Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 12,472	$ 7,889
Purchases	10,000	0
Sales	(230)	0
Issuances	0	0
Settlements	0	0
Other	9,661	3,874
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	28,593	12,472	$ 7,889
Total gains (losses) (realized/unrealized):
Included in earnings	(3,310)	709
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(3,872)	709
Equity securities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Equity securities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	(3,310)	709	2,821
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(3,872)	709	1,211
Equity securities | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Equity securities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Equity securities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Short-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	0
Purchases	18,046	0
Sales	0	0
Issuances	0	0
Settlements	(8,560)	(1,871)
Other	7,290	1,690
Transfers into Level 3	55	0
Transfers out of Level 3	0	0
Fair Value, end of period	16,945	0	0
Total gains (losses) (realized/unrealized):
Included in earnings	114	181
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	73	0
Short-term investments | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	77	181	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Short-term investments | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Short-term investments | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Short-term investments | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	73	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	73	0	0
Short-term investments | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	(36)	0	0
Cash equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	(1,377)
Other	0	1,230
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	0	0	0
Total gains (losses) (realized/unrealized):
Included in earnings	0	147
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0
Cash equivalents | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	147	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Cash equivalents | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Cash equivalents | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Cash equivalents | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Cash equivalents | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	72,937	0
Purchases	49,677	1,170
Sales	0	0
Issuances	0	0
Settlements	(3,855)	(899)
Other	(21,814)	71,408
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	141,041	72,937	0
Total gains (losses) (realized/unrealized):
Included in earnings	44,096	1,258
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	47,951	359
Other assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	44,096	1,258	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	47,951	359	0
Other assets | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Other assets | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Other assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Other assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Reinsurance recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	931,207	13,239,539
Purchases	135,353	629,259
Sales	0	0
Issuances	0	0
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	430,911	931,207	13,239,539
Total gains (losses) (realized/unrealized):
Included in earnings	(635,649)	(12,937,591)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(607,225)	(545,001)
Reinsurance recoverables | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(635,649)	(12,937,591)	3,604,075
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(607,225)	(545,001)	3,889,923
Reinsurance recoverables | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Reinsurance recoverables | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Reinsurance recoverables | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Reinsurance recoverables | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Separate account assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	0
Purchases	7,715	0
Sales	(3,000)	0
Issuances	0	0
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	4,645	0	0
Total gains (losses) (realized/unrealized):
Included in earnings	(70)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(70)	0
Separate account assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0
Separate account assets | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0
Separate account assets | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	(70)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(70)
Separate account assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0
Separate account assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0
Receivables from parent and affiliates | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings			0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings			0
Receivables from parent and affiliates | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings			0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings			0
Receivables from parent and affiliates | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings			0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings			0
Receivables from parent and affiliates | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings			23
Future policy benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(9,047,956)	(13,227,814)
Purchases	0	0
Sales	0	0
Issuances	(1,006,165)	(1,101,695)
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	(4,540,747)	(9,047,956)	(13,227,814)
Total gains (losses) (realized/unrealized):
Included in earnings	5,513,374	5,281,553
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	5,256,263	4,647,753
Future policy benefits | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	5,513,374	5,281,553	(3,610,281)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	5,256,263	4,647,753	(3,896,128)
Future policy benefits | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Future policy benefits | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Future policy benefits | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Future policy benefits | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Policyholders' account balances
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(3,245,773)	(1,155,274)
Purchases	0	0
Sales	0	0
Issuances	(1,094,824)	(265,807)
Settlements	0	0
Other	1,248,413	(1,746,371)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	(3,502,096)	(3,245,773)	(1,155,274)
Total gains (losses) (realized/unrealized):
Included in earnings	(409,912)	(78,321)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(289,548)	5,476
Policyholders' account balances | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(409,912)	(78,321)	(30,199)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(289,548)	5,476	3,853
Policyholders' account balances | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Policyholders' account balances | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Policyholders' account balances | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Policyholders' account balances | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Available-for-sale | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(16,829)	(832)	(5,019)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(14,416)	(1,778)	(4,773)
Available-for-sale | Fixed maturities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Available-for-sale | Fixed maturities | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Available-for-sale | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	(56,470)	(6,318)	19,106
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(59,239)	(5,346)	18,962
Available-for-sale | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	(242)	388	145
Available-for-sale | Fixed maturities | US government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	55,000
Purchases	0	0
Sales	0	(55,000)
Issuances	0	0
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	0	0	55,000
Total gains (losses) (realized/unrealized):
Included in earnings	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0
Available-for-sale | Fixed maturities | Foreign government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	150	163
Purchases	501	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	724	150	163
Total gains (losses) (realized/unrealized):
Included in earnings	73	(13)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	69	(15)
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	385,634	174,776
Purchases	323,603	95,294
Sales	(62,827)	(5,085)
Issuances	0	0
Settlements	(102,377)	(28,690)
Other	106,408	156,667
Transfers into Level 3	10,475	9,313
Transfers out of Level 3	(106,124)	(5,727)
Fair Value, end of period	507,496	385,634	174,776
Total gains (losses) (realized/unrealized):
Included in earnings	(47,296)	(10,914)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(45,235)	(11,298)
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	173,944	2,065
Purchases	81,576	74,800
Sales	0	(29)
Issuances	0	0
Settlements	(1,993)	(1,761)
Other	0	32,859
Transfers into Level 3	0	107,038
Transfers out of Level 3	(122,485)	(45,193)
Fair Value, end of period	104,724	173,944	2,065
Total gains (losses) (realized/unrealized):
Included in earnings	(26,318)	4,165
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(28,489)	4,189
Trading | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	755
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	(801)
Fair Value, end of period	0	0	755
Total gains (losses) (realized/unrealized):
Included in earnings	0	46
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	46
Trading | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Trading | Fixed maturities | Other income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	46	87
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	46	87
Trading | Fixed maturities | Interest credited to policyholders' account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0
Trading | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0
Trading | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	$ 0	$ 0	$ 0