Revenue (Tables)

12 Months Ended

Dec. 31, 2019

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, 2019, 2018, and 2017:

	Year ended December 31,
(in millions)	2019		2018		2017
Passenger non-loyalty	$	17,578	$	17,506	$	16,934
Passenger loyalty - air transportation	2,487		2,307		2,263
Passenger ancillary sold separately	711		642		566
Total passenger revenues	$	20,776	$	20,455	$	19,763

Components of Air Traffic Liability

As of the years ended December 31, 2019 and 2018, 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, 2019		December 31, 2018
Air traffic liability - passenger travel and ancillary passenger services	$	2,125	$	2,059
Air traffic liability - loyalty program	3,385		3,011
Total Air traffic liability	$	5,510	$	5,070

Rollforwards of the Company's Air traffic liability - loyalty program for the years ended December 31, 2019 and 2018 were as follows (in millions):

	Year ended December 31,
	2019			2018
Air traffic liability - loyalty program - beginning balance	$	3,011		$	2,667
Amounts deferred associated with points awarded	2,941			2,717
Revenue recognized from points redeemed - Passenger	(2,487		)	(2,307		)
Revenue recognized from points redeemed - Other	(80		)	(66		)
Air traffic liability - loyalty program - ending balance	$	3,385		$	3,011

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, 2019 and 2018 were as follows (in millions):

	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

	Air traffic liability
Balance at December 31, 2017	$	4,565
Current period sales (passenger travel, ancillary services, flight loyalty, and partner loyalty)	21,026
Revenue from amounts included in contract liability opening balances	(3,479		)
Revenue from current period sales	(17,042		)
Balance at December 31, 2018	$	5,070