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Label Element Value
Risk Return Abstract rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName GMO TRUST
Prospectus Date rr_ProspectusDate Jun. 30, 2024
GMO Emerging Country Debt Fund  
Risk Return Abstract rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading GMO EMERGING COUNTRY DEBT FUND
Objective [Heading] rr_ObjectiveHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Investment objective</span>
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Total return in excess of that of its benchmark, the J.P. Morgan EMBI Global Diversified.
Expense [Heading] rr_ExpenseHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Fees and expenses</span>
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The tables below describe 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 tables and examples below.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Annual Fund operating expenses</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">(expenses that you bear each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination <span style="color:#000000;font-family:Times New Roman;font-size:8pt;font-style:italic;">June 30, 2025</span>
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Portfolio turnover</span>
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 29, 2024, the Fund’s portfolio turnover rate (excluding short-term investments) was 20% 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 29, 2024, excluding transactions in U.S. Treasury Fund and other short-term investments, was 20% of the average value of its portfolio securities.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 20.00%
Expense Example [Heading] rr_ExpenseExampleHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Example</span>
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. 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 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 <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Principal investment strategies</span>
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The Fund invests primarily in debt of emerging country sovereign and quasi-sovereign issuers. “Sovereign” refers to a government and “quasi-sovereign” refers to a governmental agency, political subdivision or other instrumentality or issuer that is majority owned, directly or indirectly, or whose obligations are guaranteed, by a government. Under normal circumstances, the Fund invests directly and indirectly (e.g., through other GMO Funds or derivatives) at least 80% of its assets in debt investments tied economically to emerging countries (see “Name Policies”). In general, the Fund considers “emerging countries” to be countries whose securities are included in the Fund’s benchmark or countries that have similar national domestic products or default histories to those of countries whose securities are included in the Fund’s benchmark. The Fund’s performance is likely to be more volatile than that of its benchmark.The Fund typically gains its investment exposure by purchasing debt investments or by investing in derivatives, typically credit default swaps. The Fund may invest in debt investments of all credit qualities, including securities that are in default, and may invest in corporate bonds. (The debt investments in which the Fund invests includes below investment grade debt investments, which are commonly referred to as “high yield” or “junk bonds,” although these terms are not generally used to refer to emerging country debt securities.) The Fund invests in both non-local currency denominated debt (“external debt”) and, to a lesser extent, local currency denominated debt. The external debt investments in which the Fund invests are usually denominated in U.S. dollars, Euros, Japanese yen, Swiss francs, or British pounds sterling. After hedging, U.S. dollars typically represent at least 75% of the Fund’s currency exposures. The Fund typically invests in less liquid debt investments with the intention of holding them for an extended period of time.When constructing the Fund’s portfolio, GMO considers risk at both the Fund’s portfolio and individual security level and generally takes into account, among other factors, interest rate duration, credit spread duration, liquidity, transaction costs and default scenarios as well as the idiosyncratic risk of each instrument. When making investment decisions, GMO typically relies more heavily on its assessment of the risk-reward characteristics of individual investments in a given country than on its outlook for that particular country. GMO uses fundamental analytical techniques as the basis for its analysis of both individual investments and country outlook. In performing its analysis with respect to country outlook, GMO typically considers a country’s economic structure, fiscal sustainability, external liquidity, and ESG (environmental, social, and governance) criteria. The factors GMO considers and investment methods GMO uses can change over time.In seeking to achieve the Fund’s investment objective, GMO typically invests a portion of the Fund’s assets in over-the-counter (OTC) and exchange-traded derivatives, including options, swap contracts (including interest rate swaps, total return swaps and credit default swaps), forward currency contracts (including forward contracts on currencies of developed markets), and reverse repurchase agreements. The Fund is not limited in its use of derivatives or in the total notional value of its derivative positions. The Fund may also engage in short sales. Leverage is not a principal component of the Fund’s investment strategy. However, because of its derivative positions, the Fund may at times have gross investment exposure in excess of its net assets (i.e., the Fund may be leveraged) and, therefore may be subject to a higher risk of loss during those times than if the Fund were not leveraged. The Fund’s performance can depend substantially on the performance of assets or indices underlying its derivatives even though it does not own those assets or 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.GMO normally seeks to maintain an interest rate duration for the Fund that is similar to that of its benchmark (approximately 6.5 years as of May 31, 2024). For an additional discussion of duration, see “Additional Information About the Funds’ Investment Strategies, Risks, and Expenses — Bond Funds — Duration.”
