v3.26.1
Fair Value Measurements - Changes in Level 3 Recurring Fair Value Measurements, Assets (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Assets:        
Fair Value Beginning of Period $ 3,604,000,000 $ 3,133,000,000 $ 3,898,000,000 $ 3,481,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 10,000,000 20,000,000 16,000,000 24,000,000
Other Comprehensive Income (Loss) (14,000,000) 21,000,000 (54,000,000) 65,000,000
Purchases 433,000,000 419,000,000 593,000,000 582,000,000
Sales (161,000,000) (48,000,000) (212,000,000) (100,000,000)
Issuances and Settlements (154,000,000) (107,000,000) (367,000,000) (344,000,000)
Gross Transfers In 34,000,000 52,000,000 48,000,000 99,000,000
Gross Transfers Out (19,000,000) (33,000,000) (59,000,000) (350,000,000)
Other (37,000,000) 0 (167,000,000) 0
Fair Value End of Period 3,696,000,000 3,457,000,000 3,696,000,000 3,457,000,000
Total net realized losses (265,000,000) (258,000,000) (400,000,000) (361,000,000)
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period (1,000,000) 2,000,000 (3,000,000) 7,000,000
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period $ (15,000,000) $ 1,000,000 $ (65,000,000) $ 34,000,000
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Revenues Revenues Revenues Revenues
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Other comprehensive (loss) income Other comprehensive (loss) income Other comprehensive (loss) income Other comprehensive (loss) income
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Total net realized losses  
Issuances, assets $ 0 $ 0 $ 0 $ 0
Issuances, liabilities 0 0 0 0
Assets        
Assets:        
Total net realized losses 0 10,000,000 1,000,000 1,000,000
Bonds available for sale        
Assets:        
Fair Value Beginning of Period 3,290,000,000 2,722,000,000 3,451,000,000 3,010,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 8,000,000 15,000,000 16,000,000 14,000,000
Other Comprehensive Income (Loss) (14,000,000) 21,000,000 (54,000,000) 65,000,000
Purchases 415,000,000 396,000,000 558,000,000 545,000,000
Sales (118,000,000) (35,000,000) (155,000,000) (83,000,000)
Issuances and Settlements (149,000,000) (99,000,000) (358,000,000) (307,000,000)
Gross Transfers In 34,000,000 49,000,000 48,000,000 56,000,000
Gross Transfers Out (19,000,000) (33,000,000) (59,000,000) (264,000,000)
Other (19,000,000) (21,000,000) (19,000,000) (21,000,000)
Fair Value End of Period 3,428,000,000 3,015,000,000 3,428,000,000 3,015,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 0 0 0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period (15,000,000) 1,000,000 (65,000,000) 34,000,000
Bonds available for sale | Obligations of states, municipalities and political subdivisions        
Assets:        
Fair Value Beginning of Period 4,000,000 3,000,000 4,000,000 3,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 0 0 0
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 0 2,000,000  
Sales (1,000,000) 0 (1,000,000)  
Issuances and Settlements   0    
Gross Transfers In 0 0 0 0
Gross Transfers Out 0 0 0 0
Other 0 0 0 0
Fair Value End of Period 5,000,000 3,000,000 5,000,000 3,000,000
Bonds available for sale | Non-U.S. governments        
Assets:        
Fair Value Beginning of Period 7,000,000 7,000,000 23,000,000 7,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 0 1,000,000 0
Other Comprehensive Income (Loss) 0 0 0 0
Purchases   0 3,000,000  
Sales   0 (3,000,000)  
Issuances and Settlements   (1,000,000) (3,000,000) (1,000,000)
Gross Transfers In 0 0 0 0
Gross Transfers Out 0 0 (14,000,000) 0
Other (7,000,000) 0 (7,000,000) 0
Fair Value End of Period 0 6,000,000 0 6,000,000
Bonds available for sale | Corporate debt        
Assets:        
