Reinsurance (Reinsurance amounts included in the Statement of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Premiums:
Direct	$ 463,449	$ 459,628
Assumed	10,662	33
Ceded	(350,651)	(367,479)
Net Premiums	123,460	92,182
Policy charges and fee income:
Direct	797,210	771,189
Assumed	180,179	258,770
Ceded	(579,043)	1,879,246
Net policy charges and fee income	398,346	2,909,205
Net investment income:
Direct	747,545	519,052
Assumed	319	330
Ceded	(13,068)	(14,062)
Net investment income	734,796	505,320
Asset administration fees:
Direct	78,905	82,688
Assumed	0	0
Ceded	(26,825)	(26,056)
Net asset administration fees	52,080	56,632
Other income (loss):
Direct	104,643	44,816
Assumed	20	325
Ceded	71,778	169,854
Net other income (loss)	176,441	214,995	[1]
Realized investment gains (losses), net:
Direct	(82,883)	20,056
Assumed	32,439	(9,167)
Ceded	(55,930)	(13,694)
Realized investment gains (losses), net	(106,374)	(2,805)	[1]
Change in value of market risk benefits, net of related hedging gains (losses):
Direct	(418,994)	324,375
Assumed	(484)	1,450
Ceded	93,407	(221,829)
Net change in value of market risk benefits, net of related hedging gain (loss)	(326,071)	103,996	[1]
Policyholders’ benefits (including change in reserves):
Direct	988,124	1,001,446
Assumed	292,478	287,411
Ceded	(1,137,266)	2,817,551
Net policyholders’ benefits (including change in reserves	143,336	4,106,408
Change in estimates of liability for future policy benefits:
Direct	6,255	139,586
Assumed	1,292	(9,510)
Ceded	(965)	(142,081)
Net change in estimates of liability for future policy benefits	6,582	(12,005)
Interest credited to policyholders’ account balances:
Direct	366,527	312,190
Assumed	33,104	46,148
Ceded	(105,869)	(99,988)
Net interest credited to policyholders’ account balances	293,762	258,350	[1]
Reinsurance expense allowances and general and administrative expenses, net of capitalization and amortization	(106,548)	(391,443)
Unaffiliated activity
Premiums:
Assumed	27	30
Ceded	(35,400)	(25,152)
Policy charges and fee income:
Assumed	212	272
Ceded	(750,027)	(42,012)
Net investment income:
Ceded	(443)	0
Asset administration fees:
Ceded	(6,414)	(7,316)
Other income (loss):
Assumed	(142)	325
Ceded	42,077	23,314
Realized investment gains (losses), net:
Assumed	32,439	(9,167)
Ceded	(37,911)	(8,280)
Change in value of market risk benefits, net of related hedging gains (losses):
Assumed	(484)	1,450
Ceded	44,351	(98,008)
Policyholders’ benefits (including change in reserves):
Assumed	45	333
Ceded	(765,259)	(146,828)
Change in estimates of liability for future policy benefits:
Ceded	(9,886)	91,873
Interest credited to policyholders’ account balances:
Assumed	6,477	17,459
Ceded	$ (24,477)	$ 0

[1] Amounts reflect revision to prior period Financial Statements. See Note 16 for additional information.