XML 42 R15.htm IDEA: XBRL DOCUMENT v3.21.2
Label Element Value
GMO Alternative Allocation Fund  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading GMO ALTERNATIVE ALLOCATION FUND
Objective [Heading] rr_ObjectiveHeading Investment objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
Positive total return.
Expense [Heading] rr_ExpenseHeading Fees and expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
The table below describes the fees and expenses that you may bear for each class of shares if you buy, hold, and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund operating expenses(expenses that you bear each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination Jun. 30, 2022
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
The Fund pays transaction costs, such as commissions, when it buys and sells securities. A higher portfolio turnover rate may result in higher transaction costs and, for holders of Fund shares subject to U.S. taxes, higher income taxes. These transaction costs, which are not reflected in Annual Fund operating expenses or in the Example, affect the Fund’s performance. During its fiscal year ended February 28, 2021, the Fund’s portfolio turnover rate (including the accounts of the Fund’s wholly-owned subsidiary, GMO Alternative Allocation SPC Ltd., and excluding short-term investments) was 411% of the average value of its portfolio securities. That portfolio turnover rate includes investments in U.S. Treasury Fund, which the Fund uses as a short-term investment vehicle for cash management. The Fund’s portfolio turnover rate during its fiscal year ended February 28, 2021 (including the accounts of GMO Alternative Allocation SPC Ltd., and excluding transactions in U.S. Treasury Fund and other short-term investments) was 410% of the average value of its portfolio securities.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 411.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated, regardless of whether or not you redeem your shares at the end of such periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same as those shown in the table. The one year amounts shown reflect the expense reimbursement and waiver noted in the expense table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal investment strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund seeks annualized returns of 4% (net of fees) above cash (FTSE 3-Month Treasury Bill Index) over a complete market cycle while having a low correlation to traditional equity market indices. The Fund invests directly or indirectly (through other GMO funds) in a combination of GMO investment strategies. The Fund typically has exposure to many underlying strategies, and at any given time the Fund may have significant exposure to a single or a few strategies. Below are some of the strategies in which GMO expects the Fund to invest:
•
Fixed Income Absolute Return:   strategy of exploiting opportunities in global debt and currency markets by investing in fixed income instruments of varying maturities, durations and credit qualities (including bonds, forward contracts, swap contracts or other derivatives)
​
•
Event-Driven:   strategy of investing primarily in equity securities of companies that GMO expects to experience a material corporate event or catalyst in the relative short-term. These events are typically agreed-to merger and acquisition transactions but also may include corporate buy-ins, hostile mergers, pre-bid acquisitions, corporate spin-offs, likely transactions, restructurings, and corporate litigation and regulatory events.
​
•
Systematic Put Writing:   put option writing strategy on U.S. and non-U.S. stock indices based on GMO’s evaluation of the income the Fund can receive for writing put options on a given index relative to the income for writing put options on other indices, taking into consideration the historical risk premium for writing put options on those indices.
​
•
Global Macro:   long/short strategy across a range of global equity, bond, currency, and commodity markets using exchange-traded futures, forward currency contracts, and swaps on commodity indices, as well as other investments, using GMO’s proprietary investment models for systematic global tactical asset allocation and equity, bond, currency and commodity market selection.
​
•
Long/Short Equities:   global, regional and/or industry-specific long-short equity exposures
​
•
Long/Short Asset Allocation:   strategy of taking long positions in asset and sub-asset classes that GMO expects will outperform relative to the asset and sub-asset classes to which the Fund has short investment exposure.
​
•
High Yield:   systematic, factor-based strategy of investing in high yield bonds and other instruments providing high yield bond exposure, including fallen angel bonds (bonds originally issued as investment grade that have since been downgraded to below investment grade), short-dated bonds, exchange-traded funds (“ETFs”), total return swaps on high yield indices, and options on ETFs and high yield indices.
​
GMO may discontinue or add new strategies at any time, and the factors GMO considers can change over time. The Fund may have long and/or short exposure to any asset class (e.g., U.S. equity, international equity, emerging market equity, developed and emerging market fixed income) and may hold or “use” exchange-traded and over-the-counter derivatives of any kind. The Fund is not limited in its use of derivatives or in the total notional value of its derivative positions. Because of its derivative positions, the Fund typically has gross investment exposure in excess of its net assets (i.e. the Fund may be leveraged) and, therefore, is subject to heightened risk of loss. The Fund may invest in
securities of any credit quality (including below investment grade securities commonly referred to as “high yield” or “junk bonds”) or maturity. The Fund may invest in securities of companies of any market capitalization. The Fund may lend its portfolio securities.
