Note 9 - Subsequent Event (Details Textual) - Forecast [Member] $ in Billions	12 Months Ended
Jul. 23, 2025 USD ($)
Sponsors Fee After Fee Waiver, Percentage	0.12%
Maximum Amount of Trust Assets for Sponsor's Fee After Fee Waiver	$ 2.5

The maximum amount of trust assets for sponsor's fee after fee waiver.

No definition available.

Name:	etha_MaximumAmountOfTrustAssetsForSponsorsFeeAfterFeeWaiver
Namespace Prefix:	etha_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant