Investments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Summary of Investment Holdings [Line Items]
Number of securities, total | security	1,063	1,284
Securities lending rate of collateral required	1.02
Debt Securities
Summary of Investment Holdings [Line Items]
Assets held by insurance regulators	$ 14	$ 13
Foreign government and agency securities
Summary of Investment Holdings [Line Items]
Securities lending rate of collateral required	1.05
Loaned securities
Summary of Investment Holdings [Line Items]
Securities lending rate of collateral required	1
Securities received as collateral	$ 61	$ 16