SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Significant Accounting Policies - Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Other Liabilities, Current [Abstract]
Accrued Capital Expenditures	$ 21				$ 15				$ 13
Accrued Property Tax	5				9
Customer advances and deposits	29				32
Other current liabilities	$ 55	$ 60	$ 59	$ 54	$ 56	$ 66	$ 57	$ 52