SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$ 2,520	$ 4,783	$ 2,375	$ 2,177	$ 3,464	$ 3,950	$ 7,173	$ 7,274	$ 9,673	$ 9,451	$ 9,201	$ 9,019	$ 13,503
Segment interest expense, debt				14
Segment investment advisory fees				(21)
Segment earnings (loss) from continuing operations, before income taxes	(61)			83					1,873	2,365
Segment assets	219,069	$ 215,358	$ 209,551	209,432	$ 207,460	$ 200,475	$ 215,358	$ 207,460	219,069	209,432	204,169	$ 195,220
Consolidation/Elimination
Segment Reporting Information [Line Items]
Segment revenues	(7)			(7)					(19)	(19)
Segment earnings (loss) from continuing operations, before income taxes	0			(1)					0	0
Segment assets	0								0		(3)
Insurance
Segment Reporting Information [Line Items]
Segment revenues	1,713								7,309	7,227
Segment earnings (loss) from continuing operations, before income taxes	(229)			(99)					1,385	1,875
Segment assets	205,176								205,176		191,033
Insurance | Intersegment Eliminations
Segment Reporting Information [Line Items]
Segment interest expense, debt	18								42	39
Investment Management
Segment Reporting Information [Line Items]
Segment revenues	814								2,383	2,243
Segment earnings (loss) from continuing operations, before income taxes	168			$ 183					488	490
Segment assets	13,893								13,893		13,139
Fair value of marketable securities	723								723		893
Cash segregated in special bank accounts	62								62		$ 53
Investment Management | Intersegment Eliminations
Segment Reporting Information [Line Items]
Segment investment advisory fees	$ 29								$ 65	$ 58