Fair Value Measurements - Investments - Schedule of Fair Value Measurements of Investments, by Major Class (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio companies	$ 10,482,237	$ 9,009,449
Unrealized appreciation on foreign currency forward contracts	31,711	27,607
Unrealized depreciation on foreign currency forward contracts	(4,579)	(5,177)
Investments in Money Market Funds	1,875,256	963,528
Total	12,384,625	9,995,407
Level I
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio companies	22,538	23,278
Unrealized appreciation on foreign currency forward contracts	0	0
Unrealized depreciation on foreign currency forward contracts	0	0
Investments in Money Market Funds	1,875,256	963,528
Total	1,897,794	986,806
Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio companies	10,198	0
Unrealized appreciation on foreign currency forward contracts	31,711	27,607
Unrealized depreciation on foreign currency forward contracts	(4,579)	(5,177)
Investments in Money Market Funds	0	0
Total	37,330	22,430
Level III
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio companies	10,444,090	8,980,760
Unrealized appreciation on foreign currency forward contracts	0	0
Unrealized depreciation on foreign currency forward contracts	0	0
Investments in Money Market Funds	0	0
Total	10,444,090	8,980,760
Investments Measured at Net Asset Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Portfolio companies	5,411	5,411
Unrealized appreciation on foreign currency forward contracts	0	0
Unrealized depreciation on foreign currency forward contracts	0	0
Investments in Money Market Funds	0	0
Total	$ 5,411	$ 5,411