Investments (Rollforward of the Allowance for Credit Losses for Fixed Maturity Securities by Sector (Details) $ in Millions	9 Months Ended
Sep. 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
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(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
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(1)
Write-offs charged against allowance	(3)
Fixed maturity securities, allowance for credit losses, end of period	2
RMBS
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	1
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	0
Write-offs charged against allowance	0
Fixed maturity securities, allowance for credit losses, end of period	1
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	1
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	0
Write-offs charged against allowance	(1)
Fixed maturity securities, allowance for credit losses, end of period	1
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 \| RMBS
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Fixed maturity securities, allowance for credit losses, beginning of period	0
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.

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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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Amount of decrease in 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) from sale.

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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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