v3.25.3
Fair Value Measurements - Financial Instruments on a Recurring Basis (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale $ 4,226 $ 4,325
Total assets 4,226 4,325
Corporate debt securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 2,600 2,744
Mortgage-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 982 914
Asset-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 396 431
Municipal securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 178 183
U.S. Treasury notes    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 22 5
Other    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 48 48
(Level 1)    
Fair value of assets measured on recurring basis    
Total assets 0 0
(Level 1) | Corporate debt securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 1) | Mortgage-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 1) | Asset-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 1) | Municipal securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 1) | U.S. Treasury notes    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 1) | Other    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 2)    
Fair value of assets measured on recurring basis    
Total assets 4,226 4,325
(Level 2) | Corporate debt securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 2,600 2,744
(Level 2) | Mortgage-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 982 914
(Level 2) | Asset-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 396 431
(Level 2) | Municipal securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 178 183
(Level 2) | U.S. Treasury notes    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 22 5
(Level 2) | Other    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 48 48
(Level 3)    
Fair value of assets measured on recurring basis    
Total assets 0 0
(Level 3) | Corporate debt securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 3) | Mortgage-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 3) | Asset-backed securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 3) | Municipal securities    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 3) | U.S. Treasury notes    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale 0 0
(Level 3) | Other    
Fair value of assets measured on recurring basis    
Debt securities, available-for-sale $ 0 $ 0