Statement of Changes in Shareholders' Equity (Unaudited) - USD ($)	Total	Shares [Member]	General Shares [Member]
Balance - Value at Dec. 31, 2017	$ 2,262,359,193	$ 2,262,358,528	$ 665
Balance - Shares at Dec. 31, 2017		136,000,000	40
Purchases of Shares - Value	659,595,300	$ 659,595,300
Purchases of Shares - Shares		39,000,000
Redemption of Shares - Value	(203,710,810)	$ (203,710,810)
Redemption of Shares - Shares		(12,200,000)
Net Increase (Decrease) due to Share Transactions, value	455,884,490	$ 455,884,490
Net Increase (Decrease) due to Share Transactions, shares		26,800,000
Net Income (Loss)
Net Investment Income (Loss)	2,630,823	$ 2,630,822	$ 1
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	58,024,422	58,024,404	18
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(19,889,616)	(19,889,610)	(6)
Net Income (Loss)	40,765,629	40,765,616	13
Net Change in Shareholders' Equity, value	496,650,119	$ 496,650,106	13
Net Change in Shareholders' Equity, shares		26,800,000
Balance - Value at Mar. 31, 2018	2,759,009,312	$ 2,759,008,634	$ 678
Balance - Shares at Mar. 31, 2018		162,800,000	40
Balance - Value at Dec. 31, 2018	1,932,576,856	$ 1,932,576,278	$ 578
Balance - Shares at Dec. 31, 2018		133,800,000	40
Purchases of Shares - Value	48,178,241	$ 48,178,241
Purchases of Shares - Shares		3,200,000
Redemption of Shares - Value	(401,013,118)	$ (401,013,118)
Redemption of Shares - Shares		(25,600,000)
Net Increase (Decrease) due to Share Transactions, value	(352,834,877)	$ (352,834,877)
Net Increase (Decrease) due to Share Transactions, shares		(22,400,000)
Net Income (Loss)
Net Investment Income (Loss)	7,030,465	$ 7,030,463	$ 2
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(38,448,137)	(38,448,126)	(11)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	224,208,198	224,208,131	67
Net Income (Loss)	192,790,526	192,790,468	58
Net Change in Shareholders' Equity, value	(160,044,351)	$ (160,044,409)	58
Net Change in Shareholders' Equity, shares		(22,400,000)
Balance - Value at Mar. 31, 2019	$ 1,772,532,505	$ 1,772,531,869	$ 636
Balance - Shares at Mar. 31, 2019		111,400,000	40