Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Unrealized gains (losses) for assets/liabilities still held:
Market risk benefit assets	$ 2,534,340	$ 2,550,164	$ 2,534,340	$ 2,550,164	$ 2,637,363
Market risk benefit liabilities	4,668,492	4,370,960	4,668,492	4,370,960	$ 4,281,244
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	20,274	28,650	20,515	28,709
Purchases	2,173	0	2,173	273
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(20,274)	0	(20,274)	0
Fair Value, end of period	2,173	28,330	2,173	28,330
Total gains (losses) (realized/unrealized):
Included in earnings	0	(320)	(241)	(652)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(320)	(241)	(652)
Equity securities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Equity securities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	(320)	(241)	(652)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(320)	(241)	(652)
Equity securities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Equity securities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Equity securities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other invested assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	32	1	143	1
Purchases	0	1	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	50	763	50	763
Total gains (losses) (realized/unrealized):
Included in earnings	18	761	(93)	762
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	18	761	(93)	762
Other invested assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	18	761	(93)	762
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	18	761	(93)	762
Other invested assets | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Short-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	104,761	3,351	105,540	1,759
Purchases	329	304	2,829	2,306
Sales	(102,000)	(8)	(103,524)	(8)
Issuances	0	0	0	0
Settlements	(2,386)	(1,293)	(2,420)	(1,387)
Other	0	0	(1,398)	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	795	2,674	795	2,674
Total gains (losses) (realized/unrealized):
Included in earnings	91	320	(232)	4
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(8)	308	(331)	(8)
Short-term investments | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	125	308	153	(8)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(8)	308	20	(8)
Short-term investments | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Short-term investments | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Short-term investments | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	(34)	0	(385)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	(351)	0
Short-term investments | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	12	0	12
Cash equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	103	0	33	0
Purchases	346	605	552	605
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(208)	0	(224)	0
Other	0	0	(33)	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	278	605	278	605
Total gains (losses) (realized/unrealized):
Included in earnings	37	0	(50)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	7	0	(80)	0
Cash equivalents | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	37	0	(50)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	7	0	(80)	0
Cash equivalents | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Receivables from parents and affiliates
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	379,360	121,378	351,390	0
Purchases	5,408	111,140	60,703	232,518
Sales	(3,519)	(51,199)	(12,772)	(51,199)
Issuances	0	0	0	0
Settlements	(16,938)	0	(19,727)	0
Other	0	0	5,867	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(18,098)	0
Fair Value, end of period	366,535	181,319	366,535	181,319
Total gains (losses) (realized/unrealized):
Included in earnings	2,224	0	(828)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	4,705	0	1,613	0
Receivables from parents and affiliates | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	1,824	0	(2,247)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	3,898	0	0	0
Receivables from parents and affiliates | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Receivables from parents and affiliates | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Receivables from parents and affiliates | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	403	0	1,422	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	807	0	1,613	0
Receivables from parents and affiliates | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	(3)	0	(3)	0
Reinsurance recoverables and deposit receivables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	716,745	250,878	645,193	192,642
Purchases	0	90,809	66,272	163,385
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(6,021)	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	722,068	309,681	722,068	309,681
Total gains (losses) (realized/unrealized):
Included in earnings	11,344	(32,006)	10,603	(46,346)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(139,483)	(62,503)	(98,327)	(113,962)
Reinsurance recoverables and deposit receivables | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	11,344	(32,006)	10,603	(46,346)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(139,483)	(62,503)	(98,327)	(113,962)
Reinsurance recoverables and deposit receivables | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Reinsurance recoverables and deposit receivables | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Reinsurance recoverables and deposit receivables | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Reinsurance recoverables and deposit receivables | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Separate account assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	12,242	7,894	10,547	5,985
