BUSINESS SEGMENT INFORMATION - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 262,496	$ 249,818
Operating Segments | Individual Retirement
Segment Reporting Information [Line Items]
Total assets	129,265	123,627
Operating Segments | Group Retirement
Segment Reporting Information [Line Items]
Total assets	47,745	43,590
Operating Segments | Investment Management and Research
Segment Reporting Information [Line Items]
Total assets	10,736	10,170
Operating Segments | Protection Solutions
Segment Reporting Information [Line Items]
Total assets	47,166	46,832
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 27,584	$ 25,599