v3.26.1
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 31 Months Ended 60 Months Ended 120 Months Ended
May 31, 2026
May 31, 2026
May 31, 2026
May 31, 2026
Without Sales Load [Member] | C000005502        
Average Annual Return [Line Items]        
Average Annual Return, Percent 13.37%   4.70% 6.43%
Without Sales Load [Member] | C000049236        
Average Annual Return [Line Items]        
Average Annual Return, Percent 13.06%   4.44% 6.16%
Without Sales Load [Member] | C000049237        
Average Annual Return [Line Items]        
Average Annual Return, Percent 12.79%   4.18% 5.89%
Without Sales Load [Member] | C000244825        
Average Annual Return [Line Items]        
Average Annual Return, Percent 13.49% 12.68%    
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.13%   0.17% 1.70%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.13%   0.17% 1.70%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.13%   0.17% 1.70%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.13% 6.00%    
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 12.59%   4.59% 5.47%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 12.59%   4.59% 5.47%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 12.59%   4.59% 5.47%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 12.59% 11.68%