v3.26.1
GMO Emerging Country Debt Fund Average Annual Total Returns
12 Months Ended 53 Months Ended 60 Months Ended 120 Months Ended 336 Months Ended 380 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   20.51%   5.83% 6.96%   12.24%
Performance Inception Date Apr. 19, 1994            
Class III | After Taxes on Distributions              
Prospectus [Line Items]              
Average Annual Return, Percent   17.50%   2.08% 3.47%   7.44%
Class III | After Taxes on Distributions and Sales              
Prospectus [Line Items]              
Average Annual Return, Percent   12.10%   2.66% 3.73%   7.58%
Class III | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   14.30%   1.78% 4.26%   8.40%
Class IV              
Prospectus [Line Items]              
Average Annual Return, Percent   20.57%   5.89% 7.03% 9.78%  
Performance Inception Date Jan. 09, 1998            
Class IV | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent [1]   14.30%   1.78% 4.26% 6.97%  
Class VI              
Prospectus [Line Items]              
Average Annual Return, Percent   20.62% 6.51%    
Performance Inception Date Jul. 29, 2021            
Class VI | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark)[Member]              
Prospectus [Line Items]              
Average Annual Return, Percent   14.30% 2.09%        
[1] Effective March 1, 2020, the Fund’s benchmark is the J.P. Morgan EMBI Global Diversified. In order to present a performance comparison that tracks changes in the Fund’s benchmark over time, the J.P. Morgan EMBI Global Diversified + (Composite index) is shown in the table above and reflects the performance of (i) the J.P. Morgan EMBI through 8/31/1995, (ii) the J.P. Morgan EMBI + through 12/31/1999, (iii) the J.P. Morgan EMBI Global through 2/29/2020 and (iv) the J.P. Morgan EMBI Global Diversified thereafter.