v3.26.3
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 60 Months Ended 120 Months Ended
Aug. 31, 2026
Aug. 31, 2026
Aug. 31, 2026
C000131659_0_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000131659_0_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000131659_0_BBIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     1.40%
C000239880_0_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000239880_0_BBIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.90%    
C000201028_2_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000201028_2_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000201028_2_BBIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.92%    
C000131661_2_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000131661_2_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000131661_2_BBIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     1.40%
C000225827_1_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000225827_1_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000225827_1_BBIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 0.02%    
C000225826_0_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000225826_0_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000225826_0_BBIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 0.02%    
C000125598_1_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000125598_1_BBIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.29%)  
C000125598_1_BBIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     1.40%
C000248144_1_BBIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.89%    
C000248144_1_BBIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 4.10%    
C000131659_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.15%    
C000131659_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   0.41%  
C000131659_NoLoadClassMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     2.25%
C000239880_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.73%    
C000239880_NoLoadClassMember_2025-09-01_2026-08-31Member      
Average Annual Return [Line Items]      
Average Annual Return, Percent 4.01%    
C000201028_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.91%    
C000201028_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   3.78%  
C000201028_NoLoadClassMember_2025-09-01_2026-08-31Member      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.21%    
C000201028_0_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.53%    
C000201028_0_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   3.17%  
C000201028_0_AdditionalIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.54%    
C000201028_1_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 4.12%    
C000201028_1_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   3.95%  
C000201028_1_AdditionalIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.41%    
C000131661_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.85%    
C000131661_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   2.29%  
C000131661_NoLoadClassMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     2.44%
C000131661_0_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.15%    
C000131661_0_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   1.70%  
C000131661_0_AdditionalIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     1.98%
C000131661_1_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.79%    
C000131661_1_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   2.21%  
C000131661_1_AdditionalIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     2.47%
C000225827_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.27%    
C000225827_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   0.32%  
C000225827_NoLoadClassMember_2025-09-01_2026-08-31Member      
Average Annual Return [Line Items]      
Average Annual Return, Percent 0.35%    
C000225827_0_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 2.98%    
C000225827_0_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   0.30%  
C000225827_0_AdditionalIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 0.30%    
C000225826_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.59%    
C000225826_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.20%)  
C000225826_NoLoadClassMember_2025-09-01_2026-08-31Member      
Average Annual Return [Line Items]      
Average Annual Return, Percent 0.20%    
C000125598_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.74%    
C000125598_NoLoadClassMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   0.01%  
C000125598_NoLoadClassMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     2.47%
C000125598_0_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 1.98%    
C000125598_0_AdditionalIndexMember_5YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent   (0.07%)  
C000125598_0_AdditionalIndexMember_10YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent     2.21%
C000248144_NoLoadClassMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.89%    
C000248144_NoLoadClassMember_2025-09-01_2026-08-31Member      
Average Annual Return [Line Items]      
Average Annual Return, Percent 4.74%    
C000248144_0_AdditionalIndexMember_1YRMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.53%    
C000248144_0_AdditionalIndexMember_LOCMember      
Average Annual Return [Line Items]      
Average Annual Return, Percent 4.24%