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Significant Accounting Policies - Roll Forward of Frequent Flier Deferred Revenue (Details) - Transportation Advance Ticket Arrangement - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Movement in Deferred Revenue [Roll Forward] |  |
Total Frequent flyer deferred revenue - beginning balance | $ 4,783 | $ 4,889
Total miles awarded | 2,451 | 2,077
Travel miles redeemed (Passenger revenue) | (2,068) | (2,004)
Non-travel miles redeemed (Other operating revenue) | (161) | (179)
Total Frequent flyer deferred revenue - ending balance | $ 5,005 | $ 4,783

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- Definition Frequent flyer mileage miles awarded in period. + References No definition available. + Details
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- Definition Non-travel miles redemption, frequent flyer deferred revenue. + References No definition available. + Details
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- Definition Travel miles redemption, frequent flyer deferred revenue. + References No definition available. + Details
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- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130532-203044 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130549-203045 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130531-203044 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Details
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