Investments (Allowance for Credit Loss for Fixed Maturity Securities AFS by Sector) Details (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Allowance balance, beginning of period	$ 44	$ 0
ACL not previously recorded	0	68
Changes for securities with previously recorded ACL	2	(1)
Securities sold or exchanged	(9)	(29)
Securities intended/required to be sold prior to recovery of amortized cost basis	0	(1)
Allowance balance, end of period	37	37
U.S. corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Allowance balance, beginning of period	28	0
ACL not previously recorded	0	51
Changes for securities with previously recorded ACL	4	1
Securities sold or exchanged	(4)	(23)
Securities intended/required to be sold prior to recovery of amortized cost basis	0	(1)
Allowance balance, end of period	28	28
Foreign government
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Allowance balance, beginning of period	5	0
ACL not previously recorded	0	6
Changes for securities with previously recorded ACL	0	0
Securities sold or exchanged	(5)	(6)
Securities intended/required to be sold prior to recovery of amortized cost basis	0	0
Allowance balance, end of period	0	0
Foreign corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Allowance balance, beginning of period	9	0
ACL not previously recorded	0	9
Changes for securities with previously recorded ACL	0	0
Securities sold or exchanged	0	0
Securities intended/required to be sold prior to recovery of amortized cost basis	0	0
Allowance balance, end of period	9	9
RMBS
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Allowance balance, beginning of period	2	0
ACL not previously recorded	0	2
Changes for securities with previously recorded ACL	(2)	(2)
Securities sold or exchanged	0	0
Securities intended/required to be sold prior to recovery of amortized cost basis	0	0
Allowance balance, end of period	$ 0	$ 0

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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82922868-210454

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