Fair Value Beginning of Period 85,000,000 115,000,000 113,000,000 240,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 1,000,000 1,000,000 1,000,000 (8,000,000)
Other Comprehensive Income (Loss) (6,000,000) 1,000,000 (8,000,000) 11,000,000
Purchases 2,000,000 2,000,000 6,000,000 5,000,000
Sales (2,000,000) (2,000,000) (7,000,000) (6,000,000)
Issuances and Settlements (1,000,000) (26,000,000) (1,000,000) (150,000,000)
Gross Transfers In 8,000,000 49,000,000 9,000,000 49,000,000
Gross Transfers Out 0 (31,000,000) (26,000,000) (32,000,000)
Other (11,000,000) 38,000,000 (11,000,000) 38,000,000
Fair Value End of Period 76,000,000 147,000,000 76,000,000 147,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 0 0 0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period (5,000,000) (6,000,000) (7,000,000) 0
Bonds available for sale | RMBS        
Assets:        
Fair Value Beginning of Period 1,486,000,000 1,656,000,000 1,546,000,000 1,894,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 7,000,000 8,000,000 13,000,000 15,000,000
Other Comprehensive Income (Loss) (4,000,000) 9,000,000 (41,000,000) 42,000,000
Purchases 5,000,000 8,000,000 14,000,000 8,000,000
Sales 0 0 0 (3,000,000)
Issuances and Settlements (45,000,000) (47,000,000) (91,000,000) (101,000,000)
Gross Transfers In 0 0 8,000,000 3,000,000
Gross Transfers Out 0 (1,000,000) 0 (225,000,000)
Other 1,000,000 0 1,000,000 0
Fair Value End of Period 1,450,000,000 1,633,000,000 1,450,000,000 1,633,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 0 0 0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period (4,000,000) (2,000,000) (41,000,000) 15,000,000
Bonds available for sale | CMBS        
Assets:        
Fair Value Beginning of Period 25,000,000 26,000,000 24,000,000 26,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (1,000,000) 1,000,000 (1,000,000) 1,000,000
Other Comprehensive Income (Loss) 1,000,000 1,000,000 1,000,000 1,000,000
Purchases 0 0 0 0
Sales (6,000,000) 0 (8,000,000) (4,000,000)
Issuances and Settlements 0 (1,000,000) (2,000,000) (1,000,000)
Gross Transfers In 20,000,000 0 25,000,000 4,000,000
Gross Transfers Out 0 (1,000,000) 0 (1,000,000)
Other 0 0 0 0
Fair Value End of Period 39,000,000 26,000,000 39,000,000 26,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 0 0 0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 1,000,000 0 0 0
Bonds available for sale | CLO/ABS        
Assets:        
Fair Value Beginning of Period 1,683,000,000 915,000,000 1,741,000,000 840,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 1,000,000 5,000,000 2,000,000 6,000,000
Other Comprehensive Income (Loss) (5,000,000) 10,000,000 (6,000,000) 11,000,000
Purchases 406,000,000 386,000,000 533,000,000 532,000,000
Sales (109,000,000) (33,000,000) (136,000,000) (70,000,000)
Issuances and Settlements (103,000,000) (24,000,000) (261,000,000) (54,000,000)
Gross Transfers In 6,000,000 0 6,000,000 0
Gross Transfers Out (19,000,000) 0 (19,000,000) (6,000,000)
Other (2,000,000) (59,000,000) (2,000,000) (59,000,000)
Fair Value End of Period 1,858,000,000 1,200,000,000 1,858,000,000 1,200,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 0 0 0
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period (7,000,000) 9,000,000 (17,000,000) 19,000,000
Other bond securities        
Assets:        
Fair Value Beginning of Period 167,000,000 171,000,000 170,000,000 164,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (1,000,000) 2,000,000 (1,000,000) 6,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 1,000,000 2,000,000 1,000,000
Sales (9,000,000) 0 (9,000,000) 0
Issuances and Settlements (4,000,000) (2,000,000) (7,000,000) (7,000,000)
Gross Transfers In 0 2,000,000 0 33,000,000
Gross Transfers Out 0 0 0 (23,000,000)
Other 3,000,000 0 3,000,000 0
