INVESTMENTS - TRADING SECURITIES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Realized and Unrealized Gain (Loss) on Trading Securities [Abstract]
Net investment gains (losses) recognized during the period on securities held at the end of the period	$ (64)	$ 51
Net investment gains (losses) recognized on securities sold during the period	1	2
Unrealized and realized gains (losses) on trading securities arising during the period	(63)	53
Interest and dividend income from trading securities	66	40
Net investment income (loss) from trading securities	$ 3	$ 93