Other Insurance Liabilities and Separate Accounts - Separate Account Assets (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 1,924	$ 3,311
Separate accounts liabilities	1,924	3,311	$ 3,271	$ 3,250
Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	1,899	3,499
Recurring | Other Receivables
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	25
Recurring | Other Payables
Fair Value, Separate Account Investment [Line Items]
Separate accounts liabilities		188
Recurring | Cash and cash equivalents
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	160	165
Recurring | Debt securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	396	856
Recurring | Debt securities | U.S. government securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	26	186
Recurring | Debt securities | States, municipalities and political subdivisions
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	12	14
Recurring | Debt securities | U.S. corporate securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	293	524
Recurring | Debt securities | Foreign securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	48	51
Recurring | Mortgage-backed securities | Residential mortgage-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	9	71
Recurring | Mortgage-backed securities | Commercial mortgage-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	3	3
Recurring | Other asset-backed securities
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	5	7
Recurring | Common/collective trusts
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 1,343	$ 2,478