Segments of Operations - Narrative (Details) $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($) segment	Mar. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of segments \| segment	2
Net investment income	$ 188	$ 104
Neon Capital Limited
Segment Reporting Information [Line Items]
Net investment income		(6)
Continuing operations
Segment Reporting Information [Line Items]
Earnings from Real-Estate Related Investments, net of DAC	29	6
Continuing operations \| Real estate-related investments
Segment Reporting Information [Line Items]
Net investment income	29	12
Property and Casualty Insurance
Segment Reporting Information [Line Items]
Net investment income	159	93
Property and casualty insurance underwriting	134	87
Investment and other income, net	154	84
Other lines \| Property and Casualty Insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	$ 0	(2)
Other lines \| Property and Casualty Insurance \| Neon Capital Limited
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		(1)
Investment and other income, net		(9)
Neon Capital Limited \| Other lines \| Property and Casualty Insurance
Segment Reporting Information [Line Items]
Net investment income		$ (6)

Earnings from real-estate related investments, net of DAC

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- Definition

Net investment income plus other income less other expenses.

+ References

No definition available.

+ Details

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- Definition

Underwriting income (loss) for the property and casualty insurance segment, which is calculated as premiums earned less losses and loss adjustment expenses less commissions and other underwriting expenses.

+ References

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- Definition

Amount, after 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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=120400993&loc=SL114874131-224263

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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8672-108599

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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