This annual shareholder report contains important information about the Calvert High Yield Bond Fund for the period of October 1, 2024 to September 30, 2025.

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/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.

Additional Information Phone Number

1-800-368-2745

Additional Information Website

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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	$104	1.01%

Expenses Paid, Amount

$ 104

Expense Ratio, Percent

1.01%

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 allocations by sector, especially within broadcasting, telecommunications and railroad hurt performance relative to the Index

↓ Selections within auto & auto parts and homebuilders & real estate were punitive

↓ Selections by credit rating hampered results, particularly in BB-rated and CCC-rated bonds

↓ Selections within credits with duration between 2 and 5 years and greater than 10 years detracted

↑ The Fund’s selections by sector contributed to relative performance, particularly within paper, retail and railroad

↑ The Fund’s significant underweight position in the energy sector was helpful along with the lack of exposure to the gaming sector and an overweight exposure within the services sector

↑ Allocations by credit rating aided relative performance, especially within credits rated CCC and lower. An underweight position within B-rated credits was also additive

↑ Selections within bonds with duration less than two years contributed to relative returns

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 Index
9/15	$10,000	$10,000	$10,000
10/15	$9,889	$10,032	$10,273
11/15	$9,626	$9,995	$10,042
12/15	$9,569	$9,945	$9,783
1/16	$9,501	$10,055	$9,628
2/16	$9,496	$10,127	$9,673
3/16	$9,815	$10,251	$10,101
4/16	$10,026	$10,321	$10,504
5/16	$10,110	$10,329	$10,580
6/16	$10,157	$10,511	$10,695
7/16	$10,382	$10,597	$10,965
8/16	$10,537	$10,609	$11,209
9/16	$10,587	$10,611	$11,282
10/16	$10,624	$10,541	$11,317
11/16	$10,590	$10,304	$11,272
12/16	$10,688	$10,334	$11,494
1/17	$10,776	$10,371	$11,648
2/17	$10,877	$10,451	$11,830
3/17	$10,858	$10,447	$11,805
4/17	$10,962	$10,534	$11,939
5/17	$11,032	$10,615	$12,046
6/17	$11,105	$10,606	$12,058
7/17	$11,176	$10,659	$12,197
8/17	$11,169	$10,751	$12,194
9/17	$11,247	$10,713	$12,304
10/17	$11,274	$10,726	$12,351
11/17	$11,283	$10,710	$12,318
12/17	$11,306	$10,757	$12,354
1/18	$11,344	$10,654	$12,433
2/18	$11,262	$10,553	$12,317
3/18	$11,201	$10,606	$12,241
4/18	$11,194	$10,535	$12,323
5/18	$11,143	$10,592	$12,321
6/18	$11,127	$10,577	$12,363
7/18	$11,233	$10,599	$12,501
8/18	$11,315	$10,651	$12,592
9/18	$11,360	$10,606	$12,665
10/18	$11,214	$10,517	$12,458
11/18	$11,155	$10,564	$12,345
12/18	$10,984	$10,730	$12,074
1/19	$11,366	$10,878	$12,629
2/19	$11,523	$10,889	$12,842
3/19	$11,608	$11,086	$12,968
4/19	$11,742	$11,102	$13,149
5/19	$11,684	$11,272	$12,982
6/19	$11,901	$11,431	$13,300
7/19	$11,976	$11,465	$13,369
8/19	$12,052	$11,725	$13,421
9/19	$12,121	$11,674	$13,463
10/19	$12,163	$11,712	$13,494
11/19	$12,199	$11,709	$13,531
12/19	$12,362	$11,727	$13,814
1/20	$12,366	$11,937	$13,815
2/20	$12,247	$12,116	$13,601
3/20	$11,103	$11,879	$12,001
4/20	$11,481	$12,117	$12,457
5/20	$11,877	$12,230	$13,027
6/20	$11,916	$12,332	$13,154
7/20	$12,441	$12,549	$13,783
8/20	$12,496	$12,477	$13,918
9/20	$12,400	$12,454	$13,773
10/20	$12,467	$12,410	$13,838
11/20	$12,842	$12,572	$14,392
12/20	$12,996	$12,615	$14,666
1/21	$13,031	$12,536	$14,722
2/21	$13,024	$12,374	$14,773
3/21	$13,030	$12,230	$14,799
4/21	$13,144	$12,333	$14,961
5/21	$13,155	$12,380	$15,004
6/21	$13,318	$12,470	$15,209
7/21	$13,342	$12,595	$15,263
8/21	$13,391	$12,587	$15,347
9/21	$13,360	$12,479	$15,352
10/21	$13,314	$12,469	$15,324
11/21	$13,201	$12,484	$15,167
12/21	$13,437	$12,476	$15,453
1/22	$13,075	$12,202	$15,028
2/22	$12,915	$12,036	$14,893
3/22	$12,793	$11,713	$14,755
4/22	$12,335	$11,276	$14,218
5/22	$12,335	$11,338	$14,254
6/22	$11,618	$11,112	$13,284
7/22	$12,309	$11,391	$14,084
8/22	$12,004	$11,095	$13,747
9/22	$11,531	$10,617	$13,194
10/22	$11,828	$10,500	$13,569
11/22	$12,042	$10,892	$13,823
12/22	$11,961	$10,855	$13,719
1/23	$12,376	$11,192	$14,256
2/23	$12,182	$10,917	$14,071
3/23	$12,365	$11,173	$14,230
4/23	$12,462	$11,241	$14,367
5/23	$12,312	$11,124	$14,230
6/23	$12,472	$11,107	$14,462
7/23	$12,619	$11,118	$14,668
8/23	$12,627	$11,051	$14,710
9/23	$12,482	$10,788	$14,539
10/23	$12,336	$10,625	$14,359
11/23	$12,839	$11,104	$15,012
12/23	$13,250	$11,525	$15,566
1/24	$13,258	$11,497	$15,568
2/24	$13,256	$11,360	$15,615
3/24	$13,430	$11,471	$15,801
4/24	$13,331	$11,203	$15,643
5/24	$13,493	$11,389	$15,820
6/24	$13,633	$11,493	$15,973
7/24	$13,820	$11,754	$16,286
8/24	$14,019	$11,927	$16,545
9/24	$14,138	$12,090	$16,816
10/24	$14,080	$11,816	$16,723
11/24	$14,218	$11,940	$16,915
12/24	$14,167	$11,760	$16,842
1/25	$14,318	$11,831	$17,075
2/25	$14,400	$12,075	$17,186
3/25	$14,266	$12,073	$17,001
4/25	$14,379	$12,115	$17,002
5/25	$14,561	$12,054	$17,287
6/25	$14,786	$12,242	$17,608
7/25	$14,817	$12,224	$17,679
8/25	$14,963	$12,371	$17,894
9/25	$15,033	$12,502	$18,031

