SPECIAL ITEMS SPECIAL ITEMS - MERGER-RELATED COSTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Merger-related Costs [Line Items]
Contracted services	$ 314	$ 247	$ 214
Special items—merger-related costs	118	117
Virgin America Inc. [Member]
Merger-related Costs [Line Items]
Contracted services	52	32
Severance Costs	40	22
Banking Fees and Commissions	0	36
Legal Fees	3	22
Business Acquisition, Transaction Costs	23	5
Special items—merger-related costs	$ 118	$ 117