Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) oz		Dec. 31, 2019 USD ($) oz		Dec. 31, 2018 USD ($) oz
Beginning balance (Ounce) | oz	11,577,252		9,009,541		7,828,465
Beginning balance, average cost	$ 15,094,673,874		$ 11,255,129,376		$ 9,663,574,842
Beginning balance, fair value	$ 17,632,155,037	[1]	$ 11,547,078,166		$ 10,149,604,427
Gold bullion contributed (Ounce) | oz	6,866,938		3,668,032		2,370,108
Gold bullion contributed, average cost	$ 12,103,493,289		$ 5,226,042,788		$ 3,078,649,161
Gold bullion contributed, fair value	$ 12,103,493,289		$ 5,226,042,788		$ 3,078,649,161
Gold bullion distributed (Ounce) | oz	(1,527,240)		(1,075,809)		(1,167,483)
Gold bullion distributed, average cost	$ (2,134,454,305)		$ (1,355,372,636)		$ (1,460,213,703)
Gold bullion distributed, fair value	(2,617,761,048)		(1,418,257,979)		(1,483,295,672)
Gold bullion distributed, realized gain (loss)	$ 483,306,743		$ 62,885,343		$ 23,081,969
Gold bullion sold to pay expenses (Ounce) | oz	(35,298)		(24,512)		(21,549)
Gold bullion sold to pay expenses, average cost	$ (49,570,272)		$ (31,125,654)		$ (26,880,924)
Gold bullion sold to pay expenses, fair value	(62,451,444)		(34,028,445)		(27,290,381)
Gold bullion sold to pay expenses, realized gain (loss)	12,881,172		2,902,791		409,457
Net realized gain (loss), fair value	496,187,915		65,788,134		23,491,426
Net change in unrealized appreciation/depreciation, fair value	$ 4,373,267,647		$ 2,245,532,373		$ (194,080,795)
Ending balance (Ounce) | oz	16,881,652		11,577,252		9,009,541
Ending balance, average cost	$ 25,014,142,586		$ 15,094,673,874		$ 11,255,129,376
Ending balance, fair value	31,924,891,396	[1]	17,632,155,037	[1]	11,547,078,166
Ending balance, realized gain (loss)	$ 496,187,915		$ 65,788,134		$ 23,491,426

[1] Cost of investment in gold bullion: $25,014,142,586 and $15,094,673,874, respectively.