Investments - Summary of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Short-term Investments [Member]
Investment [Line Items]
Gross Investment Income, Operating	$ 1	$ 4	$ 4	$ 14
Principal Amount Outstanding of Loans Held-in-portfolio
Investment [Line Items]
Gross Investment Income, Operating	$ 0	$ 0	$ 0	$ 1

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.2)
-URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263

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