Shareholder Report, Holdings (Details)
|
Jul. 31, 2025 |
| C000034483 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000034483 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000034483 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000034483 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000034483 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000034483 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000034483 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000034483 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000034483 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000034483 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000034483 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000034483 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000034483 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000034483 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000034483 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000034483 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000034483 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000034483 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000034483 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000034483 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000034483 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000034483 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000034483 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074227 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000074227 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000074227 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000074227 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000074227 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000074227 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000074227 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000074227 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000074227 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074227 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000074227 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000074227 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000074227 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000074227 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000074227 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000074227 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000074227 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000074227 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000074227 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000074227 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000074227 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000074227 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000074227 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074226 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000074226 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000074226 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000074226 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000074226 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000074226 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000074226 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000074226 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000074226 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074226 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000074226 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000074226 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000074226 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000074226 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000074226 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000074226 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000074226 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000074226 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000074226 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000074226 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000074226 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000074226 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000074226 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074225 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000074225 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000074225 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000074225 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000074225 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000074225 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000074225 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000074225 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000074225 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074225 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000074225 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000074225 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000074225 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000074225 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000074225 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000074225 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000074225 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000074225 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000074225 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000074225 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000074225 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000074225 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000074225 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074224 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000074224 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000074224 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000074224 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000074224 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000074224 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000074224 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000074224 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000074224 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000074224 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000074224 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000074224 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000074224 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000074224 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000074224 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000074224 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000074224 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000074224 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000074224 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000074224 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000074224 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000074224 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000074224 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006903 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000006903 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000006903 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000006903 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000006903 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000006903 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000006903 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000006903 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000006903 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006903 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000006903 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000006903 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000006903 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000006903 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000006903 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000006903 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000006903 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000006903 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000006903 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000006903 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000006903 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000006903 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000006903 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006902 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000006902 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000006902 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000006902 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000006902 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000006902 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000006902 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000006902 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000006902 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006902 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000006902 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000006902 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000006902 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000006902 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000006902 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000006902 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000006902 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000006902 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000006902 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000006902 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000006902 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000006902 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000006902 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006901 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000006901 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000006901 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000006901 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000006901 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000006901 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000006901 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000006901 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000006901 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006901 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000006901 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000006901 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000006901 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000006901 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000006901 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000006901 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000006901 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000006901 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000006901 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000006901 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000006901 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000006901 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000006901 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006900 [Member] | Other Countries [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
61.40%
|
| C000006900 [Member] | Fitch, D Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.20%
|
| C000006900 [Member] | Fitch, CCC Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
6.80%
|
| C000006900 [Member] | Fitch, B Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.50%
|
| C000006900 [Member] | Fitch, BB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
30.40%
|
| C000006900 [Member] | Fitch, BBB Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
28.30%
|
| C000006900 [Member] | Fitch, A Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
11.00%
|
| C000006900 [Member] | Fitch, AA Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.40%
|
| C000006900 [Member] | Money Market Funds Quality [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|
| C000006900 [Member] | Moody's, C Rating [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.30%
|
| C000006900 [Member] | Not Rated [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
0.70%
|
| C000006900 [Member] | UNITED STATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
8.50%
|
| C000006900 [Member] | UNITED ARAB EMIRATES |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
2.80%
|
| C000006900 [Member] | TÜRKIYE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.50%
|
| C000006900 [Member] | SAUDI ARABIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.00%
|
| C000006900 [Member] | ROMANIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.70%
|
| C000006900 [Member] | MEXICO |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
5.50%
|
| C000006900 [Member] | INDIA |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.60%
|
| C000006900 [Member] | HUNGARY |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.20%
|
| C000006900 [Member] | CHILE |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
3.80%
|
| C000006900 [Member] | Fixed Income Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
95.90%
|
| C000006900 [Member] | US Government Debt Securities [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.30%
|
| C000006900 [Member] | Money Market Funds [Member] |
|
| Holdings [Line Items] |
|
| Percent of Total Investments |
4.10%
|