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GMO U.S. Small Cap Value Fund Average Annual Total Returns - Class VI
12 Months Ended 60 Months Ended 78 Months Ended 120 Months Ended
Feb. 28, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Prospectus [Line Items]          
Average Annual Return, Percent   15.26% 12.91% 11.60%
Performance Inception Date Jul. 02, 2019        
After Taxes on Distributions          
Prospectus [Line Items]          
Average Annual Return, Percent   14.47% 9.36% 8.79%
After Taxes on Distributions and Sales          
Prospectus [Line Items]          
Average Annual Return, Percent   9.59% 8.84% 8.18%
S&P SmallCap 600 Value Index (returns reflect no deduction for fees, expenses, or taxes)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent   6.70% 8.96% 8.84%  
S&P Composite 1500 Index (returns reflect no deduction for fees, expenses, or taxes)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent   17.02% 13.96% 15.01%