The Fund gains exposure to commodities and some other asset classes by investing through a wholly-owned subsidiary advised by GMO, which does not receive any management or other fees for its services. The subsidiary invests primarily in commodity-related derivatives (such as over-the-counter swaps on commodity indices) and fixed income investments but also may invest in any other investment in which the Fund is permitted to invest directly. References in this Prospectus to actions taken by the Fund refer to actions taken by the subsidiary as well as the Fund. The Fund does not invest directly in commodities and commodity-related derivatives (such as swaps on commodity indices).
The Fund also may invest in U.S. Treasury Fund, in money market funds unaffiliated with GMO, and directly in the types of investments typically held by money market funds.
Risk [Heading] rr_RiskHeading Principal risks of investing in the Fund
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The value of the Fund’s shares changes with the value of the Fund’s investments. Many factors can affect this value, and you may lose money by investing in the Fund. References to investments include those held directly by the Fund and indirectly through the Fund’s investments in its wholly-owned subsidiary and in any underlying funds in which it invests. The Fund is a non-diversified investment company under the Investment Company Act of 1940, as amended, and therefore a decline in the market price of a particular security held by the Fund may affect the Fund’s performance more than if the Fund were a diversified investment company. The principal risks of investing in the Fund are summarized below. For a more complete discussion of these risks, including those risks to which the Fund is exposed as a result of its investments in its wholly-owned subsidiary and in any underlying funds, see “Additional Information about the Funds’ Investment Strategies, Risks, and Expenses” and “Description of Principal Risks.”
•
Management and Operational Risk – The Fund runs the risk that GMO’s investment techniques will fail to produce the desired results, including the annualized returns the Fund is seeking to achieve. Even if the Fund achieves those returns over a market cycle, it may experience shorter periods of significantly lower returns. See “Performance” below. GMO uses quantitative models as part of its investment process. GMO’s models may not accurately predict future market movements. In addition, GMO’s models rely on assumptions and data that are subject to limitations (e.g., inaccuracies, staleness) that could adversely affect their predictive value. The Fund also runs the risk that GMO’s assessment of an investment (including a security’s fundamental fair (or intrinsic) value) is wrong or that deficiencies in GMO’s or another service provider’s internal systems or controls will cause losses for the Fund or impair Fund operations.
​
•
Leveraging Risk – The use derivatives and securities lending creates leverage. Leverage increases the Fund’s losses when the value of its investments (including derivatives) declines. In addition, the Fund’s portfolio will be leveraged if it exercises its right to delay payment on a redemption, and losses will result if the value of the Fund’s assets declines between the time a redemption request is deemed to be received by the Fund and the time the Fund liquidates assets to meet that request.
​
•
Derivatives and Short Sales Risk – The use of derivatives involves the risk that their value may not change as expected relative to changes in the value of the underlying assets, pools of assets, rates, currencies or indices. Derivatives also present other risks, including market risk, illiquidity risk, currency risk, credit risk, and counterparty risk. The market price of an option is affected by many factors, including changes in the market prices or dividend rates of underlying securities (or in the case of indices, the securities in such indices); the time remaining before expiration; changes in interest rates or exchange rates; and changes in the actual or perceived volatility of the relevant stock market and underlying securities. The Fund may create short investment exposure by taking a derivative position in which the value of the derivative moves in the opposite direction from the price of an underlying asset, pool of assets, rate, currency or index. The risks of loss associated with derivatives that provide short investment exposure and short sales of securities are theoretically unlimited.
​
•
Market Risk – Equities – The market price of an equity security may decline due to factors affecting the issuer or its industry or the economy and equity markets generally. If the Fund purchases an equity for less than its fundamental fair (or intrinsic) value as assessed by GMO and GMO’s assessment proves to be incorrect, the Fund runs the risk that the market price of the equity will not appreciate or will decline. When the Fund writes put options on stock indices, the value of those options will decline when the value of those indices declines. The value of an index depends on the value of the equity securities in the index. Also, the Fund’s investment strategy of writing put options on stock indices can be expected to cause that strategy to underperform relative to those indices when those markets rise sharply. The Fund also may purchase equities that typically trade at higher multiples of current earnings than other securities, and the market prices of these equities often are more sensitive to changes in future earnings expectations than the market prices of equities trading at lower multiples. Declines in stock market prices generally are likely to reduce the net asset value of the Fund’s shares. In addition, the value of the Fund’s shares will be adversely affected if the equities or other assets that are the subjects of the Fund’s short exposures appreciate in value.
