v3.26.3
Investments - Available-for-Sale Investments (Details)
$ in Millions
Sep. 30, 2026
USD ($)
position
Dec. 31, 2025
USD ($)
position
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 2,973 $ 106
In a continuous loss position for less than 12 Months, gross unrealized losses $ 91 $ 1
In a continuous loss position for less than 12 Months, total number of positions | position 1,999 83
In a continuous loss position for 12 Months or more, estimated fair value $ 459 $ 823
In a continuous loss position for 12 Months or more, gross unrealized losses $ 36 $ 31
In a continuous loss position for 12 Months or more, total number of positions | position 345 523
Corporate debt securities    
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 1,936 $ 106
In a continuous loss position for less than 12 Months, gross unrealized losses $ 57 $ 1
In a continuous loss position for less than 12 Months, total number of positions | position 1,172 83
In a continuous loss position for 12 Months or more, estimated fair value $ 160 $ 372
In a continuous loss position for 12 Months or more, gross unrealized losses $ 4 $ 6
In a continuous loss position for 12 Months or more, total number of positions | position 109 205
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 628 $ 0
In a continuous loss position for less than 12 Months, gross unrealized losses $ 26 $ 0
In a continuous loss position for less than 12 Months, total number of positions | position 477 0
In a continuous loss position for 12 Months or more, estimated fair value $ 214 $ 315
In a continuous loss position for 12 Months or more, gross unrealized losses $ 28 $ 21
In a continuous loss position for 12 Months or more, total number of positions | position 166 212
Asset-backed securities    
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 300 $ 0
In a continuous loss position for less than 12 Months, gross unrealized losses $ 4 $ 0
In a continuous loss position for less than 12 Months, total number of positions | position 161 0
In a continuous loss position for 12 Months or more, estimated fair value $ 42 $ 80
In a continuous loss position for 12 Months or more, gross unrealized losses $ 2 $ 2
In a continuous loss position for 12 Months or more, total number of positions | position 22 41
Municipal securities    
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 83 $ 0
In a continuous loss position for less than 12 Months, gross unrealized losses $ 3 $ 0
In a continuous loss position for less than 12 Months, total number of positions | position 160 0
In a continuous loss position for 12 Months or more, estimated fair value $ 33 $ 42
In a continuous loss position for 12 Months or more, gross unrealized losses $ 1 $ 1
In a continuous loss position for 12 Months or more, total number of positions | position 34 49
Other    
Debt Securities, Available-for-sale [Line Items]    
In a continuous loss position for less than 12 Months, estimated fair value $ 26 $ 0
In a continuous loss position for less than 12 Months, gross unrealized losses $ 1 $ 0
In a continuous loss position for less than 12 Months, total number of positions | position 29 0
In a continuous loss position for 12 Months or more, estimated fair value $ 10 $ 14
In a continuous loss position for 12 Months or more, gross unrealized losses $ 1 $ 1
In a continuous loss position for 12 Months or more, total number of positions | position 14 16