INVESTMENTS - Trading Securities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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	$ 250	$ 150	$ 87	$ 424
Net investment gains (losses) recognized on securities sold during the period	14	1	17	(23)
Unrealized and realized gains (losses) on trading securities	264	151	104	401
Interest and dividend income from trading securities	45	71	94	161
Net investment income (loss) from trading securities	$ 309	$ 222	$ 198	$ 562