Risk [Heading] rr_RiskHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Principal risks of investing in the Fund</span>
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Performance</span>
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 a composite index computed by GMO that tracks historical changes in the Fund’s benchmark over time (which has always been comprised of broad-based indices). Purchase premiums and redemption fees are not reflected in the bar chart, but are reflected in the table; as a result, the returns in the table are lower than the returns in the bar chart. Returns in the table reflect current purchase premiums and redemption fees. 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 III 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 <span style="color:#000000;font-family:Times New Roman;font-size:10pt;margin-left:3.76%;">The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">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 a composite index computed by GMO that tracks historical changes in the Fund’s benchmark over time (which has always been comprised of broad-based indices). Purchase premiums and redemption fees are not reflected in the bar chart, but are reflected in the table; as a result, the returns in the table are lower than the returns in the bar chart. Returns in the table reflect current purchase premiums and redemption fees.</span>
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">www.gmo.com</span>
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Past performance (before and after taxes) is not an </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">indication of future performance.</span>
Bar Chart [Heading] rr_BarChartHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Annual Total Returns/Class III Shares</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Years Ending December 31</span>
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Highest Quarter: 12.54% 2Q 2020
Lowest Quarter: -14.48% 1Q 2020
Year-to-Date: 5.63% As of 3/31/2024

Performance Table Heading rr_PerformanceTableHeading <span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Average Annual Total Returns</span> <br/><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Periods Ending December 31, 2023</span>
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.</span>
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred <span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns shown are not </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">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). </span>
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">After-tax returns are shown for Class III shares only; after-tax returns for other classes will vary.</span>
GMO Emerging Country Debt Fund | Risk Lose Money [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock Many factors can affect this value, and you may lose money by investing in the Fund.
GMO Emerging Country Debt Fund | Credit Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Credit Risk – The Fund runs the risk that the issuer or guarantor of a fixed income investment (including a sovereign or quasi-sovereign debt issuer) or the obligor of an obligation underlying an asset-backed security will be unable or unwilling to satisfy its obligation to pay principal and interest or otherwise to honor its obligations in a timely manner or at all. 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 a 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. In addition, investments in emerging country sovereign or quasi-sovereign debt are subject to a heightened risk that the issuer responsible for repayment of the debt may be unable or unwilling to pay interest and repay principal when due, and the Fund may lack recourse against the issuer in the event of a default. Investments in quasi-sovereign debt also are subject to the risk that the issuer will default independently of its sovereign. Investments in distressed or defaulted or other low quality debt investments generally are considered speculative and are subject to substantial risks not normally associated with investments in higher quality securities, including adverse business, financial or economic conditions that lead to their issuers’ payment defaults and insolvency proceedings. In particular, distressed or defaulted obligations might be repaid, if at all, only after lengthy workout or bankruptcy proceedings during which the issuer might not make any interest or other payments, and the Fund may incur additional expenses in its effort to be repaid. If GMO’s assessment of the eventual recovery value of a distressed or defaulted debt investment proves incorrect, the Fund may lose a substantial portion or all of its original investment or may be required to accept cash or instruments worth less than its original investment.
GMO Emerging Country Debt Fund | Market Risk Fixed Income [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Market Risk – Fixed Income – The market price of a fixed income investment can decline due to market-related factors, including rising interest or inflation 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). In addition, the market prices of emerging country sovereign and quasi-sovereign debt investments can decline due to uncertainty about their credit quality and the reliability of their payment streams.
GMO Emerging Country Debt Fund | Illiquidity Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Illiquidity Risk – Low trading volume, lack of a market maker, large position size, or legal restrictions increase the risk that the Fund or an underlying fund is limited or prevented from selling particular securities or closing derivative positions at desirable prices at a particular time or at all.
GMO Emerging Country Debt Fund | Derivatives and Short Sales Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●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, leveraging risk, commodities 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 index or underlying securities. The Fund typically creates short investment exposure by selling securities short or 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. Specifically, the net asset value of the Fund’s shares will be adversely affected if the equities or other assets that are the subject of the Fund’s short exposures appreciate in value. The risk of loss associated with derivatives that provide short investment exposure and short sales of securities is theoretically unlimited.
GMO Emerging Country Debt Fund | Counterparty Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Counterparty Risk – The Fund runs the risk that the counterparty to a derivatives contract or a clearing member used by the Fund to hold a cleared derivatives contract is unable or unwilling to make timely settlement payments, return the Fund’s collateral or otherwise honor its obligations.
