REVENUES - Contract Liabilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Contract with Customer, Liability [Roll Forward]
Opening balance, January 1, 2018	$ 0
Adoption of ASC 606 adjustment	(68)
Revenue from performance obligations satisfied during reporting period	12
Payments received in advance	(15)
Closing balance, March 31, 2018	(71)
Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, March 31, 2018	(9)
Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, March 31, 2018	$ (62)