v3.26.1
Loomis Sayles Growth Portfolio Average Annual Total Returns
12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Russell 3000 Index (reflects no deduction for mutual fund fees or expenses)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 17.15% 13.15% 14.29%
Russell 1000 Growth Index (reflects no deduction for mutual fund fees or expenses)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 18.56% 15.32% 18.13%
Class A      
Prospectus [Line Items]      
Average Annual Return, Percent 15.21% 15.06% 14.19%
Class B      
Prospectus [Line Items]      
Average Annual Return, Percent 14.90% 14.77% 13.91%
Class E      
Prospectus [Line Items]      
Average Annual Return, Percent 15.05% 14.89% 14.02%