GMO Emerging Country Debt Fund | Non-U.S. Investment Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Non-U.S. Investment Risk – The market prices of many non-U.S. securities fluctuate more than those of U.S. securities. Many non-U.S. securities 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, non-U.S. securities issuers 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 is subject to taxation by countries other than the United States, including 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 its license is 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. The risks above (such as substantial price fluctuations and market instability, illiquidity and lack of regulation) and other risks (e.g., nationalization, expropriation or other confiscation of assets of non-U.S. issuers, difficulties enforcing legal judgments or contractual rights and geopolitical risks) tend to be higher for investments in the securities of issuers tied economically to emerging countries. The economies of emerging countries often depend predominantly on only a few industries or commodities and often are more volatile than the economies of developed countries.
GMO Emerging Country Debt Fund | Market Disruption and Geopolitical Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Market Disruption and Geopolitical Risk – Geopolitical and other events (e.g., wars, pandemics, sanctions, terrorism) often disrupt securities markets and adversely affect the general economy or particular 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.
GMO Emerging Country Debt Fund | Large Shareholder Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●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 that shareholder or group will require the Fund to sell investments at disadvantageous prices, disrupt the Fund’s operations, or force the Fund’s liquidation.
GMO Emerging Country Debt Fund | Currency Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●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.
GMO Emerging Country Debt Fund | Focused Investment Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Focused Investment Risk – Investments in countries, regions, asset classes, sectors, industries, currencies, or issuers that are subject to the same or similar risk factors and investments whose market prices are closely correlated are subject to higher overall risk than investments that are more diversified or whose market prices are not as closely correlated.
GMO Emerging Country Debt Fund | Management and Operational Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Management and Operational Risk – The Fund runs the risk that GMO’s investment techniques will fail to produce intended results.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.
GMO Emerging Country Debt Fund | Leveraging Risk [Member]  
Risk Return Abstract rr_RiskReturnAbstract  
Risk [Text Block] rr_RiskTextBlock ●Leveraging Risk – The use of derivatives, short sales and securities lending can create 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 the value of the Fund’s assets declines between the time a redemption request is treated as being received by the Fund and the time the Fund liquidates assets to fund that redemption.
GMO Emerging Country Debt Fund | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
Purchase premium (as a percentage of amount invested) rr_MaximumDeferredSalesChargeOverOfferingPrice 0.75%
Redemption fee (as a percentage of amount redeemed) rr_RedemptionFeeOverRedemption 0.75%
Management fee rr_ManagementFeesOverAssets 0.50% [1]
Other expenses rr_OtherExpensesOverAssets 0.08% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.58%
Expense waiver rr_FeeWaiverOrReimbursementOverAssets none [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.58%
1 Year rr_ExpenseExampleYear01 $ 212
3 Years rr_ExpenseExampleYear03 344
5 Years rr_ExpenseExampleYear05 489
10 Years rr_ExpenseExampleYear10 910
1 Year rr_ExpenseExampleNoRedemptionYear01 134
3 Years rr_ExpenseExampleNoRedemptionYear03 259
5 Years rr_ExpenseExampleNoRedemptionYear05 396
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 795
2014 rr_AnnualReturn2014 5.98%
2015 rr_AnnualReturn2015 0.02%
2016 rr_AnnualReturn2016 13.86%
2017 rr_AnnualReturn2017 12.48%
2018 rr_AnnualReturn2018 (5.91%)
2019 rr_AnnualReturn2019 14.28%
2020 rr_AnnualReturn2020 7.23%
2021 rr_AnnualReturn2021 (1.29%)
2022 rr_AnnualReturn2022 (16.32%)
2023 rr_AnnualReturn2023 17.64%
Year to Date Return, Label rr_YearToDateReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Year-to-Date:</span>
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Mar. 31, 2024
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 5.63%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Highest Quarter:</span>
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 12.54%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel <span style="color:#000000;font-family:Times New Roman;font-size:10pt;">Lowest Quarter:</span>