Purchases	1,268	1,805	3,144	4,438
Sales	(533)	(2)	(602)	(1,258)
Issuances	0	0	0	0
Settlements	(29)	0	(40)	(125)
Other	0	0	0	0
Transfers into Level 3	0	0	0	458
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	13,322	9,799	13,322	9,799
Total gains (losses) (realized/unrealized):
Included in earnings	374	102	273	301
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	374	102	273	302
Separate account assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Separate account assets | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Separate account assets | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	374	102	273	301
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	374	102	273	302
Separate account assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Separate account assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Policyholders' account balances
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(11,817,734)	(9,752,538)	(12,624,585)	(7,697,627)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	(217,403)	(545,676)	(844,698)	(1,106,076)
Settlements	0	0	0	0
Other	0	1,117	0	1,930
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(15,113,285)	(10,083,258)	(15,113,285)	(10,083,258)
Total gains (losses) (realized/unrealized):
Included in earnings	(3,078,148)	213,839	(1,644,002)	(1,281,485)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(271,009)	973,682	132,694	838,876
Policyholders' account balances | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(3,078,148)	213,839	(1,644,002)	(1,281,485)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(271,009)	973,682	132,694	838,876
Policyholders' account balances | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Policyholders' account balances | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Policyholders' account balances | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Policyholders' account balances | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(12,504)	(207)	(31)	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(14,303)	(207)	(14,303)	(207)
Total gains (losses) (realized/unrealized):
Included in earnings	(1,799)	0	(14,272)	(207)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(1,799)	0	(14,272)	(207)
Other liabilities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(1,799)	0	(14,272)	(207)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(1,799)	0	(14,272)	(207)
Other liabilities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other liabilities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other liabilities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other liabilities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(788)	(2,567)	(7,455)	(4,263)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(2,065)	(1,404)	(8,242)	(776)
Available-for-sale | Fixed maturities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	22,347	(4,746)	31,127	(14,588)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	20,128	(5,304)	29,028	(15,825)
Available-for-sale | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	(404)	924	(1,346)	1,522
Available-for-sale | Fixed maturities | Foreign government securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	671	648	682
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	(640)	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	0	664	0	664
Total gains (losses) (realized/unrealized):
Included in earnings	0	(7)	(8)	(18)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(11)	0	(24)
Available-for-sale | Fixed maturities | Corporate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1,441,168	1,009,650	1,199,607	1,014,343
Purchases	320,259	203,749	736,787	328,790
Sales	(399,806)	(65,650)	(559,368)	(130,702)
Issuances	0	0	0	0
Settlements	(129,424)	(71,908)	(169,796)	(125,800)
Other	0	(65,480)	(4,435)	(65,480)
Transfers into Level 3	2,612	942	33,612	942
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	1,257,603	1,005,175	1,257,603	1,005,175
Total gains (losses) (realized/unrealized):
Included in earnings	22,794	(6,128)	21,196	(16,918)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	19,635	(7,077)	18,877	(16,678)
Available-for-sale | Fixed maturities | Structured securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	931,354	694,121	699,892	177,237
Purchases	352,651	37,188	474,534	521,528
Sales	(34,713)	0	(38,215)	0
Issuances	0	0	0	0
Settlements	(52,188)	(51,300)	(88,843)	(53,195)
Other	29,813	65,480	(28,544)	65,480
Transfers into Level 3	7,000	0	268,816	34,578
Transfers out of Level 3	(41,975)	(77,200)	(98,475)	(77,200)
Fair Value, end of period	1,190,303	668,035	1,190,303	668,035
Total gains (losses) (realized/unrealized):
Included in earnings	(1,639)	(254)	1,138	(393)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(1,572)	380	1,909	101
Trading | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	152,081	146,543	66,285	34,048
Purchases	127,368	111,784	209,771	225,127
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	(2,261)	(26,130)	(2,261)
Other	(29,813)	0	28,544	0
Transfers into Level 3	0	0	2,001	0
Transfers out of Level 3	(42,507)	(15,196)	(76,935)	(15,196)
Fair Value, end of period	222,095	240,820	222,095	240,820
Total gains (losses) (realized/unrealized):
Included in earnings	14,966	(50)	18,559	(898)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	15,128	(42)	21,318	(890)
Trading | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	12,517	(50)	18,707	(898)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	15,128	(42)	21,318	(890)
Trading | Fixed maturities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	$ 2,449	$ 0	$ (148)	$ 0