Note 2 - Significant Accounting Policies - Share Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021		Dec. 31, 2020
Shares issued (in shares)	83,500,000	53,075,000	[1]	359,650,000	[1]
Shares issued, amount	$ 2,989,014,129	$ 1,853,104,516		$ 12,103,493,289
Shares redeemed (in shares)	(152,550,000)	(108,550,000)	[1]	(80,000,000)	[1]
Distributions for Shares redeemed	$ (5,018,182,038)	$ (3,649,216,540)		$ (2,617,761,048)
Net increase (decrease) in Shares issued and outstanding (in shares)	(69,050,000)	(55,475,000)	[1]	279,650,000	[1]
Net increase (decrease) in net assets from capital share transactions	$ (2,029,167,909)	$ (1,796,112,024)		$ 9,485,732,241

[1] Share transactions reflect a one-for-two reverse stock split effective at market open on May 24, 2021.