v3.25.2
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 19 Months Ended 60 Months Ended 120 Months Ended
May 31, 2025
May 31, 2025
May 31, 2025
May 31, 2025
Without Sales Load [Member] | C000005502        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.52%   5.82% 5.11%
Without Sales Load [Member] | C000049236        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.25%   5.56% 4.86%
Without Sales Load [Member] | C000049237        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.96%   5.29% 4.60%
Without Sales Load [Member] | C000244825        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.72% 12.16%    
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.46%   (0.90%) 1.49%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.46%   (0.90%) 1.49%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.46%   (0.90%) 1.49%
Bloomberg U.S. Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.46% 6.56%    
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.91%   4.42% 4.31%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.91%   4.42% 4.31%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.91%   4.42% 4.31%
S&P Target Date Retirement Income Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.91% 11.10%