Business and Basis of Presentation (Schedule of Deferred Reinsurance) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Liability for Future Policy Benefit, Activity [Line Items]
Balance	$ 17,216,882		$ 17,684,170
Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance					$ 362,347
As Previously Reported | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance						$ 233,678
Unwinding amounts related to unrealized investment gains and losses | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					14,804
Effect of change in reserve basis to market risk benefits | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					141,032
Effect of change in SOP 03-1 reserve basis | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					(27,167)
Variable Annuities | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance					274,415
Variable Annuities | As Previously Reported | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance						118,579
Variable Annuities | Unwinding amounts related to unrealized investment gains and losses | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					14,804
Variable Annuities | Effect of change in reserve basis to market risk benefits | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					141,032
Variable Annuities | Effect of change in SOP 03-1 reserve basis | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Term Life
Liability for Future Policy Benefit, Activity [Line Items]
Balance	$ 17,003,374	$ 17,835,251	$ 17,482,881	$ 20,937,097
Term Life | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance					87,932
Term Life | As Previously Reported | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance						87,932
Term Life | Unwinding amounts related to unrealized investment gains and losses | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Term Life | Effect of change in reserve basis to market risk benefits | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Term Life | Effect of change in SOP 03-1 reserve basis | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Variable/Universal Life | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance					0
Variable/Universal Life | Deferred Reinsurance Gain
Liability for Future Policy Benefit, Activity [Line Items]
Balance					174,259
Variable/Universal Life | As Previously Reported | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Activity [Line Items]
Balance						27,167
Variable/Universal Life | As Previously Reported | Deferred Reinsurance Gain
Liability for Future Policy Benefit, Activity [Line Items]
Balance						$ 134,213
Variable/Universal Life | Unwinding amounts related to unrealized investment gains and losses | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Variable/Universal Life | Effect of change in reserve basis to market risk benefits | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					0
Variable/Universal Life | Effect of change in SOP 03-1 reserve basis | Deferred Reinsurance Losses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					(27,167)
Variable/Universal Life | Effect of change in SOP 03-1 reserve basis | Deferred Reinsurance Gain
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Cash flow change					$ 40,046