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Commitments and Contingencies - Airport Projects (Details) - USD ($) $ in Millions | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Other Commitments [Line Items] |  |
Assets constructed for others | $ 274 | $ 164
LAX Terminal 1.5 |  |
Other Commitments [Line Items] |  |
Outstanding remaining guaranteed obligation | 289 |
Total Not to Exceed Cost Of Airport Project | 464 |
LFMP Terminal |  |
Other Commitments [Line Items] |  |
Municipal bonds principal remaining | 407 |
Net present value of principal remaining | $ 448 |

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