Investments (Rollforward of the Allowance for Credit Losses for Fixed Maturity Securities by Sector (Details) $ in Millions	6 Months Ended
Jun. 30, 2020 USD ($)
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	$ 0
Allowance on securities where credit losses were not previously recorded	5
Allowance on securities that had an allowance recorded in a previous period	(1)
Write-offs charged against allowance	(4)
Fixed maturity securities, allowance for credit losses, end of period	4
U.S. Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	0
Allowance on securities where credit losses were not previously recorded	3
Allowance on securities that had an allowance recorded in a previous period	(1)
Write-offs charged against allowance	(3)
Fixed maturity securities, allowance for credit losses, end of period	2
Foreign Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	0
Allowance on securities where credit losses were not previously recorded	2
Allowance on securities that had an allowance recorded in a previous period	0
Write-offs charged against allowance	(1)
Fixed maturity securities, allowance for credit losses, end of period	2
Cumulative Effect, Adjusted Balance
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	4
Cumulative Effect, Adjusted Balance \| U.S. Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	3
Cumulative Effect, Adjusted Balance \| Foreign Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	$ 1

Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922900-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 9
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922900-210455

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

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- Definition

Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded.

+ References

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- Definition

Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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- Definition

Amount of writeoff of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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