INCOME TAXES - Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 423	$ 403	$ (42)
Tax effect of changes in OCI	(12)	154	(194)
Total comprehensive income tax expense (benefit)	$ 411	$ 557	$ (236)