Investments - Geographic Investment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Schedule of Investments [Line Items]
Cost	$ 12,952,035	$ 13,193,219
Fair Value	$ 12,834,206	$ 13,092,518
Fair Value as % of Net Assets	205.60%	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	$ 11,487,756	$ 11,663,322
Fair Value	$ 11,375,303	$ 11,595,231
Fair Value as % of Net Assets	182.30%	190.80%
United States | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	88.60%	88.60%
Europe
Schedule of Investments [Line Items]
Cost	$ 1,196,280	$ 1,138,542
Fair Value	$ 1,188,696	$ 1,104,837
Fair Value as % of Net Assets	19.00%	18.20%
Europe | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	9.30%	8.40%
Canada
Schedule of Investments [Line Items]
Cost	$ 118,108	$ 241,124
Fair Value	$ 119,470	$ 242,103
Fair Value as % of Net Assets	1.90%	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	$ 149,254	$ 149,595
Fair Value	$ 150,119	$ 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	1.20%	1.20%
Asia
Schedule of Investments [Line Items]
Cost	$ 637	$ 636
Fair Value	$ 618	$ 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%