Fair Value Measurements - Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 6,087	$ 6,000
Policyholder Account Balance	638	658	$ 687
Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Allowance for Credit Loss	51	36	$ 29	$ 38
Financing Receivable, after Allowance for Credit Loss	6,087	6,000
Significant Unobservable Inputs (Level 3) | Carrying Amount [1]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, after Allowance for Credit Loss	6,087	6,000
Policyholder Account Balance	638	658
Significant Unobservable Inputs (Level 3) | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, after Allowance for Credit Loss	5,584	5,362
Policyholder Account Balance	639	658
Significant Observable Inputs (Level 2) | Carrying Amount [1]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes and Debentures	3,863	3,858
Junior Subordinated Debentures	499	499
Significant Observable Inputs (Level 2) | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes and Debentures	3,533	3,339
Junior Subordinated Debentures	$ 429	$ 419