Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended						6 Months Ended
	Jun. 30, 2021 USD ($) oz		Mar. 31, 2021 USD ($) oz		Jun. 30, 2020 USD ($) oz	Mar. 31, 2020 USD ($) oz	Jun. 30, 2021 USD ($) oz		Jun. 30, 2020 USD ($) oz
Beginning balance (Ounce) | oz	16,202,345		16,881,652		12,571,766	11,577,252	16,881,652		11,577,252
Beginning balance, average cost	$ 24,106,918,759		$ 25,014,142,586		$ 16,858,848,412	$ 15,094,673,874	$ 25,014,142,586		$ 15,094,673,874
Beginning balance, fair value	$ 27,398,975,237		31,924,891,396	[1]	$ 20,227,343,435	17,632,155,037	$ 31,924,891,396	[1]	$ 17,632,155,037
Gold bullion contributed (Ounce) | oz	330,473				2,271,113		620,692		3,908,619
Gold bullion contributed, average cost	$ 614,040,347				$ 3,865,881,490		$ 1,147,897,249		$ 6,481,090,794
Gold bullion contributed, fair value	$ 614,040,347				$ 3,865,881,490		$ 1,147,897,249		$ 6,481,090,794
Gold bullion distributed (Ounce) | oz	(291,980)				(176,145)		(1,251,119)		(811,936)
Gold bullion distributed, average cost	$ (434,459,047)				$ (243,162,746)		$ (1,860,113,808)		$ (1,084,725,741)
Gold bullion distributed, fair value	(514,385,668)				(299,101,991)		(2,194,412,656)		(1,290,498,278)
Gold bullion distributed, realized gain (loss)	$ 79,926,621				$ 55,939,245		$ 334,298,848		$ 205,772,537
Gold bullion sold to pay expenses (Ounce) | oz	(9,980)				(8,216)		(20,367)		(15,417)
Gold bullion sold to pay expenses, average cost	$ (14,867,311)				$ (11,212,810)		$ (30,293,279)		$ (20,684,581)
Gold bullion sold to pay expenses, fair value	(18,028,234)				(13,693,813)		(37,218,922)		(24,978,774)
Gold bullion sold to pay expenses, realized gain (loss)	3,160,923				2,481,003		6,925,643		4,294,193
Net realized gain	83,087,544		258,136,947		58,420,248	151,646,482	341,224,491		210,066,730
Net change in unrealized appreciation/depreciation, fair value	$ 1,053,747,875		$ (3,618,692,332)		$ 2,078,877,217	$ 831,013,860	$ (2,564,944,457)		$ 2,909,891,077
Ending balance (Ounce) | oz	16,230,858		16,202,345		14,658,518	12,571,766	16,230,858		14,658,518
Ending balance, average cost	$ 24,271,632,748		$ 24,106,918,759		$ 20,470,354,346	$ 16,858,848,412	$ 24,271,632,748		$ 20,470,354,346
Ending balance, fair value	28,617,437,101	[1]	27,398,975,237		25,917,726,586	20,227,343,435	28,617,437,101	[1]	25,917,726,586
Ending balance, realized gain (loss)	$ 83,087,544		$ 258,136,947		$ 58,420,248	$ 151,646,482	$ 341,224,491		$ 210,066,730

[1] Cost of investment in gold bullion: $24,271,632,748 and $25,014,142,586, respectively.