INCOME TAXES - Net Operating Loss Carryforwards (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
INCOME TAXES
Increase (decrease) in valuation allowance	$ 251	$ (11)
Net operating loss carryforwards
Operating loss and credit carryforwards period subject to examination and adjustments	3 years
Federal income tax
Net operating loss carryforwards
Operating loss carryforwards, amount	$ 327