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Accumulated Other Comprehensive Income - Schedule of AOCI Components (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017
Fuel derivatives |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | $ 83 | $ 3
Changes in Fair Value |  | 102 |
Reclassification to earnings |  | (4) |
ASU 2017-12 Adoption Adjustment | [1] | 26 |
Fuel derivatives | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | 0 |
Interest rate derivatives |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | (4) | (7)
Changes in Fair Value |  | 1 |
Reclassification to earnings |  | (2) |
ASU 2017-12 Adoption Adjustment | [1] | 0 |
Interest rate derivatives | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | 0 |
Defined Benefit Plan Items |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | (9) | (9)
Changes in Fair Value |  | 0 |
Reclassification to earnings |  | 0 |
ASU 2017-12 Adoption Adjustment | [1] | 0 |
Defined Benefit Plan Items | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | 0 |
Other comprehensive income other changes net of tax |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | 33 | 33
Changes in Fair Value |  | 0 |
Reclassification to earnings |  | 0 |
ASU 2017-12 Adoption Adjustment | [1] | 0 |
Other comprehensive income other changes net of tax | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | 0 |
Deferred Tax |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | (25) | (8)
Changes in Fair Value |  | (24) |
Reclassification to earnings |  | (1) |
ASU 2017-12 Adoption Adjustment | [1] | 6 |
Deferred Tax | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | 2 |
AOCI Including Portion Attributable to Noncontrolling Interest |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest |  | 78 | $ 12
Changes in Fair Value |  | 79 |
Reclassification to earnings |  | 5 |
ASU 2017-12 Adoption Adjustment | [1] | (20) |
AOCI Including Portion Attributable to Noncontrolling Interest | Accounting Standards Update 2018-02 |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Reclassification to earnings | [2] | $ 2 |
[1] | The Company adopted the New Hedging Standard as of January 1, 2018. See Note 2 for further information on this adoption.
[2] | The Company adopted the Reclassification of Certain Tax Effects from AOCI as of January 1, 2018. See Note 2 for further information on this adoption.

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