v3.26.1
Shareholder Report
 6 Months Ended
May 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name MFS SERIES TRUST II
Entity Central Index Key 0000798250
Entity Investment Company Type N-1A
Document Period End Date May 31, 2026
C000102727 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class R6
Trading Symbol MFEKX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $25 0.49%
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.49%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006431 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class R4
Trading Symbol MFEJX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $30 0.58%
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.58%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006442 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class R3
Trading Symbol MFEHX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $42 0.83%
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.83%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006441 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class R2
Trading Symbol MEGRX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $55 1.08%
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.08%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006439 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class R1
Trading Symbol MFELX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $81 1.59%
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.59%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006437 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class I
Trading Symbol MFEIX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $30 0.58%
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.58%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006436 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class C
Trading Symbol MFECX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $81 1.59%
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.59%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006435 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class B
Trading Symbol MEGBX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $81 1.59%
Expenses Paid, Amount $ 81
Expense Ratio, Percent 1.59%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
C000006430 [Member]  
Shareholder Report [Line Items]  
Fund Name MFS® Growth Fund
Class Name Class A
Trading Symbol MFEGX
Annual or Semi-Annual Statement [Text Block] This semiannual shareholder report contains important information about MFS Growth Fund for the period of December 1, 2025 to May 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 $42 0.83%
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.83%
Net Assets $ 41,600,194,598
Holdings Count | Holding 69
Investment Company Portfolio Turnover 18.00%
Additional Fund Statistics [Text Block]
FUND STATISTICS AS OF 5/31/26
Net Assets ($): 41,600,194,598 Portfolio Turnover Rate (%): 18
Total Number of Holdings: 69
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 5/31/26)
Portfolio structure
Equities 99.0%
Money Market Funds 1.0%
Equity sectors
Information Technology 50.1%
Communication Services 13.5%
Consumer Discretionary 11.3%
Industrials 8.5%
Financials 5.7%
Health Care 5.4%
Consumer Staples 1.6%
Energy 1.4%
Materials 1.3%
Real Estate 0.2%
Top ten holdings
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%
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
NVIDIA Corp. 15.3%
Apple, Inc. 9.5%
Alphabet, Inc., "A" 9.3%
Microsoft Corp. 7.5%
Amazon.com, Inc. 7.3%
Broadcom, Inc. 4.6%
Mastercard, Inc., "A" 2.8%
GE Vernova, Inc. 2.3%
Meta Platforms, Inc., "A" 2.3%
Seagate Technology Holdings PLC 1.8%