Investments in Affiliates -Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2021		Sep. 30, 2020	Sep. 30, 2021		Sep. 30, 2020
Investments In And Advances To Affiliates [Line Items]
Beginning Value					$ 245,409,996
United States Treasury Obligations		$ 1,225		$ 8,761	(2,329)		$ (45,451)
Ending Value		306,144,450			306,144,450
Affiliated Investments [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value		283,470,722		296,199,196	245,409,996		105,630,007
Purchases at Cost		156,907,514		744,677,740	605,856,358		2,120,361,361
Proceeds from Sales		(134,229,066)		(419,935,133)	(545,117,184)		(1,605,246,385)
United States Treasury Obligations		(4,720)		(52,990)	(4,720)		143,830
Ending Value		306,144,450		620,888,813	306,144,450		620,888,813
Dividend Income		15,820		71,137	51,145		1,240,808
Affiliated Investments [Member] | Exchange-Traded Fund [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value		49,876,240		80,090,600	49,876,240	[1]	79,893,780
United States Treasury Obligations		(4,720)		(52,990)	(4,720)		143,830
Ending Value		49,871,520	[1]	80,037,610	49,871,520	[1]	80,037,610
Dividend Income				58,024	8,075		573,935
Affiliated Investments [Member] | Money Market Mutual Fund - Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value				216,108,596			25,736,227
Purchases at Cost				190,622,258			1,566,305,879
Proceeds from Sales				(406,730,854)			(1,592,042,106)
Ending Value	[1],[2]	256,272,930			256,272,930
Dividend Income				11,735			665,495
Affiliated Investments [Member] | Money Market Mutual Fund - Invesco Government & Agency Portfolio, Institutional Class [Member] | Money Market Mutual Fund - Invesco Premier U.S. Government Money ETF - Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value		233,594,482			195,533,756
Purchases at Cost		156,907,514		554,055,482	605,856,358		554,055,482
Proceeds from Sales		(134,229,066)		(13,204,279)	(545,117,184)		(13,204,279)
Ending Value		256,272,930		540,851,203	256,272,930		540,851,203
Dividend Income		$ 15,820		$ 1,378	$ 43,070		$ 1,378

[1] Affiliated issuer. The issuer and/or the Fund is a wholly-owned subsidiary of Invesco Ltd., or is affiliated by having an investment adviser that is under common control of Invesco Ltd. See Note 8.

[2] The rate shown is the 7-day SEC standardized yield as of September 30, 2021