Other Insurance Liabilities and Separate Accounts - Separate Account Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 3,271	$ 3,250
Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	3,226	3,204
Recurring | Other Receivables
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	45	46
Recurring | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	151	168
Recurring | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	2,503	2,507
Recurring | Debt securities | U.S. government securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	588	573
Recurring | Debt securities | States, municipalities and political subdivisions
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	21	28
Recurring | Debt securities | U.S. corporate securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	1,645	1,632
Recurring | Debt securities | Foreign securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	203	202
Recurring | Mortgage-backed securities | Residential mortgage-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	32	51
Recurring | Mortgage-backed securities | Commercial mortgage-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	3	6
Recurring | Other asset-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	11	15
Recurring | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 572	$ 529