Fair Value End of Period 158,000,000 174,000,000 158,000,000 174,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 1,000,000 (1,000,000) 6,000,000
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 0 0 0 0
Other bond securities | Corporate debt        
Assets:        
Fair Value Beginning of Period   1,000,000   1,000,000
Net Realized and Unrealized Gains (Losses) Included in Income   0   0
Other Comprehensive Income (Loss)   0   0
Gross Transfers In   0   0
Gross Transfers Out   0   0
Other   0   0
Fair Value End of Period   1,000,000   1,000,000
Other bond securities | RMBS        
Assets:        
Fair Value Beginning of Period 50,000,000 50,000,000 51,000,000 50,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 1,000,000 0 2,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 0 2,000,000 0
Sales 0 0 0 0
Issuances and Settlements (1,000,000) (1,000,000) (2,000,000) (2,000,000)
Gross Transfers In 0 0 0 0
Gross Transfers Out 0 0 0 0
Other 2,000,000 0 2,000,000 0
Fair Value End of Period 53,000,000 50,000,000 53,000,000 50,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 1,000,000 0 1,000,000 1,000,000
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 0 0 0 0
Other bond securities | CLO/ABS        
Assets:        
Fair Value Beginning of Period 117,000,000 120,000,000 119,000,000 113,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (1,000,000) 1,000,000 (1,000,000) 4,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 0 1,000,000 0 1,000,000
Sales (9,000,000) 0 (9,000,000) 0
Issuances and Settlements (3,000,000) (1,000,000) (5,000,000) (5,000,000)
Gross Transfers In 0 2,000,000 0 33,000,000
Gross Transfers Out 0 0 0 (23,000,000)
Other 1,000,000 0 1,000,000 0
Fair Value End of Period 105,000,000 123,000,000 105,000,000 123,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period (1,000,000) 1,000,000 (2,000,000) 5,000,000
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 0 0 0 0
Equity securities        
Assets:        
Fair Value Beginning of Period 54,000,000 35,000,000 55,000,000 15,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 3,000,000 3,000,000 0 4,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 14,000,000 21,000,000 30,000,000 35,000,000
Sales (34,000,000) (13,000,000) (48,000,000) (17,000,000)
Issuances and Settlements 0 0 0 0
Gross Transfers In 0 0 0 9,000,000
Gross Transfers Out 0 0 0 0
Other (23,000,000) 0 (23,000,000) 0
Fair Value End of Period 14,000,000 46,000,000 14,000,000 46,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period (1,000,000) 2,000,000 (3,000,000) 2,000,000
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 0 0 0 0
Other invested assets        
Assets:        
Fair Value Beginning of Period 93,000,000 76,000,000 92,000,000 163,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 0 1,000,000 0
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 1,000,000 3,000,000 1,000,000
Sales 0 0 0 0
Issuances and Settlements (1,000,000) (6,000,000) (2,000,000) (30,000,000)
Gross Transfers In 0 1,000,000 0 1,000,000
Gross Transfers Out 0 0 0 (63,000,000)
Other 2,000,000 21,000,000 2,000,000 21,000,000
Fair Value End of Period 96,000,000 93,000,000 96,000,000 93,000,000
Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period 0 (1,000,000) 1,000,000 (1,000,000)
Changes in Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss) for Recurring Level 3 Instruments Held at End of Period 0 0 0 0
Other assets        
Assets:        
Fair Value Beginning of Period   129,000,000 130,000,000 129,000,000
Net Realized and Unrealized Gains (Losses) Included in Income   0 0 0
Other Comprehensive Income (Loss)   0 0 0
Purchases   0    
Sales   0    
Issuances and Settlements   0    
Gross Transfers In   0 0 0
Gross Transfers Out   0 0 0
Other   0 (130,000,000) 0
Fair Value End of Period $ 0 $ 129,000,000 $ 0 $ 129,000,000