v3.26.1
Shareholder Report
 6 Months Ended
Jan. 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name MFS SERIES TRUST VII
Entity Central Index Key 0000318874
Entity Investment Company Type N-1A
Document Period End Date Jan. 31, 2026
C000118299 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class R6
Trading Symbol EQNVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R6 $30 0.55%
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.55%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118298 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class R4
Trading Symbol EQNUX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R4 $34 0.63%
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.63%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118297 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class R3
Trading Symbol EQNTX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R3 $47 0.88%
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.88%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118296 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class R2
Trading Symbol EQNSX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R2 $61 1.13%
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.13%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118295 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class R1
Trading Symbol EQNRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R1 $87 1.63%
Expenses Paid, Amount $ 87
Expense Ratio, Percent 1.63%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118294 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class I
Trading Symbol EQNIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
I $34 0.63%
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.63%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118293 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class C
Trading Symbol EQNCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
C $87 1.63%
Expenses Paid, Amount $ 87
Expense Ratio, Percent 1.63%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118292 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class B
Trading Symbol EQNBX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
B $87 1.63%
Expenses Paid, Amount $ 87
Expense Ratio, Percent 1.63%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%

Equity sectors

Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000118291 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Equity Income Fund
Class Name Class A
Trading Symbol EQNAX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Equity Income Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
A $47 0.88%
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.88%
Net Assets $ 732,526,724
Holdings Count | Holding 100
Investment Company Portfolio Turnover 31.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 732,526,724 Portfolio Turnover Rate (%): 31
Total Number of Holdings: 100
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.2%
Money Market Funds 1.8%
Equity sectors
Financials 23.7%
Health Care 12.7%
Industrials 12.3%
Information Technology 10.8%
Energy 7.7%
Consumer Staples 6.9%
Utilities 6.2%
Consumer Discretionary 6.2%
Communication Services 4.9%
Real Estate 4.5%
Materials 2.3%

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Johnson & Johnson 2.5%
Lam Research Corp. 2.3%
Alphabet, Inc., "A" 2.2%
Popular, Inc. 2.2%
Portland General Electric Co. 2.1%
Northern Trust Corp. 2.1%
Pfizer, Inc. 2.1%
AGCO Corp. 2.0%
Citigroup, Inc. 2.0%
W.P. Carey, Inc., REIT 1.9%
C000224114 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class A
Trading Symbol EEMPX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
A $69 1.24%
Expenses Paid, Amount $ 69
Expense Ratio, Percent 1.24%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 98.8%
Money Market Funds 1.2%
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
Issuer country weightings
China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224117 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class C
Trading Symbol EEMRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
C $111 2.00%
Expenses Paid, Amount $ 111
Expense Ratio, Percent 2.00%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 98.8%
Money Market Funds 1.2%
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
Issuer country weightings
China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224115 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class I
Trading Symbol EEMIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
I $56 1.00%
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.00%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 98.8%
Money Market Funds 1.2%
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
Issuer country weightings
China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224118 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class R1
Trading Symbol EEMDX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R1 $111 1.99%
Expenses Paid, Amount $ 111
Expense Ratio, Percent 1.99%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.8%
Money Market Funds 1.2%

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%

Issuer country weightings

China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224113 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class R2
Trading Symbol EEMEX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R2 $83 1.49%
Expenses Paid, Amount $ 83
Expense Ratio, Percent 1.49%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.8%
Money Market Funds 1.2%

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%

Issuer country weightings

China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224112 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class R3
Trading Symbol EEMFX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R3 $70 1.25%
Expenses Paid, Amount $ 70
Expense Ratio, Percent 1.25%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.8%
Money Market Funds 1.2%

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%

Issuer country weightings

China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224111 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class R4
Trading Symbol EEMGX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R4 $56 1.00%
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.00%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.8%
Money Market Funds 1.2%

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%

Issuer country weightings

China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]

Top ten holdings

Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000224116 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Emerging MarketsEquity Research Fund
Class Name Class R6
Trading Symbol EEMHX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Emerging Markets Equity Research Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R6 $55 0.99%
Expenses Paid, Amount $ 55
Expense Ratio, Percent 0.99%
Net Assets $ 4,559,009
Holdings Count | Holding 79
Investment Company Portfolio Turnover 28.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,559,009 Portfolio Turnover Rate (%): 28
Total Number of Holdings: 79
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 98.8%
Money Market Funds 1.2%
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%

