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GMO Implementation Fund Average Annual Total Returns - GMO Implementation Fund
 12 Months Ended 60 Months Ended 120 Months Ended 166 Months Ended
Feb. 28, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Prospectus [Line Items]          
Average Annual Return, Percent [1]   25.37% 9.20% 6.16% 6.02%
Performance Inception Date Mar. 01, 2012        
After Taxes on Distributions          
Prospectus [Line Items]          
Average Annual Return, Percent [1],[2]   23.93% 7.84% 5.03% 5.21%
After Taxes on Distributions and Sales          
Prospectus [Line Items]          
Average Annual Return, Percent [1],[2]   15.70% 6.87% 4.56% 4.64%
Consumer Price Index (returns reflect no deduction for fees, expenses, or taxes)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent [1]   2.63% 4.49% 3.20% 2.60%
Bloomberg U.S. Treasury Inflation Notes: 1-10 Year Index (returns reflect no deduction for fees, expenses, or taxes)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent [1]   7.47% 2.52% 3.32% 2.23%
Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent [1]   7.30% (0.36%) 2.01% 2.02%
MSCI World Index (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],[3]   21.09% 12.15% 12.17% 11.21%
[1] Returns include a substantial, one-time litigation settlement recovery received on December 16, 2024. This event contributed 2.69% to 2024 annual performance.
[2] After-tax returns do not reflect distributions made by the Fund for all periods prior to July 1, 2015, the date on which the Fund elected to be treated as a corporation for U.S. federal income purposes. Further, as described in “Distributions and Taxes,” the Fund elected to be treated and intends to qualify and be treated each year as a regulated investment company under Subchapter M of the Internal Revenue Code of 1986, as amended, for U.S. federal income tax purposes.
[3] 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.