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GMO Global Developed Equity Allocation Fund Average Annual Total Returns
 12 Months Ended 60 Months Ended 120 Months Ended 235 Months Ended
Feb. 28, 2025
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
MSCI World Index (Fund benchmark) (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent [1]   18.67% 11.16% 9.95%  
Class III          
Prospectus [Line Items]          
Average Annual Return, Percent   10.98% 8.87% 8.02% 7.37%
Performance Inception Date Jun. 16, 2005        
Class III | After Taxes on Distributions          
Prospectus [Line Items]          
Average Annual Return, Percent   9.31% 6.79% 6.34% 5.95%
Class III | After Taxes on Distributions and Sales          
Prospectus [Line Items]          
Average Annual Return, Percent   7.07% 6.42% 6.01% 5.75%
Class III | MSCI World Index (Fund benchmark) (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent [2]   18.67% 11.16% 9.95% 8.16%
[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.
[2] 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.