Note 2 - Significant Accounting Policies - Activity in Gold Bullion (Details)	3 Months Ended								9 Months Ended
	Sep. 30, 2019 USD ($) oz		Jun. 30, 2019 USD ($) oz	Mar. 31, 2019 USD ($) oz		Sep. 30, 2018 USD ($) oz	Jun. 30, 2018 USD ($) oz	Mar. 31, 2018 USD ($) oz	Sep. 30, 2019 USD ($) oz		Sep. 30, 2018 USD ($) oz
Beginning balance (Ounce) | oz	9,474,090			9,009,541		8,637,702		7,828,465	9,009,541		7,828,465
Gold bullion contributed (Ounce) | oz	1,625,180					269,920			2,990,628		1,889,512
Gold bullion distributed (Ounce) | oz	(81,313)					(298,773)			(970,668)		(1,098,473)
Gold bullion sold to pay expenses (Ounce) | oz	(5,970)					(5,523)			(17,514)		(16,178)
Ending balance (Ounce) | oz	11,011,987		9,474,090			8,603,326	8,637,702		11,011,987		8,603,326
Beginning balance, average cost	$ 11,930,367,963			$ 11,255,129,376		$ 10,806,316,895		$ 9,663,574,842	$ 11,255,129,376		$ 9,663,574,842
Gold bullion contributed, average cost	2,411,110,878					326,017,394			4,215,794,689		2,482,260,820
Gold bullion distributed, average cost	(103,411,024)					(373,766,620)			(1,218,395,838)		(1,374,005,462)
Gold bullion sold to pay expenses, average cost	(7,578,716)					(6,907,415)			(22,039,126)		(20,169,946)
Ending balance, average cost	14,230,489,101		$ 11,930,367,963			10,751,660,254	$ 10,806,316,895		14,230,489,101		10,751,660,254
Beginning balance, fair value	13,348,992,576			11,547,078,166	[1]	10,801,014,832		10,149,604,427	11,547,078,166	[1]	10,149,604,427
Gold bullion contributed, fair value	2,411,110,878					326,017,394			4,215,794,689		2,482,260,820
Gold bullion distributed, fair value	(120,691,118)					(369,770,728)			(1,263,373,084)		(1,400,676,047)
Gold bullion sold to pay expenses, fair value	(8,641,399)					(6,734,887)			(23,662,396)		(20,752,224)
Net realized gain (loss), fair value	18,342,777		22,410,307	5,847,432		(4,168,420)	28,860,217	2,561,066	46,600,516		27,252,863
Net change in unrealized appreciation/depreciation, fair value	706,990,277		1,012,499,328	114,176,495		(532,059,056)	(696,835,646)	205,503,998	1,833,666,100		(1,023,390,704)
Ending balance, fair value	16,356,103,991	[1]	13,348,992,576			10,214,299,135	10,801,014,832		16,356,103,991	[1]	10,214,299,135
Gold bullion distributed, realized gain (loss)	17,280,094					(3,995,892)			44,977,246		26,670,585
Gold bullion sold to pay expenses, realized gain (loss)	1,062,683					(172,528)			1,623,270		582,278
Ending balance, realized gain (loss)	$ 18,342,777		$ 22,410,307	$ 5,847,432		$ (4,168,420)	$ 28,860,217	$ 2,561,066	$ 46,600,516		$ 27,252,863

[1] Cost of investment in gold bullion: $14,230,489,101 and $11,255,129,376, respectively.