v3.26.1
MFS Research International Portfolio Expense Example - MFS Research International Portfolio
Dec. 31, 2025
USD ($)
Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 57
Expense Example, with Redemption, 3 Years 221
Expense Example, with Redemption, 5 Years 398
Expense Example, with Redemption, 10 Years 913
Class B  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 83
Expense Example, with Redemption, 3 Years 299
Expense Example, with Redemption, 5 Years 534
Expense Example, with Redemption, 10 Years 1,207
Class E  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 73
Expense Example, with Redemption, 3 Years 268
Expense Example, with Redemption, 5 Years 480
Expense Example, with Redemption, 10 Years $ 1,090