Liability For Future Policy Benefits (Benefit Reserves) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Other adjustments	$ (2,434)	$ (6,565)	$ 15,745	$ (1,030)
Balance, end of period	18,840,135	17,216,882	18,840,135	17,216,882
Other Businesses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, end of period	1,610	1,838	1,610	1,838
Nonparticipating Traditional And Limited-Pay Business
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Gain in net income			(29,000)	(35,000)
Loss in net income			28,000	34,000
Term Life
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period			10,927,833	10,911,794
Effect of cumulative changes in discount rate assumptions, beginning of period			225,711	554,896
Balance at original discount rate, beginning of period			11,153,544	11,466,690
Effect of assumption update					$ 21,466	$ (790)
Effect of actual variances from expected experience and other activity					(198,894)	(144,504)
Adjusted balance, beginning of period			10,976,116	11,321,396
Issuances			608,144	512,379
Net premiums / considerations collected			(992,948)	(1,008,159)
Interest accrual			383,336	391,662
Other adjustments			7,091
Balance at original discount rate, end of period	10,981,739	11,217,278	10,981,739	11,217,278
Effect of cumulative changes in discount rate assumptions, end of period	(111,296)	(939,494)	(111,296)	(939,494)
Balance, end of period	10,870,443	10,277,784	10,870,443	10,277,784
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period			18,426,207	17,835,251
Effect of cumulative changes in discount rate assumptions, beginning of period			331,571	962,034
Balance at original discount rate, beginning of period			18,757,778	18,797,285
Effect of assumption update					21,480	(1,044)
Effect of actual variances from expected experience and other activity					(245,193)	(191,864)
Adjusted balance, beginning of period			18,534,065	18,604,377
Issuances			608,144	512,379
Interest accrual			668,751	670,905
Benefit payments			(1,062,328)	(1,019,151)
Other adjustments			10,421	2,845
Balance at original discount rate, end of period	18,759,053	18,771,355	18,759,053	18,771,355
Effect of cumulative changes in discount rate assumptions, end of period	(159,410)	(1,767,981)	(159,410)	(1,767,981)
Balance, end of period	18,599,643	17,003,374	18,599,643	17,003,374
Balance, end of period, pre-flooring	7,729,200	6,725,590	7,729,200	6,725,590
Flooring impact, end of period	44	1,773	44	1,773
Balance, end of period, post flooring	7,729,244	6,727,363	7,729,244	6,727,363
Reinsurance recoverable	6,910,121	6,241,505	6,910,121	6,241,505
Balance after reinsurance recoverables, end of period, post-flooring	819,123	485,858	819,123	485,858
Term Life | Gross Basis
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Undiscounted expected future gross premiums	21,790,252	21,914,391	21,790,252	21,914,391
Discounted expected future gross premiums (at original discount rate)	14,899,016	15,083,578	14,899,016	15,083,578
Discounted expected future gross premiums (at current discount rate)	14,780,675	13,840,343	14,780,675	13,840,343
Undiscounted expected future benefits and expenses	$ 29,134,537	$ 29,147,479	$ 29,134,537	$ 29,147,479
Weighted-average duration of the liability in years (at original discount rate)	10 years	10 years	10 years	10 years
Weighted-average duration of the liability in years (at current discount rate)	9 years	9 years	9 years	9 years
Weighted-average interest rate (at original discount rate)	5.13%	5.18%	5.13%	5.18%
Weighted-average interest rate (at current discount rate)	4.91%	6.02%	4.91%	6.02%
Fixed Annuities
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period			$ 0	$ 0
Effect of cumulative changes in discount rate assumptions, beginning of period			0	0
Balance at original discount rate, beginning of period			0	0
Effect of assumption update					0	0
Effect of actual variances from expected experience and other activity					201	(1,257)
Issuances			25,850	28,889
Net premiums / considerations collected			(26,051)	(27,632)
Interest accrual			0	0
Other adjustments			0
Balance at original discount rate, end of period	$ 0	$ 0	0	0
Effect of cumulative changes in discount rate assumptions, end of period	0	0	0	0
Balance, end of period	0	0	0	0
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period			228,788	204,727
