INCOME TAXES - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory rate		21.00%	35.00%	35.00%
State income taxes, net of federal benefit		1.80%	1.10%	1.80%
Non-U.S. income tax rate differential		5.30%	(1.60%)	(3.60%)
Effect of tax law changes		(0.60%)	99.70%	0.00%
Basis difference in affiliates		(2.40%)	(2.10%)	(0.10%)
Tax advantaged investments		(2.00%)	(2.20%)	(2.40%)
Other, net		(0.30%)	(0.80%)	(0.70%)
Effective income tax rate		22.80%	129.10%	30.00%
Tax Reform benefit		$ 94
Impact of non-cash charge related to Tax Reform	$ 22,600		$ 22,594
Effective income tax rate before effect of Tax Cuts and Jobs Act		23.30%	29.80%