382 | 1,309,991 | 1,342,055 | 1,265,874 | 1,358,425 | 1,355,183 | 1,406,266 | 1,419,259 | 1,432,083 | 1,472,450 | 1,445,270 | 1,460,410 | 1,463,164 | 1,462,569 | 1,454,542 | 1,449,454 | 1,429,986 | 1,425,870 | 1,410,439 | 1,407,942 | 1,403,106 | 1,397,714 | 1,371,522 | 1,318,664 | 1,312,742 | 1,326,491 | 1,313,363 | 1,253,861 | 1,242,061 | 1,188,162 | 1,144,644 | 1,297,320 | 1,317,745 | 1,317,688 | 1,290,709 | 1,287,194 | 1,284,211 | 1,280,151 | 1,275,177 | 1,268,679 | 1,238,314 | 1,254,258 | 1,236,951 | 1,224,949 | 1,204,609 | 1,151,717 | 1,177,539 | 1,188,326 | 1,208,119 | 1,201,138 | 1,192,502 | 1,179,325 | 1,175,265 | 1,175,432 | 1,167,664 | 1,174,918 | 1,185,976 | 1,178,420 | 1,174,994 | 1,178,137 | 1,173,558 | 1,163,121 | 1,163,435 | 1,150,140 | 1,148,921 | 1,138,792 | 1,126,047 | 1,128,417 | 1,111,096 | 1,096,382 | 1,075,241 | 1,079,498 | 1,076,135 | 1,069,220 | 1,045,923 | 1,020,157 | 1,009,215 | 1,001,986 | 963,487 | 922,700 | 918,428 | 933,190 | 957,889 | 979,742 | 953,818 | 978,915 | 996,552 | 1,002,703 | 1,018,213 | 1,015,225 | 1,003,166 | 1,008,512 | 985,015 | 978,297 | 992,901 | 1,000,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 1,594,527 | 1,603,351 | 1,577,571 | 1,552,870 | 1,522,984 | 1,508,423 | 1,491,499 | 1,506,565 | 1,488,830 | 1,484,434 | 1,484,159 | 1,431,373 | 1,369,103 | 1,386,261 | 1,402,573 | 1,398,582 | 1,378,946 | 1,356,860 | 1,369,866 | 1,356,771 | 1,341,668 | 1,359,258 | 1,308,116 | 1,318,043 | 1,293,823 | 1,258,012 | 1,310,727 | 1,342,886 | 1,266,600 | 1,359,110 | 1,355,715 | 1,406,893 | 1,420,032 | 1,432,898 | 1,473,401 | 1,446,193 | 1,461,167 | 1,463,770 | 1,463,280 | 1,455,342 | 1,450,180 | 1,430,634 | 1,426,516 | 1,411,038 | 1,408,640 | 1,403,749 | 1,398,397 | 1,372,224 | 1,319,411 | 1,313,270 | 1,327,105 | 1,314,173 | 1,254,244 | 1,242,137 | 1,187,811 | 1,144,323 | 1,296,813 | 1,317,228 | 1,317,172 | 1,290,201 | 1,286,688 | 1,283,707 | 1,279,650 | 1,274,676 | 1,268,182 | 1,237,830 | 1,253,766 | 1,236,467 | 1,224,469 | 1,204,137 | 1,151,261 | 1,177,060 | 1,187,839 | 1,207,616 | 1,200,639 | 1,192,006 | 1,178,833 | 1,174,777 | 1,174,954 | 1,167,190 | 1,174,441 | 1,185,493 | 1,177,940 | 1,174,517 | 1,177,677 | 1,173,150 | 1,162,704 | 1,163,006 | 1,149,744 | 1,148,532 | 1,138,364 | 1,125,610 | 1,127,977 | 1,110,646 | 1,095,929 | 1,074,789 | 1,079,044 | 1,075,683 | 1,068,768 | 1,045,481 | 1,019,725 | 1,008,791 | 1,001,564 | 963,082 | 922,312 | 918,042 | 932,796 | 957,494 | 979,484 | 953,492 | 978,885 | 996,434 | 1,002,607 | 1,018,137 | 1,015,130 | 1,003,103 | 1,008,460 | 984,961 | 978,214 | 992,852 | 1,000,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,939 | 16,027 | 15,769 | 15,522 | 15,223 | 15,078 | 14,909 | 15,059 | 14,882 | 14,838 | 14,835 | 14,307 | 13,683 | 13,856 | 14,020 | 13,979 | 13,782 | 13,561 | 13,692 | 13,560 | 13,411 | 13,585 | 13,074 | 13,172 | 12,932 | 12,574 | 13,100 | 13,421 | 12,659 | 13,584 | 13,552 | 14,063 | 14,193 | 14,321 | 14,725 | 14,453 | 14,604 | 14,632 | 14,626 | 14,545 | 14,495 | 14,300 | 14,259 | 14,104 | 14,079 | 14,031 | 13,977 | 13,715 | 13,187 | 13,127 | 13,265 | 13,134 | 12,539 | 12,421 | 11,882 | 11,446 | 12,973 | 13,177 | 13,177 | 12,907 | 12,872 | 12,842 | 12,802 | 12,752 | 12,687 | 12,383 | 12,543 | 12,370 | 12,249 | 12,046 | 11,517 | 11,775 | 11,883 | 12,081 | 12,011 | 11,925 | 11,793 | 11,753 | 11,754 | 11,677 | 11,749 | 11,860 | 11,784 | 11,750 | 11,781 | 11,736 | 11,631 | 11,634 | 11,501 | 11,489 | 11,388 | 11,260 | 11,284 | 11,111 | 10,964 | 10,752 | 10,795 | 10,761 | 10,692 | 10,459 | 10,202 | 10,092 | 10,020 | 9,635 | 9,227 | 9,184 | 9,332 | 9,579 | 9,797 | 9,538 | 9,789 | 9,966 | 10,027 | 10,182 | 10,152 | 10,032 | 10,085 | 9,850 | 9,783 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 