Annual Total Returns - Class A |
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|---|---|---|---|---|---|---|---|
| MFS Aggressive Growth Allocation Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 14.88% | 11.81% | 15.98% | (17.09%) | 18.89% | 15.48% | 29.67% | (6.97%) | 22.92% | 7.24% |
| MFS Blended Research Growth Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 16.62% | 35.29% | 40.78% | (29.97%) | 28.64% | 30.47% | 32.01% | (5.11%) | 26.56% | 6.38% |
| MFS Blended Research Small Cap Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 5.52% | 4.60% | 18.49% | (18.63%) | 28.74% | 1.85% | 25.92% | (5.67%) | 13.52% | 20.01% |
| MFS Blended Research Mid Cap Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 7.76% | 19.04% | 19.41% | (13.93%) | 26.43% | 10.10% | 29.97% | (11.41%) | 18.81% | |
| MFS Blended Research Value Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 15.01% | 12.63% | 14.26% | (4.37%) | 25.90% | 1.44% | 23.00% | (8.58%) | 16.36% | 13.85% |
| MFS Conservative Allocation Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 9.54% | 6.56% | 10.44% | (13.48%) | 7.85% | 11.59% | 17.09% | (3.10%) | 10.78% | 5.42% |
| MFS Emerging Markets Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 33.48% | 10.98% | 10.88% | (20.11%) | (6.98%) | 10.17% | 19.78% | (14.02%) | 37.38% | 8.60% |
| MFS Growth Allocation Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 13.35% | 10.40% | 14.61% | (16.08%) | 15.70% | 14.46% | 26.26% | (5.87%) | 18.90% | 7.56% |
| MFS International Diversification Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 27.54% | 6.12% | 14.02% | (17.30%) | 7.41% | 14.97% | 25.68% | (11.24%) | 29.94% | 2.16% |
| MFS International Growth Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 20.78% | 8.84% | 14.52% | (15.32%) | 9.23% | 15.45% | 26.82% | (9.08%) | 32.17% | 2.39% |
| MFS International Intrinsic Equity Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 32.80% | 7.15% | 17.64% | (23.26%) | 10.29% | 20.15% | 25.56% | (9.22%) | 26.83% | 3.93% |
| MFS International Value Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 39.81% | 6.39% | 15.93% | (9.14%) | 14.44% | |||||
| MFS Managed Wealth Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 7.50% | 6.10% | 5.18% | (2.33%) | 1.13% | 2.85% | 8.67% | 1.95% | 6.67% | (1.16%) |
| MFS Moderate Allocation Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 11.71% | 8.40% | 12.49% | (15.20%) | 11.70% | 13.61% | 21.73% | (4.46%) | 14.81% | 6.47% |