v3.26.1
INVESTMENTS - Investments (Details)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
borrower
Dec. 31, 2025
USD ($)
borrower
Schedule of Investments [Line Items]    
Amortized Cost $ 29,674.6 [1] $ 29,249.9 [2]
Fair Value $ 29,349.3 [1] $ 29,484.8 [2]
Loans on non-accrual status, as a percent of total investments at amortized cost 2.40% 1.80%
Loans on non-accrual status, as a percent of total investments at fair value 1.40% 1.20%
Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 100.00% 100.00%
Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 100.00% 100.00%
Senior Direct Lending Program    
Schedule of Investments [Line Items]    
Number of borrowers | borrower 72 39
Ivy Hill Asset Management, L.P.    
Schedule of Investments [Line Items]    
Amortized Cost $ 3,628.0 $ 3,190.0
Fair Value $ 13,063.0 $ 11,599.0
Number of borrowers | borrower 24  
Midwest | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 23.30% 22.90%
West | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 21.30% 20.30%
West | Senior Direct Lending Program | Investments, At Fair Value | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 3.90% 3.80%
West | Ivy Hill Asset Management, L.P. | Investments, At Fair Value | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 9.70% 8.30%
Southeast | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 17.30% 18.80%
Northeast | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 17.10% 15.10%
Mid-Atlantic | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 15.00% 16.30%
International | Investments, At Fair Value | Geographic Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 6.00% 6.60%
Software and Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 6,793.0 $ 7,030.9
Fair Value $ 6,451.2 $ 7,032.3
Software and Services | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 22.00% 23.80%
Financial Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 3,686.8 $ 3,434.9
Fair Value $ 3,935.8 $ 3,664.3
Financial Services | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 13.40% 12.40%
Health Care Equipment and Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 3,277.9 $ 3,472.0
Fair Value $ 2,895.2 $ 3,333.5
Health Care Equipment and Services | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 9.90% 11.30%
Commercial and Professional Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 2,873.4 $ 2,806.9
Fair Value $ 2,811.9 $ 2,776.7
Commercial and Professional Services | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 9.60% 9.40%
Consumer Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,973.4 $ 1,641.7
Fair Value $ 1,972.1 $ 1,663.4
Consumer Services | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 6.70% 5.60%
Insurance    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,483.2 $ 1,457.4
Fair Value $ 1,570.5 $ 1,521.4
Insurance | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 5.40% 5.20%
Capital Goods    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,338.7 $ 1,288.4
Fair Value $ 1,437.5 $ 1,349.9
Capital Goods | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 4.90% 4.60%
Consumer Distribution and Retail    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,418.3 $ 1,449.9
Fair Value $ 1,377.6 $ 1,424.7
Consumer Distribution and Retail | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 4.70% 4.80%
Investment Funds and Vehicles    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,159.4 $ 1,120.8
Fair Value $ 1,180.5 $ 1,142.0
Investment Funds and Vehicles | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 4.00% 3.90%
Sports, Media and Entertainment    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,020.5 $ 1,150.3
Fair Value $ 1,121.0 $ 1,191.6
Sports, Media and Entertainment | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 3.80% 4.00%
Pharmaceuticals, Biotechnology and Life Sciences    
Schedule of Investments [Line Items]    
Amortized Cost $ 846.3 $ 800.4
Fair Value $ 835.2 $ 794.9
Pharmaceuticals, Biotechnology and Life Sciences | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 2.80% 2.70%
Materials    
Schedule of Investments [Line Items]    
Amortized Cost $ 698.2 $ 665.5
Fair Value $ 672.9 $ 656.6
Materials | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 2.30% 2.20%
Consumer Durables and Apparel    
Schedule of Investments [Line Items]    
Amortized Cost $ 555.9 $ 577.2
Fair Value $ 549.4 $ 583.9
Consumer Durables and Apparel | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 1.90% 2.00%
Independent Power and Renewable Electricity Producers    
Schedule of Investments [Line Items]    
Amortized Cost $ 370.6 $ 581.2
Fair Value $ 452.0 $ 642.7
Independent Power and Renewable Electricity Producers | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 1.50% 2.20%
Automobiles and Components    
Schedule of Investments [Line Items]    
Amortized Cost $ 385.1 $ 392.5
Fair Value $ 373.2 $ 382.7
Automobiles and Components | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 1.30% 1.30%
Other | Investments, At Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Composition, percent of fair value 5.80% 4.60%
First lien senior secured loans    
Schedule of Investments [Line Items]    
Amortized Cost $ 17,859.0 $ 18,103.0
Fair Value 17,333.0 17,858.0
Second lien senior secured loans    
Schedule of Investments [Line Items]    
Amortized Cost 1,495.0 1,558.0
Fair Value 1,293.0 1,487.0
Subordinated certificates of the SDLP    
Schedule of Investments [Line Items]    
Amortized Cost 1,140.0 1,103.0
Fair Value 1,154.0 1,117.0
Senior subordinated loans    
Schedule of Investments [Line Items]    
Amortized Cost 1,888.0 1,690.0
Fair Value 1,822.0 1,585.0
Preferred equity    
Schedule of Investments [Line Items]    
Amortized Cost 2,605.0 2,597.0
Fair Value 2,348.0 2,475.0
Ivy Hill Asset Management, L.P.    
Schedule of Investments [Line Items]    
Amortized Cost 2,646.0 2,231.0
Fair Value 2,843.0 2,434.0
Other equity    
Schedule of Investments [Line Items]    
Amortized Cost 2,042.0 1,968.0
Fair Value 2,556.0 2,529.0
Unitranche loans    
Schedule of Investments [Line Items]    
Amortized Cost 13,092.0 11,349.0
Fair Value $ 12,818.0 $ 11,239.0
[1] As of June 30, 2026, the estimated net unrealized loss for federal tax purposes was approximately $0.2 billion based on a tax cost basis of approximately $29.5 billion. As of June 30, 2026, the estimated aggregate gross unrealized loss for federal income tax purposes was approximately $1.5 billion and the estimated aggregate gross unrealized gain for federal income tax purposes was approximately $1.3 billion.     
[2] As of December 31, 2025, the estimated net unrealized gain for federal tax purposes was approximately $300 million based on a tax cost basis of $29.2 billion. As of December 31, 2025, the estimated aggregate gross unrealized gain for federal income tax purposes was approximately $1.3 billion and the estimated aggregate gross unrealized loss for federal income tax purposes was approximately $1.0 billion.