Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Investments in Securities, cost	$ 757,591,880	$ 1,432,111,774
US Treasury Bill Securities [Member]
Investments in Securities, cost	474,568,360	664,622,057
Affiliated Investments [Member]
Affiliated Investments, at Cost	$ 283,023,520	$ 767,489,717