Reinsurance (Reinsurance amounts included in the Statement of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024		Jun. 30, 2025	Jun. 30, 2024
Premiums:
Direct	$ 474,905	$ 462,458		$ 938,353	$ 922,086
Assumed	15,360	30		26,022	63
Ceded	(351,539)	(367,567)		(702,189)	(735,046)
Net Premiums	138,726	94,921		262,186	187,103
Policy charges and fee income:
Direct	782,872	785,299		1,580,082	1,556,488
Assumed	180,472	239,838		360,651	498,608
Ceded	(492,728)	(636,303)		(1,071,771)	1,242,943
Net policy charges and fee income	470,616	388,834		868,962	3,298,039
Net investment income:
Direct	776,177	592,448		1,523,722	1,111,500
Assumed	320	333		639	663
Ceded	(13,244)	(12,788)		(26,312)	(26,850)
Net investment income	763,253	579,993		1,498,049	1,085,313
Asset administration fees:
Direct	76,328	79,776		155,233	162,464
Assumed	0	0		0	0
Ceded	(26,361)	(24,663)		(53,186)	(50,719)
Net asset administration fees	49,967	55,113		102,047	111,745
Other income (loss):
Direct	184,960	84,931		289,606	129,747
Assumed	312	24		331	349
Ceded	54,774	56,163		126,550	226,017
Net other income (loss)	240,046	141,118	[1]	416,487	356,113	[1]
Realized investment gains (losses), net:
Direct	(769,462)	765,146		(852,345)	785,202
Assumed	(1,088)	72,351		31,351	63,184
Ceded	(48,814)	(32,749)		(104,744)	(46,443)
Realized investment gains (losses), net	(819,364)	804,748	[1]	(925,738)	801,943	[1]
Change in value of market risk benefits, net of related hedging gains (losses):
Direct	(243,907)	(298,559)		(662,901)	25,816
Assumed	375	1,072		(109)	2,522
Ceded	(42,637)	15,304		50,770	(206,525)
Net change in value of market risk benefits, net of related hedging gain (loss)	(286,169)	(282,183)	[1]	(612,240)	(178,187)	[1]
Policyholders’ benefits (including change in reserves):
Direct	1,075,813	909,374		2,063,937	1,910,820
Assumed	270,684	245,810		563,162	533,221
Ceded	(1,047,189)	(1,019,305)		(2,184,455)	1,798,246
Net policyholders’ benefits (including change in reserves	299,308	135,879		442,644	4,242,287
Change in estimates of liability for future policy benefits:
Direct	(131,798)	72,870		(125,544)	212,456
Assumed	(23,668)	74,378		(22,376)	64,868
Ceded	47,996	(153,422)		47,032	(295,503)
Net change in estimates of liability for future policy benefits	(107,470)	(6,174)		(100,888)	(18,179)
Interest credited to policyholders’ account balances:
Direct	243,526	297,194		610,052	609,384
Assumed	34,682	36,344		67,786	82,492
Ceded	(109,631)	(107,314)		(215,499)	(207,302)
Net interest credited to policyholders’ account balances	168,577	226,224	[1]	462,339	484,574	[1]
Reinsurance expense allowances and general and administrative expenses, net of capitalization and amortization	(89,104)	(117,347)		(195,653)	(508,790)
Unaffiliated activity
Premiums:
Assumed	27	30		54	60
Ceded	(34,509)	(26,827)		(69,908)	(51,979)
Policy charges and fee income:
Assumed	448	356		659	628
Ceded	(57,735)	(44,958)		(807,763)	(86,970)
Net investment income:
Ceded	(419)	0		(862)	0
Asset administration fees:
Ceded	(6,230)	(7,007)		(12,644)	(14,323)
Other income (loss):
Assumed	120	24		(23)	453
Ceded	36,546	29,431		78,622	52,745
Realized investment gains (losses), net:
Assumed	(1,088)	72,351		31,351	63,184
Ceded	(32,676)	(12,360)		(70,587)	(20,640)
Change in value of market risk benefits, net of related hedging gains (losses):
Assumed	375	1,072		(109)	2,522
Ceded	5,994	34,461		50,346	(63,547)
Policyholders’ benefits (including change in reserves):
Assumed	189	28		234	361
Ceded	(87,034)	(64,243)		(852,294)	(211,071)
Change in estimates of liability for future policy benefits:
Ceded	(7,353)	29		(17,239)	91,902
Interest credited to policyholders’ account balances:
Assumed	8,071	7,657		14,548	25,116
Ceded	$ (24,818)	$ (1)		$ (49,294)	$ (1)

[1] Amounts reflect revision to prior period Financial Statements. See Note 17 for additional information.