Intangible Assets and Goodwill (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 59	$ 68	$ 64
Amount of fair value in excess of carrying amount				$ 2,200
Percentage of fair value in excess of carrying amount				33.00%
Atlantic Aviation
Finite-Lived Intangible Assets [Line Items]
Amount of fair value in excess of carrying amount				$ 1,900
MIC Hawaii
Finite-Lived Intangible Assets [Line Items]
Amount of fair value in excess of carrying amount				280
IMTT
Finite-Lived Intangible Assets [Line Items]
Amount of fair value in excess of carrying amount				$ 20
Percentage increase in discount rate	0.25%
Change in fair value from goodwill sensitivity	$ 70
Trade names
Finite-Lived Intangible Assets [Line Items]
Finite and indefinite lived trade names net	12
Indefinite-lived Intangible Assets | Atlantic Aviation
Finite-Lived Intangible Assets [Line Items]
Finite and indefinite lived trade names net	7
Indefinite-lived Intangible Assets | MIC Hawaii
Finite-Lived Intangible Assets [Line Items]
Finite and indefinite lived trade names net	$ 5