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AOCI - Schedule of AOCI Components (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2018
Fuel derivatives |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | $ 365 | $ 3
ASU 2017-12 Adoption Adjustment | [1] |  | 26
Changes in Fair Value |  | 159 | 559
Ending Balance |  | 504 | 504
Fuel derivatives | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 0
Interest rate derivatives |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | (2) | (7)
ASU 2017-12 Adoption Adjustment | [1] |  | 0
Changes in Fair Value |  | 0 | 2
Reclassification to earnings |  | (1) | (4)
Ending Balance |  | (1) | (1)
Interest rate derivatives | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 0
Defined Benefit Plan Items |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | (9) | (9)
ASU 2017-12 Adoption Adjustment | [1] |  | 0
Changes in Fair Value |  | 0 | 0
Reclassification to earnings |  | 0 | 0
Ending Balance |  | (9) | (9)
Defined Benefit Plan Items | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 0
Other comprehensive income other changes net of tax |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | 36 | 33
ASU 2017-12 Adoption Adjustment | [1] |  | 0
Changes in Fair Value |  | 7 | 10
Reclassification to earnings |  | 0 | 0
Ending Balance |  | 43 | 43
Other comprehensive income other changes net of tax | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 0
Deferred Tax |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | (92) | (8)
ASU 2017-12 Adoption Adjustment | [1] |  | 6
Changes in Fair Value |  | (38) | (132)
Reclassification to earnings |  | 5 | 7
Ending Balance |  | (125) | (125)
Deferred Tax | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 2
AOCI Including Portion Attributable to Noncontrolling Interest |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Beginning Balance |  | 298 | 12
ASU 2017-12 Adoption Adjustment | [1] |  | (20)
Changes in Fair Value |  | 128 | 439
Reclassification to earnings |  | (14) | (21)
Ending Balance |  | 412 | 412
AOCI Including Portion Attributable to Noncontrolling Interest | Accounting Standards Update 2018-02 |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings | [2] |  | 2
Reclassification out of Accumulated Other Comprehensive Income | Fuel derivatives |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Reclassification to earnings |  | $ 20 | $ 32
[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, which allowed the Company to reclassify to Retained earnings any tax effects stranded in AOCI as a result of the Tax Cuts and Jobs Act enacted in December 2017.

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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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