INVESTMENTS - Trading Securities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Net investment gains (losses) recognized during the period on securities held at the end of the period	$ (13)	$ 15	$ 88	$ 492
Net investment gains (losses) recognized on securities sold during the period	16	14	45	(7)
Unrealized and realized gains (losses) on trading securities	3	29	133	485
Interest and dividend income from trading securities	60	62	159	227
Net investment income (loss) from trading securities	$ 63	$ 91	$ 292	$ 712