Document And Entity Information Statistical Measurement [Axis] Note To Financial Statement Details Textual Significant Accounting Policies Investment, Policy [Policy Text Block] Schedules of Investments (Unaudited) ecd_NonRule10b51ArrTrmntdFlag Non-Rule 10b5-1 Arrangement Terminated [Flag] Note 2 - Significant Accounting Policies ecd_NonRule10b51ArrAdoptedFlag Non-Rule 10b5-1 Arrangement Adopted [Flag] Note 8 - Financial Highlights Trading Arrangements, by Individual [Table] Schedules of Investments (Unaudited) - Investments (Details) Material Terms of Trading Arrangement [Text Block] Schedules of Investments (Unaudited) - Investments (Details) (Parentheticals) Related and Nonrelated Parties [Axis] Note 2 - Significant Accounting Policies - Activity in Ether (Details) Note 8 - Financial Highlights - Financial Highlights (Details) Notes To Financial Statements Notes To Financial Statements [Abstract] Statistical Measurement [Domain] Maximum [Member] Net asset value per Share (Note 2C) (in dollars per share) Total investment, percentage of net asset value Shares, par value (in dollars per share) Cash Flows from Operating Activities us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash provided by (used in) operating activities Cash Provided by Financing Activities Business Description and Basis of Presentation [Text Block] us-gaap_SharesIssuedPricePerShare Shares Issued, Price Per Share (in dollars per share) us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash provided by (used in) financing activities us-gaap_ManagementAndServiceFeesBaseRate Management and Service Fees, Base Rate us-gaap_LiabilitiesFairValueDisclosure Total Liabilities us-gaap_AssetsFairValueDisclosure Total Assets Net increase (decrease) in Shares issued and outstanding (in shares) Accounting Policies [Abstract] Ether sold to pay expenses Ether sold to pay expenses, realized gain (loss) Contributions for Shares issued Income Statement [Abstract] Cash Net increase (decrease) in net assets from capital share transactions Ether Beginning balance Ending balance Net decrease in net assets resulting from operations Net decrease in net assets resulting from operations Adjustments to reconcile the net increase (decrease) in net assets resulting from operations to net cash provided by (used in) operating activities: Liabilities Offering of the Shares [Policy Text Block] Disclosure of accounting policy for creation and redemption of shares. Expenses etha_MaximumAmountOfTrustAssetsForSponsorsFeeAfterFeeWaiver Maximum Amount of Trust Assets for Sponsor's Fee After Fee Waiver The maximum amount of trust assets for sponsor's fee after fee waiver. etha_SponsorsFeeAfterFeeWaiverPercentage Sponsors Fee After Fee Waiver, Percentage The percentage of sponsor's fee after fee waiver. us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties Sponsor’s fee payable Change in operating assets and liabilities: Accounting Standards Update and Change in Accounting Principle [Table] Income Tax, Policy [Policy Text Block] Fair Value, by Balance Sheet Grouping [Table] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net decrease in cash Related and Nonrelated Parties [Domain] us-gaap_CashAndCashEquivalentsFairValueDisclosure Cash Related Party Transaction [Table] Related Party Transactions Disclosure [Text Block] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations Cash, beginning of period Cash, end of period Statement [Table] Statement of Financial Position [Abstract] Financial Support for Nonconsolidated Legal Entity [Table] Financial Highlights [Table Text Block] Tabular disclosure of financial highlights. Sponsor’s fee payable Proceeds from ether sold etha_SponsorFeesWaived Sponsor Fees Waived Sponsor’s fee waived Amount of sponsor fees waived during period. Financial Highlights [Text Block] Presentation of financial highlights related to investment performance and operations. Investment in ether, at fair value Beginning balance, fair value Ending balance, fair value Ether purchased, fair value us-gaap_NetAssetValuePerShare Net asset value per Share, beginning of period (in dollars per share) Net asset value per Share, end of period (in dollars per share) Document Type Document Information [Line Items] Document Quarterly Report Document Information [Table] Entity Interactive Data Current Assets Commitments and Contingencies Disclosure [Text Block] Document Transition Report Statement [Line Items] Net Assets Net Assets Net Assets, Beginning of Period Net Assets, End of Period us-gaap_OperatingExpenses Total expenses Net change in unrealized appreciation/depreciation Net change in unrealized appreciation/depreciation, fair value Net change in unrealized appreciation/depreciation Net decrease in net assets per Share (in dollars per share) Ethereum purchased for Shares issued Stock Issued Proceeds from issuance of Shares us-gaap_PolicyTextBlockAbstract Accounting Policies us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements us-gaap_TableTextBlock Notes Tables Document Fiscal Period Focus Document Fiscal Year Focus Amendment Flag Concentration Risk [Table] Capital Share Transactions: Operations: Document Period End Date Investment [Table Text Block] Concentration Risk Disclosure [Text Block] etha_PaymentsToAcquireInvestmentInCryptoAssets Purchases of ether Amount of cash outflow for investments in crypto assets. Net assets, percentage of net asset value The percentage of net assets of net assets. Legal Entity [Axis] Significant Accounting Policies [Text Block] etha_ValueOfStockClassifiedAsTemporaryEquitySurrenderedDuringReportingPeriod Distributions for Shares redeemed Represents the value of stock classified as temporary equity surrendered during the reporting period. Shares issued and redeemed etha_SharesOfStockClassifiedAsTemporaryEquitySurrenderedDuringReportingPeriod Shares redeemed (in