Significant Accounting Policies - Schedule of Liability For Future Policy Benefits To Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Significant Of Accounting Policies [Line Items]
Net liability for future policy benefits—long duration health	$ 19,460,353	$ 18,097,341	$ 24,499,640	$ 25,074,108	$ 15,242,641
Additional insurance liabilities				2,008,399	2,218,116
Unearned and advance premium	254,567	253,360		243,612	61,971
Policy claims and other benefits payable	514,875	509,356		476,710	402,693
Other policyholders' funds	236,958	123,236		98,459	97,968
Total policy liabilities	20,466,753	18,983,293		25,892,889	15,805,273
Life
Significant Of Accounting Policies [Line Items]
Net liability for future policy benefits—long duration health	15,390,289	14,014,147	19,585,183	20,047,549	10,943,039
Health
Significant Of Accounting Policies [Line Items]
Net liability for future policy benefits—long duration health	$ 2,379,415	$ 2,203,789	$ 2,942,663	$ 3,018,160	$ 2,081,486