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Financial Derivative Instruments - Location and Amount Recognized in Income by Hedging Relationship (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Cash Flow Hedging |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | $ (658) | $ (93)
Cash Flow Hedging | Fuel derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | (654) | (84)
Cash Flow Hedging | Interest rate derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | (4) | (9)
Fuel and oil |  |
Derivative [Line Items] |  |
Derivatives designated as hedging instruments | (203) | 16
Fuel and oil | Cash Flow Hedging | Fuel derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | (203) | 16
Fuel and oil | Cash Flow Hedging | Interest rate derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | 0 | 0
Other (gains)/losses, net |  |
Derivative [Line Items] |  |
Derivatives designated as hedging instruments | 0 | 6
Other (gains)/losses, net | Cash Flow Hedging | Fuel derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | 0 | 6
Other (gains)/losses, net | Cash Flow Hedging | Interest rate derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | 0 | 0
Other operating expenses |  |
Derivative [Line Items] |  |
Derivatives designated as hedging instruments | 2 |
Other operating expenses | Cash Flow Hedging | Fuel derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | 0 |
Other operating expenses | Cash Flow Hedging | Interest rate derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income | $ 2 |
Interest expense |  |
Derivative [Line Items] |  |
Derivatives designated as hedging instruments |  | 1
Interest expense | Cash Flow Hedging | Fuel derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income |  | 0
Interest expense | Cash Flow Hedging | Interest rate derivative contracts |  |
Derivative [Line Items] |  |
Amount of (gain) loss reclassified from AOCI into income |  | $ 1

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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959 + Details
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- Definition Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e689-108580 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e637-108580 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959 + Details
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