Liability For Future Policy Benefits (Additional Insurance Reserves) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Additional Liability, Long-Duration Insurance [Line Items]
Balance after reinsurance recoverables, including amounts in AOCI, end of period	$ 346,549	$ 226,829
Other Businesses
Additional Liability, Long-Duration Insurance [Line Items]
Balance after reinsurance recoverables, including amounts in AOCI, end of period	6,905	0
Variable/Universal Life
Additional Liability, Long-Duration Insurance [Line Items]
Balance, including amounts in AOCI, post-flooring	16,351,053	14,280,793
Flooring impact and amounts in AOCI	617,186	831,583
Balance, excluding amounts in AOCI, beginning of period, pre-flooring	16,968,239	15,112,376
Effect of assumption update			$ (41,977)	$ 154,058
Effect of actual variances from expected experience and other activity			173,587	326,790
Adjusted balance, beginning of period			17,099,849	15,593,224
Assessments collected	846,682	843,853
Interest accrual	438,236	397,904
Benefits paid	(294,911)	(258,579)
Balance, excluding amounts in AOCI, end of period, pre-flooring	18,089,856	16,576,402
Flooring impact and amounts in AOCI	(407,664)	(343,625)
Balance, including amounts in AOCI, end of period, post-flooring	17,682,192	16,232,777
Less: Reinsurance recoverables	17,442,639	16,005,948
Balance after reinsurance recoverables, including amounts in AOCI, end of period	$ 239,553	$ 226,829
Weighted-average duration of the liability in years (at original discount rate)	21 years	22 years
Weighted-average interest rate (at original discount rate)	3.34%	3.39%
Fixed Annuities
Additional Liability, Long-Duration Insurance [Line Items]
Balance, including amounts in AOCI, post-flooring	$ 0	$ 0
Flooring impact and amounts in AOCI	0	0
Balance, excluding amounts in AOCI, beginning of period, pre-flooring	0	0
Effect of assumption update			0	0
Effect of actual variances from expected experience and other activity			62,992	0
Adjusted balance, beginning of period			62,992	0
Assessments collected	43,033	0
Interest accrual	1,330	0
Benefits paid	0	0
Balance, excluding amounts in AOCI, end of period, pre-flooring	107,355	0
Flooring impact and amounts in AOCI	(7,264)	0
Balance, including amounts in AOCI, end of period, post-flooring	100,091	0
Less: Reinsurance recoverables	0	0
Balance after reinsurance recoverables, including amounts in AOCI, end of period	$ 100,091	0
Weighted-average duration of the liability in years (at original discount rate)	22 years
Weighted-average interest rate (at original discount rate)	2.73%
Term Life And Fixed Annuities | Total
Additional Liability, Long-Duration Insurance [Line Items]
Balance, including amounts in AOCI, post-flooring	$ 16,351,053	14,280,793
Flooring impact and amounts in AOCI	617,186	831,583
Balance, excluding amounts in AOCI, beginning of period, pre-flooring	16,968,239	15,112,376
Effect of assumption update			(41,977)	154,058
Effect of actual variances from expected experience and other activity			236,579	326,790
Adjusted balance, beginning of period			$ 17,162,841	$ 15,593,224
Assessments collected	889,715	843,853
Interest accrual	439,566	397,904
Benefits paid	(294,911)	(258,579)
Balance, excluding amounts in AOCI, end of period, pre-flooring	18,197,211	16,576,402
Flooring impact and amounts in AOCI	(414,928)	(343,625)
Balance, including amounts in AOCI, end of period, post-flooring	17,782,283	16,232,777
Less: Reinsurance recoverables	17,442,639	16,005,948
Balance after reinsurance recoverables, including amounts in AOCI, end of period	$ 339,644	$ 226,829