Reinsurance - Components of Company's Reinsurance Recoverable on Market Risk Benefits (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Effects of Reinsurance [Line Items]
Reinsurance recoverable on market risk benefits, at fair value	$ 126	$ 149
Variable annuity
Effects of Reinsurance [Line Items]
Reinsurance recoverable on market risk benefits, at fair value	72	90
Other product lines
Effects of Reinsurance [Line Items]
Reinsurance recoverable on market risk benefits, at fair value	$ 54	$ 59

Amount, after allowance for credit loss, recoverable under reinsurance for contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 29G
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480046/944-40-55-29G

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 7B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-7B

Name:	us-gaap_MarketRiskBenefitReinsuranceRecoverableAfterAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant