Fair Value Measurements - Fair Value Option (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 20		$ 22
Changes in fair value of assets using fair value option	$ 0	$ 0

For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612

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