BUSINESS SEGMENT INFORMATION - RECONCILIATION OF ASSETS FROM SEGMENT TO CONSOLIDATED (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 221,504	$ 225,930
Operating Segments | Individual Retirement
Segment Reporting Information [Line Items]
Total assets	110,810	120,608
Operating Segments | Group Retirement
Segment Reporting Information [Line Items]
Total assets	43,323	40,472
Operating Segments | Investment Management and Research
Segment Reporting Information [Line Items]
Total assets	9,052	10,079
Operating Segments | Protection Solutions
Segment Reporting Information [Line Items]
Total assets	37,272	34,296
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 21,047	$ 20,475