​
•
Market Risk – Fixed Income – The market price of a fixed income investment can decline due to market-related factors, including rising interest rates and widening credit spreads, or decreased liquidity due, for example, to market uncertainty about the value of a fixed income investment (or class of fixed income investments).
​
•
Credit Risk – The Fund runs the risk that the issuer or guarantor of a fixed income investment or the obligors of obligations underlying an asset-backed security will be unable or unwilling to satisfy their obligations to pay principal and interest or otherwise to honor their obligations in a timely manner. The market price of a fixed income investment will normally decline as a result of the failure of an issuer, guarantor, or obligor to meet its payment obligations, or in anticipation of such failure. Below investment grade investments have speculative characteristics, and negative changes in economic conditions or other circumstances are more likely to impair the ability of issuers of those investments to make principal and interest payments than issuers of investment grade investments.
​
•
Counterparty Risk – The Fund runs the risk that the counterparty to a derivatives contract, a clearing member used by the Fund to hold a cleared derivatives contract, or a borrower of the Fund’s securities is unable or unwilling to make timely settlement payments, return the Fund’s margin, or otherwise honor its obligations.
​
•
Fund of Funds Risk – The Fund is indirectly exposed to all of the risks of an investment in its wholly-owned subsidiary and the underlying funds (including ETFs) in which it invests, including the risk that its wholly-owned subsidiary and those underlying funds will not perform as expected. Because the Fund bears the fees and expenses of the underlying funds in which it invests, the increase in fees and expenses of an underlying fund or a reallocation of the Fund’s investments to underlying funds with higher fees or expenses will increase the Fund’s total expenses.
​
•
Futures Contracts Risk – The loss to the Fund resulting from its use of futures contracts is potentially unlimited. Futures markets are highly volatile, and the use of futures contracts increases the volatility of the Fund’s net asset value. A liquid secondary market may not exist for any particular futures contract at any particular time, and the Fund may be unable when it wishes to effect closing transactions to terminate its exposure under that contract. When the Fund uses futures contracts for hedging purposes, it runs the risk that changes in the prices of the contracts will not correlate perfectly with changes in the securities, index, or other asset underlying the contracts or movements in the prices of the Fund’s investments that are subject to the hedge. In addition, the Fund may be unable to recover or may be delayed in recovering margin or other amounts deposited with a futures commission merchant or futures clearinghouse. Foreign futures contracts are often less liquid and more volatile than U.S. futures contracts.
​
•
Non-U.S. Investment Risk – The market prices of many non-U.S. securities (particularly of companies tied economically to emerging countries) fluctuate more than those of U.S. securities. Many non-U.S. securities markets (particularly emerging markets) are less stable, smaller, less liquid, and less regulated than U.S. securities markets, and the cost of trading in those markets often is higher than in U.S. securities markets. In addition, issuers of non-U.S. securities (particularly those tied economically to emerging countries) often are not subject to as much regulation as U.S. issuers, and the reporting, recordkeeping, accounting, custody, and auditing standards to which those issuers are subject often are not as rigorous as U.S. standards. In addition, the Fund may be subject to non-U.S. taxes, potentially on a retroactive basis, on (i) capital gains it realizes or dividends, interest, or other amounts it realizes or accrues in respect of non-U.S. investments; (ii) transactions in those investments; and (iii) repatriation of proceeds generated from the sale or other disposition of those investments. Also, the Fund needs a license to invest directly in securities traded in many non-U.S. securities markets, and the Fund is subject to the risk that it could not invest if its license were terminated or suspended. In some non-U.S. securities markets, prevailing custody and trade settlement practices (e.g., the requirement to pay for securities prior to receipt) expose the Fund to credit and other risks. Further, adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. These and other risks (e.g., nationalization, expropriation or other confiscation of assets of non-U.S. issuers, limitations on, or difficulties enforcing, legal judgments, contractual rights, or other remedies) tend to be greater for investments in the securities of companies tied economically to emerging countries. The economies of emerging countries often depend predominantly on only a few industries or revenues from particular commodities, and often are more volatile than the economies of developed countries.
