Policyholders' Liabilities (Additional Insurance Reserves) (Details) - Variable/Universal Life - Policyholder Contract Deposit - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Policyholder Account Balance, Unearned Revenue Reserve	$ 3,067,336	$ 2,398,788
Policyholder Account Balance, Unearned Revenue Reserve, Issuance	612,196	594,026
Policyholder Account Balance, Unearned Revenue Reserve, Amortization Expense	(111,353)	(96,077)
Other adjustments	(95)	53
Policyholder Account Balance, Unearned Revenue Reserve	3,568,084	2,896,790
Policyholder Account Balance, Unearned Revenue Reserve, Reinsurance	1,656,299	1,498,140
Unearned revenue reserve net of reinsurance recoverables	$ 1,911,785	$ 1,398,650