Revenue (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Passenger Revenue

The following table provides the components of Passenger revenue recognized for the years ended December 31, 2020, 2019, and 2018:

	Year ended December 31,
(in millions)	2020		2019		2018
Passenger non-loyalty	$	6,303	$	17,578	$	17,506
Passenger loyalty - air transportation	1,003		2,487		2,307
Passenger ancillary sold separately	359		711		642
Total passenger revenues	$	7,665	$	20,776	$	20,455

Components of Air Traffic Liability

As of the years ended December 31, 2020 and 2019, the components of Air traffic liability, including contract liabilities based on tickets sold, unused funds available to the Customer, and loyalty points available for redemption, net of expected spoilage, within the Consolidated Balance Sheet were as follows:

	Balance as of
(in millions)	December 31, 2020		December 31, 2019
Air traffic liability - passenger travel and ancillary passenger services	$	2,686	$	2,125
Air traffic liability - loyalty program	4,447		3,385
Total Air traffic liability	$	7,133	$	5,510

Rollforwards of the Company's Air traffic liability - loyalty program for the years ended December 31, 2020 and 2019 were as follows (in millions):

	Year ended December 31,
	2020		2019
Air traffic liability - loyalty program - beginning balance	$	3,385	$	3,011
Amounts deferred associated with points awarded	1,958		2,941
Revenue recognized from points redeemed - Passenger	(1,003)		(2,487)
Revenue recognized from points redeemed - Other	(60)		(80)
Unused funds converted to loyalty points	167		—
Air traffic liability - loyalty program - ending balance	$	4,447	$	3,385

Rollforward of Air Traffic Liability

Air traffic liability includes consideration received for ticket and loyalty related performance obligations which have not been satisfied as of a given date. Rollforwards of the amounts included in Air traffic liability as of December 31, 2020 and 2019 were as follows (in millions):

	Air traffic liability
Balance at December 31, 2019	$	5,510
Current period sales (passenger travel, ancillary services, flight loyalty, and partner loyalty)	9,348
Revenue from amounts included in contract liability opening balances	(2,317)
Revenue from current period sales	(5,408)
Balance at December 31, 2020	$	7,133

	Air traffic liability
Balance at December 31, 2018	$	5,070
Current period sales (passenger travel, ancillary services, flight loyalty, and partner loyalty)	21,296
Revenue from amounts included in contract liability opening balances	(3,816)
Revenue from current period sales	(17,040)
Balance at December 31, 2019	$	5,510