Investments, Available-for-sale Impairment Losses Recognized in Earnings (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Available-For-Sale Impairment Losses [Abstract]
Loss on mortgage loans due to changes in expected credit losses	$ 21
Fixed Maturity Securities Available-for-sale [Member]
Available-For-Sale Impairment Losses [Abstract]
Impairment losses recognized in earnings	111	$ 44	$ 21
Change in unrealized gains on fixed maturity securities	1,600	2,600	(1,800)
Fixed Maturity Securities Available-for-sale [Member] \| Corporate and Other Bonds [Member]
Available-For-Sale Impairment Losses [Abstract]
Impairment losses recognized in earnings	87	33	12
Fixed Maturity Securities Available-for-sale [Member] \| Asset-Backed [Member]
Available-For-Sale Impairment Losses [Abstract]
Impairment losses recognized in earnings	$ 24	$ 11	$ 9

Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=121553693&loc=SL6284422-111562

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Amount of credit loss expense (reversal of expense) for financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(11))
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Amount of unrealized gain (loss) on investment.

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-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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