Note 9 - Investing in Index Futures (Details Textual) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2026	Dec. 31, 2025
Average Month-End Notional Amount of Derivative Contracts	$ 970,666,678	$ 1,010,924,315

Average month end notional amount specified by the derivative contracts.

No definition available.

Name:	gsg_AverageMonthEndNotionalAmountOfDerivativeContracts
Namespace Prefix:	gsg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration