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AOCI - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Reclassification Out of Accumulated Other Comprehensive Income [Line Items] |  |
Fuel and oil | $ 1,015 | $ 1,018
Interest Expense | (31) | (32)
Less: Tax Expense | (117) | $ (139)
Interest rate derivatives |  |
Reclassification Out of Accumulated Other Comprehensive Income [Line Items] |  |
Reclassification to earnings | (1) |
Reclassification out of Accumulated Other Comprehensive Income |  |
Reclassification Out of Accumulated Other Comprehensive Income [Line Items] |  |
Net of Tax | 9 |
Reclassification out of Accumulated Other Comprehensive Income | Fuel derivatives |  |
Reclassification Out of Accumulated Other Comprehensive Income [Line Items] |  |
Reclassification to earnings | (11) |
Less: Tax Expense | 3 |
Net of Tax | 8 |
Reclassification out of Accumulated Other Comprehensive Income | Interest rate derivatives |  |
Reclassification Out of Accumulated Other Comprehensive Income [Line Items] |  |
Net of Tax | $ 1 |

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- Definition Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(a),(d)) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 + Details
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324 + Details
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- Definition Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1377-109256 + Details
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