v3.25.1
Shareholder Report, Line Graph (Details) - USD ($)
 12 Months Ended 60 Months Ended 120 Months Ended
Feb. 28, 2025
Feb. 28, 2025
Feb. 28, 2025
Feb. 28, 2025
Feb. 29, 2024
Feb. 28, 2023
Feb. 28, 2022
Feb. 28, 2021
Feb. 29, 2020
Feb. 28, 2019
Feb. 28, 2018
Feb. 28, 2017
Feb. 29, 2016
Feb. 28, 2015
C000002007 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A with initial sales charge (4.25%)                          
Average Annual Return, Percent 0.75% (2.01%) 0.17%                      
C000002007 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A without sales charge                          
Account Value $ 10,172 $ 10,172 $ 10,172 $ 10,172 $ 9,667 $ 9,523 $ 10,561 $ 10,824 $ 10,781 $ 9,847 $ 9,583 $ 9,642 $ 9,737 $ 9,575
Average Annual Return, Percent 5.23% (1.15%) 0.61%                      
C000002012 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name B with CDSC (declining over six years from 4% to 0%)                          
Average Annual Return, Percent [1] 0.45% (2.26%) (0.15%)                      
C000002012 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name B without sales charge                          
Account Value $ 9,856 $ 9,856 $ 9,856 9,856 9,436 9,366 10,466 10,808 10,846 9,980 9,785 9,910 10,093 10,000
Average Annual Return, Percent 4.45% (1.90%) (0.15%)                      
C000002013 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C with CDSC (1% for 12 months)                          
Average Annual Return, Percent [2] 3.44% (1.89%) (0.15%)                      
C000002013 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C without sales charge                          
Account Value $ 9,850 $ 9,850 $ 9,850 9,850 9,431 9,360 10,468 10,808 10,835 9,972 9,787 9,911 10,093 10,000
Average Annual Return, Percent 4.44% (1.89%) (0.15%)                      
C000002006 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name I without sales charge                          
Account Value $ 10,867 $ 10,867 $ 10,867 10,867 10,302 10,124 11,213 11,463 11,389 10,377 10,084 10,111 10,185 10,000
Average Annual Return, Percent 5.49% (0.93%) 0.84%                      
C000002015 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R1 without sales charge                          
Account Value $ 9,856 $ 9,856 $ 9,856 9,856 9,436 9,366 10,466 10,808 10,846 9,980 9,785 9,920 10,093 10,000
Average Annual Return, Percent 4.45% (1.90%) (0.15%)                      
C000002017 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R2 without sales charge                          
Account Value $ 10,360 $ 10,360 $ 10,360 10,360 9,870 9,748 10,839 11,136 11,120 10,182 9,933 10,020 10,144 10,000
Average Annual Return, Percent 4.97% (1.41%) 0.35%                      
C000002018 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R3 without sales charge                          
Account Value $ 10,612 $ 10,612 $ 10,612 10,612 10,085 9,935 11,030 11,304 11,248 10,274 10,009 10,060 10,169 10,000
Average Annual Return, Percent 5.23% (1.16%) 0.60%                      
C000002008 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R4 without sales charge                          
Account Value $ 10,882 $ 10,882 $ 10,882 10,882 10,316 10,137 11,213 11,463 11,389 10,377 10,074 10,111 10,185 10,000
Average Annual Return, Percent 5.49% (0.91%) 0.85%                      
C000117927 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R6 without sales charge                          
Account Value $ 10,996 $ 10,996 $ 10,996 $ 10,996 10,414 10,223 11,299 11,539 11,453 10,424 10,108 10,134 10,196 10,000
Average Annual Return, Percent 5.59% (0.81%) 0.95%                      
C000033358 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A with initial sales charge (4.25%)                          
Average Annual Return, Percent 3.90% 2.44%   3.44%                    
C000033358 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A without sales charge                          
Account Value $ 14,018 $ 14,018 $ 14,018 $ 14,018 12,918 12,028 12,928 12,525 11,897 11,099 10,461 10,237 9,038 9,575
Average Annual Return, Percent 8.52% 3.34%   3.89%                    
C000033359 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C with CDSC (1% for 12 months)                          
Average Annual Return, Percent [3] 6.71% 2.58%   3.12%                    
C000033359 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C without sales charge                          
Account Value $ 13,597 $ 13,597 13,597 $ 13,597 12,624 11,831 12,824 12,518 11,971 11,259 10,683 10,542 9,376 10,000
Average Annual Return, Percent 7.71% 2.58%   3.12%                    
C000033360 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name I without sales charge                          
Account Value $ 15,010 $ 15,010 15,010 $ 15,010 13,798 12,815 13,739 13,278 12,581 11,707 10,998 10,745 9,463 10,000
Average Annual Return, Percent 8.78% 3.59%   4.14%                    
C000068409 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R1 without sales charge                          
Account Value $ 13,598 $ 13,598 $ 13,598 $ 13,598 12,624 11,841 12,825 12,519 11,981 11,260 10,683 10,533 9,375 10,000
Average Annual Return, Percent 7.72% 2.56% 3.12%                      
C000068410 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R2 without sales charge                          
Account Value $ 14,292 $ 14,292 $ 14,292 14,292 13,203 12,323 13,279 12,898 12,282 11,486 10,844 10,647 9,423 10,000
Average Annual Return, Percent 8.25% 3.08% 3.64%                      
C000068411 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R3 without sales charge                          
Account Value $ 14,652 $ 14,652 $ 14,652 14,652 13,503 12,561 13,512 13,091 12,425 11,601 10,925 10,691 9,439 10,000
Average Annual Return, Percent 8.51% 3.35% 3.89%                      
C000068412 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R4 without sales charge                          
Account Value $ 15,009 $ 15,009 $ 15,009 15,009 13,797 12,814 13,750 13,288 12,581 11,717 11,007 10,753 9,471 10,000
Average Annual Return, Percent 8.79% 3.59% 4.14%                      
C000117928 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R6 without sales charge                          
Account Value $ 15,151 $ 15,151 $ 15,151 15,151 13,915 12,911 13,830 13,353 12,641 11,753 11,039 10,766 9,473 10,000
Average Annual Return, Percent 8.88% 3.69% 4.24%                      
C000100956 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A with initial sales charge (5.75%)                          
Average Annual Return, Percent 3.56% 10.29% 8.51%                      
C000100956 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name A without sales charge                          
Account Value $ 22,638 $ 22,638 $ 22,638 22,638 20,603 20,208 20,808 17,584 13,077 13,399 12,304 11,720 8,541 9,425
Average Annual Return, Percent 9.88% 11.60% 9.16%                      
C000100957 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name B with CDSC (declining over six years from 4% to 0%)                          
Average Annual Return, Percent [4] 5.04% 10.50% 8.34%                      
C000100957 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name B without sales charge                          
Account Value $ 22,274 $ 22,274 $ 22,274 $ 22,274 20,428 20,184 20,941 17,830 13,356 13,784 12,757 12,242 8,990 10,000
Average Annual Return, Percent 9.04% 10.77% 8.34%                      
C000100958 [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C with CDSC (1% for 12 months)                          
Average Annual Return, Percent [5] 8.06% 10.77%   8.34%                    
C000100958 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name C without sales charge                          
Account Value $ 22,274 $ 22,274 $ 22,274 $ 22,274 20,423 20,174 20,938 17,831 13,354 13,785 12,753 12,244 8,992 10,000
Average Annual Return, Percent 9.06% 10.77%   8.34%                    
C000100959 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name I without sales charge                          
Account Value $ 24,620 $ 24,620 24,620 $ 24,620 22,352 21,862 22,469 18,940 14,048 14,360 13,152 12,495 9,085 10,000
Average Annual Return, Percent 10.15% 11.88%   9.43%                    
C000100960 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R1 without sales charge                          
Account Value $ 22,279 $ 22,279 22,279 $ 22,279 20,422 20,180 20,933 17,832 13,360 13,785 12,758 12,244 8,990 10,000
Average Annual Return, Percent 9.09% 10.77%   8.34%                    
