Investments - Geographic Investment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Schedule of Investments [Line Items]
Cost	$ 13,327,359	$ 13,193,219
Fair Value	$ 13,252,800	$ 13,092,518
Fair Value as % of Net Assets	210.80%	215.50%
Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
United States
Schedule of Investments [Line Items]
Cost	$ 11,897,748	$ 11,663,322
Fair Value	$ 11,768,803	$ 11,595,231
Fair Value as % of Net Assets	187.20%	190.80%
United States \| Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	88.80%	88.60%
Europe
Schedule of Investments [Line Items]
Cost	$ 1,161,035	$ 1,138,542
Fair Value	$ 1,210,929	$ 1,104,837
Fair Value as % of Net Assets	19.20%	18.20%
Europe \| Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	9.20%	8.40%
Canada
Schedule of Investments [Line Items]
Cost	$ 119,027	$ 241,124
Fair Value	$ 122,667	$ 242,103
Fair Value as % of Net Assets	2.00%	4.00%
Canada \| Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	0.90%	1.80%
Bermuda/Cayman Islands
Schedule of Investments [Line Items]
Cost	$ 148,911	$ 149,595
Fair Value	$ 149,748	$ 149,735
Fair Value as % of Net Assets	2.40%	2.50%
Bermuda/Cayman Islands \| Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	1.10%	1.20%
Asia
Schedule of Investments [Line Items]
Cost	$ 638	$ 636
Fair Value	$ 653	$ 612
Fair Value as % of Net Assets	0.00%	0.00%
Asia \| Investment Owned, At Fair Value \| Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	0.00%	0.00%