LONG-TERM DEBT - SCHEDULE OF LONG-TERM DEBT (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 159	$ 57
Total	2,806		$ 2,964
Debt Issuance Costs, Net	(16)		(18)
Less current portion	337		319
Long-term debt, less current portion	$ 2,469		$ 2,645
Weighted-average fixed-interest rate	4.30%		4.40%
Weighted-average variable-interest rate	2.60%		2.40%
Fixed rate notes payable due through 2028 [Member]
Debt Instrument [Line Items]
Total	$ 1,090		$ 1,179
Variable rate notes payable due through 2028 [Member]
Debt Instrument [Line Items]
Total	$ 1,732		$ 1,803