Commitments and Contingencies - Airport Projects (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
LAX Terminal 1.5
Other Commitments [Line Items]
Total Expected Cost Of Airport Project	$ 479
Outstanding remaining guaranteed obligation	212
Assets constructed for others, net	198	$ 164
LFMP Terminal
Other Commitments [Line Items]
Municipal bonds principal remaining	407
Net present value of principal remaining	$ 449