Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended								9 Months Ended
	Sep. 30, 2021 USD ($) oz		Jun. 30, 2021 USD ($) oz	Mar. 31, 2021 USD ($) oz		Sep. 30, 2020 USD ($) oz	Jun. 30, 2020 USD ($) oz	Mar. 31, 2020 USD ($) oz	Sep. 30, 2021 USD ($) oz		Sep. 30, 2020 USD ($) oz
Beginning balance (Ounce) | oz	16,230,858			16,881,652		14,658,518		11,577,252	16,881,652		11,577,252
Beginning balance, average cost	$ 24,271,632,748			$ 25,014,142,586		$ 20,470,354,346		$ 15,094,673,874	$ 25,014,142,586		$ 15,094,673,874
Beginning balance, fair value	$ 28,617,437,101			31,924,891,396	[1]	$ 25,917,726,586		17,632,155,037	$ 31,924,891,396	[1]	$ 17,632,155,037
Gold bullion contributed (Ounce) | oz	237,945					2,187,720			858,637		6,096,339
Gold bullion contributed, average cost	$ 428,654,583					$ 4,165,602,762			$ 1,576,551,832		$ 10,646,693,556
Gold bullion contributed, fair value	$ 428,654,583					$ 4,165,602,762			$ 1,576,551,832		$ 10,646,693,556
Gold bullion distributed (Ounce) | oz	(444,564)					(176,520)			(1,695,683)		(988,456)
Gold bullion distributed, average cost	$ (665,324,199)					$ (254,187,327)			$ (2,525,438,007)		$ (1,338,913,068)
Gold bullion distributed, fair value	(793,300,448)					(327,658,445)			(2,987,713,104)		(1,618,156,723)
Gold bullion distributed, realized gain (loss)	$ 127,976,249					$ 73,471,118			$ 462,275,097		$ 279,243,655
Gold bullion sold to pay expenses (Ounce) | oz	(10,166)					(9,260)			(30,533)		(24,677)
Gold bullion sold to pay expenses, average cost	$ (15,213,954)					$ (13,240,877)			$ (45,507,233)		$ (33,925,458)
Gold bullion sold to pay expenses, fair value	(18,313,072)					(17,644,516)			(55,531,994)		(42,623,290)
Gold bullion sold to pay expenses, realized gain (loss)	3,099,118					4,403,639			10,024,761		8,697,832
Net realized gain	131,075,367		$ 83,087,544	258,136,947		77,874,757	$ 58,420,248	151,646,482	472,299,858		287,941,487
Net change in unrealized appreciation/depreciation, fair value	$ (456,228,532)		$ 1,053,747,875	(3,618,692,332)		$ 1,620,716,613	$ 2,078,877,217	831,013,860	$ (3,021,172,989)		$ 4,530,607,690
Ending balance (Ounce) | oz	16,014,073		16,230,858			16,660,458	14,658,518		16,014,073		16,660,458
Ending balance, average cost	$ 24,019,749,178		$ 24,271,632,748			$ 24,368,528,904	$ 20,470,354,346		$ 24,019,749,178		$ 24,368,528,904
Ending balance, fair value	27,909,324,999	[1]	28,617,437,101			31,436,617,757	25,917,726,586		27,909,324,999	[1]	31,436,617,757
Ending balance, realized gain (loss)	$ 131,075,367		$ 83,087,544	$ 258,136,947		$ 77,874,757	$ 58,420,248	$ 151,646,482	$ 472,299,858		$ 287,941,487

[1] Cost of investment in gold bullion: $24,019,749,178 and $25,014,142,586, respectively.