Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands		Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		$ 42,552,406	$ 34,986,160
Market risk benefit assets		2,534,340	2,637,363	$ 2,550,164
Fixed maturities, trading		4,591,073	3,845,045
Equity securities		810,444	2,623,820
Other invested assets	[1]	2,300,289	1,582,094
Reinsurance recoverables and deposit receivables		50,219,999	48,247,817
Receivables from parent and affiliates		687,750	678,028
Separate account assets		117,646,018	118,143,256
TOTAL ASSETS		247,209,104	238,454,729
Market risk benefit liabilities		4,668,492	4,281,244	$ 4,370,960
Payables to parent and affiliates	[1]	2,533,766	3,653,848
Total liabilities		241,527,389	233,752,749
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		1,069,651	1,099,241
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		441,047	541,066
Foreign government securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		392,794	310,334
U.S. corporate public securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		17,167,045	13,238,428
U.S. corporate private securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		6,369,334	5,754,097
Foreign corporate public securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		4,512,249	3,698,851
Foreign corporate private securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		6,512,374	5,341,633
Asset-backed securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		4,404,426	3,750,663
Commercial mortgage-backed securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		1,141,171	895,775
Residential mortgage-backed securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		542,315	356,072
Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		42,552,406	34,986,160
Market risk benefit assets		2,534,340	2,637,363
Fixed maturities, trading		4,591,073	3,845,045
Equity securities		810,444	2,623,820
Short-term investments		285,892	496,285
Cash equivalents		2,086,871	2,851,283
Other invested assets		54,293	24,499
Reinsurance recoverables and deposit receivables		722,068	645,193
Receivables from parent and affiliates		591,995	520,462
Subtotal excluding separate account assets		54,229,382	48,630,110
Separate account assets		110,542,137	111,699,552
TOTAL ASSETS		164,771,519	160,329,662
Market risk benefit liabilities		4,668,492	4,281,244
Policyholders’ account balances		15,113,285	12,624,585
Payables to parent and affiliates		2,488,102	3,615,277
Other liabilities		16,338	7,350
Total liabilities		22,286,217	20,528,456
Assets netting		(16,294,182)	(15,308,195)
Liabilities netting		(26,373,747)	(23,619,586)
Derivative liability, cash collateral		(10,080,000)	(8,311,000)
Fair Value, Measurements, Recurring | Payables to parent and affiliates
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities netting		(26,154,677)	(23,617,643)
Fair Value, Measurements, Recurring | Other liabilities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities netting		(219,070)	(1,943)
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		1,069,651	1,099,241
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		441,047	541,066
Fair Value, Measurements, Recurring | Foreign government securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		392,794	310,334
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		17,167,045	13,238,428
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		6,369,334	5,754,097
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		4,512,249	3,698,851
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		6,512,374	5,341,633
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		4,404,426	3,750,663
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		1,141,171	895,775
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		542,315	356,072
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
Market risk benefit assets		0	0
Fixed maturities, trading		0	0
Equity securities		781,142	2,587,791
Short-term investments		50,206	0
Cash equivalents		53,710	0
Other invested assets		268,456	2,302
Reinsurance recoverables and deposit receivables		0	0
Receivables from parent and affiliates		0	0
Subtotal excluding separate account assets		1,153,514	2,590,093
Separate account assets		447,982	273,288
TOTAL ASSETS		1,601,496	2,863,381
Market risk benefit liabilities		0	0
Policyholders’ account balances		0	0
Payables to parent and affiliates		0	0
Other liabilities		221,105	7,988
Total liabilities		221,105	7,988
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 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 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		40,104,500	33,086,013
Market risk benefit assets		0	0
Fixed maturities, trading		4,368,978	3,778,760
Equity securities		27,129	15,514
Short-term investments		234,891	390,745
Cash equivalents		2,032,883	2,851,250
Other invested assets		16,079,969	15,330,249
Reinsurance recoverables and deposit receivables		0	0
Receivables from parent and affiliates		225,460	169,072
Subtotal excluding separate account assets		63,073,810	55,621,603
Separate account assets		110,080,833	111,415,717
TOTAL ASSETS		173,154,643	167,037,320
Market risk benefit liabilities		0	0
Policyholders’ account balances		0	0
Payables to parent and affiliates		28,642,779	27,232,920
Other liabilities		0	1,274
Total liabilities		28,642,779	27,234,194
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		1,069,651	1,099,241
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		441,047	541,066
Fair Value, Measurements, Recurring | Level 2 | Foreign government securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		392,794	309,686
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		17,167,045	13,238,428
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		5,585,347	4,996,400
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		4,505,308	3,692,124
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		6,045,699	4,906,450
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		3,300,752	3,126,089
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		1,066,342	820,457
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		530,515	356,072
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		2,447,906	1,900,147
Market risk benefit assets		2,534,340	2,637,363
Fixed maturities, trading		222,095	66,285
Equity securities		2,173	20,515
Short-term investments		795	105,540
Cash equivalents		278	33
Other invested assets		50	143
Reinsurance recoverables and deposit receivables		722,068	645,193
Receivables from parent and affiliates		366,535	351,390
Subtotal excluding separate account assets		6,296,240	5,726,609
Separate account assets		13,322	10,547
TOTAL ASSETS		6,309,562	5,737,156
Market risk benefit liabilities		4,668,492	4,281,244
Policyholders’ account balances		15,113,285	12,624,585
Payables to parent and affiliates		0	0
Other liabilities		14,303	31
Total liabilities		19,796,080	16,905,860
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 securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale		0	648
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		783,987	757,697
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		6,941	6,727
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		466,675	435,183
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		1,103,674	624,574
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		74,829	75,318
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		11,800	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		112,000	44,000
Separate account assets
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value investment measured at NAV per share		$ 7,104,000	$ 6,444,000

[1] See Note 4 for details of balances associated with variable interest entities.