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Commitments and Contingencies - Airport Projects (Details) - USD ($) $ in Millions | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Other Commitments [Line Items] |  |  |
ACFO |  | $ 120 | $ 1,768
Assets constructed for others, net |  | 120 | 1,637
Construction Obligation |  | 120 | 1,701
FLL Terminal |  |  |
Other Commitments [Line Items] |  |  |
ACFO |  | 0 | 313
Assets constructed for others, net | [1] | 0 | 304
Construction Obligation |  | 0 | 308
LAX Terminal 1 |  |  |
Other Commitments [Line Items] |  |  |
Outstanding remaining guaranteed obligation |  | 111 |
ACFO |  | 0 | 485
Assets constructed for others, net | [1] | 0 | 459
Construction Obligation |  | 0 | 476
LAX Terminal 1.5 |  |  |
Other Commitments [Line Items] |  |  |
Total Expected Cost Of Airport Project |  | 479 |
Outstanding remaining guaranteed obligation |  | 125 |
ACFO | [2] | 120 | 99
Assets constructed for others, net | [1],[2] | 120 | 99
Construction Obligation | [2] | 120 | 99
LFMP Terminal |  |  |
Other Commitments [Line Items] |  |  |
ACFO |  | 0 | 545
Assets constructed for others, net | [1] | 0 | 460
Construction Obligation |  | 0 | 502
Municipal bonds principal remaining |  | 416 |
Net present value of principal remaining |  | 459 |
LFMP Parking Garage |  |  |
Other Commitments [Line Items] |  |  |
ACFO |  | 0 | 200
Assets constructed for others, net | [1] | 0 | 200
Construction Obligation |  | 0 | 200
HOU International Terminal |  |  |
Other Commitments [Line Items] |  |  |
ACFO | [3] | 0 | 126
Assets constructed for others, net | [1],[3] | 0 | 115
Construction Obligation | [3] | $ 0 | $ 116
[1] | Net of accumulated depreciation.
[2] | Project still in progress.
[3] | Project completed in 2015 at Houston William P. Hobby Airport ("HOU").

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