Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)		3 Months Ended								9 Months Ended
		Sep. 30, 2024 USD ($) oz		Jun. 30, 2024 USD ($) oz	Mar. 31, 2024 USD ($) oz		Sep. 30, 2023 USD ($) oz	Jun. 30, 2023 USD ($) oz	Mar. 31, 2023 USD ($) oz	Sep. 30, 2024 USD ($) oz		Sep. 30, 2023 USD ($) oz
Beginning balance (Ounce) | oz		12,170,050			12,815,382		14,427,193		14,434,521	12,815,382		14,434,521
Beginning balance, average cost		$ 19,214,436,000			$ 20,091,705,096		$ 22,523,345,572		$ 22,205,551,004	$ 20,091,705,096		$ 22,205,551,004
Beginning balance, fair value		$ 28,367,168,773			26,430,443,509	[1]	$ 27,588,399,386		26,160,403,750	$ 26,430,443,509	[1]	$ 26,160,403,750
Gold bullion contributed (Ounce) | oz		423,243					91,874			638,853		871,166
Gold bullion contributed, average cost		$ 1,054,388,295					$ 177,161,971			$ 1,530,389,834		$ 1,713,355,219
Gold bullion contributed, fair value		$ 1,054,388,295					$ 177,161,971			$ 1,530,389,834		$ 1,713,355,219
Gold bullion distributed (Ounce) | oz		(678,362)					(1,325,807)			(1,523,844)		(2,094,633)
Gold bullion distributed, average cost		$ (1,079,002,068)					$ (2,072,232,823)			$ (2,407,965,274)		$ (3,263,072,164)
Gold bullion distributed, fair value		(1,646,906,995)					(2,548,143,264)			(3,483,017,794)		(4,000,377,981)
Gold bullion distributed, realized gain (loss)		$ 567,904,927					$ 475,910,441			$ 1,075,052,520		$ 737,305,817
Gold bullion sold to pay expenses (Ounce) | oz		(7,524)					(9,023)			(22,984)		(26,817)
Gold bullion sold to pay expenses, average cost		$ (11,952,661)					$ (14,096,294)			$ (36,260,090)		$ (41,655,633)
Gold bullion sold to pay expenses, fair value		(18,225,544)					(17,493,954)			(51,967,184)		(51,805,319)
Gold bullion sold to pay expenses, realized gain (loss)		6,272,883					3,397,660			15,620,566		10,149,686
Net realized gain, fair value		574,177,810					479,308,101			1,090,673,086		747,455,503
Net change in unrealized appreciation/depreciation, fair value		$ 2,985,283,203		$ 1,148,315,128	$ 1,665,679,232		$ (1,018,117,461)	$ (1,104,430,686)	$ 2,214,631,754	$ 5,799,277,563		$ 92,083,607
Ending balance (Ounce) | oz		11,907,407		12,170,050			13,184,237	14,427,193		11,907,407		13,184,237
Ending balance, average cost		$ 19,177,869,566		$ 19,214,436,000			$ 20,614,178,426	$ 22,523,345,572		$ 19,177,869,566		$ 20,614,178,426
Ending balance, fair value		31,315,885,542	[1]	$ 28,367,168,773			24,661,114,779	$ 27,588,399,386		31,315,885,542	[1]	24,661,114,779
Ending balance, realized gain (loss)		574,177,810					479,308,101			1,090,673,086		747,455,503
Gain (Loss) from Litigation Settlement	[2]	$ 0					$ 0			$ 86,528	[3]	$ 0

[1] Cost of investment in gold bullion: $19,177,869,566 and $20,091,705,096, respectively.

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

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