Investments in Affiliates - Summary of Transactions in, and Earnings from, Investments in Affiliates (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021	Sep. 30, 2022		Sep. 30, 2021
Investments In And Advances To Affiliates [Line Items]
Beginning Value				$ 317,739,851
Change in Unrealized Appreciation (Depreciation)	$ 112,273		$ 5,798	(219,055)		$ (1,939)
Ending Value	225,041,490			225,041,490
Affiliated Investments [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value	280,055,248		206,651,848	317,739,851		69,754,530
Purchases at Cost	73,678,311		109,005,646	404,024,877		419,398,603
Proceeds from Sales	(128,627,344)		(95,895,019)	(496,649,975)		(269,388,378)
Change in Unrealized Appreciation (Depreciation)	(75,979)		(4,267)	(84,517)		(6,547)
Realized Gain (Loss)	11,254			11,254
Ending Value	225,041,490		219,758,208	225,041,490		219,758,208
Dividend Income	1,298,415		11,959	1,877,905		29,628
Affiliated Investments [Member] | Invesco Government & Agency Portfolio, Institutional Class [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value	243,992,848		180,561,925	281,668,913		53,703,257
Purchases at Cost	73,678,311		99,008,412	404,024,877		399,360,439
Proceeds from Sales	(112,630,793)		(95,895,019)	(480,653,424)		(269,388,378)
Ending Value	205,040,366		183,675,318	205,040,366		183,675,318
Dividend Income	1,185,038		11,959	1,737,949		26,968
Affiliated Investments [Member] | Exchange-Traded Fund [Member]
Investments In And Advances To Affiliates [Line Items]
Beginning Value	36,062,400		26,089,923	36,070,938	[1]	16,051,273
Purchases at Cost			9,997,234			20,038,164
Proceeds from Sales	(15,996,551)			(15,996,551)
Change in Unrealized Appreciation (Depreciation)	(75,979)		(4,267)	(84,517)		(6,547)
Realized Gain (Loss)	11,254			11,254
Ending Value	20,001,124	[1]	$ 36,082,890	20,001,124	[1]	36,082,890
Dividend Income	$ 113,377			$ 139,956		$ 2,660

[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.