LONG-TERM DEBT - SCHEDULE OF LONG-TERM DEBT (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Debt Issuance Costs, Net	$ (15)		$ (15)
Total	2,449		2,569
Less current portion	387		307
Long-term debt, less current portion	$ 2,062		$ 2,262
Weighted-average fixed-interest rate	4.20%		4.20%
Weighted-average variable-interest rate	3.30%		2.80%
Long-term debt payments	$ 120	$ 101
Repayments of Debt	23
Fixed rate notes payable due through 2028 [Member]
Debt Instrument [Line Items]
Total	877		$ 959
Variable rate notes payable due through 2028 [Member]
Debt Instrument [Line Items]
Total	$ 1,587		$ 1,625