Revenue Recognition (Tables)

3 Months Ended

Mar. 31, 2018

Revenue from Contract with Customer [Abstract]

Schedule of disaggregation of revenue

Passenger revenue is primarily composed of passenger ticket sales, loyalty travel awards and travel-related services performed in conjunction with a passenger’s flight.

	Three Months Ended March 31,
(in millions)	2018		2017
Ticket	$	7,653	$	7,105
Loyalty travel awards	618		582
Travel-related services	494		491
Total passenger revenue	$	8,765	$	8,178

Other Revenue

	Three Months Ended March 31,
(in millions)	2018		2017
Ancillary businesses and refinery	$	521	$	312
Loyalty program	347		305
Miscellaneous	133		143
Total other revenue	$	1,001	$	760

Schedule of activity in frequent flyer liability

The table below presents the activity of the current and noncurrent frequent flyer liability, and includes miles earned through travel and miles sold, which are primarily through marketing agreements.

(in millions)	2018			2017
Balance at January 1	$	6,321		$	5,922
Travel mileage credits redeemed	(618		)	(582		)
Non-travel mileage credits redeemed	(40		)	(40		)
Mileage credits earned	731			690
Balance at March 31	$	6,394		$	5,990

Schedule of revenue by geographic region

Our passenger revenue by geographic region (as defined by the U.S. Department of Transportation) is summarized in the following table:

	Three Months Ended March 31,
(in millions)	2018		2017
Domestic	$	6,301	$	5,894
Atlantic	1,059		923
Latin America	827		793
Pacific	578		568
Total passenger revenue	$	8,765	$	8,178