SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Significant Accounting Policies - Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Liabilities, Current [Abstract]
Accrued Capital Expenditures	$ 15	$ 21	$ 15
Accrued Property Tax	7	5
Customer advances and deposits	18	29
Other current liabilities	$ 40	$ 55