Reportable Segments (Schedule of Assets of Reportable Segments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	$ 3,202	$ 3,141
Goodwill	2,043	2,043
Total Assets	6,861	7,444
Operating Segments
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	3,202	3,141
Total Assets	6,861	6,796
IMTT | Operating Segments
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	2,323	2,249
Total Assets	4,172	4,020
Atlantic Aviation
Segment Reporting Information [Line Items]
Goodwill	495	496
Atlantic Aviation | Operating Segments
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	567	565
Total Assets	2,060	1,676
MIC Hawaii
Segment Reporting Information [Line Items]
Goodwill	120	120
MIC Hawaii | Operating Segments
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	301	300
Total Assets	537	501
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	11	27
Total Assets	92	599
Discontinued Operations, Held-for-sale
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	0	0
Total Assets	$ 0	$ 648