v3.25.2
N-6
Aug. 18, 2025
Prospectus:  
Document Type N-6
Entity Registrant Name Massachusetts Mutual Variable Life Separate Account I
Entity Central Index Key 0000836249
Entity Investment Company Type N-6
Document Period End Date Dec. 31, 2024
Amendment Flag false
Item 2. Key Information [Line Items]  
Item 18. Portfolio Companies (N-6) [Text Block]

Fund Type

Fund and Adviser/Sub-Adviser

Current
Expenses
(expenses/
average assets)

Average Annual
Total Returns

(as of 12/31/2024)

1 Year 5 Year 10 Year
Large Cap Blend

MFS® Research Series (Initial Class)
Adviser: Massachusetts Financial Services Company
Sub-Adviser: N/A

 0.74%(*) 18.87% 11.88% 11.66%
Portfolio Companies [Table Text Block]

Fund Type

Fund and Adviser/Sub-Adviser

Current
Expenses
(expenses/
average assets)

Average Annual
Total Returns

(as of 12/31/2024)

1 Year 5 Year 10 Year
Large Cap Blend

MFS® Research Series (Initial Class)
Adviser: Massachusetts Financial Services Company
Sub-Adviser: N/A

 0.74%(*) 18.87% 11.88% 11.66%
MFS® Research Series [Member]  
Item 2. Key Information [Line Items]  
Portfolio Company Name [Text Block] MFS® Research Series (Initial Class)
Portfolio Company Adviser [Text Block] Massachusetts Financial Services Company
Portfolio Company Subadviser [Text Block] N/A
Current Expenses [Percent] 0.74%
Average Annual Total Returns, 1 Year [Percent] 18.87%
Average Annual Total Returns, 5 Years [Percent] 11.88%
Average Annual Total Returns, 10 Years [Percent] 11.66%