v3.26.1
GMO Global Asset Allocation Fund Average Annual Total Returns
 12 Months Ended 23 Months Ended 48 Months Ended 60 Months Ended 63 Months Ended 120 Months Ended 342 Months Ended
Feb. 28, 2025
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
MSCI ACWI (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]   17.49% 16.42%          
Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent   1.25%     (0.33%)   1.35%  
Class III                
Prospectus [Line Items]                
Average Annual Return, Percent   5.13%     3.90%   4.46% 6.50%
Performance Inception Date Jun. 28, 1996              
Class III | After Taxes on Distributions                
Prospectus [Line Items]                
Average Annual Return, Percent   3.52%     2.32%   3.05% 4.73%
Class III | After Taxes on Distributions and Sales                
Prospectus [Line Items]                
Average Annual Return, Percent   3.49%     2.54%   3.08% 4.70%
Class III | GMO Global Asset Allocation Index (Fund benchmark)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent [2]   11.60%     6.57%   6.63% 5.91%
Class III | MSCI ACWI (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 [3]   17.49%     10.06%   9.23% 7.25%
Class III | Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent   1.25%     (0.33%)   1.35% 4.23%
Class R6                
Prospectus [Line Items]                
Average Annual Return, Percent   5.13%     3.89% 4.96%  
Performance Inception Date Sep. 30, 2019              
Class R6 | GMO Global Asset Allocation Index (Fund benchmark)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent [2]   11.60%     6.57% 7.40%    
Class R6 | MSCI ACWI (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 [3]   17.49%     10.06% 11.36%    
Class R6 | Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent   1.25%     (0.33%) (0.28%)    
Class I                
Prospectus [Line Items]                
Average Annual Return, Percent   4.98%   2.84%    
Performance Inception Date Jan. 06, 2021              
Class I | GMO Global Asset Allocation Index (Fund benchmark)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent [2]   11.60%   4.82%        
Class I | MSCI ACWI (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 [3]   17.49%   8.45%        
Class I | Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)[Member]                
Prospectus [Line Items]                
Average Annual Return, Percent   1.25%   (2.01%)        
[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] This benchmark provides a performance comparison that tracks changes in the Fund’s benchmark over time. See “Fund Benchmarks and Comparative Indices” for the time periods covered by each index included in the composite benchmark.
[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.