v3.26.3
Fair Value Measurements - Changes in Level 3 Recurring Fair Value Measurements, Assets (Details) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Assets:        
Fair Value Beginning of Period $ 3,696,000,000 $ 3,457,000,000 $ 3,898,000,000 $ 3,481,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (16,000,000) (1,000,000) 0 23,000,000
Other Comprehensive Income (Loss) (67,000,000) 7,000,000 (121,000,000) 72,000,000
Purchases 431,000,000 524,000,000 1,024,000,000 1,106,000,000
Sales (144,000,000) (32,000,000) (356,000,000) (132,000,000)
Issuances and Settlements (110,000,000) (205,000,000) (477,000,000) (549,000,000)
Gross Transfers In 25,000,000 9,000,000 73,000,000 108,000,000
Gross Transfers Out (92,000,000) (26,000,000) (151,000,000) (376,000,000)
Other 0 0 (167,000,000) 0
Fair Value End of Period 3,723,000,000 3,733,000,000 3,723,000,000 3,733,000,000
Total net realized losses $ (110,000,000) $ (490,000,000) $ (510,000,000) $ (851,000,000)
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
Issuances, assets $ 0 $ 0 $ 0 $ 0
Issuances, liabilities 0 0 0 0
Assets        
Assets:        
Total net realized losses (8,000,000) (7,000,000) (7,000,000) (6,000,000)
Bonds available for sale        
Assets:        
Fair Value Beginning of Period 3,428,000,000 3,015,000,000 3,451,000,000 3,010,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 2,000,000 1,000,000 18,000,000 15,000,000
Other Comprehensive Income (Loss) (67,000,000) 7,000,000 (121,000,000) 72,000,000
Purchases 362,000,000 483,000,000 920,000,000 1,028,000,000
Sales (142,000,000) (16,000,000) (297,000,000) (99,000,000)
Issuances and Settlements (108,000,000) (203,000,000) (466,000,000) (510,000,000)
Gross Transfers In 25,000,000 1,000,000 73,000,000 57,000,000
Gross Transfers Out (92,000,000) (24,000,000) (151,000,000) (288,000,000)
Other 0 0 (19,000,000) (21,000,000)
Fair Value End of Period 3,408,000,000 3,264,000,000 3,408,000,000 3,264,000,000
Bonds available for sale | Obligations of states, municipalities and political subdivisions        
Assets:        
Fair Value Beginning of Period 5,000,000 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) (1,000,000) 0 (1,000,000) 0
Purchases 0 0 2,000,000 0
Sales 0 0 (1,000,000) 0
Issuances and Settlements 0 0 0 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 4,000,000 3,000,000 4,000,000 3,000,000
Bonds available for sale | Non-U.S. governments        
Assets:        
Fair Value Beginning of Period   6,000,000 23,000,000 7,000,000
Net Realized and Unrealized Gains (Losses) Included in Income   0 1,000,000 0
Other Comprehensive Income (Loss)   0 0 0
Purchases   0 3,000,000 0
Sales   0 (3,000,000) 0
Issuances and Settlements   0 (3,000,000) (1,000,000)
Gross Transfers In   1,000,000 0 1,000,000
Gross Transfers Out   0 (14,000,000) 0
Other   0 (7,000,000) 0
Fair Value End of Period 0 7,000,000 0 7,000,000
Bonds available for sale | Corporate debt        
Assets:        
Fair Value Beginning of Period 76,000,000 147,000,000 113,000,000 240,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (3,000,000) (2,000,000) (2,000,000) (10,000,000)
Other Comprehensive Income (Loss) 9,000,000 (15,000,000) 1,000,000 (4,000,000)
Purchases 0 0 6,000,000 5,000,000
Sales 0 (2,000,000) (7,000,000) (8,000,000)
Issuances and Settlements (4,000,000) (2,000,000) (5,000,000) (152,000,000)
Gross Transfers In 0 0 9,000,000 49,000,000
Gross Transfers Out (44,000,000) (6,000,000) (70,000,000) (38,000,000)
Other 0 0 (11,000,000) 38,000,000
Fair Value End of Period 34,000,000 120,000,000 34,000,000 120,000,000
Bonds available for sale | RMBS        
Assets:        
Fair Value Beginning of Period 1,450,000,000 1,633,000,000 1,546,000,000 1,894,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 7,000,000 7,000,000 20,000,000 22,000,000
Other Comprehensive Income (Loss) (42,000,000) 8,000,000 (83,000,000) 50,000,000
Purchases 0 46,000,000 14,000,000 54,000,000
Sales (15,000,000) 0 (15,000,000) (3,000,000)
Issuances and Settlements (48,000,000) (51,000,000) (139,000,000) (152,000,000)
Gross Transfers In 0 0 8,000,000 3,000,000
Gross Transfers Out (2,000,000) (17,000,000) (2,000,000) (242,000,000)
Other 0 0 1,000,000 0
Fair Value End of Period 1,350,000,000 1,626,000,000 1,350,000,000 1,626,000,000
Bonds available for sale | CMBS        
