v3.26.1
S000001147 [Member] Average Annual Total Returns
 4 Months Ended 12 Months Ended 60 Months Ended 70 Months Ended 120 Months Ended 173 Months Ended 192 Months Ended 309 Months Ended 345 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Bloomberg U.S. Aggregate Bond Index                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.30% (0.36%)   2.01%        
CLASS I                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.81% (0.55%)   2.08%        
Performance Inception Date               Mar. 31, 2000  
CLASS M                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.58% (0.76%)   1.86%        
Performance Inception Date                 Mar. 31, 1997
CLASS M | After Taxes on Distributions                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   5.85% (2.04%)   0.51%        
Performance Inception Date                 Mar. 31, 1997
CLASS M | After Taxes on Distributions and Sales                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   4.46% (1.13%) [2]   0.86% [2]        
Performance Inception Date                 Mar. 31, 1997
Administrative Class                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.43% (0.88%)   1.74%        
Performance Inception Date             Dec. 18, 2009    
Plan Class                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.86% (0.48%)   2.16%        
Performance Inception Date           Jul. 31, 2011      
Class I-2                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.73% (0.62%)   0.08% [3]        
Performance Inception Date       Mar. 06, 2020          
Class I-3                  
Prospectus [Line Items]                  
Performance Inception Date Aug. 25, 2025                
[1]
Class I-3 shares of the Fund have an inception date of August 25, 2025, and therefore do not have a full year of performance history as of the date of this Prospectus.
[2] The “After Taxes on Distributions and Sale of Fund Shares” return is higher than the “After Taxes on Distributions” return because of realized losses that would have been sustained upon sale of Fund shares immediately after the relevant period.
[3] Returns for Class I-2 shares are provided since inception (March 6, 2020).