v3.26.1
GMO U.S. Opportunistic Value Fund Average Annual Total Returns
 12 Months Ended 28 Months Ended 35 Months Ended 37 Months Ended 60 Months Ended 120 Months Ended
Feb. 28, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Class III              
Prospectus [Line Items]              
Average Annual Return, Percent   14.80%   11.91%  
Performance Inception Date Feb. 15, 2023            
Class III | MSCI USA Value Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   13.71%   11.74%      
Class III | MSCI USA Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   17.75%   20.82%      
Class III | S&P Composite 1500 Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent   17.02%   19.71%      
Class VI              
Prospectus [Line Items]              
Average Annual Return, Percent   14.93%     13.28%
Performance Inception Date Dec. 13, 2022            
Class VI | After Taxes on Distributions              
Prospectus [Line Items]              
Average Annual Return, Percent   11.06%     10.09%
Class VI | After Taxes on Distributions and Sales              
Prospectus [Line Items]              
Average Annual Return, Percent   10.48%     9.50%
Class VI | MSCI USA Value Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   13.71%     11.30%    
Class VI | MSCI USA Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   17.75%     20.98%    
Class VI | S&P Composite 1500 Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent   17.02%     19.95%    
Class R6              
Prospectus [Line Items]              
Average Annual Return, Percent   14.88% 15.89%    
Performance Inception Date Aug. 28, 2023            
Class R6 | MSCI USA Value Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   13.71% 15.00%        
Class R6 | MSCI USA Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   17.75% 22.22%        
Class R6 | S&P Composite 1500 Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent   17.02% 21.21%        
Class I              
Prospectus [Line Items]              
Average Annual Return, Percent   14.64%   11.80%  
Performance Inception Date Feb. 15, 2023            
Class I | MSCI USA Value Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   13.71%   11.74%      
Class I | MSCI USA Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   17.75%   20.82%      
Class I | S&P Composite 1500 Index (returns reflect no deduction for fees, expenses, or taxes)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent   17.02%   19.71%      
[1] MSCI data may not be reproduced or used for any other purpose. MSCI provides no warranties, has not prepared or approved this report, and has no liability hereunder.