Assets:        
Fair Value Beginning of Period 39,000,000 26,000,000 24,000,000 26,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 (5,000,000) (1,000,000) (4,000,000)
Other Comprehensive Income (Loss) 0 5,000,000 1,000,000 6,000,000
Purchases 14,000,000 0 14,000,000 0
Sales 0 0 (8,000,000) (4,000,000)
Issuances and Settlements 0 (4,000,000) (2,000,000) (5,000,000)
Gross Transfers In 0 0 25,000,000 4,000,000
Gross Transfers Out (3,000,000) 0 (3,000,000) (1,000,000)
Other (20,000,000) 0 (20,000,000) 0
Fair Value End of Period 30,000,000 22,000,000 30,000,000 22,000,000
Bonds available for sale | CLO/ABS        
Assets:        
Fair Value Beginning of Period 1,858,000,000 1,200,000,000 1,741,000,000 840,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (2,000,000) 1,000,000 0 7,000,000
Other Comprehensive Income (Loss) (33,000,000) 9,000,000 (39,000,000) 20,000,000
Purchases 348,000,000 437,000,000 881,000,000 969,000,000
Sales (127,000,000) (14,000,000) (263,000,000) (84,000,000)
Issuances and Settlements (56,000,000) (146,000,000) (317,000,000) (200,000,000)
Gross Transfers In 25,000,000 0 31,000,000 0
Gross Transfers Out (43,000,000) (1,000,000) (62,000,000) (7,000,000)
Other 20,000,000 0 18,000,000 (59,000,000)
Fair Value End of Period 1,990,000,000 1,486,000,000 1,990,000,000 1,486,000,000
Other bond securities        
Assets:        
Fair Value Beginning of Period 158,000,000 174,000,000 170,000,000 164,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (1,000,000) 1,000,000 (2,000,000) 7,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 14,000,000 4,000,000 15,000,000
Sales (1,000,000) 0 (10,000,000) 0
Issuances and Settlements (2,000,000) (1,000,000) (9,000,000) (8,000,000)
Gross Transfers In 0 0 0 33,000,000
Gross Transfers Out 0 (2,000,000) 0 (25,000,000)
Other 0 0 3,000,000 0
Fair Value End of Period 156,000,000 186,000,000 156,000,000 186,000,000
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
Purchases   0   0
Sales   0   0
Issuances and Settlements   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 53,000,000 50,000,000 51,000,000 50,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (1,000,000) 0 (1,000,000) 2,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 0 3,000,000 2,000,000 3,000,000
Sales (1,000,000) 0 (1,000,000) 0
Issuances and Settlements (1,000,000) 0 (3,000,000) (2,000,000)
Gross Transfers In 0 0 0 0
Gross Transfers Out 0 0 0 0
Other 0 0 2,000,000 0
Fair Value End of Period 50,000,000 53,000,000 50,000,000 53,000,000
Other bond securities | CLO/ABS        
Assets:        
Fair Value Beginning of Period 105,000,000 123,000,000 119,000,000 113,000,000
Net Realized and Unrealized Gains (Losses) Included in Income 0 1,000,000 (1,000,000) 5,000,000
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 2,000,000 11,000,000 2,000,000 12,000,000
Sales 0 0 (9,000,000) 0
Issuances and Settlements (1,000,000) (1,000,000) (6,000,000) (6,000,000)
Gross Transfers In 0 0 0 33,000,000
Gross Transfers Out 0 (2,000,000) 0 (25,000,000)
Other 0 0 1,000,000 0
Fair Value End of Period 106,000,000 132,000,000 106,000,000 132,000,000
Equity securities        
Assets:        
Fair Value Beginning of Period 14,000,000 46,000,000 55,000,000 15,000,000
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 67,000,000 21,000,000 97,000,000 56,000,000
Sales (1,000,000) (16,000,000) (49,000,000) (33,000,000)
Issuances and Settlements 0 0 0 0
Gross Transfers In 0 8,000,000 0 17,000,000
Gross Transfers Out 0 0 0 0
Other 0 0 (23,000,000) 0
Fair Value End of Period 81,000,000 61,000,000 81,000,000 61,000,000
Other invested assets        
Assets:        
Fair Value Beginning of Period 96,000,000 93,000,000 92,000,000 163,000,000
Net Realized and Unrealized Gains (Losses) Included in Income (18,000,000) (5,000,000) (17,000,000) (5,000,000)
Other Comprehensive Income (Loss) 0 0 0 0
Purchases 0 6,000,000 3,000,000 7,000,000
Sales 0 0 0 0
Issuances and Settlements 0 (1,000,000) (2,000,000) (31,000,000)
Gross Transfers In 0 0 0 1,000,000
Gross Transfers Out 0 0 0 (63,000,000)
Other 0 0 2,000,000 21,000,000
Fair Value End of Period 78,000,000 93,000,000 78,000,000 93,000,000
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 0 0
Sales   0 0 0
Issuances and Settlements   0 0 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