Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Fixed maturity securities, amortized cost	$ 20,915,245	$ 18,715,483
Fixed maturity securities, allowance for credit loss	36,751	37,466
Financing receivable, allowance for credit loss	3,004	1,791
Premium receivable, allowance for credit loss	35,110	30,660
Uncollectible reinsurance	$ 8,404	$ 8,064
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.20	$ 0.20
Common stock, issued (in shares)	256,544,757	264,546,100
Common stock, outstanding (in shares)	256,544,757	264,546,100
Common stock, authorized (in shares)	1,250,000,000
Treasury stock, at cost (in shares)	272,469,871	264,468,528