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (14.48%)
1 Year rr_AverageAnnualReturnYear01 15.88%
5 Years rr_AverageAnnualReturnYear05 3.24%
10 Years rr_AverageAnnualReturnYear10 4.13%
Incept. rr_AverageAnnualReturnSinceInception 11.88%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 19, 1994
GMO Emerging Country Debt Fund | Class IV  
Risk Return Abstract rr_RiskReturnAbstract  
Purchase premium (as a percentage of amount invested) rr_MaximumDeferredSalesChargeOverOfferingPrice 0.75%
Redemption fee (as a percentage of amount redeemed) rr_RedemptionFeeOverRedemption 0.75%
Management fee rr_ManagementFeesOverAssets 0.45% [1]
Other expenses rr_OtherExpensesOverAssets 0.08% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.53%
Expense waiver rr_FeeWaiverOrReimbursementOverAssets none [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.53%
1 Year rr_ExpenseExampleYear01 $ 207
3 Years rr_ExpenseExampleYear03 329
5 Years rr_ExpenseExampleYear05 462
10 Years rr_ExpenseExampleYear10 850
1 Year rr_ExpenseExampleNoRedemptionYear01 129
3 Years rr_ExpenseExampleNoRedemptionYear03 244
5 Years rr_ExpenseExampleNoRedemptionYear05 369
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 735
1 Year rr_AverageAnnualReturnYear01 15.96%
5 Years rr_AverageAnnualReturnYear05 3.30%
10 Years rr_AverageAnnualReturnYear10 4.18%
Incept. rr_AverageAnnualReturnSinceInception 9.18%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 09, 1998
GMO Emerging Country Debt Fund | Class VI  
Risk Return Abstract rr_RiskReturnAbstract  
Purchase premium (as a percentage of amount invested) rr_MaximumDeferredSalesChargeOverOfferingPrice 0.75%
Redemption fee (as a percentage of amount redeemed) rr_RedemptionFeeOverRedemption 0.75%
Management fee rr_ManagementFeesOverAssets 0.405% [1]
Other expenses rr_OtherExpensesOverAssets 0.07% [2]
Total annual fund operating expenses rr_ExpensesOverAssets 0.48%
Expense waiver rr_FeeWaiverOrReimbursementOverAssets none [1]
Total annual fund operating expenses after expense reimbursement/waiver (Fund and underlying fund expenses) rr_NetExpensesOverAssets 0.48%
1 Year rr_ExpenseExampleYear01 $ 202
3 Years rr_ExpenseExampleYear03 313
5 Years rr_ExpenseExampleYear05 434
10 Years rr_ExpenseExampleYear10 790
1 Year rr_ExpenseExampleNoRedemptionYear01 124
3 Years rr_ExpenseExampleNoRedemptionYear03 228
5 Years rr_ExpenseExampleNoRedemptionYear05 342
10 Years rr_ExpenseExampleNoRedemptionYear10 $ 674
1 Year rr_AverageAnnualReturnYear01 16.01%
5 Years rr_AverageAnnualReturnYear05
10 Years rr_AverageAnnualReturnYear10
Incept. rr_AverageAnnualReturnSinceInception (2.04%)
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 29, 2021
GMO Emerging Country Debt Fund | Return After Taxes on Distributions | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 11.29%
5 Years rr_AverageAnnualReturnYear05 (0.63%)
10 Years rr_AverageAnnualReturnYear10 0.56%
Incept. rr_AverageAnnualReturnSinceInception 6.96%
GMO Emerging Country Debt Fund | Return After Taxes on Distributions and Sale of Shares | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 9.31%
5 Years rr_AverageAnnualReturnYear05 0.92%
10 Years rr_AverageAnnualReturnYear10 1.62%
Incept. rr_AverageAnnualReturnSinceInception 7.35%
GMO Emerging Country Debt Fund | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark) | Class III  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 11.09% [3]
5 Years rr_AverageAnnualReturnYear05 1.63% [3]
10 Years rr_AverageAnnualReturnYear10 2.90% [3]
Incept. rr_AverageAnnualReturnSinceInception 8.27% [3]
GMO Emerging Country Debt Fund | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark) | Class IV  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 11.09% [3]
5 Years rr_AverageAnnualReturnYear05 1.63% [3]
10 Years rr_AverageAnnualReturnYear10 2.90% [3]
Incept. rr_AverageAnnualReturnSinceInception 6.71% [3]
GMO Emerging Country Debt Fund | J.P. Morgan EMBI Global Diversified + (Composite index) (Fund benchmark) | Class VI  
Risk Return Abstract rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 11.09% [3]
5 Years rr_AverageAnnualReturnYear05 [3]
10 Years rr_AverageAnnualReturnYear10 [3]
Incept. rr_AverageAnnualReturnSinceInception (4.26%) [3]
[1] Includes both management fee of 0.35% 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 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. This waiver will continue through at least June 30, 2025 and may not be terminated prior to this date without the action or consent of the Trust’s Board of Trustees.
[2] The amount includes interest expense incurred by the Fund as a result of entering into reverse repurchase agreements and/or margin on cleared swap contracts, if any. “Other expenses” (before addition of interest expense) and interest expense were approximately 0.04% for Class III and IV, 0.03% for Class VI and 0.04%, respectively.
[3] 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.