Business and Basis of Presentation (Schedule of Deferred Policy Acquisition Costs) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022		Sep. 30, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Deferred Policy Acquisition Cost [Line Items]
Balance	$ 6,923,554	$ 6,930,425	[1]	$ 6,824,407	$ 7,029,307	$ 2,493,082
As Previously Reported
Deferred Policy Acquisition Cost [Line Items]
Balance		6,616,097					$ 2,433,936
Change of Effect
Deferred Policy Acquisition Cost [Line Items]
Balance		314,328				74,702
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Other						(15,556)
Term Life
Deferred Policy Acquisition Cost [Line Items]
Balance	716,441	648,837		633,774	577,084	462,099
Term Life | As Previously Reported
Deferred Policy Acquisition Cost [Line Items]
Balance							462,098
Term Life | Change of Effect
Deferred Policy Acquisition Cost [Line Items]
Balance						0
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Other						1
Variable/Universal Life
Deferred Policy Acquisition Cost [Line Items]
Balance	$ 2,765,005	$ 2,442,883		$ 2,336,967	$ 2,561,011	2,030,983
Variable/Universal Life | As Previously Reported
Deferred Policy Acquisition Cost [Line Items]
Balance							$ 1,971,838
Variable/Universal Life | Change of Effect
Deferred Policy Acquisition Cost [Line Items]
Balance						74,702
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Other						$ (15,557)

[1] Prior period amounts adjusted for the implementation of Accounting Standard Update ("ASU") 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.