v3.26.1
Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value by Hierarchy Level (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements $ 105,356 $ 141,878
Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 6,983,354 [1] 5,984,291 [2]
Total assets at fair value 7,088,710 [1],[3] 6,126,169 [2],[4]
Derivative Liabilities $ 119 $ 478
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Liabilities Other Liabilities
Total liabilities at fair value $ 119 $ 478
Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 831,212 [1] 719,108 [2]
Total assets at fair value 859,730 [1],[3] 806,831 [2],[4]
Derivative Liabilities 0 0
Total liabilities at fair value 0 0
Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 6,140,996 [1] 5,254,048 [2]
Total assets at fair value 6,217,834 [1],[3] 5,308,203 [2],[4]
Derivative Liabilities 0 0
Total liabilities at fair value 0 0
Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 11,146 [1] 11,135 [2]
Total assets at fair value 11,146 [1],[3] 11,135 [2],[4]
Derivative Liabilities 119 478
Total liabilities at fair value 119 478
Loaned securities and securities sold under repurchase agreements | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [4]   64,830
Loaned securities and securities sold under repurchase agreements | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 70,939 [3] 54,155 [4]
Loaned securities and securities sold under repurchase agreements | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 3,428  
Loaned securities and securities sold under repurchase agreements | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 2,471  
Loaned securities and securities sold under repurchase agreements | Level I | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [4]   64,830
Loaned securities and securities sold under repurchase agreements | Level I | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 0 [3] 0 [4]
Loaned securities and securities sold under repurchase agreements | Level I | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 0  
Loaned securities and securities sold under repurchase agreements | Level I | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 0  
Loaned securities and securities sold under repurchase agreements | Level II | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [4]   0
Loaned securities and securities sold under repurchase agreements | Level II | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 70,939 [3] 54,155 [4]
Loaned securities and securities sold under repurchase agreements | Level II | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 3,428  
Loaned securities and securities sold under repurchase agreements | Level II | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 2,471  
Loaned securities and securities sold under repurchase agreements | Level III | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [4]   0
Loaned securities and securities sold under repurchase agreements | Level III | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 0 [3] 0 [4]
Loaned securities and securities sold under repurchase agreements | Level III | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 0  
Loaned securities and securities sold under repurchase agreements | Level III | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements [3] 0  
Fixed-maturities available for sale | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 6,226,793 4,271,916
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 278,838 116,713
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 215,590 167,126
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 3,077,524 1,957,005
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,327,021 884,258
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 336,999 241,444
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 502,490 376,847
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 485,783 481,718
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | Mortgage insurance-linked notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,429 [5] 45,689 [6]
Fixed-maturities available for sale | Fair Value, Measurements, Recurring | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,119 1,116
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 277,604 115,189
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 277,604 115,189
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | Mortgage insurance-linked notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 [5] 0 [6]
Fixed-maturities available for sale | Level I | Fair Value, Measurements, Recurring | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 5,949,189 4,156,727
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,234 1,524
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 215,590 167,126
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 3,077,524 1,957,005
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,327,021 884,258
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 336,999 241,444
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 502,490 376,847
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 485,783 481,718
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | Mortgage insurance-linked notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,429 [5] 45,689 [6]
Fixed-maturities available for sale | Level II | Fair Value, Measurements, Recurring | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,119 1,116
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | RMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | CLO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | Mortgage insurance-linked notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 [5] 0 [6]
Fixed-maturities available for sale | Level III | Fair Value, Measurements, Recurring | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 44,951 65,661
Trading securities | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 25,684 35,912
Trading securities | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 15,207 24,791
Trading securities | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 4,060 4,958
Trading securities | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level I | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level I | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level I | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 44,951 65,661
Trading securities | Level II | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 25,684 35,912
Trading securities | Level II | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 15,207 24,791
Trading securities | Level II | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 4,060 4,958