Effect of cumulative changes in discount rate assumptions, beginning of period			19,521	24,876
Balance at original discount rate, beginning of period			248,309	229,603
Effect of assumption update					(3,643)	0
Effect of actual variances from expected experience and other activity					391	6,793
Adjusted balance, beginning of period			245,057	236,396
Issuances			25,850	28,889
Interest accrual			6,752	6,300
Benefit payments			(23,877)	(25,504)
Other adjustments			(149)	(84)
Balance at original discount rate, end of period	253,633	245,997	253,633	245,997
Effect of cumulative changes in discount rate assumptions, end of period	(14,751)	(34,327)	(14,751)	(34,327)
Balance, end of period	238,882	211,670	238,882	211,670
Balance, end of period, pre-flooring	238,882	211,670	238,882	211,670
Flooring impact, end of period	0	0	0	0
Balance, end of period, post flooring	238,882	211,670	238,882	211,670
Reinsurance recoverable	20,461	17,097	20,461	17,097
Balance after reinsurance recoverables, end of period, post-flooring	218,421	194,573	218,421	194,573
Fixed Annuities | Gross Basis
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Undiscounted expected future gross premiums	0	0	0	0
Discounted expected future gross premiums (at original discount rate)	0	0	0	0
Discounted expected future gross premiums (at current discount rate)	0	0	0	0
Undiscounted expected future benefits and expenses	$ 341,000	$ 328,212	$ 341,000	$ 328,212
Weighted-average duration of the liability in years (at original discount rate)	7 years	7 years	7 years	7 years
Weighted-average duration of the liability in years (at current discount rate)	6 years	6 years	6 years	6 years
Weighted-average interest rate (at original discount rate)	3.90%	3.62%	3.90%	3.62%
Weighted-average interest rate (at current discount rate)	4.82%	5.95%	4.82%	5.95%
Fixed Annuity Netting
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Adjusted balance, beginning of period			$ 201	$ (1,257)
Term Life And Fixed Annuities
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Balance, beginning of period			10,927,833	10,911,794
Effect of cumulative changes in discount rate assumptions, beginning of period			225,711	554,896
Balance at original discount rate, beginning of period			11,153,544	11,466,690
Effect of assumption update					21,466	(790)
Effect of actual variances from expected experience and other activity					(198,693)	(145,761)
Adjusted balance, beginning of period			10,976,317	11,320,139
Issuances			633,994	541,268
Net premiums / considerations collected			(1,018,999)	(1,035,791)
Interest accrual			383,336	391,662
Other adjustments			7,091
Balance at original discount rate, end of period	$ 10,981,739	$ 11,217,278	10,981,739	11,217,278
Effect of cumulative changes in discount rate assumptions, end of period	(111,296)	(939,494)	(111,296)	(939,494)
Balance, end of period	10,870,443	10,277,784	10,870,443	10,277,784
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, end of period, pre-flooring	7,968,082	6,937,260	7,968,082	6,937,260
Flooring impact, end of period	44	1,773	44	1,773
Balance, end of period, post flooring	7,968,126	6,939,033	7,968,126	6,939,033
Reinsurance recoverable	6,930,582	6,258,602	6,930,582	6,258,602
Balance after reinsurance recoverables, end of period, post-flooring	1,037,544	680,431	1,037,544	680,431
Term Life And Fixed Annuities | Total
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period			18,654,995	18,039,978
Effect of cumulative changes in discount rate assumptions, beginning of period			351,092	986,910
Balance at original discount rate, beginning of period			19,006,087	19,026,888
Effect of assumption update					17,837	(1,044)
Effect of actual variances from expected experience and other activity					$ (244,802)	$ (185,071)
Adjusted balance, beginning of period			18,779,122	18,840,773
Issuances			633,994	541,268
Interest accrual			675,503	677,205
Benefit payments			(1,086,205)	(1,044,655)
Other adjustments			10,272	2,761
Balance at original discount rate, end of period	19,012,686	19,017,352	19,012,686	19,017,352
Effect of cumulative changes in discount rate assumptions, end of period	(174,161)	(1,802,308)	(174,161)	(1,802,308)
Balance, end of period	$ 18,838,525	$ 17,215,044	$ 18,838,525	$ 17,215,044