Investments (Net Investment Income - Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Equity Method Investments
Net Investment Income [Line Items]
Gross Investment Income, Operating	$ 89	$ 205

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.2)
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration