v3.26.1
Investments - Available-for-Sale Investments (Details)
$ in Millions
Mar. 31, 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 $ 879 $ 106
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 8 $ 1
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 611 83
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 720 $ 823
In a Continuous Loss Position for 12 Months or More, Gross Unrealized Losses $ 30 $ 31
In a Continuous Loss Position for 12 Months or More, Total Number of Positions | position 451 523
Corporate debt securities    
Debt Securities, Available-for-sale [Line Items]    
In a Continuous Loss Position for Less than 12 Months, Estimated Fair Value $ 639 $ 106
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 6 $ 1
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 454 83
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 316 $ 372
In a Continuous Loss Position for 12 Months or More, Gross Unrealized Losses $ 5 $ 6
In a Continuous Loss Position for 12 Months or More, Total Number of Positions | position 169 205
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
In a Continuous Loss Position for Less than 12 Months, Estimated Fair Value $ 240 $ 0
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 2 $ 0
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 157 0
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 282 $ 315
In a Continuous Loss Position for 12 Months or More, Gross Unrealized Losses $ 21 $ 21
In a Continuous Loss Position for 12 Months or More, Total Number of Positions | position 188 212
Asset-backed securities    
Debt Securities, Available-for-sale [Line Items]    
In a Continuous Loss Position for Less than 12 Months, Estimated Fair Value $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 0 0
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 68 $ 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 32 41
Municipal securities    
Debt Securities, Available-for-sale [Line Items]    
In a Continuous Loss Position for Less than 12 Months, Estimated Fair Value $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 0 0
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 40 $ 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 46 49
Other    
Debt Securities, Available-for-sale [Line Items]    
In a Continuous Loss Position for Less than 12 Months, Estimated Fair Value $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Gross Unrealized Losses $ 0 $ 0
In a Continuous Loss Position for Less than 12 Months, Total Number of Positions | position 0 0
In a Continuous Loss Position for 12 Months or More, Estimated Fair Value $ 14 $ 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 16 16