Reinsurance (Income Statement Reinsurance Results) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Premiums:
Direct	$ 1,871,264	$ 1,909,878	$ 1,923,708
Assumed	776	162	184
Ceded	(1,597,257)	(1,706,364)	(1,831,716)
Net premiums	274,783	203,676	92,176
Policy charges and fee income:
Direct	3,436,953	3,647,883	3,491,735
Assumed	608,458	582,003	587,466
Ceded	(2,313,454)	(2,700,129)	(3,454,881)
Net policy charges and fee income	1,731,957	1,529,757	624,320
Net investment income:
Direct	920,674	555,404	372,822
Assumed	1,513	1,049	1,579
Ceded	(38,186)	(6,218)	(7,051)
Net investment income	884,001	550,235	367,350
Asset administration fees:
Direct	351,600	403,359	360,438
Assumed	0	0	0
Ceded	(67,418)	(201,182)	(341,300)
Net asset administration fees	284,182	202,177	19,138
Other income (loss):
Direct	(731,796)	227,035	78,445
Assumed	271	(66)	(1)
Ceded	(3,457)	35,790	165
Amortization of reinsurance income	73,122	4,449	4,647
Net other income	(661,860)	267,208	83,256
Realized investment gains (losses), net:
Direct	1,838,136	7,663,351	(3,593,799)
Assumed	(244,000)	12,593	0
Ceded	(552,701)	(12,971,350)	3,530,823
Realized investment gains (losses), net	1,041,435	(5,295,406)	(62,976)
Policyholders’ benefits (including change in reserves):
Direct	3,951,690	3,611,402	3,584,011
Assumed	1,504,204	849,599	1,055,277
Ceded	(4,846,502)	(3,805,091)	(4,341,139)
Net policyholders’ benefits (including change in reserves)	609,392	655,910	298,149
Interest credited to policyholders’ account balances:
Direct	883,398	563,821	536,886
Assumed	74,402	138,202	136,153
Ceded	(440,312)	(816,608)	(439,664)
Net interest credited to policyholders’ account balances	517,488	(114,585)	233,375
Reinsurance expense allowances and general and administrative expenses, net of capitalization and amortization	(427,208)	(2,265,350)	(1,589,113)
Unaffiliated activity
Premiums:
Assumed	149	162	184
Ceded	(35,867)	(19,785)	(10,526)
Policy charges and fee income:
Assumed	2,113	0	0
Ceded	(81,781)	(65,451)	(53,871)
Net investment income:
Ceded	10,802	687	0
Other income (loss):
Assumed	270	(68)	1
Realized investment gains (losses), net:
Assumed	778,620	0	0
Ceded	(38,317)	(49,460)	73,108
Policyholders’ benefits (including change in reserves):
Assumed	2,566	429	949
Ceded	(87,370)	(200,973)	(69,720)
Interest credited to policyholders’ account balances:
Assumed	$ (95,285)	$ 0	$ 0