Future Contract Benefit - Summary of Gross Premiums and Interest Accretion (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Payout Annuities
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 40	$ 16	$ 84	$ 88
Interest accretion	22	21	65	64
Traditional Life
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	311	310	942	937
Interest accretion	$ 37	$ 35	$ 111	$ 106

Amount of gross premium income recognized for liability for future policy benefit.

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-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

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-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

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