Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)		3 Months Ended								9 Months Ended
		Sep. 30, 2025 USD ($) oz		Jun. 30, 2025 USD ($) oz	Mar. 31, 2025 USD ($) oz		Sep. 30, 2024 USD ($) oz	Jun. 30, 2024 USD ($) oz	Mar. 31, 2024 USD ($) oz	Sep. 30, 2025 USD ($) oz		Sep. 30, 2024 USD ($) oz
Beginning balance (Ounce) | oz		14,208,071			12,625,208		12,170,050		12,815,382	12,625,208		12,815,382
Beginning balance, average cost		$ 26,671,492,201			$ 21,152,229,978		$ 19,214,436,000		$ 20,091,705,096	$ 21,152,229,978		$ 20,091,705,096
Beginning balance, fair value		$ 46,708,323,436			32,962,525,082	[1]	$ 28,367,168,773		26,430,443,509	$ 32,962,525,082	[1]	$ 26,430,443,509
Gold bullion contributed (Ounce) | oz		1,471,996					423,243			3,581,277		638,853
Gold bullion contributed, average cost		$ 5,197,790,806					$ 1,054,388,295			$ 11,664,066,010		$ 1,530,389,834
Gold bullion contributed, fair value		$ 5,197,790,806					$ 1,054,388,295			$ 11,664,066,010		$ 1,530,389,834
Gold bullion distributed (Ounce) | oz		(204,521)					(678,362)			(714,801)		(1,523,844)
Gold bullion distributed, average cost		$ (391,801,749)					$ (1,079,002,068)			$ (1,310,335,636)		$ (2,407,965,274)
Gold bullion distributed, fair value		(686,327,136)					(1,646,906,995)			(2,272,484,935)		(3,483,017,794)
Gold bullion distributed, realized gain (loss)		$ 294,525,387					$ 567,904,927			$ 962,149,299		$ 1,075,052,520
Gold bullion sold to pay expenses (Ounce) | oz		(8,887)					(7,524)			(25,025)		(22,984)
Gold bullion sold to pay expenses, average cost		$ (16,999,320)					$ (11,952,661)			$ (45,478,414)		$ (36,260,090)
Gold bullion sold to pay expenses, fair value		(30,185,717)					(18,225,544)			(78,972,348)		(51,967,184)
Gold bullion sold to pay expenses, realized gain (loss)		13,174,107					6,272,883			33,481,644		15,620,566
Net realized gain, fair value		307,699,494					574,177,810			995,630,943		1,090,673,086
Gain (Loss) from Litigation Settlement	[3]	12,290	[2]				0			12,290	[2]	86,528	[4]
Net change in unrealized appreciation/depreciation, fair value		$ 7,667,296,712		$ 1,848,491,660	$ 6,378,044,471		$ 2,985,283,203	$ 1,148,315,128	$ 1,665,679,232	$ 15,893,832,843		$ 5,799,277,563
Ending balance (Ounce) | oz		15,466,659		14,208,071			11,907,407	12,170,050		15,466,659		11,907,407
Ending balance, average cost		$ 31,460,481,938		$ 26,671,492,201			$ 19,177,869,566	$ 19,214,436,000		$ 31,460,481,938		$ 19,177,869,566
Ending balance, fair value		59,164,609,885	[1]	$ 46,708,323,436			31,315,885,542	$ 28,367,168,773		59,164,609,885	[1]	31,315,885,542
Ending balance, realized gain (loss)		$ 307,699,494					$ 574,177,810			$ 995,630,943		$ 1,090,673,086

[1] Cost of investment in gold bullion: $31,460,481,938 and $21,152,229,978, respectively.

[2] Includes a payment received from a class action settlement related to gold of $12,290.

[3] Represents a payment received from a class action settlement related to gold.

[4] Includes a payment received from a class action settlement related to gold of $86,528.