SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents Items
Notes Receivable, Related Parties, Noncurrent	$ 0	$ 0	$ (1,369)
non-cash payment from subsidiary of ETP	0	541	793
Non-Cash Settlement of Tax Liability	(8)	0	0
Non-Cash Settlement of Tax Receivable	0		0
Accrued Capital Expenditures	11	15	21
Interest Paid, Net	75	75	76
Increase (Decrease) in Notes Receivables	$ 18	$ 40	$ 16