Investments - Debt Securities by Contractual Maturity Periods (Details) $ in Millions	Jun. 30, 2025 USD ($)
Amortized Cost
Due in one year or less	$ 620
Due after one year through five years	3,587
Due after five years through ten years	2,280
Due after ten years	2,033
Mortgage and other asset-backed securities	277
Total	8,797
Fair Value
Due in one year or less	543
Due after one year through five years	3,556
Due after five years through ten years	2,203
Due after ten years	1,838
Mortgage and other asset-backed securities	249
Total	$ 8,389