Investments - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]
Mortgage loans, net	$ 770	$ 784
Short-term investments	6,541	4,537
Accrued investment income	614	615
Fixed income securities
Debt Securities, Available-for-Sale [Line Items]
Accrued investment income	575	574
Residential Mortgage
Debt Securities, Available-for-Sale [Line Items]
Mortgage loans, net	$ 80	$ 61