Investments - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Investments [Line Items]
Gross investment income	$ 163	$ 60	$ 216	$ 115
Investment expense	(11)	(1)	(11)	(2)
Net investment income	152	59	205	113
Fixed maturity securities, available-for-sale
Schedule of Investments [Line Items]
Gross investment income	117	18	134	35
Equity securities
Schedule of Investments [Line Items]
Gross investment income	13	2	17	4
Preferred securities
Schedule of Investments [Line Items]
Gross investment income	11	7	17	12
Commercial mortgage loans
Schedule of Investments [Line Items]
Gross investment income	7	0	7	0
Invested cash and short-term investments
Schedule of Investments [Line Items]
Gross investment income	8	9	33	18
Other investments
Schedule of Investments [Line Items]
Gross investment income	$ 7	$ 24	$ 8	$ 46

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
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-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.2)
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Amount of expenses related to the generation of investment income.

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-Publisher FASB
-Name Accounting Standards Codification
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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

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