Derivative Instruments - Gains (Losses) on Derivatives Not Designated as Hedging (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	$ 675,000,000	$ 63,000,000
Investment related gains (losses)
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	1,692,000,000	(184,000,000)
Investment related gains (losses) \| Equity options
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	849,000,000	(142,000,000)
Investment related gains (losses) \| Futures
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	(11,000,000)	(5,000,000)
Investment related gains (losses) \| Swap [Member]
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	18,000,000	2,000,000
Investment related gains (losses) \| Foreign currency forwards
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	6,000,000	(7,000,000)
Investment related gains (losses) \| Embedded derivatives
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	830,000,000	(32,000,000)
Interest sensitive contract benefits \| Embedded derivatives
Derivative [Line Items]
Total gains (losses) for derivatives not designated as hedges	(1,017,000,000)	247,000,000
Cash flow hedges \| Derivatives designated as hedges \| Foreign currency swaps
Derivative [Line Items]
Foreign currency swap gain (loss) reclassified to income	$ 0	$ 0

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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