C000100961 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R2 without sales charge                          
Account Value $ 23,426 $ 23,426 23,426 $ 23,426 21,374 21,023 21,702 18,388 13,706 14,077 12,963 12,371 9,042 10,000
Average Annual Return, Percent 9.60% 11.32%   8.89%                    
C000100962 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R3 without sales charge                          
Account Value $ 24,033 $ 24,033 24,033 $ 24,033 21,876 21,445 22,091 18,664 13,880 14,223 13,062 12,436 9,070 10,000
Average Annual Return, Percent 9.86% 11.61%   9.16%                    
C000100963 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R4 without sales charge                          
Account Value $ 24,624 $ 24,624 24,624 $ 24,624 22,360 21,871 22,469 18,945 14,050 14,361 13,152 12,492 9,088 10,000
Average Annual Return, Percent 10.12% 11.88%   9.43%                    
C000117930 [Member] | Without Sales Load [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name R6 without sales charge                          
Account Value $ 24,866 $ 24,866 24,866 $ 24,866 22,563 22,048 22,634 19,060 14,121 14,411 13,187 12,517 9,091 10,000
Average Annual Return, Percent 10.20% 11.98%   9.54%                    
Bloomberg U S Aggregate Bond Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name Bloomberg U.S. Aggregate Bond Index                          
Account Value $ 11,613 $ 11,613 $ 11,613 $ 11,613 10,976 10,622 11,766 12,086 11,921 10,674 10,346 10,294 10,150 10,000
Average Annual Return, Percent [6],[7] 5.81% (0.52%) 1.51%                      
Standard And Poor s 500 Stock Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name Standard & Poor's 500 Stock Index                          
Account Value $ 33,877 $ 33,877 $ 33,877 33,877 28,611 21,932 23,759 20,414 15,549 14,371 13,729 11,724 9,381 10,000
Average Annual Return, Percent 18.41% [8] 16.85% [8] 12.98% [9]                      
MFS Diversified Income Fund Blended Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name MFS Diversified Income Fund Blended Index                          
Account Value $ 15,548 $ 15,548 $ 15,548 15,548 14,088 12,996 14,109 13,611 12,653 11,825 11,196 10,893 9,542 10,000
Average Annual Return, Percent 10.36% [9] 4.21% [9] 4.51% [8]                      
Russell 3000 Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name Russell 3000® Index                          
Account Value $ 32,076 $ 32,076 $ 32,076 $ 32,076 27,291 21,221 23,085 20,557 15,191 14,210 13,527 11,639 9,216 10,000
Average Annual Return, Percent [10],[11] 17.53% 16.12%   12.36%                    
Bloomberg U S Government Mortgage Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name Bloomberg U.S. Government/Mortgage Index                          
Account Value $ 11,127 $ 11,127 $ 11,127 $ 11,127 10,545 10,306 11,403 11,686 11,613 10,539 10,196 10,219 10,269 10,000
Average Annual Return, Percent [6],[7] 5.53% (0.85%) 1.07%                      
Russell 2000 Value Index [Member]                            
Account Value [Line Items]                            
Line Graph and Table Measure Name Russell 2000® Value Index                          
Account Value $ 19,508 $ 19,508 $ 19,508 $ 19,508 $ 18,134 $ 17,171 $ 17,961 $ 16,843 $ 11,940 $ 13,163 $ 12,606 $ 12,243 $ 8,665 $ 10,000
Average Annual Return, Percent [10],[11] 7.58% 10.32%   6.91%                    
[1] Assuming redemption at the end of the applicable period.
[2] Assuming redemption at the end of the applicable period.
[3] Assuming redemption at the end of the applicable period.
[4] Assuming redemption at the end of the applicable period.
[5] Assuming redemption at the end of the applicable period.
[6] Effective May 1, 2024, the Bloomberg U.S. Aggregate Bond Index replaced the Bloomberg U.S. Government/Mortgage Index as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the Bloomberg U.S. Government/Mortgage Index as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
[7] Source: FactSet Research Systems Inc.
[8] Source: FactSet Research Systems Inc.
[9] Source: FactSet Research Systems Inc.
[10] Effective May 1, 2024, the Russell 3000® Index replaced the Russell 2000® Value Index as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the Russell 2000® Value Index as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
[11] Source: FactSet Research Systems Inc.