Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) oz		Dec. 31, 2016 USD ($) oz		Dec. 31, 2015 USD ($) oz
Beginning balance (Ounce) | oz	6,308,062		4,905,568		5,182,164
Gold bullion contributed (Ounce) | oz	2,194,645		3,036,655		696,554
Gold bullion distributed (Ounce) | oz	(657,409)		(1,618,237)		(959,873)
Gold bullion sold to pay expenses (Ounce) | oz	(16,833)		(15,924)		(13,277)
Ending balance (Ounce) | oz	7,828,465		6,308,062		4,905,568
Beginning balance, average cost	$ 7,706,923,343		$ 5,910,175,908		$ 6,254,868,124
Gold bullion contributed, average cost	2,782,113,163		3,784,339,342		830,130,993
Gold bullion distributed, average cost	(804,830,293)		(1,968,318,439)		(1,158,780,335)
Gold bullion sold to pay expenses, average cost	(20,631,371)		(19,273,468)		(16,042,874)
Ending balance, average cost	9,663,574,842		7,706,923,343		5,910,175,908
Beginning balance, fair value	7,311,674,849	[1]	5,210,940,144		6,214,710,412
Gold bullion contributed, fair value	2,782,113,163		3,784,339,342		830,130,993
Gold bullion distributed, fair value	(826,600,408)		(1,992,755,088)		(1,071,599,347)
Gold bullion sold to pay expenses, fair value	(21,077,170)		(19,905,623)		(15,431,681)
Net realized gain (loss), fair value	22,215,914		25,068,804		(87,792,181)
Net change in unrealized appreciation/depreciation, fair value	881,278,079		303,987,270		(659,078,052)
Ending balance, fair value	10,149,604,427	[1]	7,311,674,849	[1]	5,210,940,144
Gold bullion distributed, realized gain (loss)	21,770,115		24,436,649		(87,180,988)
Gold bullion sold to pay expenses, realized gain (loss)	445,799		632,155		(611,193)
Ending balance, realized gain (loss)	$ 22,215,914		$ 25,068,804		$ (87,792,181)

[1] Cost of investment in gold bullion: $9,663,574,842 and $7,706,923,343, respectively.