Liability For Future Policy Benefits (Additional Insurance Reserves) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Insurance [Abstract]
Balance, including amounts in AOCI, post-flooring	$ 14,280,793	$ 12,664,445
Flooring impact and amounts in AOCI	831,583	1,269,237
Balance, excluding amounts in AOCI, beginning of period, pre-flooring	15,112,376	13,933,682
Effect of assumption update			$ 154,058	$ 22,910
Effect of actual variances from expected experience and other activity			161,320	26,204
Adjusted balance, beginning of period			$ 15,427,754	$ 13,982,796
Assessments collected	586,734	513,593
Interest accrual	261,019	237,869
Benefits paid	(158,757)	(151,097)
Balance, excluding amounts in AOCI, end of period, pre-flooring	16,116,750	14,583,161
Flooring impact and amounts in AOCI	(1,642,621)	(1,094,298)
Balance, including amounts in AOCI, end of period, post-flooring	14,474,129	13,488,863
Less: Reinsurance recoverables	14,286,902	13,268,534
Balance after reinsurance recoverables, including amounts in AOCI, end of period	187,227	220,329
Gross assessments	$ 903,426	$ 785,370
Weighted-average duration of the liability in years (at original discount rate)	22 years	22 years
Weighted-average interest rate (at original discount rate)	3.40%	3.39%