Schedule II - Condensed Financial Information of Registrant (Statements of Income (Parent Company)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Net investment (losses) gains	$ 47,042	$ 202,397	$ 90,632
Other income	381	3,396	4,177
Total revenues	12,142,938	11,166,499	9,455,466
Operating costs and expense	10,388,535	9,446,818	8,172,561
Income before income taxes	1,754,403	1,719,681	1,282,905
Federal income taxes:
Net federal income tax (expense) benefit	(370,557)	(334,727)	(251,890)
Income (Loss) From Investment Funds For the Year Ended	16,743	145,099	220,014
Net income to common stockholders	1,381,359	1,381,062	1,022,490
Dividends from subsidiaries	1,261,166	22,807	520,251
Parent Company
Condensed Income Statements, Captions [Line Items]
Management fees and investment income including dividends from subsidiaries of $1,261,166, $22,807, and $520,251 for the years ended December 31, 2023, 2022 and 2021, respectively	1,325,997	32,585	548,512
Net investment (losses) gains	(5,895)	1,007	1,474
Other income	368	1,916	1,138
Total revenues	1,320,470	35,508	551,124
Operating costs and expense	272,750	192,175	214,995
Interest expense	126,397	129,633	144,837
Income before income taxes	921,323	(286,300)	191,292
Federal income taxes:
Federal income taxes provided by subsidiaries on a separate return basis	253,292	414,660	294,731
Federal income tax expense on a consolidated return basis	(284,757)	(258,776)	(226,900)
Net federal income tax (expense) benefit	(31,465)	155,884	67,831
Income (loss) before undistributed equity in net income of subsidiaries	889,858	(130,416)	259,123
Income (Loss) From Investment Funds For the Year Ended	491,501	1,511,478	763,367
Net income to common stockholders	$ 1,381,359	$ 1,381,062	$ 1,022,490