Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	$ 19,025,401	$ 13,278,166
Fixed maturities, trading	1,936,159	3,302,392
Equity securities	143,072	111,267
Other invested assets	1,088,613	1,209,925
Other assets	1,327,393	1,140,948
Reinsurance recoverables	34,561,825	38,598,767
Receivables from parent and affiliates	224,921	278,131
Separate account assets	114,051,246	149,797,828
TOTAL ASSETS	189,299,841	221,661,364
Payables to parent and affiliates	2,126,571	31,775
Other liabilities	3,407,156	2,264,477
Total liabilities	184,936,310	215,706,270
Future policy benefits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative, Net Liability	4,541,000	9,048,000
Embedded Derivative, Fair Value of Embedded Derivative Gross Asset	801,000	610,000
Embedded Derivative, Fair Value of Embedded Derivative Gross Liability	5,342,000	9,658,000
Other liabilities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative, Net Liability	10,000	13,000
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	19,025,401	13,278,166
Fixed maturities, trading	1,936,159	3,302,392
Equity securities	143,072	111,267
Short-term investments	98,160	145,437
Cash equivalents	1,432,182	436,632
Other invested assets	47,111	268,525
Other assets	141,041	72,937
Reinsurance recoverables	430,911	931,207
Receivables from parent and affiliates	148,075	162,045
Subtotal excluding separate account assets	23,402,112	18,708,608
Separate account assets	108,789,313	144,111,658
TOTAL ASSETS	132,191,425	162,820,266
Future policy benefits	4,540,747	9,047,956
Policyholders’ account balances	3,502,096	3,245,773
Payables to parent and affiliates	2,084,917	0
Other liabilities	(9,267)	18,525
Total liabilities	10,118,493	12,312,254
Asset Netting	(7,637,939)	(6,818,009)
Liability Netting	(16,568,912)	(12,568,082)
Netting	(8,931,000)	(5,750,000)
Fair Value, Measurements, Recurring | Other invested assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Netting	(7,637,939)	(6,818,009)
Fair Value, Measurements, Recurring | Payables to parent and affiliates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability Netting	(16,568,242)	(12,563,253)
Fair Value, Measurements, Recurring | Other liabilities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability Netting	(670)	(4,829)
Fair Value, Measurements, Recurring | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	281,792	333,940
Fair Value, Measurements, Recurring | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	628,200	630,521
Fair Value, Measurements, Recurring | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	273,462	350,471
Fair Value, Measurements, Recurring | U.S. corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	6,443,944	5,131,872
Fair Value, Measurements, Recurring | U.S. corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	3,816,729	2,004,875
Fair Value, Measurements, Recurring | Foreign corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	1,378,222	929,902
Fair Value, Measurements, Recurring | Foreign corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	3,766,330	2,753,911
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	1,442,354	547,310
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	658,152	575,184
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	336,216	20,180
Fair Value, Measurements, Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fixed maturities, trading	0	0
Equity securities	108,076	58,160
Short-term investments	0	9,997
Cash equivalents	0	13,999
Other invested assets	4,223	246,097
Other assets	0	0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	0	0
Subtotal excluding separate account assets	112,299	328,253
Separate account assets	102,243	52,100
TOTAL ASSETS	214,542	380,353
Future policy benefits	0	0
Policyholders’ account balances	0	0
Payables to parent and affiliates	0	0
Other liabilities	899	10,730
Total liabilities	899	10,730
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	18,412,457	12,718,438
Fixed maturities, trading	1,936,159	3,302,392
Equity securities	6,403	40,635
Short-term investments	81,215	135,440
Cash equivalents	1,432,182	422,633
Other invested assets	7,680,827	6,840,437
Other assets	0	0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	148,075	162,045
Subtotal excluding separate account assets	29,697,318	23,622,020
Separate account assets	108,682,425	144,059,558
TOTAL ASSETS	138,379,743	167,681,578
Future policy benefits	0	0
Policyholders’ account balances	0	0
Payables to parent and affiliates	18,653,159	12,563,253
Other liabilities	(9,496)	12,624
Total liabilities	18,643,663	12,575,877
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	281,792	333,940
Fair Value, Measurements, Recurring | Level 2 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	628,200	630,521
Fair Value, Measurements, Recurring | Level 2 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	272,738	350,321
Fair Value, Measurements, Recurring | Level 2 | U.S. corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	6,443,944	5,131,872
Fair Value, Measurements, Recurring | Level 2 | U.S. corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	3,573,269	1,873,370
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	1,371,354	921,008
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	3,509,162	2,508,676
Fair Value, Measurements, Recurring | Level 2 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	1,421,852	484,861
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	573,930	463,689
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	336,216	20,180
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	612,944	559,728
Fixed maturities, trading	0	0
Equity securities	28,593	12,472
Short-term investments	16,945	0
Cash equivalents	0	0
Other invested assets	0	0
Other assets	141,041	72,937
Reinsurance recoverables	430,911	931,207
Receivables from parent and affiliates	0	0
Subtotal excluding separate account assets	1,230,434	1,576,344
Separate account assets	4,645	0
TOTAL ASSETS	1,235,079	1,576,344
Future policy benefits	4,540,747	9,047,956
Policyholders’ account balances	3,502,096	3,245,773
Payables to parent and affiliates	0	0
Other liabilities	0	0
Total liabilities	8,042,843	12,293,729
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 3 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	724	150
Fair Value, Measurements, Recurring | Level 3 | U.S. corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	243,460	131,505
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate public securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	6,868	8,894
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate private securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	257,168	245,235
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	20,502	62,449
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	84,222	111,495
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale	0	0
Other invested assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value investment measured at NAV per share	69,000	79,000
Separate account assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value investment measured at NAV per share	$ 5,262,000	$ 5,686,000