COMMITMENT AND CONTINGENT LIABILITIES COMMITMENT AND CONTINGENT LIABILITIES - Restructuring (Details) - AXA - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Employee Severance
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	$ 23	$ 22
Additions / Expense Incurred	7	17
Cash payments	(3)	(14)
Other reductions	0	(2)
Balance, end of Year	27	23
Facility Closing
Restructuring Cost and Reserve [Line Items]
Balance, beginning of year	165	170
Additions / Expense Incurred	0	29
Deferred rent	2	10
Cash payments	(11)	(48)
Interest accretion	1	4
Balance, end of Year	$ 157	$ 165