Liability for Future Policy Benefits (Benefit Reserves) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Other adjustments	$ (3,952)	$ (55,099)	[1]	$ (27,008)	[1]
Interest accrual	486,253	433,631		344,789
Other Businesses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	2,127	2,902
Balance after transition, at current discount rate	1,765	2,127		2,902
Total
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	18,042,105	21,177,064
Balance after transition, at current discount rate	18,656,760	18,042,105		21,177,064
Term Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period	10,911,794	12,485,056		12,791,701
Effect of cumulative changes in discount rate assumptions, beginning of period	554,896	(1,826,120)		(2,461,823)
Balance at original discount rate, beginning of period	11,466,690	10,658,936		10,329,878
Effect of assumption update		(790)		1,295,294		$ 39,089
Effect of actual variances from expected experiences and other activity		(200,513)		(112,661)		246,712
Adjusted balance, beginning of period		11,265,387		11,841,569		10,615,679
Issuances	712,495	439,874		747,703
Net Premium / Consideration Collected	(1,345,514)	(1,339,902)		(1,193,642)
Interest accural	521,176	525,149		489,196
Balance at original discount rate, end of period	11,153,544	11,466,690		10,658,936
Effect of cumulative changes in discount rate assumptions, end of period	(225,711)	(554,896)		1,826,120
Balance, end of period	10,927,833	10,911,794		12,485,056
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	17,835,251	20,937,097		21,897,943
Effect of cumulative changes in discount rate assumptions, beginning of period	962,035	(3,607,275)		(4,893,834)
Balance at original discount rate, beginning of period	18,797,286	17,329,822		17,004,109
Effect of assumption update		(1,044)		1,756,995		40,236
Effect of actual variance from expected experience and other activity		(263,243)		(206,175)		268,005
Adjusted balance, beginning of period		18,532,999		18,880,642		17,312,350
Issuances	712,495	439,874		747,703
Interest accrual	895,023	888,525		832,663
Benefit Payments	(1,386,583)	(1,416,823)		(1,566,091)
Other adjustments	3,844	5,068		3,197
Balance at original discount rate, end of period	18,757,778	18,797,286		17,329,822
Effect of cumulative changes in discount rate assumptions, end of period	(331,571)	(962,035)		3,607,275
Balance after transition, at current discount rate	18,426,207	17,835,251		20,937,097
Balance, end of period, pre-flooring	7,498,374	6,923,457		8,452,041
Flooring impact, end of period	44	0		951
Balance, end of period, post-flooring	7,498,418	6,923,457		8,452,992
Less: Reinsurance Recoverable	6,817,488	6,497,257		7,855,802
Balance after transition, net of reinsurance recoverable	680,930	426,200		597,190
Term Life | Gross Basis
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Undiscounted expected future gross premiums	21,871,767	22,223,836		24,005,621
Discounted expected future gross premiums (at original discount rate)	15,027,611	15,322,180		16,246,950
Discounted expected future gross premiums (at current discount rate)	14,748,999	14,587,657		19,102,730
Undiscounted expected future benefits and expenses	29,118,532	29,330,574		27,127,403
Interest accrual	373,845	363,375		343,467
Gross premiums	$ 1,804,955	$ 1,831,360		$ 1,822,261
Weighted-average duration of the liability in years (at original discount rate)	10 years	11 years		10 years
Weighted-average duration of the liability in years (at current discount rate)	10 years	10 years		11 years
Weighted-Average Interest Rate (At Original Discount Rate)	5.17%	5.23%		5.30%
Weighted-average interest rate (at current discount rate)	4.99%	5.39%		2.55%
Fixed Annuities
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period	$ 0	$ 0		$ 0
Effect of cumulative changes in discount rate assumptions, beginning of period	0	0		0
Balance at original discount rate, beginning of period	0	0		0
Effect of assumption update		0		0		0
Effect of actual variances from expected experiences and other activity		(989)		(1,143)		0
Adjusted balance, beginning of period						0
Issuances	36,646	30,469		29,700
Net Premium / Consideration Collected	(35,657)	(29,326)		(29,700)
Interest accural	0	0		0
Balance at original discount rate, end of period	0	0		0
Effect of cumulative changes in discount rate assumptions, end of period	0	0		0
Balance, end of period	0	0		0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	204,727	237,065		237,094
Effect of cumulative changes in discount rate assumptions, beginning of period	24,876	(16,704)		(27,090)
