BUSINESS SEGMENT INFORMATION - Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 2,031	$ 2,314
Adjustments related to:
Investment expenses	19	19
Operating Segments | Individual Retirement
Segment Reporting Information [Line Items]
Total revenues	619	904
Operating Segments | Group Retirement
Segment Reporting Information [Line Items]
Total revenues	245	230
Operating Segments | Investment Management and Research
Segment Reporting Information [Line Items]
Total revenues	909	742
Operating Segments | Protection Solutions
Segment Reporting Information [Line Items]
Total revenues	644	633
Corporate and Other
Segment Reporting Information [Line Items]
Total revenues	197	238
Segment Reconciling Items
Adjustments related to:
GMxB features	(586)	(485)
Investment gains (losses)	87	(11)
Investment income (loss) from certain derivative instruments	20	0
Other adjustments to segment revenues	(104)	63
Intersegment Eliminations
Adjustments related to:
Investment expenses	16	15
Investment management and other fees	$ 23	$ 22