Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended
	Mar. 31, 2021 USD ($) oz		Mar. 31, 2020 USD ($) oz
Beginning balance (Ounce) | oz	16,881,652		11,577,252
Beginning balance, average cost	$ 25,014,142,586		$ 15,094,673,874
Beginning balance, fair value	$ 31,924,891,396	[1]	$ 17,632,155,037
Gold bullion contributed (Ounce) | oz	290,219		1,637,506
Gold bullion contributed, average cost	$ 533,856,902		$ 2,615,209,304
Gold bullion contributed, fair value	$ 533,856,902		$ 2,615,209,304
Gold bullion distributed (Ounce) | oz	(959,139)		(635,791)
Gold bullion distributed, average cost	$ (1,425,654,761)		$ (841,562,995)
Gold bullion distributed, fair value	(1,680,026,988)		(991,396,287)
Gold bullion distributed, realized gain (loss)	$ 254,372,227		$ 149,833,292
Gold bullion sold to pay expenses (Ounce) | oz	(10,387)		(7,201)
Gold bullion sold to pay expenses, average cost	$ (15,425,968)		$ (9,471,771)
Gold bullion sold to pay expenses, fair value	(19,190,688)		(11,284,961)
Gold bullion sold to pay expenses, realized gain (loss)	3,764,720		1,813,190
Net realized gain (loss), fair value	258,136,947		151,646,482
Net change in unrealized appreciation/depreciation, fair value	$ (3,618,692,332)		$ 831,013,860
Ending balance (Ounce) | oz	16,202,345		12,571,766
Ending balance, average cost	$ 24,106,918,759		$ 16,858,848,412
Ending balance, fair value	27,398,975,237	[1]	20,227,343,435
Ending balance, realized gain (loss)	$ 258,136,947		$ 151,646,482

[1] Cost of investment in gold bullion: $24,106,918,759 and $25,014,142,586, respectively.