15,945 | 16,034 | 15,776 | 15,529 | 15,230 | 15,084 | 14,915 | 15,066 | 14,888 | 14,844 | 14,842 | 14,314 | 13,691 | 13,863 | 14,026 | 13,986 | 13,789 | 13,569 | 13,699 | 13,568 | 13,417 | 13,593 | 13,081 | 13,180 | 12,938 | 12,580 | 13,107 | 13,429 | 12,666 | 13,591 | 13,557 | 14,069 | 14,200 | 14,329 | 14,734 | 14,462 | 14,612 | 14,638 | 14,633 | 14,553 | 14,502 | 14,306 | 14,265 | 14,110 | 14,086 | 14,037 | 13,984 | 13,722 | 13,194 | 13,133 | 13,271 | 13,142 | 12,542 | 12,421 | 11,878 | 11,443 | 12,968 | 13,172 | 13,172 | 12,902 | 12,867 | 12,837 | 12,797 | 12,747 | 12,682 | 12,378 | 12,538 | 12,365 | 12,245 | 12,041 | 11,513 | 11,771 | 11,878 | 12,076 | 12,006 | 11,920 | 11,788 | 11,748 | 11,750 | 11,672 | 11,744 | 11,855 | 11,779 | 11,745 | 11,777 | 11,732 | 11,627 | 11,630 | 11,497 | 11,485 | 11,384 | 11,256 | 11,280 | 11,106 | 10,959 | 10,748 | 10,790 | 10,757 | 10,688 | 10,455 | 10,197 | 10,088 | 10,016 | 9,631 | 9,223 | 9,180 | 9,328 | 9,575 | 9,795 | 9,535 | 9,789 | 9,964 | 10,026 | 10,181 | 10,151 | 10,031 | 10,085 | 9,850 | 9,782 | 9,929 | 10,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 7,969,291 | 8,013,391 | 7,884,548 | 7,761,093 | 7,611,724 | 7,538,958 | 7,454,370 | 7,529,661 | 7,441,024 | 7,419,059 | 7,417,634 | 7,153,641 | 6,841,331 | 6,927,838 | 7,010,211 | 6,989,417 | 6,890,933 | 6,780,641 | 6,845,845 | 6,779,780 | 6,705,279 | 6,792,406 | 6,536,906 | 6,586,043 | 6,465,791 | 6,286,909 | 6,549,956 | 6,710,273 | 6,329,372 | 6,792,124 | 6,775,915 | 7,031,330 | 7,096,295 | 7,160,413 | 7,362,248 | 7,226,351 | 7,302,052 | 7,315,820 | 7,312,844 | 7,272,708 | 7,247,272 | 7,149,931 | 7,129,348 | 7,052,195 | 7,039,710 | 7,015,529 | 6,988,570 | 6,857,611 | 6,593,322 | 6,563,711 | 6,632,456 | 6,566,814 | 6,269,303 | 6,210,305 | 5,940,811 | 5,723,218 | 6,486,599 | 6,588,723 | 6,588,441 | 6,453,546 | 6,435,968 | 6,421,056 | 6,400,756 | 6,375,884 | 6,343,395 | 6,191,571 | 6,271,292 | 6,184,757 | 6,124,744 | 6,023,043 | 5,758,585 | 5,887,696 | 5,941,629 | 6,040,593 | 6,005,691 | 5,962,508 | 5,896,626 | 5,876,326 | 5,877,158 | 5,838,320 | 5,874,591 | 5,929,878 | 5,892,098 | 5,874,971 | 5,890,687 | 5,867,791 | 5,815,607 | 5,817,173 | 5,750,699 | 5,744,605 | 5,693,959 | 5,630,236 | 5,642,086 | 5,555,480 | 5,481,910 | 5,376,203 | 5,397,491 | 5,380,675 | 5,346,098 | 5,229,613 | 5,100,784 | 5,046,075 | 5,009,932 | 4,817,436 | 4,613,499 | 4,592,140 | 4,665,950 | 4,789,447 | 4,898,709 | 4,769,089 | 4,894,575 | 4,982,761 | 5,013,515 | 5,091,064 | 5,076,124 | 5,015,829 | 5,042,562 | 4,925,075 | 4,891,486 | 4,964,506 | 5,000,000 |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 7,972,633 | $ 8,016,753 | $ 7,887,853 | $ 7,764,351 | $ 7,614,920 | $ 7,542,113 | $ 7,457,495 | $ 7,532,827 | $ 7,444,150 | $ 7,422,172 | $ 7,420,795 | $ 7,156,864 | $ 6,845,514 | $ 6,931,303 | $ 7,012,864 | $ 6,992,911 | $ 6,894,729 | $ 6,784,298 | $ 6,849,331 | $ 6,783,854 | $ 6,708,341 | $ 6,796,290 | $ 6,540,580 | $ 6,590,215 | $ 6,469,117 | $ 6,290,060 | $ 6,553,636 | $ 6,714,430 | $ 6,332,998 | $ 6,795,548 | $ 6,778,577 | $ 7,034,464 | $ 7,100,160 | $ 7,164,488 | $ 7,367,003 | $ 7,230,964 | $ 7,305,833 | $ 7,318,852 | $ 7,316,398 | $ 7,276,711 | $ 7,250,902 | $ 7,153,168 | $ 7,132,581 | $ 7,055,191 | $ 7,043,199 | $ 7,018,743 | $ 6,991,982 | $ 6,861,118 | $ 6,597,056 | $ 6,566,352 | $ 6,635,524 | $ 6,570,864 | $ 6,271,222 | $ 6,210,687 | $ 5,939,056 | $ 5,721,614 | $ 6,484,063 | $ 6,586,141 | $ 6,585,862 | $ 6,451,007 | $ 6,433,439 | $ 6,418,535 | $ 6,398,251 | $ 6,373,380 | $ 6,340,912 | $ 6,189,148 | $ 6,268,828 | $ 6,182,335 | $ 6,122,346 | $ 6,020,687 | $ 5,756,303 | $ 5,885,301 | $ 5,939,196 | $ 6,038,078 | $ 6,003,194 | $ 5,960,031 | $ 5,894,167 | $ 5,873,883 | $ 5,874,769 | $ 5,835,951 | $ 5,872,203 | $ 5,927,465 | $ 5,889,701 | $ 5,872,586 | $ 5,888,386 | $ 5,865,750 | $ 5,813,521 | $ 5,815,028 | $ 5,748,721 | $ 5,742,659 | $ 5,691,820 | $ 5,628,052 | $ 5,639,885 | $ 5,553,229 | $ 5,479,647 | $ 5,373,943 | $ 5,395,221 | $ 5,378,413 | $ 5,343,841 | $ 5,227,404 | $ 5,098,626 | $ 5,043,956 | $ 5,007,821 | $ 4,815,408 | $ 4,611,559 | $ 4,590,211 | $ 4,663,980 | $ 4,787,472 | $ 4,897,418 | $ 4,767,458 | $ 4,894,426 | $ 4,982,170 | $ 5,013,033 | $ 5,090,684 | $ 5,075,649 | $ 5,015,515 | $ 5,042,299 | $ 4,924,804 | $ 4,891,071 | $ 4,964,261 | $ 5,000,000 |
| Shareholder Report, Average Annual Return (Details) | 12 Months Ended | 60 Months Ended | 120 Months Ended |
| Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | |
| C000013484 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class A with Maximum Sales Charge | ||
| Average Annual Return, Percent | 10.71% | 3.61% | 4% |
| C000013486 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class C | ||
| Average Annual Return, Percent | 12.28% | 3.50% | 3.72% |
| C000013488 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class I | ||
| C000013487 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class R | ||
| C000142452 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class R6 | ||
| Without Sales Load [Member] | C000013484 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 14.38% | 4.31% | 4.34% |
| Without Sales Load [Member] | C000013486 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 13.28% | 3.50% | 3.72% |
| Without Sales Load [Member] | C000013488 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 14.67% | 4.54% | 4.60% |
| Without Sales Load [Member] | C000013487 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 13.86% | 4% | 4.07% |
| Without Sales Load [Member] | C000142452 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 14.77% | 4.63% | 4.70% |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||
| Average Annual Return, Percent | 11.20% | 0.18% | 1.82% |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||
| Average Annual Return, Percent | 11.20% | 0.18% | 1.82% |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||
| Average Annual Return, Percent | 11.20% | 0.18% | 1.82% |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||
| Average Annual Return, Percent | 11.20% | 0.18% | 1.82% |
| EATON VANCE Index: Bloomberg U.S. Universal Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Universal Index | ||
| Average Annual Return, Percent | 11.20% | 0.18% | 1.82% |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||
| Average Annual Return, Percent | 16.49% | 4.36% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||
| Average Annual Return, Percent | 16.47% | 4.38% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||
| Average Annual Return, Percent | 16.49% | 4.36% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||
| Average Annual Return, Percent | 16.47% | 4.38% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||
| Average Annual Return, Percent | 16.49% | 4.36% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||
| Average Annual Return, Percent | 16.47% | 4.38% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||
| Average Annual Return, Percent | 16.49% | 4.36% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||
| Average Annual Return, Percent | 16.47% | 4.38% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Constrained Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Constrained Index | ||
| Average Annual Return, Percent | 16.49% | 4.36% | 4.77% |
| EATON VANCE Index: ICE BofA U.S. High Yield Index | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. High Yield Index | ||
