Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ (68)	$ 50
Other Comprehensive Income Loss, Pension And Other Postretirement Benefit Plans, Net Actuarial Loss And Prior Service Cost Arising During Period, Tax	0	0
Other Comprehensive Income, Change in Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	$ 3	$ (1)

Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration