FAIR VALUE MEASUREMENTS (Basis of Fair Value Measurements on a Recurring Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ (475)	$ (476)
Cash and Cash Equivalents, Fair Value Disclosure	9	7
Available-for-sale Securities, Debt Securities	0	2
Long-term Debt, Fair Value	(604)	(571)
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	2	2	$ 1
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Amortized Cost Basis	0	2
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	9	7
Financial Instruments Gross Unrealized Gains	0	0
Financial Instruments Gross Unrealized Loss	0	0
Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments Gross Unrealized Gains	0	0
Financial Instruments Gross Unrealized Loss	$ (129)	$ (95)