v3.25.1
Investments in Affiliates - Summary of Transactions in, and Earnings from, Investments in Affiliates (Excluding Affiliated Money Market Funds) (Detail) - USD ($)
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Investments In And Advances To Affiliates [Line Items]    
Beginning Value $ 1,269,897,511  
Change in Unrealized Appreciation (Depreciation) (307,037) $ (683,324)
Ending Value 1,196,885,957  
Dividend Income 9,610,738 11,887,569
Investment, Affiliated Issuer [Member]    
Investments In And Advances To Affiliates [Line Items]    
Beginning Value 876,644,367  
Ending Value 799,613,441  
Affiliated Investments [Member]    
Investments In And Advances To Affiliates [Line Items]    
Purchases at Cost 205,099,074 425,170,155
Proceeds from Sales (281,997,433) (324,561,159)
Change in Unrealized Appreciation (Depreciation) (132,567) (275,333)
Affiliated Investments [Member] | Investment, Affiliated Issuer [Member]    
Investments In And Advances To Affiliates [Line Items]    
Beginning Value 876,644,367 908,120,125
Ending Value 799,613,441 1,008,453,788
Dividend Income 9,610,738 11,887,569
Affiliated Investments [Member] | Invesco Government & Agency Portfolio, Institutional Class [Member]    
Investments In And Advances To Affiliates [Line Items]    
Purchases at Cost 205,099,074 425,170,155
Proceeds from Sales (281,997,433) (324,561,159)
Affiliated Investments [Member] | Invesco Government & Agency Portfolio, Institutional Class [Member] | Investment, Affiliated Issuer [Member]    
Investments In And Advances To Affiliates [Line Items]    
Beginning Value 661,273,167 692,738,727
Ending Value 584,374,808 793,347,723
Dividend Income 7,299,169 9,121,130
Affiliated Investments [Member] | Invesco Short Term Treasury ETF [Member]    
Investments In And Advances To Affiliates [Line Items]    
Change in Unrealized Appreciation (Depreciation) (132,567) (275,333)
Affiliated Investments [Member] | Invesco Short Term Treasury ETF [Member] | Investment, Affiliated Issuer [Member]    
Investments In And Advances To Affiliates [Line Items]    
Beginning Value 215,371,200 215,381,398
Ending Value 215,238,633 215,106,065
Dividend Income $ 2,311,569 $ 2,766,439