v3.26.1
Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Assets    
Fixed income securities, at fair value $ 60,809 $ 59,115
Equity securities 11,159 8,398
Short-term investments 4,872 4,887
Other investments 1,153 1,114
Total assets at fair value 76,470 72,025
Counterparty and cash collateral netting (6) (1)
Total 77,533 73,291
Liabilities    
Preferred stock measured at cost 101 99
Equity Method Investments 479 466
Equity securities 10,071 8,026
U.S. government and agencies    
Assets    
Fixed income securities, at fair value 12,351 18,133
Municipal    
Assets    
Fixed income securities, at fair value 6,334 5,643
Foreign government    
Assets    
Fixed income securities, at fair value 1,625 1,460
ABS    
Assets    
Fixed income securities, at fair value 1,971 1,352
MBS    
Assets    
Fixed income securities, at fair value 2,121 2,126
Recurring basis    
Assets    
Fixed income securities, at fair value 60,809 59,115
Equity securities 10,579 7,833
Short-term investments 4,872 4,887
Other investments 14 11
Other investments (6) (1)
Other assets 135 147
Total assets at fair value 76,409 71,993
Counterparty and cash collateral netting (6) (1)
Liabilities    
Other liabilities (6) (3)
Other liabilities 6 19
Counterparty and cash collateral netting 6 19
Total recurring basis liabilities (6) (3)
Recurring basis | U.S. government and agencies    
Assets    
Fixed income securities, at fair value 12,351 18,133
Recurring basis | Municipal    
Assets    
Fixed income securities, at fair value 6,334 5,643
Recurring basis | Corporate - public    
Assets    
Fixed income securities, at fair value 23,514 19,919
Recurring basis | Corporate - privately placed    
Assets    
Fixed income securities, at fair value 12,893 10,482
Recurring basis | Foreign government    
Assets    
Fixed income securities, at fair value 1,625 1,460
Recurring basis | ABS    
Assets    
Fixed income securities, at fair value 1,971 1,352
Recurring basis | MBS    
Assets    
Fixed income securities, at fair value 2,121 2,126
Non-recurring basis    
Assets    
Total assets at fair value 61 32
Quoted prices in active markets for identical assets (Level 1)    
Assets    
Total assets at fair value 24,250 27,487
Quoted prices in active markets for identical assets (Level 1) | Recurring basis    
Assets    
Fixed income securities, at fair value 12,351 18,124
Equity securities 10,347 7,572
Short-term investments 1,547 1,791
Other investments 0 0
Other assets 5 0
Total assets at fair value 24,250 27,487
Liabilities    
Other liabilities (5) (2)
Total recurring basis liabilities (5) (2)
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | U.S. government and agencies    
Assets    
Fixed income securities, at fair value 12,351 18,124
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | Municipal    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | Corporate - public    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | Corporate - privately placed    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | Foreign government    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | ABS    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Recurring basis | MBS    
Assets    
Fixed income securities, at fair value 0 0
Quoted prices in active markets for identical assets (Level 1) | Non-recurring basis    
Assets    
Total assets at fair value 0 0
Significant other observable inputs (Level 2)    
Assets    
Total assets at fair value 51,666 44,023
Significant other observable inputs (Level 2) | Recurring basis    
Assets    
Fixed income securities, at fair value 48,114 40,683
Equity securities 214 239
Short-term investments 3,319 3,090
Other investments 19 11
Other assets 0 0
Total assets at fair value 51,666 44,023
Liabilities    
Other liabilities (7) (19)
Total recurring basis liabilities (7) (19)
Significant other observable inputs (Level 2) | Recurring basis | U.S. government and agencies    
Assets    
Fixed income securities, at fair value 0 9
Significant other observable inputs (Level 2) | Recurring basis | Municipal    
Assets    
Fixed income securities, at fair value 6,331 5,614
Significant other observable inputs (Level 2) | Recurring basis | Corporate - public    
Assets    
Fixed income securities, at fair value 23,502 19,907
Significant other observable inputs (Level 2) | Recurring basis | Corporate - privately placed    
Assets    
Fixed income securities, at fair value 12,726 10,295
Significant other observable inputs (Level 2) | Recurring basis | Foreign government    
Assets    
Fixed income securities, at fair value 1,625 1,460
Significant other observable inputs (Level 2) | Recurring basis | ABS    
Assets    
Fixed income securities, at fair value 1,878 1,330
Significant other observable inputs (Level 2) | Recurring basis | MBS    
Assets    
Fixed income securities, at fair value 2,052 2,068
Significant other observable inputs (Level 2) | Non-recurring basis    
Assets    
Total assets at fair value 0 0
Significant unobservable inputs (Level 3)    
Assets    
Total assets at fair value 560 516
Significant unobservable inputs (Level 3) | Recurring basis    
Assets    
Fixed income securities, at fair value 344 308
Equity securities 18 22
Short-term investments 6 6
Other investments 1 1
Other assets 130 147
Total assets at fair value 499 484
Liabilities    
Other liabilities 0 (1)
Total recurring basis liabilities 0 (1)
Significant unobservable inputs (Level 3) | Recurring basis | U.S. government and agencies    
Assets    
Fixed income securities, at fair value 0 0
Significant unobservable inputs (Level 3) | Recurring basis | Municipal    
Assets    
Fixed income securities, at fair value 3 29
Significant unobservable inputs (Level 3) | Recurring basis | Corporate - public    
Assets    
Fixed income securities, at fair value 12 12
Significant unobservable inputs (Level 3) | Recurring basis | Corporate - privately placed    
Assets    
Fixed income securities, at fair value 167 187
Significant unobservable inputs (Level 3) | Recurring basis | Foreign government    
Assets    
Fixed income securities, at fair value 0 0
Significant unobservable inputs (Level 3) | Recurring basis | ABS    
Assets    
Fixed income securities, at fair value 93 22
Significant unobservable inputs (Level 3) | Recurring basis | MBS    
Assets    
Fixed income securities, at fair value 69 58
Significant unobservable inputs (Level 3) | Non-recurring basis    
Assets    
Total assets at fair value 61 32
Reported to NAV    
Assets    
Investments reported at NAV 1,063 1,266
Liabilities    
Equity securities 479 466
Limited partnerships $ 584 $ 800