Average Annual Return [Table Text Block]

Fund	1 Year	5 Years	10 Years
Class A	6.31%	3.92%	4.50%
Class A with 3.25% Maximum Sales Charge	2.87%	3.24%	4.16%
Bloomberg U.S. Universal Index	3.40%	0.08%	2.26%
ICE BofA U.S. High Yield Index	7.23%	5.53%	6.07%

No Deduction of Taxes [Text Block]

Performance does not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.

Updated Performance Information Location [Text Block]

For more recent performance information, visit www.eatonvance.com/performance.php.

AssetsNet

$ 501,317,043

Holdings Count | Holding

317

Advisory Fees Paid, Amount

$ 2,156,680

InvestmentCompanyPortfolioTurnover

35.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets	$501,317,043
# of Portfolio Holdings	317
Portfolio Turnover Rate	35%
Total Advisory Fees Paid	$2,156,680

Holdings [Text Block]

Asset Allocation (% of total investments)

Value	Value
Other^{Footnote Reference†}	0.9%
Senior Floating-Rate Loans	6.3%
Short-Term Investments	7.5%
Corporate Bonds	85.3%

Footnote	Description
Footnote^†	Investment types less than 1% each

Credit Quality (% of total investments)^{Footnote Referencea}

Value	Value
Not Rated	0.9%
CCC or Lower	11.7%
B	38.1%
BB	47.3%
BBB	2.0%

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

1-800-368-2745

C000077417

Shareholder Report [Line Items]

Fund Name

Calvert High Yield Bond Fund

Class Name

Class C

Trading Symbol

CHBCX

Annual or Semi-Annual Statement [Text Block]

This annual shareholder report contains important information about the Calvert High Yield Bond Fund for the period of October 1, 2024 to September 30, 2025.

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/calvert-fund-documents.php. You can also request this information by contacting us at 1-800-368-2745.

Additional Information Phone Number

1-800-368-2745

Additional Information Website

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	$181	1.76%

Expenses Paid, Amount

$ 181

Expense Ratio, Percent

1.76%