v3.26.1
Investment Information - Summary of available for sale securities (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value $ 36,453   $ 35,051      
Gross Unrealized Gains 159   408      
Gross Unrealized Losses (415)   (290)      
Allowance for Expected Credit Losses (16)   (20)      
Cost or Amortized Cost 36,725   34,953      
Fixed maturities            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 33,155   32,426      
Gross Unrealized Gains 158   406      
Gross Unrealized Losses (414)   (289)      
Allowance for Expected Credit Losses (16) $ (13) (20) $ (28) $ (21) $ (22)
Cost or Amortized Cost 33,427   32,329      
Corporate bonds            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 14,231   14,058      
Gross Unrealized Gains 102   265      
Gross Unrealized Losses (198)   (142)      
Allowance for Expected Credit Losses (6) (6) (10) (16) (12) (12)
Cost or Amortized Cost 14,333   13,945      
U.S. government and government agencies            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 8,060   7,445      
Gross Unrealized Gains 8   23      
Gross Unrealized Losses (64)   (21)      
Allowance for Expected Credit Losses 0   0      
Cost or Amortized Cost 8,116   7,443      
Asset backed securities            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 3,677   3,574      
Gross Unrealized Gains 6   20      
Gross Unrealized Losses (26)   (15)      
Allowance for Expected Credit Losses (9)   (8)      
Cost or Amortized Cost 3,706   3,577      
Non-U.S. government securities            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 2,876   3,270      
Gross Unrealized Gains 26   53      
Gross Unrealized Losses (77)   (81)      
Allowance for Expected Credit Losses (1) $ (1) (1) $ (2) $ (1) $ (1)
Cost or Amortized Cost 2,928   3,299      
Residential mortgage backed securities            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 2,643   2,705      
Gross Unrealized Gains 11   34      
Gross Unrealized Losses (38)   (21)      
Allowance for Expected Credit Losses 0   0      
Cost or Amortized Cost 2,670   2,692      
Commercial mortgage backed securities            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 1,549   1,212      
Gross Unrealized Gains 5   11      
Gross Unrealized Losses (7)   (5)      
Allowance for Expected Credit Losses 0   (1)      
Cost or Amortized Cost 1,551   1,207      
Municipal bonds            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 119   162      
Gross Unrealized Gains 0   0      
Gross Unrealized Losses (4)   (4)      
Allowance for Expected Credit Losses 0   0      
Cost or Amortized Cost 123   166      
Short-term investments            
Debt Securities, Available-for-sale [Line Items]            
Estimated Fair Value 3,298   2,625      
Gross Unrealized Gains 1   2      
Gross Unrealized Losses (1)   (1)      
Allowance for Expected Credit Losses 0   0      
Cost or Amortized Cost $ 3,298   $ 2,624