Schedule of Investments - Futures Contracts		12 Months Ended
		Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract
Schedule of Investments [Line Items]
Currency Futures Contracts, Value		$ 511,601,546	$ 541,184,203
Futures [Member] | United States of America, Dollars [Member] | Long [Member]
Schedule of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		5,164	5,801
Currency Futures Contracts, Expiration Date		Mar. 31, 2019	Mar. 31, 2018
Currency Futures Contracts, Notional Value		$ 494,375,540	$ 532,682,626
Currency Futures Contracts, Value	[1]	(4,534,517)	(7,972,637)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (4,534,517)	$ (7,972,637)

[1] Unrealized Appreciation (Depreciation) and Value are presented above, net by contract.