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Special Charges - Additional Information (Detail) | 3 Months Ended
--- | ---
Mar. 31, 2018 USD ($) | Mar. 31, 2017 USD ($) Technician
Special Charges [Line Items] |  |
Severance and benefits costs | $ 14,000,000 | $ 37,000,000
Fair value adjustment for aircraft purchased | 23,000,000 |
Fair value adjustment for aircraft purchased, net of taxes | $ 17,000,000 |
Severance-related accrual expected payment date | 2019 |
Grounded aircraft related accrual expected payment date | 2025 |
International Brotherhood of Teamsters |  |
Special Charges [Line Items] |  |
Severance and benefits costs | $ 8,000,000 | 21,000,000
Severance and benefits costs net of tax | 7,000,000 | $ 14,000,000
Voluntary early out program | International Brotherhood of Teamsters |  |
Special Charges [Line Items] |  |
Number of positions eliminated | Technician |  | 1,000
Voluntary early out program | International Brotherhood of Teamsters | Maximum |  |
Special Charges [Line Items] |  |
Severance payment per participant |  | $ 100,000
Management Reorganization Initiative |  |
Special Charges [Line Items] |  |
Severance and benefits costs | 6,000,000 | 16,000,000
Severance and benefits costs net of tax | $ 4,000,000 | $ 10,000,000

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- Definition Amount expected to be recognized in earnings for the specified restructuring cost. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)) -URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747 + Details
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