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	$ 287	$ 159	$ 101	$ 477
Net investment gains (losses) recognized on securities sold during the period	25	3	29	(21)
Unrealized and realized gains (losses) on trading securities	312	162	130	456
Interest and dividend income from trading securities	48	73	99	165
Net investment income (loss) from trading securities	$ 360	$ 235	$ 229	$ 621