Statement of Changes in Shareholders' Equity - USD ($)	Total	General Shares [Member]	Shares [Member]
Balance - Value at Dec. 31, 2015	$ 1,133,614,816	$ 1,026	$ 1,133,613,790
Balance - Shares at Dec. 31, 2015		40	44,200,000
Purchases of Shares - Value	629,567,756		$ 629,567,756
Purchases of Shares - Shares			25,200,000
Redemption of Shares - Value	(944,874,133)		$ (944,874,133)
Redemption of Shares - Shares			(37,400,000)
Net Increase (Decrease) due to Share Transactions, value	(315,306,377)		$ (315,306,377)
Net Increase (Decrease) due to Share Transactions, shares			(12,200,000)
Net Income (Loss)
Net Investment Income (Loss)	(4,226,535)	$ (5)	$ (4,226,530)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	38,975,014	44	38,974,970
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	(7,147,679)	(8)	(7,147,671)
Net Income (Loss)	27,600,800	31	27,600,769
Net Change in Shareholders' Equity, value	(287,705,577)	31	$ (287,705,608)
Net Change in Shareholders' Equity, shares			(12,200,000)
Balance - Value at Dec. 31, 2016	845,909,239	$ 1,057	$ 845,908,182
Balance - Shares at Dec. 31, 2016		40	32,000,000
Purchases of Shares - Value	392,781,258		$ 392,781,258
Purchases of Shares - Shares			15,800,000
Redemption of Shares - Value	(643,718,534)		$ (643,718,534)
Redemption of Shares - Shares			(25,600,000)
Net Increase (Decrease) due to Share Transactions, value	(250,937,276)		$ (250,937,276)
Net Increase (Decrease) due to Share Transactions, shares			(9,800,000)
Return of Capital Distributions	(538,669)	$ (1)	$ (538,668)
Net Income (Loss)
Net Investment Income (Loss)	552,896	1	552,895
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	(51,965,199)	(81)	(51,965,118)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	(10,293,438)	(16)	(10,293,422)
Net Income (Loss)	(61,705,741)	(96)	(61,705,645)
Net Change in Shareholders' Equity, value	(313,181,686)	(97)	$ (313,181,589)
Net Change in Shareholders' Equity, shares			(9,800,000)
Balance - Value at Dec. 31, 2017	532,727,553	$ 960	$ 532,726,593
Balance - Shares at Dec. 31, 2017		40	22,200,000
Purchases of Shares - Value	406,980,619		$ 406,980,619
Purchases of Shares - Shares			16,600,000
Redemption of Shares - Value	(478,633,142)		$ (478,633,142)
Redemption of Shares - Shares			(19,400,000)
Net Increase (Decrease) due to Share Transactions, value	(71,652,523)		$ (71,652,523)
Net Increase (Decrease) due to Share Transactions, shares			(2,800,000)
Return of Capital Distributions	(5,572,383)	$ (9)	$ (5,572,374)
Net Income (Loss)
Net Investment Income (Loss)	5,644,151	9	5,644,142
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	29,593,358	45	29,593,313
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	3,612,436	14	3,612,422
Net Income (Loss)	38,849,945	68	38,849,877
Net Change in Shareholders' Equity, value	(38,374,961)	59	$ (38,375,020)
Net Change in Shareholders' Equity, shares			(2,800,000)
Balance - Value at Dec. 31, 2018	$ 494,352,592	$ 1,019	$ 494,351,573
Balance - Shares at Dec. 31, 2018		40	19,400,000