Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended						6 Months Ended
	Jun. 30, 2023 USD ($) oz		Mar. 31, 2023 USD ($) oz		Jun. 30, 2022 USD ($) oz	Mar. 31, 2022 USD ($) oz	Jun. 30, 2023 USD ($) oz		Jun. 30, 2022 USD ($) oz
Beginning balance (Ounce) | oz	14,286,334		14,434,521		16,608,310	15,784,325	14,434,521		15,784,325
Beginning balance, average cost	$ 22,113,171,288		$ 22,205,551,004		$ 25,367,951,331	$ 23,722,912,868	$ 22,205,551,004		$ 23,722,912,868
Beginning balance, fair value	$ 28,282,655,788		26,160,403,750	[1]	$ 32,255,828,173	28,729,048,695	$ 26,160,403,750	[1]	$ 28,729,048,695
Gold bullion contributed (Ounce) | oz	424,647				413,312		779,292		1,429,491
Gold bullion contributed, average cost	$ 852,839,106				$ 782,395,238		$ 1,536,193,248		$ 2,716,902,584
Gold bullion contributed, fair value	$ 852,839,106				$ 782,395,238		$ 1,536,193,248		$ 2,716,902,584
Gold bullion distributed (Ounce) | oz	(274,793)				(608,940)		(768,826)		(791,486)
Gold bullion distributed, average cost	$ (428,666,963)				$ (934,514,898)		$ (1,190,839,341)		$ (1,209,438,348)
Gold bullion distributed, fair value	(536,575,410)				(1,127,722,686)		(1,452,234,717)		(1,461,644,030)
Gold bullion distributed, realized gain (loss)	$ 107,908,447				$ 193,207,788		$ 261,395,376		$ 252,205,682
Gold bullion sold to pay expenses (Ounce) | oz	(8,995)				(10,618)		(17,794)		(20,266)
Gold bullion sold to pay expenses, average cost	$ (13,997,859)				$ (16,267,696)		$ (27,559,339)		$ (30,813,129)
Gold bullion sold to pay expenses, fair value	(17,848,718)				(19,974,426)		(34,311,365)		(37,736,285)
Gold bullion sold to pay expenses, realized gain (loss)	3,850,859				3,706,730		6,752,026		6,923,156
Net realized gain (loss), fair value	111,759,306		156,388,096		196,914,518	62,214,320	268,147,402		259,128,838
Net change in unrealized appreciation/depreciation, fair value	$ (1,104,430,686)		$ 2,214,631,754		$ (2,284,892,586)	$ 1,881,741,015	$ 1,110,201,068		$ (403,151,571)
Ending balance (Ounce) | oz	14,427,193		14,286,334		16,402,064	16,608,310	14,427,193		16,402,064
Ending balance, average cost	$ 22,523,345,572		$ 22,113,171,288		$ 25,199,563,975	$ 25,367,951,331	$ 22,523,345,572		$ 25,199,563,975
Ending balance, fair value	27,588,399,386	[1]	28,282,655,788		29,802,548,231	32,255,828,173	27,588,399,386	[1]	29,802,548,231
Ending balance, realized gain (loss)	$ 111,759,306		$ 156,388,096		$ 196,914,518	$ 62,214,320	$ 268,147,402		$ 259,128,838

[1] Cost of investment in gold bullion: $22,523,345,572 and $22,205,551,004, respectively.