Other Insurance Liabilities and Separate Accounts - Separate Account Assets (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 3,200	$ 3,228
Separate accounts liabilities	3,200	3,228	$ 3,318	$ 5,087
Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	3,159	3,313
Other Receivables | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	41
Other Payables | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts liabilities		85
Cash and cash equivalents | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	153	156
Debt securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	2,563	2,677
Debt securities | U.S. government securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	671	717
Debt securities | States, municipalities and political subdivisions | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	26	27
Debt securities | U.S. corporate securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	1,610	1,667
Debt securities | Foreign securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	198	201
Mortgage-backed securities | Residential mortgage-backed securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	37	41
Mortgage-backed securities | Commercial mortgage-backed securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	6	6
Other asset-backed securities | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	15	18
Common/collective trusts | Recurring
Fair Value, Separate Account Investment [Line Items]
Separate accounts assets	$ 443	$ 480