​
•
Event-Driven Risk – If the Fund purchases securities in anticipation of a proposed merger, acquisition, exchange offer, tender offer, or other similar transaction and that transaction later appears likely to be delayed or unlikely to be consummated or, in fact, is not consummated or is delayed, the market price of the securities purchased by the Fund may decline sharply, resulting in losses to the Fund. The risk/reward payout of event-driven strategies (such as merger arbitrage) typically is asymmetric, with the losses in failed transactions often far exceeding the gains in successful transactions. Event-driven strategies are subject to the risk of overall market movements, and the Fund may experience losses even if a transaction is consummated. The Fund’s investments in derivatives or short sales of securities to hedge or otherwise adjust investment exposure in connection with an event-driven transaction may not perform as expected or may otherwise reduce the Fund’s gains or increase its losses.
​
•
Currency Risk – Fluctuations in exchange rates can adversely affect the market value of the Fund’s foreign currency holdings and investments denominated in foreign currencies.
​
•
Commodities Risk – Commodity prices can be extremely volatile, and exposure to commodities can cause the value of the Fund’s shares to decline or fluctuate in a rapid and unpredictable manner.
​
•
Market Disruption and Geopolitical Risk – Geopolitical and other events (e.g., wars, pandemics, sanctions, terrorism) may disrupt securities markets and adversely affect global economies and markets. Those events, as well as other changes in non-U.S.and U.S. economic and political conditions, could exacerbate other risks or otherwise reduce the value of the Fund’s investments.
​
•
Focused Investment Risk – Investments focused in asset classes, countries, regions, sectors, industries, currencies, or issuers that are subject to the same or similar risk factors and investments whose prices are closely correlated are subject to greater overall risk than investments that are more diversified or whose prices are not as closely correlated.
​
•
Illiquidity Risk – Low trading volume, lack of a market maker, large position size or legal restrictions may limit or prevent the Fund from selling particular securities or closing derivative positions at desirable prices.
​
•
Large Shareholder Risk – To the extent that a large number of shares of the Fund is held by a single shareholder (e.g., an institutional investor or another GMO Fund) or a group of shareholders with a common investment strategy (e.g., GMO asset allocation accounts), the Fund is subject to the risk that a redemption by those shareholders of all or a large portion of their Fund shares will require the Fund to sell securities at disadvantageous prices, disrupt the Fund’s operations, or force the Fund’s liquidation.
​
•
Smaller Company Risk – Smaller companies may have limited product lines, markets, or financial resources, lack the competitive strength of larger companies, have less experienced managers or depend on a few key employees. The securities of companies with smaller market capitalizations often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than the securities of companies with larger market capitalizations.
Risk Lose Money [Text] rr_RiskLoseMoney Many factors can affect this value, and you may lose money by investing in the Fund.
Risk Nondiversified Status [Text] rr_RiskNondiversifiedStatus The value of the Fund’s shares changes with the value of the Fund’s investments. Many factors can affect this value, and you may lose money by investing in the Fund. References to investments include those held directly by the Fund and indirectly through the Fund’s investments in its wholly-owned subsidiary and in any underlying funds in which it invests. The Fund is a non-diversified investment company under the Investment Company Act of 1940, as amended, and therefore a decline in the market price of a particular security held by the Fund may affect the Fund’s performance more than if the Fund were a diversified investment company. The principal risks of investing in the Fund are summarized below. For a more complete discussion of these risks, including those risks to which the Fund is exposed as a result of its investments in its wholly-owned subsidiary and in any underlying funds, see “Additional Information about the Funds’ Investment Strategies, Risks, and Expenses” and “Description of Principal Risks.”
