Reserves for Future Policy Benefits and Claims Payable - Assessments and Interest Expense, Closed Block Life (Details) - Closed Block Life - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Liability for Future Policy Benefit, Activity [Line Items]
Assessments	$ (47)	$ (148)
Interest Expense	$ 14	$ 56

Amount of interest income (expense) for present value of total expected payment to policyholder in excess of present value of total expected assessment. Excludes benefit classified as market risk benefit or under provisions of Topic 815 on derivative and hedging.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 13I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480046/944-40-55-13I

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-6

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-6

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-6

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration