SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$ 2,142	$ 5,029	$ 9,709	$ 9,952	$ 15,705
Segment earnings (loss) from continuing operations, before income taxes	(573)	2,503
Segment assets	209,098		203,678	$ 194,663
Consolidation/Elimination
Segment Reporting Information [Line Items]
Segment revenues	(7)	(5)
Segment earnings (loss) from continuing operations, before income taxes	(1)	1
Segment assets	0		(3)
Insurance
Segment Reporting Information [Line Items]
Segment revenues	1,393	4,265
Segment earnings (loss) from continuing operations, before income taxes	(724)	2,333
Segment assets	194,898		190,542
Insurance | Intersegment Eliminations
Segment Reporting Information [Line Items]
Segment interest expense, debt	11	12
Investment Management
Segment Reporting Information [Line Items]
Segment revenues	756	769
Segment earnings (loss) from continuing operations, before income taxes	152	169
Segment assets	14,200		13,139
Fair value of marketable securities	1,183		893
Cash segregated in special bank accounts	73		$ 53
Investment Management | Intersegment Eliminations
Segment Reporting Information [Line Items]
Segment investment advisory fees	$ 18	$ 17