v3.24.3
Average Annual Total Returns
 12 Months Ended 38 Months Ended 60 Months Ended 83 Months Ended 97 Months Ended 112 Months Ended 120 Months Ended 176 Months Ended 185 Months Ended 256 Months Ended 257 Months Ended 258 Months Ended 260 Months Ended 262 Months Ended 274 Months Ended 430 Months Ended
Sep. 30, 2024
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
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Dec. 31, 2023
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Dec. 31, 2023
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Dec. 31, 2023
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Dec. 31, 2023
Class A                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   7.88%   4.89%       3.71%                       7.18%
Performance Inception Date Feb. 19, 1988                                      
Class 529-A                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   8.09%   4.90%       3.67%                 6.05%      
Performance Inception Date Feb. 19, 2002                                      
Class C                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   10.23%   4.91%       3.46%                     5.71%  
Performance Inception Date Mar. 15, 2001                                      
Class 529-C                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   10.17%   4.86%       3.65%                 6.02%      
Performance Inception Date Feb. 19, 2002                                      
Class 529-E                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   11.81%   5.46%       3.84%                   5.87%    
Performance Inception Date Mar. 15, 2002                                      
Class F-1                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.04%   5.67%       4.07%                     5.97%  
Performance Inception Date Mar. 15, 2001                                      
Class F-2                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.38%   5.98%       4.37%   6.00%                    
Performance Inception Date Aug. 04, 2008                                      
Class F-2 | After Taxes on Distributions                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   9.27%   3.44%       1.78%                        
Class F-2 | After Taxes on Distributions and Sales                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   7.23%   3.49%       2.14%                        
Class F-3                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.50%   6.09% 4.92%                              
Performance Inception Date Jan. 27, 2017                                      
Class 529-F-1                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.24%   5.87%       4.27%     7.00%                  
Performance Inception Date Sep. 16, 2002                                      
Class 529-F-3                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.42% 5.59%                                  
Performance Inception Date Oct. 30, 2020                                      
Class 529-F-2                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.39% 5.55%                                  
Performance Inception Date Oct. 30, 2020                                      
Class R-1                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   11.28%   4.91%       3.31%             6.01%          
Performance Inception Date Jul. 11, 2002                                      
Class R-2                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   11.29%   4.93%       3.32%         5.68%              
Performance Inception Date Jun. 18, 2002                                      
Class R-3                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   11.77%   5.40%       3.79%           6.22%            
Performance Inception Date Jun. 21, 2002                                      
Class R-4                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.11%   5.72%       4.11%       6.84%                
Performance Inception Date Jul. 19, 2002                                      
Class R-5                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.43%   6.03%       4.42%               6.58%        
Performance Inception Date May 15, 2002                                      
Class R-6                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.49%   6.09%       4.48% 7.72%                      
Performance Inception Date May 01, 2009                                      
Class R-2E                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   11.60%   5.24%     3.51%                          
Performance Inception Date Aug. 29, 2014                                      
Class R-5E                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent   12.33%   5.93%   5.88%                            
Performance Inception Date Nov. 20, 2015                                      
Bloomberg U.S. Aggregate Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent [1]   5.53%   1.10%       1.81%   2.88%                    
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index (reflects no deductions for sales charges, account fees, expenses or U.S. federal income taxes)                                        
Prospectus [Line Items]                                        
Average Annual Return, Percent [1]   13.44%   5.35%       4.59%   7.03%                    
[1] Effective July 24, 2024, the fund’s primary benchmark changed from the Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index (“the Previous Primary Benchmark”) to the Bloomberg U.S. Aggregate Index, a broad-based index that represents the overall applicable securities market, as required by the U.S. Securities and Exchange Commission (“SEC”). The Previous Primary Benchmark provides a means to compare the fund’s results to a benchmark that the investment adviser believes is more representative of the fund’s investment universe. There is no change in the fund’s investment strategies as a result of the benchmark change.