Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 25, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Common stock dividends per share declared (in dollars per share)		$ 0.1	$ 0.1	$ 0.3000	$ 0.3
Proceeds from notes payable				$ 1,300
Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock dividends per share declared (in dollars per share)	$ 0.10
Proceeds from notes payable	$ 74
American Airlines, Inc. [Member]
Subsequent Event [Line Items]
Proceeds from notes payable				$ 1,300
American Airlines, Inc. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from notes payable	$ 74