shares) Number of shares of stock classified as temporary equity surrendered during the reporting period. etha_IncreaseDecreaseInNetAssets Decrease in net assets Increase (decrease) in net assets. Entity File Number Ether purchased Ether Purchased Quantity of ether purchased for the creation of shares. Entity Tax Identification Number Ether purchased, average cost Average cost of ether purchased for the creation of shares. etha_EtherSoldToPayTrustExpenses Ether sold to pay expenses Quantity of ether sold to pay the trust's expenses. BlackRock Financial Management, Inc. [Member] Represents BlackRock Financial Management, Inc. Entity [Domain] Entity Central Index Key Activity in Ether [Table Text Block] Tabular disclosure of the quantity, average cost, fair value and realized gain (loss) related to activity in ether. Entity Registrant Name Calculation of Net Asset Value [Policy Text Block] Disclosure of accounting policy for creation and redemption of shares. Ether sold for the redemption of Shares The net realized gain (loss) from ether sold for the redemption of shares during the period. Entity Current Reporting Status Trust Expenses [Text Block] The entire disclosure for expenses incurred by the Trust. Entity Incorporation, State or Country Code etha_EtherSoldToPayTrustExpensesAverageCost Ether sold to pay expenses, average cost Average cost of ether gold bullion sold to pay the trust's expenses Current Fiscal Year End Date etha_EtherSoldToPayTrustExpensesFairValue Ether sold to pay expenses, fair value Fair value of ether sold to pay the trust's expenses. Entity Ex Transition Period Indemnification [Text Block] Includes disclosure of indemnification. Entity Filer Category Entity Shell Company etha_LegalFeesPerYear Legal Fees Per Year Maximum per annum in legal fees and expenses the sponsor has agreed to assume. Entity Emerging Growth Company Entity Small Business etha_SharesPrescribedAggregation Shares Prescribed Aggregation (in shares) Prescribed aggregation at which shares are issued and redeemed. Net investment loss Net investment loss etha_InvestmentPaidForRedemptionOfSharesCost Investment Paid for Redemption of Shares, Cost Amount of cost of investment paid for redemption of shares. Sponsor’s fee Sponsor Fees Loss Contingencies [Table] Entity Address, State or Province Statement of Stockholders' Equity [Abstract] Entity Address, City or Town Ethereum paid for Shares redeemed Investment Paid for Shares Redeemed Amount of investment paid for shares redeemed in noncash transaction. Entity Address, Address Line One Statement of Cash Flows [Abstract] City Area Code Local Phone Number Entity Address, Postal Zip Code Title of 12(b) Security Equity Components [Axis] Security Exchange Name Trading Symbol Class of Stock [Axis] Realized gain Amount of realized gain on investment. Equity Component [Domain] etha_Redemptions Payments for Shares redeemed The cash outflow to surrender redeemable capital shares in connection with a redemption order. etha_RealizedInvestmentLosses Realized loss Amount of realized loss on investment. Entity Common Stock, Shares Outstanding etha_EtherDistributedFairValue Ether sold for the redemption of shares, fair value Fair value of ether distributed for the redemption of shares. etha_EtherDistributedAverageCost Ether sold for the redemption of shares, average cost Average cost of ether distributed for the redemption of shares. etha_NetRealizedGainLossFromEtherDistributedForTheRedemptionOfShares Ether sold for the redemption of shares, realized gain (loss) The net realized gain (loss) from ether distributed for the redemption of shares during the period. etha_EtherDistributed Ether sold for the redemption of shares The quantity of ether distributed. Basis of Accounting, Policy [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] etha_PolicyTable Fair Value Disclosures [Text Block] Supplemental disclosure of non-cash information: Ether fair value Net Realized and Unrealized Loss us-gaap_GainLossOnInvestments Net realized and unrealized loss Net realized loss Net realized gain (loss), fair value Net realized loss Net realized (gain) loss Ending balance, realized gain (loss) Shares, issued (in shares) Shares issued and outstanding (in shares) Schedule of Investments [Text Block] Investment Holdings [Table] us-gaap_InvestmentCompanyInvestmentIncomeLossFromOperationsPerShare Net decrease in net assets from operations (in dollars per share) Net investment loss (in dollars per share) Net realized and unrealized loss (in dollars per share) Investment Company, Financial Highlights [Table] Investment in ether, at cost Beginning balance, average cost Ending balance, average cost Investment Holdings, Other than Securities [Table] Total return, at net asset value us-gaap_NonInvestmentAssetsLessNonInvestmentLiabilitiesPercentOfNetAssets Liabilities in Excess of Other Assets, percentage of net asset value us-gaap_InvestmentCompanyInvestmentIncomeLossRatio Net investment loss us-gaap_NonInvestmentAssetsLessNonInvestmentLiabilities Liabilities in Excess of Other Assets Ratio to average net assets: us-gaap_InvestmentCompanyExpenseRatioAfterIncentiveAllocation Total expenses after fees waived Other Commitments [Table] us-gaap_InvestmentCompanyExpenseRatioBeforeIncentiveAllocation Total expenses Ether paid for in-kind redemption of Shares Investment Company, Gain (Loss) on in-kind Redemption Segment Reporting, Policy [Policy Text Block] us-gaap_StockIssuedDuringPeriodValueNewIssues Stock Issued During Period, Value, New Issues Nature of Operation, Product Information, Concentration of Risk [Table] ecd_Rule10b51ArrTrmntdFlag Rule 10b5-1 Arrangement Terminated [Flag] ecd_Rule10b51ArrAdoptedFlag Rule 10b5-1 Arrangement Adopted [Flag] Shares issued (in shares) Stock Issued During Period, Shares, New Issues (in shares) Commitments and contingent liabilities (Note 6)