Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended								9 Months Ended
	Sep. 30, 2023 USD ($) oz		Jun. 30, 2023 USD ($) oz	Mar. 31, 2023 USD ($) oz		Sep. 30, 2022 USD ($) oz	Jun. 30, 2022 USD ($) oz	Mar. 31, 2022 USD ($) oz	Sep. 30, 2023 USD ($) oz		Sep. 30, 2022 USD ($) oz
Beginning balance (Ounce) | oz	14,427,193			14,434,521		16,402,064		15,784,325	14,434,521		15,784,325
Beginning balance, average cost	$ 22,523,345,572			$ 22,205,551,004		$ 25,199,563,975		$ 23,722,912,868	$ 22,205,551,004		$ 23,722,912,868
Beginning balance, fair value	$ 27,588,399,386			26,160,403,750	[1]	$ 29,802,548,231		28,729,048,695	$ 26,160,403,750	[1]	$ 28,729,048,695
Gold bullion contributed (Ounce) | oz	91,874					39,877			871,166		1,469,368
Gold bullion contributed, average cost	$ 177,161,971					$ 69,345,194			$ 1,713,355,219		$ 2,786,247,778
Gold bullion contributed, fair value	$ 177,161,971					$ 69,345,194			$ 1,713,355,219		$ 2,786,247,778
Gold bullion distributed (Ounce) | oz	(1,325,807)					(1,032,942)			(2,094,633)		(1,824,428)
Gold bullion distributed, average cost	$ (2,072,232,823)					$ (1,587,284,995)			$ (3,263,072,164)		$ (2,796,723,343)
Gold bullion distributed, fair value	(2,548,143,264)					(1,757,256,432)			(4,000,377,981)		(3,218,900,462)
Gold bullion distributed, realized gain (loss)	$ 475,910,441					$ 169,971,437			$ 737,305,817		$ 422,177,119
Gold bullion sold to pay expenses (Ounce) | oz	(9,023)					(10,410)			(26,817)		(30,676)
Gold bullion sold to pay expenses, average cost	$ (14,096,294)					$ (15,995,515)			$ (41,655,633)		$ (46,808,644)
Gold bullion sold to pay expenses, fair value	(17,493,954)					(18,260,882)			(51,805,319)		(55,997,167)
Gold bullion sold to pay expenses, realized gain (loss)	3,397,660					2,265,367			10,149,686		9,188,523
Net realized gain (loss), fair value	479,308,101		$ 111,759,306	156,388,096		172,236,804	$ 196,914,518	62,214,320	747,455,503		431,365,642
Net change in unrealized appreciation/depreciation, fair value	$ (1,018,117,461)		$ (1,104,430,686)	2,214,631,754		$ (2,526,022,421)	$ (2,284,892,586)	1,881,741,015	$ 92,083,607		$ (2,929,173,992)
Ending balance (Ounce) | oz	13,184,237		14,427,193			15,398,589	16,402,064		13,184,237		15,398,589
Ending balance, average cost	$ 20,614,178,426		$ 22,523,345,572			$ 23,665,628,659	$ 25,199,563,975		$ 20,614,178,426		$ 23,665,628,659
Ending balance, fair value	24,661,114,779	[1]	27,588,399,386			25,742,590,494	29,802,548,231		24,661,114,779	[1]	25,742,590,494
Ending balance, realized gain (loss)	$ 479,308,101		$ 111,759,306	$ 156,388,096		$ 172,236,804	$ 196,914,518	$ 62,214,320	$ 747,455,503		$ 431,365,642

[1] Cost of investment in gold bullion: $20,614,178,426 and $22,205,551,004, respectively.