Significant Accounting Policies - Schedule of Components of Distributable Earnings/(Accumulated Deficits) on a Tax Basis (Details) - USD ($)		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Schedule of Components of Distributable Earnings/(Accumulated Deficits) on a Tax Basis [Abstract]
Undistributed ordinary income		$ 246,251	$ 1,918,290	$ 2,389,267
Accumulated capital and other losses	[1]	(523,575,571)	(515,131,566)	(512,809,528)
Other temporary differences		(23,477)	(41,229)	(57,438)
Unrealized appreciation/(depreciation)		(20,515,555)	(31,349,330)	(37,631,079)
Components of distributable earnings/(accumulated deficits) at year end		$ (543,868,352)	$ (544,603,835)	$ (548,108,778)

[1] Under the Regulated Investment Company Modernization Act of 2010, net capital losses recognized for tax years beginning after December 22, 2010, may be carried forward indefinitely, and their character is retained as short-term or long-term losses. As of September 30, 2025, the Company had a long-term capital loss carryforward available to offset future realized capital gains of $521,474,790 and a short-term capital loss carryforward of $2,100,781. Net capital losses incurred after October 31 (post-October losses) and net investment losses incurred after December 31 (late-year losses), and within the taxable year, may be elected to be deferred to the first business day of the Fund’s next taxable year. As of the most recent fiscal period ended September 30, 2025, the Fund did not elect to defer any late year losses.