Balance at original discount rate, beginning of period	229,603	220,361		210,004
Effect of assumption update		0		0		0
Effect of actual variance from expected experience and other activity		6,991		(1,639)		(1,422)
Adjusted balance, beginning of period		236,594		218,722		208,582
Issuances	36,646	30,469		29,700
Interest accrual	8,440	7,836		7,454
Benefit Payments	(33,287)	(27,138)		(25,328)
Other adjustments	(84)	(286)		(47)
Balance at original discount rate, end of period	248,309	229,603		220,361
Effect of cumulative changes in discount rate assumptions, end of period	(19,521)	(24,876)		16,704
Balance after transition, at current discount rate	228,788	204,727		237,065
Balance, end of period, pre-flooring	228,788	204,727		237,065
Flooring impact, end of period	0	0		0
Balance, end of period, post-flooring	228,788	204,727		237,065
Less: Reinsurance Recoverable	18,489	16,460		19,314
Balance after transition, net of reinsurance recoverable	210,299	188,267		217,751
Fixed Annuities | Gross Basis
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Undiscounted expected future gross premiums	0	0		0
Discounted expected future gross premiums (at original discount rate)	0	0		0
Discounted expected future gross premiums (at current discount rate)	0	0		0
Undiscounted expected future benefits and expenses	332,902	306,286		293,095
Interest accrual	8,440	7,836		7,454
Gross premiums	$ 41,111	$ 32,105		$ 35,672
Weighted-average duration of the liability in years (at original discount rate)	7 years	7 years		7 years
Weighted-average duration of the liability in years (at current discount rate)	6 years	6 years		7 years
Weighted-Average Interest Rate (At Original Discount Rate)	3.70%	3.60%		3.47%
Weighted-average interest rate (at current discount rate)	4.95%	5.33%		2.49%
Fixed Annuity
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Adjusted balance, beginning of period		$ (989)		$ (1,143)
Term Life and Fixed Annuities
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period	$ 10,911,794	12,485,056		12,791,701
Effect of cumulative changes in discount rate assumptions, beginning of period	554,896	(1,826,120)		(2,461,823)
Balance at original discount rate, beginning of period	11,466,690	10,658,936		10,329,878
Effect of assumption update		(790)		1,295,294		39,089
Effect of actual variances from expected experiences and other activity		(201,502)		(113,804)		246,712
Adjusted balance, beginning of period		11,264,398		11,840,426		10,615,679
Issuances	749,141	470,343		777,403
Net Premium / Consideration Collected	(1,381,171)	(1,369,228)		(1,223,342)
Interest accural	521,176	525,149		489,196
Balance at original discount rate, end of period	11,153,544	11,466,690		10,658,936
Effect of cumulative changes in discount rate assumptions, end of period	(225,711)	(554,896)		1,826,120
Balance, end of period	10,927,833	10,911,794		12,485,056
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	18,039,978	21,174,162		22,135,037
Effect of cumulative changes in discount rate assumptions, beginning of period	986,911	(3,623,979)		(4,920,924)
Balance at original discount rate, beginning of period	19,026,889	17,550,183		17,214,113
Effect of assumption update		(1,044)		1,756,995		40,236
Effect of actual variance from expected experience and other activity		(256,252)		(207,814)		266,583
Adjusted balance, beginning of period		18,769,593		19,099,364		$ 17,520,932
Issuances	749,141	470,343		777,403
Interest accrual	903,463	896,361		840,117
Benefit Payments	(1,419,870)	(1,443,961)		(1,591,419)
Other adjustments	3,760	4,782		3,150
Balance at original discount rate, end of period	19,006,087	19,026,889		17,550,183
Effect of cumulative changes in discount rate assumptions, end of period	(351,092)	(986,911)		3,623,979
Balance after transition, at current discount rate	18,654,995	18,039,978		21,174,162
Balance, end of period, pre-flooring	7,727,162	7,128,184		8,689,106
Flooring impact, end of period	44	0		951
Balance, end of period, post-flooring	7,727,206	7,128,184		8,690,057
Less: Reinsurance Recoverable	6,835,977	6,513,717		7,875,116
Balance after transition, net of reinsurance recoverable	891,229	614,467		$ 814,941
Nonparticipating Traditional and Limited-Pay Business
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Loss in net income	31,000	82,000
Gain in net income	$ 30,000	$ 83,000

[1] Prior period amounts reflect the implementation of ASU 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.