Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) oz		Dec. 31, 2017 USD ($) oz		Dec. 31, 2016 USD ($) oz
Beginning balance (Ounce) | oz	7,828,465		6,308,062		4,905,568
Gold bullion contributed (Ounce) | oz	2,370,108		2,194,645		3,036,655
Gold bullion distributed (Ounce) | oz	(1,167,483)		(657,409)		(1,618,237)
Gold bullion sold to pay expenses (Ounce) | oz	(21,549)		(16,833)		(15,924)
Ending balance (Ounce) | oz	9,009,541		7,828,465		6,308,062
Beginning balance, average cost	$ 9,663,574,842		$ 7,706,923,343		$ 5,910,175,908
Gold bullion contributed, average cost	3,078,649,161		2,782,113,163		3,784,339,342
Gold bullion distributed, average cost	(1,460,213,703)		(804,830,293)		(1,968,318,439)
Gold bullion sold to pay expenses, average cost	(26,880,924)		(20,631,371)		(19,273,468)
Ending balance, average cost	11,255,129,376		9,663,574,842		7,706,923,343
Beginning balance, fair value	10,149,604,427	[1]	7,311,674,849		5,210,940,144
Gold bullion contributed, fair value	3,078,649,161		2,782,113,163		3,784,339,342
Gold bullion distributed, fair value	(1,483,295,672)		(826,600,408)		(1,992,755,088)
Gold bullion sold to pay expenses, fair value	(27,290,381)		(21,077,170)		(19,905,623)
Net realized gain (loss), fair value	23,491,426		22,215,914		25,068,804
Net change in unrealized appreciation/depreciation, fair value	(194,080,795)		881,278,079		303,987,270
Ending balance, fair value	11,547,078,166	[1]	10,149,604,427	[1]	7,311,674,849
Gold bullion distributed, realized gain (loss)	23,081,969		21,770,115		24,436,649
Gold bullion sold to pay expenses, realized gain (loss)	$ 409,457		$ 445,799		$ 632,155

[1] Cost of investment in gold bullion: $11,255,129,376 and $9,663,574,842, respectively.