Investments - 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
Schedule of Investments [Line Items]
Gross investment income	$ 367	$ 58	$ 584	$ 173
Investment expense	(31)	(1)	(43)	(3)
Net investment income	336	57	541	170
Fixed maturity securities, available-for-sale
Schedule of Investments [Line Items]
Gross investment income	286	18	419	54
Equity securities
Schedule of Investments [Line Items]
Gross investment income	5	3	14	7
Preferred securities
Schedule of Investments [Line Items]
Gross investment income	15	5	40	17
Commercial mortgage loans
Schedule of Investments [Line Items]
Gross investment income	24	0	31	0
Invested cash and short-term investments
Schedule of Investments [Line Items]
Gross investment income	0	9	8	24
Limited partnerships
Schedule of Investments [Line Items]
Gross investment income	25	0	25	0
Tax deferred property exchange income
Schedule of Investments [Line Items]
Gross investment income	5	20	28	55
Other investments
Schedule of Investments [Line Items]
Gross investment income	$ 7	$ 3	$ 19	$ 16

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)
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Amount of expenses related to the generation of investment income.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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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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