v3.25.4
S000006334 [Member] Average Annual Total Returns
 4 Months Ended 12 Months Ended 60 Months Ended 70 Months Ended 120 Months Ended 322 Months Ended 432 Months Ended
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 (reflects no deduction for fees, expenses or taxes)              
Prospectus [Line Items]              
Average Annual Return, Percent [1],[2]   7.30% (0.36%)   2.01%   5.06%
I Class              
Prospectus [Line Items]              
Average Annual Return, Percent [2],[3]   7.50% (0.64%)   1.93%   5.07%
Performance Inception Date [3]             Jan. 01, 1990
I Class | After Taxes on Distributions              
Prospectus [Line Items]              
Average Annual Return, Percent [2],[3]   5.87% (1.83%)   0.73%   3.47%
Performance Inception Date [3]             Jan. 01, 1990
I Class | After Taxes on Distributions and Sales              
Prospectus [Line Items]              
Average Annual Return, Percent [2],[3]   4.42% (1.00%)   0.96%   3.40%
Performance Inception Date [3]             Jan. 01, 1990
N Class              
Prospectus [Line Items]              
Average Annual Return, Percent [2]   7.34% (0.79%)   1.73% 4.02%  
Performance Inception Date           Mar. 01, 1999  
Plan Class              
Prospectus [Line Items]              
Average Annual Return, Percent [2]   7.54% (0.59%) 0.37%    
Performance Inception Date       Feb. 28, 2020      
Class I-3              
Prospectus [Line Items]              
Performance Inception Date Aug. 25, 2025            
[1]
The Bloomberg U.S. Aggregate Bond Index is a market capitalization-weighted index of investment grade, U.S. dollar-denominated, fixed-rate debt issues, including Treasuries, government-related and corporate securities, mortgage-backed securities (agency fixed-rate and hybrid adjustable-rate mortgage), asset-backed securities and commercial mortgage-backed securities (agency and non-agency).
[2] 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.
[3] Performance data includes the performance of the predecessor entity for periods before the Fund’s registration became effective. The predecessor entity was not registered under the 1940 Act and, therefore, was not subject to certain investment restrictions that are imposed by the 1940 Act. If the predecessor entity had been registered under the 1940 Act, the predecessor entity’s performance may have been lower.