Label	Element	Value
GMO Emerging Country Debt Fund
Risk/Return:	rr_RiskReturnAbstract
Supplement to Prospectus [Text Block]	rr_SupplementToProspectusTextBlock	GMO TRUST Supplement dated May 18, 2021 to the GMO Trust Prospectus, dated June 30, 2020, as supplemented GMO Emerging Country Debt Fund and GMO Emerging Country Debt Shares Fund
Risk/Return [Heading]	rr_RiskReturnHeading	GMO Emerging Country Debt Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	GMO Emerging Country Debt Fund (“ECDF”) charges a purchase premium of 0.75% of the amount invested and a redemption fee of 0.75% of the amount redeemed. In addition, GMO Emerging Country Debt Shares Fund (“ECD Shares Fund”) pays ECDF a purchase premium of 0.75% of the amount invested and a redemption fee of 0.75% of the amount redeemed. The sections captioned “Shareholder fees” for ECDF and ECD Shares Fund on pages 92 and 96, respectively, of the Prospectus are amended to reflect this fee reduction.

This table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection instructions
-Paragraph 1
-Subparagraph b

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Risk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicated

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 2

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- Definition

This element contains the text of a prospectus supplement (submission type 497) not already contained in an element containing amended text or other data from a previous submission.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A

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