Statement of Changes in Shareholders' Equity - USD ($)	Total	General Shares [Member]	Shares [Member]
Balance - Value at Dec. 31, 2014	$ 1,007,005,854	$ 959	$ 1,007,004,895
Balance - Shares at Dec. 31, 2014		40	42,000,000
Purchases of Shares - Value	1,924,757,103		$ 1,924,757,103
Purchases of Shares - Shares			76,000,000
Redemption of Shares - Value	(1,858,289,353)		$ (1,858,289,353)
Redemption of Shares - Shares			(73,800,000)
Net Increase (Decrease) due to Share Transactions, value	66,467,750		$ 66,467,750
Net Increase (Decrease) due to Share Transactions, shares			2,200,000
Net Income (Loss)
Net Investment Income (Loss)	(8,953,085)	$ (10)	$ (8,953,075)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	79,592,223	89	79,592,134
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Currency Futures Contracts	(10,497,926)	(12)	(10,497,914)
Net Income (Loss)	60,141,212	67	60,141,145
Net Change in Shareholders' Equity, value	126,608,962	67	$ 126,608,895
Net Change in Shareholders' Equity, shares			2,200,000
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