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s annual total returns from year to year for the periods indicated and by comparing the Fund’s average annual total returns for different calendar periods with those of the FTSE 3-Month Treasury Bill Index. Share classes not shown would have substantially similar annual returns to those below because all share classes invest in the same portfolio of securities. Annual returns vary among share classes to the extent that they bear different expenses. Share classes that bear higher expenses than the share classes shown below would have lower returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant if you are tax-exempt or if you hold your Fund shares through tax-advantaged arrangements (such as a 401(k) plan or individual retirement account). After-tax returns are shown for Class VI shares only; after-tax returns for other classes will vary. Updated performance information for the Fund is available at www.gmo.com. Past performance (before and after taxes) is not an indication of future performance.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s annual total returns from year to year for the periods indicated and by comparing the Fund’s average annual total returns for different calendar periods with those of the FTSE 3-Month Treasury Bill Index.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.gmo.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading] rr_BarChartHeading Annual Total Returns/Class VI SharesYears Ending December 31
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest Quarter: 2.91% (4Q2020)
Lowest Quarter: -6.99% (1Q2020)
Year-to-Date (as of 3/31/21): -2.26%
Year to Date Return, Label rr_YearToDateReturnLabel Year-to-Date
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Mar. 31, 2021
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (2.26%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Quarter:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 2.91%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Quarter:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.99%)
Performance Table Heading rr_PerformanceTableHeading Average Annual Total ReturnsPeriods Ending December 31, 2020
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant if you are tax-exempt or if you hold your Fund shares through tax-advantaged arrangements (such as a 401(k) plan or individual retirement account).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Class VI shares only; after-tax returns for other classes will vary.
GMO Alternative Allocation Fund | Class II  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.95% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.49% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.61%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.65%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.50%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 153
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 506
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 883
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,942
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 153
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 506
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 883
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,942
GMO Alternative Allocation Fund | Class III  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.88% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.49% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.61%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.58%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.43%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 146
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 484
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 846
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,866
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 146
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 484
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 846
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,866
GMO Alternative Allocation Fund | Class IV  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.835% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.49% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.61%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.54%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 142
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 472
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 825
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,822
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 142
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 472
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 825
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,822
GMO Alternative Allocation Fund | Class V  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.815% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.49% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.61%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.52%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.37%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 139
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 466
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 815
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,800
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 139
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 466
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 815
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,800
GMO Alternative Allocation Fund | Class VI  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.785% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.49% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.61%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.49%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.34%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 136
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 456
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 799
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,767
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 136
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 456
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 799
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,767
Annual Return 2020 rr_AnnualReturn2020 (0.27%)
1 Year rr_AverageAnnualReturnYear01 (0.27%)
Since Inception rr_AverageAnnualReturnSinceInception 1.48%
Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2019
GMO Alternative Allocation Fund | Class VI | After Taxes on Distributions  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (1.18%)
Since Inception rr_AverageAnnualReturnSinceInception 0.33%
Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2019
GMO Alternative Allocation Fund | Class VI | After Taxes on Distributions and Sale of Fund Shares  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 (0.11%)
Since Inception rr_AverageAnnualReturnSinceInception 0.69%
Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2019
GMO Alternative Allocation Fund | Class VI | FTSE 3-Month Treasury Bill Index (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments)  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.58%
Since Inception rr_AverageAnnualReturnSinceInception 1.21%
Inception Date rr_AverageAnnualReturnInceptionDate May 01, 2019