| Average Annual Return, Percent | 16.47% | 4.38% | 4.77% |
| Shareholder Report, Holdings (Details) | Oct. 31, 2024 |
| C000013484 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000013484 | CCC or Lower | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| C000013484 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 37.30% |
| C000013484 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 44.30% |
| C000013484 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| C000013484 | Asset Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.90% |
| C000013484 | AssetShort-Term Investments | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| C000013484 | AssetSenior Floating-Rate Loans | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013484 | AssetCorporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 86.60% |
| C000013486 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000013486 | CCC or Lower | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| C000013486 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 37.30% |
| C000013486 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 44.30% |
| C000013486 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| C000013486 | Asset Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.90% |
| C000013486 | AssetShort-Term Investments | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| C000013486 | AssetSenior Floating-Rate Loans | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013486 | AssetCorporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 86.60% |
| C000013488 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000013488 | CCC or Lower | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| C000013488 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 37.30% |
| C000013488 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 44.30% |
| C000013488 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| C000013488 | Asset Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.90% |
| C000013488 | AssetShort-Term Investments | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| C000013488 | AssetSenior Floating-Rate Loans | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013488 | AssetCorporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 86.60% |
| C000013487 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000013487 | CCC or Lower | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| C000013487 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 37.30% |
| C000013487 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 44.30% |
| C000013487 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| C000013487 | Asset Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.90% |
| C000013487 | AssetShort-Term Investments | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| C000013487 | AssetSenior Floating-Rate Loans | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013487 | AssetCorporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 86.60% |
| C000142452 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| C000142452 | CCC or Lower | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| C000142452 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 37.30% |
| C000142452 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 44.30% |
| C000142452 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| C000142452 | Asset Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 1.90% |
| C000142452 | AssetShort-Term Investments | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| C000142452 | AssetSenior Floating-Rate Loans | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000142452 | AssetCorporate Bonds | |
| Holdings [Line Items] | |
| Percent of Total Investments | 86.60% |
