Income Taxes - Schedule of Aggregate Unrealized Appreciation of Company investment Federal Income Tax (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Aggregate Gross Unrealized Appreciation	$ 119.0	$ 118.3
Aggregate Gross Unrealized Depreciation	158.6	115.9
Net Unrealized Appreciation (Depreciation) over cost for U.S. federal income tax purposes	(39.6)	2.4
Aggregate cost of securities for U.S. federal income tax purposes (in billions)	$ 3,600.0	$ 3,200.0

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Amount of cost of investment for federal income tax purpose.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(h)(2)(iv))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

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Amount of cumulative increase in investment from unrealized gain when value exceeds cost for federal income tax purpose.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(h)(2)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

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- Definition

Amount of cumulative decrease in investment from unrealized loss when cost for federal income tax purpose exceeds value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(h)(2)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

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- Definition

Amount of cumulative increase (decrease) in investment from unrealized gain (loss) when value exceeds (is less than) cost for federal income tax purpose.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(h)(2)(iii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

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