GMO Alternative Allocation Fund | Class R6  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.95% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.53% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.12%
Total other expenses rr_OtherExpensesOverAssets 0.66%
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.69%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.16%) [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.53%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 156
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 517
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 903
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,984
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 156
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 517
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 903
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,984
GMO Alternative Allocation Fund | Class I  
Risk/Return: rr_RiskReturnAbstract  
Management fee rr_ManagementFeesOverAssets 0.95% [1]
Dividend and interest expense on short sales rr_Component1OtherExpensesOverAssets 0.51% [2]
All other expenses rr_Component3OtherExpensesOverAssets 0.22% [4]
Total other expenses rr_OtherExpensesOverAssets 0.73% [4]
Acquired fund fees and expenses (underlying fund expenses) rr_AcquiredFundFeesAndExpensesOverAssets 0.09% [3]
Total annual fund operating expenses rr_ExpensesOverAssets 1.77%
Expense reimbursement/waiver rr_FeeWaiverOrReimbursementOverAssets (0.15%) [1],[4]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 1.62%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 165
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 543
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 945
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,071
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 165
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 543
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 945
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,071
1 Year rr_AverageAnnualReturnYear01 (0.48%)
Since Inception rr_AverageAnnualReturnSinceInception 0.95%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 04, 2019
GMO Alternative Allocation Fund | Class I | FTSE 3-Month Treasury Bill Index (returns reflect no deduction for fees or expenses, but are net of withholding tax on dividend reinvestments)  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 0.58%
Since Inception rr_AverageAnnualReturnSinceInception 0.90%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 04, 2019
[1] Includes both management fee of 0.73% and class-specific shareholder service fee, if any, for each class of shares. For additional information about the shareholder service fee applicable to each class of shares of the Fund, please see the table included in the section of the Prospectus entitled “Multiple Classes and Eligibility.” Grantham, Mayo, Van Otterloo & Co. LLC (“GMO”) has contractually agreed to waive its fees with respect to and/or reimburse the Fund to the extent that the Fund’s total annual fund operating expenses (after applying all other contractual and voluntary expense limitation arrangements in effect at the time) exceed the following amounts for each class of shares, in each case representing the average daily net assets for the indicated class of shares: 0.99% for Class II shares; 0.92% for Class III shares; 0.875% for Class IV shares; 0.855% for Class V shares; 0.825% for Class VI shares; 0.99% for Class R6 shares; and 0.99% for Class I shares (each, an “Expense Cap”). Fees and expenses of the “non-interested” Trustees and legal counsel and independent compliance consultant to the “non-interested” Trustees, investment-related costs (such as brokerage commissions, interest, and acquired fund fees and expenses), payments out of assets attributable to Class I shares for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries, taxes, litigation and indemnification expenses, judgments, and other extraordinary or non-recurring expenses not incurred in the ordinary course of the Fund’s business (collectively, “Excluded Expenses”), are excluded from the Expense Cap. GMO is permitted to recover from the Fund, on a class-by-class basis, expenses it has borne or reimbursed pursuant to an Expense Cap (whether through reduction of its fees or otherwise) to the extent that the Fund’s total annual fund operating expenses (excluding Excluded Expenses) later fall below that Expense Cap set forth above or any lower expense limit in effect when GMO seeks to recover the expenses. The Fund, however, is not obligated to pay any such amount more than three years after GMO bore or reimbursed an expense. Any such recovery will not cause the Fund to exceed the Expense Caps set forth above or any lower expense limits as is in effect at the time GMO seeks to recover expenses. GMO also has contractually agreed to waive or reduce the Fund’s management fees and shareholder service fees to the extent necessary to offset the management fees and shareholder service fees paid to GMO that are directly or indirectly borne by the Fund or a class of shares of the Fund as a result of the Fund’s direct or indirect investments in other series of GMO Trust (“GMO Funds”). Management fees and shareholder service fees will not be waived below zero. The reimbursement and waiver arrangements described above, including the Expense Cap, will remain in effect through at least June 30, 2022 and may not be terminated prior to this date without the action or consent of the Trust’s Board of Trustees.
[2] “Dividend and interest expense on short sales” reflects interest expense and dividends paid on borrowed securities. Dividends paid on borrowed securities are an expense of short sales. Such expenses are required to be treated as a Fund expense for accounting purposes and are not payable to GMO. The Fund also receives income in connection with short sales, which is reflected in the Fund’s net income but is not reflected as an offset to dividend expenses on short sales in the Fund’s annual fund operating expenses table. Any interest expense amount or dividends paid on securities sold short will vary based on the extent of Fund’s use of those investments. Excluding interest expense and dividends paid on borrowed securities, the total annual fund operating expenses for each class of shares of the Fund would be lower by 0.49% for Class II, III, IV, V and VI, 0.53% for Class R6 and 0.51% for Class I.
[3] Consists of approximately 0.09% in underlying fund fees and expenses and less than 0.01% in purchase premiums and redemption fees paid to underlying funds. The underlying funds also receive income in connection with short sales, which is reflected in the Fund’s net income but is not reflected as an offset to dividend expenses on short sales in the Fund’s annual fund operating expenses table.
[4] Includes estimate of payments for sub-transfer agency, recordkeeping and other administrative services for Class I’s initial fiscal year. GMO has contractually agreed to waive its fees with respect to and/or reimburse Class I shares to the extent that amounts paid by the Fund out of the net assets attributable to Class I shares for sub-transfer agency, recordkeeping and other administrative services provided by financial intermediaries for the benefit of Class I shareholders exceed 0.10% of the average daily net assets attributable to Class I shares. This reimbursement will continue through at least June 30, 2022 and may not be terminated prior to this date without the action or consent of the Trust’s Board of Trustees.