v3.26.1
Shareholder Report, Holdings (Details)
Oct. 31, 2025
C000221691 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [1]
C000221691 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [1]
C000221691 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [1]
C000221691 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [1]
C000221691 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [1]
C000221691 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [1]
C000221691 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [1]
C000221691 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [1]
C000221691 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [1]
C000221691 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [1]
C000221691 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000221691 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000221691 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000221691 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000221691 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [2]
C000221691 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000221691 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [2]
C000221691 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000221691 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000060792 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [3]
C000060792 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [3]
C000060792 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [3]
C000060792 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [3]
C000060792 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [3]
C000060792 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [3]
C000060792 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [3]
C000060792 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [3]
C000060792 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [3]
C000060792 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [3]
C000060792 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000060792 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000060792 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000060792 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000060792 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [4]
C000060792 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000060792 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [4]
C000060792 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000060792 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000127160 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [5]
C000127160 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [5]
C000127160 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [5]
C000127160 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [5]
C000127160 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [5]
C000127160 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [5]
C000127160 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [5]
C000127160 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [5]
C000127160 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [5]
C000127160 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [5]
C000127160 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000127160 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000127160 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000127160 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000127160 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [6]
C000127160 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000127160 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [6]
C000127160 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000127160 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000166835 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [7]
C000166835 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [7]
C000166835 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [7]
C000166835 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [7]
C000166835 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [7]
C000166835 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [7]
C000166835 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [7]
C000166835 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [7]
C000166835 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [7]
C000166835 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [7]
C000166835 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000166835 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000166835 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000166835 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000166835 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [8]
C000166835 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000166835 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [8]
C000166835 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000166835 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000057099 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [9]
C000057099 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [9]
C000057099 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [9]
C000057099 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [9]
C000057099 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [9]
C000057099 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [9]
C000057099 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [9]
C000057099 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [9]
C000057099 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [9]
C000057099 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [9]
C000057099 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000057099 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000057099 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000057099 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000057099 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [10]
C000057099 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000057099 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [10]
C000057099 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000057099 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018696 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [11]
C000018696 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [11]
C000018696 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [11]
C000018696 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [11]
C000018696 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [11]
C000018696 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [11]
C000018696 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [11]
C000018696 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [11]
C000018696 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [11]
C000018696 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [11]
C000018696 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000018696 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000018696 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000018696 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000018696 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [12]
C000018696 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018696 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [12]
C000018696 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000018696 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018695 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [13]
C000018695 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [13]
C000018695 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [13]
C000018695 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [13]
C000018695 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [13]
C000018695 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [13]
C000018695 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [13]
C000018695 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [13]
C000018695 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [13]
C000018695 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [13]
C000018695 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000018695 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000018695 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000018695 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000018695 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [14]
C000018695 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018695 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [14]
C000018695 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000018695 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018693 [Member] | One011778 B C Unlimited Liability Co 3 875 6 125 due 1 15 28 10 15 30 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90% [15]
C000018693 [Member] | Cloud Software Group Inc 6 50 9 00 due 3 31 29 8 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.00% [15]
C000018693 [Member] | LifePoint Health Inc zero coupon 11 00 due 1 15 29 6 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [15]
C000018693 [Member] | Jane Street Group 6 125 7 125 due 4 30 31 51 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.10% [15]
C000018693 [Member] | Churchill Downs Inc 4 75 6 75 due 4 1 27 5 1 31 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [15]
C000018693 [Member] | Talen Energy Supply LLC 6 25 8 625 due 5 17 30 2 1 36 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [15]
C000018693 [Member] | Yum Brands Inc 3 625 5 375 due 1 15 30 4 1 32 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [15]
C000018693 [Member] | Hilton Domestic Operating Co Inc 4 00 5 875 due 5 1 28 9 15 33 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.20% [15]
C000018693 [Member] | CCO Holdings LLC 4 25 5 375 due 5 1 27 1 15 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90% [15]
C000018693 [Member] | TransDigm Inc 4 625 7 125 due 8 15 28 1 31 34 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80% [15]
C000018693 [Member] | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000018693 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
C000018693 [Member] | Loan Participations and Assignments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000018693 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 86.70%
C000018693 [Member] | Foreign Government Bond [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [16]
C000018693 [Member] | Convertible Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000018693 [Member] | Convertible Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00% [16]
C000018693 [Member] | Preferred Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000018693 [Member] | Exchange Traded Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
[1] Excluding short-term investments
[2] Less than one-tenth of a percent.
[3] Excluding short-term investments
[4] Less than one-tenth of a percent.
[5] Excluding short-term investments
[6] Less than one-tenth of a percent.
[7] Excluding short-term investments
[8] Less than one-tenth of a percent.
[9] Excluding short-term investments
[10] Less than one-tenth of a percent.
[11] Excluding short-term investments
[12] Less than one-tenth of a percent.
[13] Excluding short-term investments
[14] Less than one-tenth of a percent.
[15] Excluding short-term investments
[16] Less than one-tenth of a percent.