INVESTMENTS (TROUBLED DEBT RESTRUCTURING) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Gross interest income on restructured loans included in net investment income (loss)	$ 0	$ 0	$ 1
Commercial Real Estate Portfolio Segment
Financing Receivable, Modifications [Line Items]
Outstanding Recorded Investment Post Modification	$ 0	$ 15

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

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