Schedule of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 2,179	$ 3,006	$ 2,002
Other assets:
Restricted cash	124	204	276
Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows	2,303	3,212	2,322	$ 3,615
Prepaid Expenses and Other
Current assets:
Restricted cash		2	44
United Airlines, Inc.
Current assets:
Cash and cash equivalents	2,173	3,000	1,996
Other assets:
Restricted cash	124	204	276
Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows	$ 2,297	3,206	2,316	$ 3,609
United Airlines, Inc. | Prepaid Expenses and Other
Current assets:
Restricted cash		$ 2	$ 44