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Fair Value Measurements - Measured on Recurring Basis (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Fuel derivatives: |  |  |
Derivative Asset, Fair Value, Gross Asset | [1] | $ 444 | $ 1,937
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Liability | [1] | (805) | (3,465)
Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Treasury bills |  | 1,345 | 1,248
Interest rate derivatives (see Note 10) |  |  | 0
Fuel derivatives: |  |  |
Other available for sale securities |  | 83 | 66
Total assets |  | 2,772 | 2,651
Fuel derivatives: |  |  |
Interest rate derivatives (see Note 10) |  | 0 | 0
Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Treasury bills |  | 0 | 0
Interest rate derivatives (see Note 10) |  |  | 2
Fuel derivatives: |  |  |
Other available for sale securities |  | 0 | 0
Total assets |  | 658 | 1,437
Fuel derivatives: |  |  |
Interest rate derivatives (see Note 10) |  | (35) | (49)
Total Liabilities |  | (145) | (823)
Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Treasury bills |  | 0 | 0
Interest rate derivatives (see Note 10) |  |  | 0
Fuel derivatives: |  |  |
Other available for sale securities |  |  | 27
Total assets |  | 402 | 993
Fuel derivatives: |  |  |
Interest rate derivatives (see Note 10) |  | 0 | 0
Total Liabilities |  | (660) | (2,642)
Cash Equivalents | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Cash equivalents | [2] | 1,344 | 1,337
Cash Equivalents | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Cash equivalents | [2] | 0 | 0
Cash Equivalents | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Cash equivalents | [2] | 0 | 0
Commercial paper | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Cash equivalents |  | 0 | 0
Commercial paper | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Cash equivalents |  | 325 | 200
Commercial paper | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Cash equivalents |  | 0 | 0
Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Cash equivalents |  | 0 | 0
Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Cash equivalents |  | 11 | 13
Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Cash equivalents |  | 0 | 0
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Cash equivalents |  |  | 0
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Cash equivalents |  |  | 33
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Cash equivalents |  |  | 0
Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Assets |  |  |
Investments |  | 0 | 0
Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Assets |  |  |
Investments |  | 280 | 220
Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Assets |  |  |
Investments |  | 0 | 0
Swap | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 0 | 0
Derivative Asset, Fair Value, Gross Asset | [4] |  | 0
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Liability | [3] | 0 | 0
Swap | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 42 | 931
Derivative Asset, Fair Value, Gross Asset | [4] |  | 38
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Liability | [3] | (110) | (774)
Swap | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 0 | 0
Derivative Asset, Fair Value, Gross Asset | [4] |  | 0
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Liability | [3] | 0 | 0
Options Held | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 0 | 0
Derivative Asset, Fair Value, Gross Asset | [4] | 0 | 0
Fuel derivatives: |  |  |
Derivative Asset, Fair Value, Gross Liability | [4] | 0 | 0
Derivative Liability, Fair Value, Gross Liability | [3] | 0 | 0
Options Held | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 0 | 0
Derivative Asset, Fair Value, Gross Asset | [4] | 0 | 0
Fuel derivatives: |  |  |
Derivative Asset, Fair Value, Gross Liability | [4] | 0 | 0
Derivative Liability, Fair Value, Gross Liability | [3] | 0 | 0
Options Held | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 163 | 956
Derivative Asset, Fair Value, Gross Asset | [4] | 239 | 10
Fuel derivatives: |  |  |
Derivative Asset, Fair Value, Gross Liability | [4] | (96) | (26)
Derivative Liability, Fair Value, Gross Liability | [3] | (564) | (2,616)
Period end date | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Treasury bills |  | 1,345 | 1,248
Interest rate derivatives (see Note 10) |  |  | 2
Fuel derivatives: |  |  |
Other available for sale securities |  | 83 | 93
Total assets |  | 3,832 | 5,081
Fuel derivatives: |  |  |
Interest rate derivatives (see Note 10) |  | (35) | (49)
Total Liabilities |  | (805) | (3,465)
Period end date | Cash Equivalents | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Cash equivalents | [2] | 1,344 | 1,337
Period end date | Commercial paper | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Cash equivalents |  | 325 | 200
Period end date | Certificates of deposit | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Cash equivalents |  | 11 | 13
Period end date | Eurodollar Time Deposits | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Cash equivalents |  |  | 33
Period end date | Certificates of deposit | Fair Value, Measurements, Recurring |  |  |
Assets |  |  |
Investments |  | 280 | 220
Period end date | Swap | Fair Value, Measurements, Recurring |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 42 | 931
Derivative Asset, Fair Value, Gross Asset | [4] |  | 38
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Liability | [3] | (110) | (774)
Period end date | Options Held | Fair Value, Measurements, Recurring |  |  |
Fuel derivatives: |  |  |
Derivative Liability, Fair Value, Gross Asset | [3] | 163 | 956
Derivative Asset, Fair Value, Gross Asset | [4] | 239 | 10
Fuel derivatives: |  |  |
Derivative Asset, Fair Value, Gross Liability | [4] | (96) | (26)
Derivative Liability, Fair Value, Gross Liability | [3] | $ (564) | $ (2,616)
[1] | Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.
[2] | Cash equivalents are primarily composed of money market investments.
[3] | In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10
[4] | In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.

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