Investments - Investment Portfolio at Cost and Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023
Schedule of Investments [Line Items]
Cost	$ 68,985,671		$ 51,021,723
Fair Value	$ 68,419,777		$ 50,743,911
Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	100.00%		100.00%
First lien debt
Schedule of Investments [Line Items]
Cost	$ 62,076,029	[1],[2],[3]	$ 45,837,261	[4]
Fair Value	$ 61,455,274	[1],[3]	$ 45,534,013
First lien debt | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	89.80%		89.70%
Second lien debt
Schedule of Investments [Line Items]
Cost	$ 2,790,046	[1],[2],[3]	$ 1,826,541	[4],[5]
Fair Value	$ 2,723,460	[1],[3]	$ 1,736,088	[5]
Second lien debt | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	3.90%		3.40%
Unsecured debt
Schedule of Investments [Line Items]
Cost	$ 179,863		$ 18,182
Fair Value	$ 177,801		$ 18,171
Unsecured debt | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	0.30%		0.00%
Structured finance obligations
Schedule of Investments [Line Items]
Cost	$ 719,574	[1],[3]	$ 443,228	[4],[5]
Fair Value	731,648	[1],[2],[3]	436,863	[5]
Structured finance obligations - debt instruments
Schedule of Investments [Line Items]
Cost	582,324		443,228
Fair Value	$ 590,509		$ 436,863
Structured finance obligations - debt instruments | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	0.90%		0.90%
Structured finance obligations - equity instruments
Schedule of Investments [Line Items]
Cost	$ 137,250		$ 0
Fair Value	$ 141,139		$ 0
Structured finance obligations - equity instruments | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	0.20%		0.00%
Investments in Joint Ventures
Schedule of Investments [Line Items]
Cost	$ 1,932,706	[1],[2],[3]	$ 2,120,206	[4],[5]
Fair Value	$ 1,914,411	[1],[3]	$ 2,161,525	[5]
Investments in Joint Ventures | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	2.80%		4.30%
Equity and other
Schedule of Investments [Line Items]
Cost	$ 1,287,453		$ 776,305
Fair Value	$ 1,417,183		$ 857,251
Equity and other | Investments At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
% of Total Investments at Fair Value	2.10%		1.70%

[1] All securities are exempt from registration under the Securities Act of 1933, as amended (the “Securities Act”), including investments in joint ventures but excluding Loar Holdings Inc. - Common Equity and Moderna Inc - Common Stock, and may be deemed to be “restricted securities.” As of December 31, 2024, the aggregate fair value of these securities is $68,353.7 million or 175.85% of the Company’s net assets. The initial acquisition dates have been included for such securities.

[2] The cost represents the original cost adjusted for the amortization of discounts and premiums, as applicable, on debt investments using the effective interest method in accordance with accounting principles generally accepted in the United States of America (“GAAP”).

[3] Unless otherwise indicated, all debt and equity investments held by the Company (which such term “Company” shall include the Company’s consolidated subsidiaries for purposes of this Consolidated Schedule of Investments) are denominated in dollars. As of December 31, 2024, the Company had investments denominated in Canadian Dollars (CAD), Euros (EUR), British Pounds (GBP), Swiss Francs (CHF), Danish Krone (DKK), Swedish Krona (SEK), Norwegian Krone (NOK), New Zealand Dollars (NZD), and Australian Dollars (AUD). All debt investments are income producing unless otherwise indicated. All equity investments are non-income producing unless otherwise noted. Certain portfolio company investments are subject to contractual restrictions on sales. The total par amount (in thousands) is presented for debt investments, while the number of shares or units (in whole amounts) owned is presented for equity investments. Each of the Company’s investments is pledged as collateral, under one or more of its credit facilities unless otherwise indicated.

[4] The cost represents the original cost adjusted for the amortization of discounts and premiums, as applicable, on debt investments using the effective interest method in accordance with accounting principles generally accepted in the United States of America (“GAAP”).

[5] Unless otherwise indicated, all debt and equity investments held by the Company (which such term “Company” shall include the Company’s consolidated subsidiaries for purposes of this Consolidated Schedule of Investments) are denominated in dollars. As of December 31, 2023, the Company had investments denominated in Canadian Dollars (CAD), Euros (EUR), British Pounds (GBP), Swiss Francs (CHF), Danish Krone (DKK), Swedish Krona (SEK), Norwegian Krone (NOK), and New Zealand Dollars (NZD). All debt investments are income producing unless otherwise indicated. All equity investments are non-income producing unless otherwise noted. Certain portfolio company investments are subject to contractual restrictions on sales. The total par amount (in thousands) is presented for debt investments, while the number of shares or units (in whole amounts) owned is presented for equity investments. Each of the Company’s investments is pledged as collateral, under one or more of its credit facilities unless otherwise indicated.