v3.26.1
Fair Value - Summary of Changes in Fair Value Associated with Level 3 Assets (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance $ 95 $ 105 $ 105 $ 105
Calls/ Maturities/ Paydowns/ Other 2 1 3 7
Purchases 150 0 150 8
Sales 0 0 (5) 0
Net Realized (Gain)/Loss on Sales 0 0 (7) 0
Change in Valuation 3 0 4 (14)
Net Transfers In (Out) 0 0 0 0
Fair value, ending balance 250 106 250 106
Corporate and other debt        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance 4 5 4 5
Calls/ Maturities/ Paydowns/ Other 0 0 0 0
Purchases 0 0 0 0
Sales 0 0 0 0
Net Realized (Gain)/Loss on Sales 0 0 0 0
Change in Valuation 0 0 0 0
Net Transfers In (Out) 0 0 0 0
Fair value, ending balance 4 5 4 5
Nonredeemable preferred stocks        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance 49 60 60 52
Calls/ Maturities/ Paydowns/ Other 0 0 0 0
Purchases 0 0 0 8
Sales 0 0 (5) 0
Net Realized (Gain)/Loss on Sales 0 0 (7) 0
Change in Valuation 0 0 1 0
Net Transfers In (Out) 0 0 0 0
Fair value, ending balance 49 60 49 60
Common equities | Common Stocks, excluding Other Risk        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance 5 9 5 23
Calls/ Maturities/ Paydowns/ Other 0 0 0 0
Purchases 0 0 0 0
Sales 0 0 0 0
Net Realized (Gain)/Loss on Sales 0 0 0 0
Change in Valuation 3 0 3 (14)
Net Transfers In (Out) 0 0 0 0
Fair value, ending balance 8 9 8 9
Common equities | Other risk investments        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance 37 31 36 25
Calls/ Maturities/ Paydowns/ Other 2 1 3 7
Purchases 0 0 0 0
Sales 0 0 0 0
Net Realized (Gain)/Loss on Sales 0 0 0 0
Change in Valuation 0 0 0 0
Net Transfers In (Out) 0 0 0 0
Fair value, ending balance 39 $ 32 39 $ 32
Other asset-backed        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value, beginning balance 0   0  
Calls/ Maturities/ Paydowns/ Other 0   0  
Purchases 150   150  
Sales 0   0  
Net Realized (Gain)/Loss on Sales 0   0  
Change in Valuation 0   0  
Net Transfers In (Out) 0   0  
Fair value, ending balance $ 150   $ 150