Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended						6 Months Ended
	Jun. 30, 2019 USD ($) oz		Mar. 31, 2019 USD ($) oz		Jun. 30, 2018 USD ($) oz	Mar. 31, 2018 USD ($) oz	Jun. 30, 2019 USD ($) oz		Jun. 30, 2018 USD ($) oz
Beginning balance (Ounce) | oz	9,695,079		9,009,541		8,725,190	7,828,465	9,009,541		7,828,465
Gold bullion contributed (Ounce) | oz	546,477				689,115		1,365,448		1,619,592
Gold bullion distributed (Ounce) | oz	(761,506)				(770,898)		(889,355)		(799,700)
Gold bullion sold to pay expenses (Ounce) | oz	(5,960)				(5,705)		(11,544)		(10,655)
Ending balance (Ounce) | oz	9,474,090		9,695,079		8,637,702	8,725,190	9,474,090		8,637,702
Beginning balance, average cost	$ 12,152,880,181		$ 11,255,129,376		$ 10,859,308,652	$ 9,663,574,842	$ 11,255,129,376		$ 9,663,574,842
Gold bullion contributed, average cost	739,781,522				918,575,987		1,804,683,811		2,156,243,426
Gold bullion distributed, average cost	(954,820,867)				(964,441,439)		(1,114,984,814)		(1,000,238,842)
Gold bullion sold to pay expenses, average cost	(7,472,873)				(7,126,305)		(14,460,410)		(13,262,531)
Ending balance, average cost	11,930,367,963		12,152,880,181		10,806,316,895	10,859,308,652	11,930,367,963		10,806,316,895
Beginning balance, fair value	12,559,005,466		11,547,078,166	[1]	11,550,842,235	10,149,604,427	11,547,078,166	[1]	10,149,604,427
Gold bullion contributed, fair value	739,781,522				918,575,987		1,804,683,811		2,156,243,426
Gold bullion distributed, fair value	(976,968,626)				(992,947,997)		(1,142,681,966)		(1,030,905,319)
Gold bullion sold to pay expenses, fair value	(7,735,421)				(7,479,964)		(15,020,997)		(14,017,337)
Net realized gain (loss), fair value	22,410,307		5,847,432		28,860,217	2,561,066	28,257,739		31,421,283
Net change in unrealized appreciation/depreciation, fair value	1,012,499,328		114,176,495		(696,835,646)	205,503,998	1,126,675,823		(491,331,648)
Ending balance, fair value	13,348,992,576	[1]	12,559,005,466		10,801,014,832	11,550,842,235	13,348,992,576	[1]	10,801,014,832
Gold bullion distributed, realized gain (loss)	22,147,759				28,506,558		27,697,152		30,666,477
Gold bullion sold to pay expenses, realized gain (loss)	262,548				353,659		560,587		754,806
Ending balance, realized gain (loss)	$ 22,410,307		$ 5,847,432		$ 28,860,217	$ 2,561,066	$ 28,257,739		$ 31,421,283

[1] Cost of investment in gold bullion: $11,930,367,963 and $11,255,129,376, respectively.