Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale, Amortized Cost	$ 2,135	$ 2,197
Debt Securities, Available-for-sale, Allowance for Credit Loss	2	3
Premium Receivable, Allowance for Credit Loss	$ 3	$ 4
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000
Preferred Stock, Shares Issued	0	0
Common stock, par value	$ 0.01
Common stock, shares authorized	130,000,000
Common stock, shares issued	46,659,144	46,659,144
Common stock, shares outstanding	45,224,972
Equity investments in pooled funds [Member]
Other Investment Not Readily Marketable, Fair Value	$ 546	$ 463
Variable Interest Entity, Primary Beneficiary [Member]
Long-term debt	$ 2,671	$ 2,710