Trading securities | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level III | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level III | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Trading securities | Level III | Fair Value, Measurements, Recurring | CMBS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Equity securities | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 32,411 36,632
Equity securities | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 22,074 29,630
Equity securities | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 6,291 2,956
Equity securities | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 4,046 4,046
Equity securities | Loaned securities and securities sold under repurchase agreements | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 28,518 [3] 22,893 [4]
Equity securities | Loaned securities and securities sold under repurchase agreements | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 28,518 [3] 22,893 [4]
Equity securities | Loaned securities and securities sold under repurchase agreements | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 0 [3] 0 [4]
Equity securities | Loaned securities and securities sold under repurchase agreements | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loaned securities and securities sold under repurchase agreements 0 [3] 0 [4]
Other invested assets | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 56,299 [1],[7] 7,089 [2],[8]
Other invested assets | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 49,199 [1],[7] 0 [2],[8]
Other invested assets | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 [1],[7] 0 [8]
Other invested assets | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 7,100 [1],[7] 7,089 [2],[8]
Short-term investments | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 622,900 1,602,993
Short-term investments | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 22,058 429,722
Short-term investments | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 12,841  
Short-term investments | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 70,581 11,729
Short-term investments | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 11,019 2,447
Short-term investments | Fair Value, Measurements, Recurring | Other investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 45,491 [9] 939,711 [10]
Short-term investments | Fair Value, Measurements, Recurring | Money market instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 460,910 219,384
Short-term investments | Level I | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 482,335 574,289
Short-term investments | Level I | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 20,943 354,905
Short-term investments | Level I | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0  
Short-term investments | Level I | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level I | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level I | Fair Value, Measurements, Recurring | Other investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 482 [9] 0 [10]
Short-term investments | Level I | Fair Value, Measurements, Recurring | Money market instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 460,910 219,384
Short-term investments | Level II | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 140,565 1,028,704
Short-term investments | Level II | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 1,115 74,817
Short-term investments | Level II | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 12,841  
Short-term investments | Level II | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 70,581 11,729
Short-term investments | Level II | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 11,019 2,447
Short-term investments | Level II | Fair Value, Measurements, Recurring | Other investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 45,009 [9] 939,711 [10]
Short-term investments | Level II | Fair Value, Measurements, Recurring | Money market instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level III | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level III | Fair Value, Measurements, Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level III | Fair Value, Measurements, Recurring | State and municipal obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0  
Short-term investments | Level III | Fair Value, Measurements, Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level III | Fair Value, Measurements, Recurring | Other ABS    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Short-term investments | Level III | Fair Value, Measurements, Recurring | Other investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 [9] 0 [10]
Short-term investments | Level III | Fair Value, Measurements, Recurring | Money market instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total investments at fair value 0 0
Partnership investments | Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other invested assets—at fair value $ 3 $ 3
[1] Does not include other invested assets of $3 million that are primarily invested in limited partnership investments valued using the net asset value as a practical expedient.
[2] Does not include other invested assets of $3 million that are primarily invested in limited partnership investments valued using the net asset value as a practical expedient.
[3] Securities loaned to third-party borrowers under securities lending agreements or sold under repurchase agreements are classified as other assets on our condensed consolidated balance sheets. See Note 7 for more information on our securities lending and repurchase agreements.
[4] Securities loaned to third-party borrowers under securities lending agreements are classified as other assets on our condensed consolidated balance sheets. See Note 7 for more information on our securities lending agreements.
[5] Includes mortgage insurance-linked notes purchased by Radian Group in connection with the Mortgage XOL Program. See Note 8 for more information.
[6] Includes mortgage insurance-linked notes purchased by Radian Group in connection with the Mortgage XOL Program. See Note 8 for more information.
[7] Consists primarily of Lloyd’s overseas deposits, which are deposits held to provide security for the payment of policyholder claims in certain overseas jurisdictions. See Note 7 for additional information about our Lloyd’s overseas deposits.
[8] Consists primarily of interests in private debt and equity investments.
[9] Primarily consists of commercial paper.
[10] Consists of commercial paper.