Issuer country weightings

China 24.1%
Taiwan 22.6%
South Korea 12.2%
India 11.9%
Brazil 7.8%
Mexico 3.3%
Hong Kong 3.0%
Indonesia 2.7%
United Arab Emirates 2.3%
Other Countries 10.1%
Largest Holdings [Text Block]
Top ten holdings
Taiwan Semiconductor Manufacturing Co. Ltd. 13.6%
Tencent Holdings Ltd. 7.1%
SK Hynix, Inc. 4.0%
Samsung Electronics Co. Ltd. 3.9%
HDFC Bank Ltd. 2.4%
China Construction Bank Corp. 2.2%
Reliance Industries Ltd. 1.9%
Emirates NBD Bank PJSC 1.8%
Mahindra & Mahindra Ltd. 1.8%
Alibaba Group Holding Ltd., ADR 1.7%
C000232770 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class R6
Trading Symbol UIVRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R6 $32 0.62%
Expenses Paid, Amount $ 32
Expense Ratio, Percent 0.62%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%

Top ten holdings

Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232771 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class R4
Trading Symbol UIVQX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R4 $34 0.65%
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.65%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)

Portfolio structure

Equities 97.7%
Money Market Funds 2.3%

Equity sectors

Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%

Top ten holdings

Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]

Top ten holdings

Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232772 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class R3
Trading Symbol UIVPX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R3 $47 0.90%
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.90%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232777 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class R2
Trading Symbol UIVNX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R2 $60 1.15%
Expenses Paid, Amount $ 60
Expense Ratio, Percent 1.15%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232774 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class R1
Trading Symbol UIVMX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
R1 $86 1.65%
Expenses Paid, Amount $ 86
Expense Ratio, Percent 1.65%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232775 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class I
Trading Symbol UIVIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
I $34 0.65%
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.65%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232776 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class C
Trading Symbol UIVCX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
C $86 1.65%
Expenses Paid, Amount $ 86
Expense Ratio, Percent 1.65%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com
C000232773 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Intrinsic Value Fund
Class Name Class A
Trading Symbol UIVVX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Intrinsic Value Fund for the period of August 1, 2025 to January 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at funds.mfs.com. You can also request this information by contacting us at 1‑800‑225‑2606 or by sending an e-mail request to orderliterature@mfs.com.
Material Fund Change Notice [Text Block]
This report describes planned changes to the Fund since August 1, 2025 .
Additional Information Phone Number 1‑800‑225‑2606
Additional Information Email orderliterature@mfs.com
Additional Information Website funds.mfs.com
Expenses [Text Block]
FUND EXPENSES
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment (annualized)
A $47 0.90%
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.90%
Material Change Date Apr. 30, 2026
Net Assets $ 4,763,250
Holdings Count | Holding 76
Investment Company Portfolio Turnover 11.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 1/31/26
Net Assets ($): 4,763,250 Portfolio Turnover Rate (%): 11
Total Number of Holdings: 76
Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]
PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 1/31/26)
Portfolio structure
Equities 97.7%
Money Market Funds 2.3%
Equity sectors
Financials 22.0%
Information Technology 17.9%
Health Care 15.4%
Materials 15.0%
Industrials 12.9%
Consumer Staples 5.6%
Consumer Discretionary 5.2%
Energy 2.4%
Real Estate 1.3%
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
MFS uses the Global Industry Classification Standard (GICS®) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.
Largest Holdings [Text Block]
Top ten holdings
Microsoft Corp. 6.2%
Amazon.com, Inc. 4.6%
Charles Schwab Corp. 3.0%
Wheaton Precious Metals Corp. 2.9%
Taiwan Semiconductor Manufacturing Co. Ltd., ADR 2.6%
Colgate-Palmolive Co. 2.6%
Bank of America Corp. 2.5%
Franco-Nevada Corp. 2.5%
Becton, Dickinson and Co. 2.5%
CME Group, Inc. 2.2%
Material Fund Change [Text Block]
MATERIAL FUND CHANGES
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Material Fund Change Name [Text Block]
Effective April 30, 2026, the MFS Intrinsic Value Fund will be renamed the MFS Intrinsic Equity Fund. In connection with the name change, the fund will adopt a policy to invest at least 80% of its assets in equity securities.
Summary of Change Legend [Text Block]
This is a summary of certain changes to the fund since August 1, 2025. For more complete information, you may review the fund's prospectus, as supplemented from time to time, at funds.mfs.com or upon request at 1‑800‑225‑2606.
Updated Prospectus Phone Number 1‑800‑225‑2606
Updated Prospectus Web Address funds.mfs.com