v3.25.2
Shareholder Report, Holdings (Details)
Jun. 30, 2025
C000018122 | Cash & equivalents  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000018122 | US Treasury  
Holdings [Line Items]  
Percent of Net Asset Value 14.60%
C000018122 | Not rated  
Holdings [Line Items]  
Percent of Net Asset Value 17.20%
C000018122 | CCC  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000018122 | B  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000018122 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 13.40%
C000018122 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 38.00%
C000018122 | A  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018122 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000018122 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000018122 | Municipal  
Holdings [Line Items]  
Percent of Net Asset Value 38.70%
C000018122 | IndustryShort-Term Investments  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018122 | IndustryMetals & Mining  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000018122 | IndustryIndependent Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000018122 | IndustrySovereigns  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000018122 | IndustryLife Insurance  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000018122 | IndustryABS Home Equity  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018122 | IndustryBanking  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000018122 | IndustryFinance Companies  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000018122 | IndustryCable Satellite  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000018122 | IndustryTechnology  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018122 | IndustryABS Other  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
C000018122 | IndustryTreasuries  
Holdings [Line Items]  
Percent of Net Asset Value 17.70%
C000018123 | Cash & equivalents  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000018123 | US Treasury  
Holdings [Line Items]  
Percent of Net Asset Value 14.60%
C000018123 | Not rated  
Holdings [Line Items]  
Percent of Net Asset Value 17.20%
C000018123 | CCC  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000018123 | B  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000018123 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 13.40%
C000018123 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 38.00%
C000018123 | A  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018123 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000018123 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000018123 | Municipal  
Holdings [Line Items]  
Percent of Net Asset Value 38.70%
C000018123 | IndustryShort-Term Investments  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018123 | IndustryMetals & Mining  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000018123 | IndustryIndependent Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000018123 | IndustrySovereigns  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000018123 | IndustryLife Insurance  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000018123 | IndustryABS Home Equity  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018123 | IndustryBanking  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000018123 | IndustryFinance Companies  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000018123 | IndustryCable Satellite  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000018123 | IndustryTechnology  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018123 | IndustryABS Other  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
C000018123 | IndustryTreasuries  
Holdings [Line Items]  
Percent of Net Asset Value 17.70%
C000018124 | Cash & equivalents  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000018124 | US Treasury  
Holdings [Line Items]  
Percent of Net Asset Value 14.60%
C000018124 | Not rated  
Holdings [Line Items]  
Percent of Net Asset Value 17.20%
C000018124 | CCC  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000018124 | B  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000018124 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 13.40%
C000018124 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 38.00%
C000018124 | A  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018124 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000018124 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000018124 | Municipal  
Holdings [Line Items]  
Percent of Net Asset Value 38.70%
C000018124 | IndustryShort-Term Investments  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018124 | IndustryMetals & Mining  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000018124 | IndustryIndependent Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000018124 | IndustrySovereigns  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000018124 | IndustryLife Insurance  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000018124 | IndustryABS Home Equity  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000018124 | IndustryBanking  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000018124 | IndustryFinance Companies  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000018124 | IndustryCable Satellite  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000018124 | IndustryTechnology  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000018124 | IndustryABS Other  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
C000018124 | IndustryTreasuries  
Holdings [Line Items]  
Percent of Net Asset Value 17.70%
C000125493 | Cash & equivalents  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000125493 | US Treasury  
Holdings [Line Items]  
Percent of Net Asset Value 14.60%
C000125493 | Not rated  
Holdings [Line Items]  
Percent of Net Asset Value 17.20%
C000125493 | CCC  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000125493 | B  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000125493 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 13.40%
C000125493 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 38.00%
C000125493 | A  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000125493 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000125493 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000125493 | Municipal  
Holdings [Line Items]  
Percent of Net Asset Value 38.70%
C000125493 | IndustryShort-Term Investments  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000125493 | IndustryMetals & Mining  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000125493 | IndustryIndependent Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000125493 | IndustrySovereigns  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000125493 | IndustryLife Insurance  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000125493 | IndustryABS Home Equity  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000125493 | IndustryBanking  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000125493 | IndustryFinance Companies  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000125493 | IndustryCable Satellite  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000125493 | IndustryTechnology  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000125493 | IndustryABS Other  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
C000125493 | IndustryTreasuries  
Holdings [Line Items]  
Percent of Net Asset Value 17.70%
C000018133 | Cash & equivalents  
Holdings [Line Items]  
Percent of Net Asset Value 4.70%
C000018133 | US Treasury  
Holdings [Line Items]  
Percent of Net Asset Value 16.70%
C000018133 | Not rated  
Holdings [Line Items]  
Percent of Net Asset Value 17.60%
C000018133 | CCC  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000018133 | B  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000018133 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 7.40%
C000018133 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 42.10%
C000018133 | A  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
C000018133 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000018133 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000018133 | Life Insurance  
Holdings [Line Items]  
Percent of Net Asset Value 41.40%
C000018133 | IndustryShort-Term Investments  
Holdings [Line Items]  
Percent of Net Asset Value 5.80%
C000018133 | IndustryABS Home Equity  
Holdings [Line Items]  
Percent of Net Asset Value 3.70%
C000018133 | IndustryBanking  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000018133 | IndustryFinance Companies  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000018133 | IndustryTechnology  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000018133 | IndustryABS Other  
Holdings [Line Items]  
Percent of Net Asset Value 6.50%
C000018133 | IndustryTreasuries  
Holdings [Line Items]  
Percent of Net Asset Value 19.10%
C000018133 | IndustryCollateralized Loan Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000018133 | IndustryABS Car Loan  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%