Details about Accumulated Other Comprehensive Income Components (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2015
United Airlines, Inc.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Additional gains related to investments and other	$ 1	$ 1

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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