ESTIMATES, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND BALANCE SHEET DETAIL Estimates, Significant Accounting Policies and Balance Sheet Detail - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Non-Current Liabilities [Line Items]
Liability, Other Retirement Benefits, Noncurrent	$ 117	$ 120
Asset Retirement Obligation	26	57	$ 54	$ 58
Other Accrued Liabilities, Current	90	64
Other Liabilities, Noncurrent	$ 233	$ 241