Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Amortized Cost	$ 1,979
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	$ 0
Premium Receivable, Allowance for Credit Loss	$ 6	$ 9
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000
Preferred Stock, Shares Issued	0
Common stock, par value	$ 0.01
Common stock, shares authorized	130,000,000
Common stock, shares issued	46,658,990	46,477,068
Common stock, shares outstanding	44,939,916
Treasury stock, shares	1,719,074	172,929
Equity investments in pooled funds [Member]
Other Investment Not Readily Marketable, Fair Value	$ 590	$ 683
Variable Interest Entity, Primary Beneficiary [Member]
Long-term debt	$ 3,184	$ 4,056