Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) oz		Mar. 31, 2022 USD ($) oz
Beginning balance (Ounce) | oz	14,434,521		15,784,325
Beginning balance, average cost	$ 22,205,551,004		$ 23,722,912,868
Beginning balance, fair value	$ 26,160,403,750	[1]	$ 28,729,048,695
Gold bullion contributed (Ounce) | oz	354,645		1,016,179
Gold bullion contributed, average cost	$ 683,354,142		$ 1,934,507,346
Gold bullion contributed, fair value	$ 683,354,142		$ 1,934,507,346
Gold bullion distributed (Ounce) | oz	(494,033)		(182,546)
Gold bullion distributed, average cost	$ (762,172,378)		$ (274,923,450)
Gold bullion distributed, fair value	(915,659,307)		(333,921,344)
Gold bullion distributed, realized gain (loss)	$ 153,486,929		$ 58,997,894
Gold bullion sold to pay expenses (Ounce) | oz	(8,799)		(9,648)
Gold bullion sold to pay expenses, average cost	$ (13,561,480)		$ (14,545,433)
Gold bullion sold to pay expenses, fair value	(16,462,647)		(17,761,859)
Gold bullion sold to pay expenses, realized gain (loss)	2,901,167		3,216,426
Net realized gain (loss), fair value	156,388,096		62,214,320
Net change in unrealized appreciation/depreciation, fair value	$ 2,214,631,754		$ 1,881,741,015
Ending balance (Ounce) | oz	14,286,334		16,608,310
Ending balance, average cost	$ 22,113,171,288		$ 25,367,951,331
Ending balance, fair value	28,282,655,788	[1]	32,255,828,173
Ending balance, realized gain (loss)	$ 156,388,096		$ 62,214,320

[1] Cost of investment in gold bullion: $22,113,171,288 and $22,205,551,004, respectively.