Revenue Recognition - Loyalty Program Liability (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021
Loyalty program activity
Miles earned	$ 1,558	$ 915
Miles redeemed for air travel	(1,287)	(669)
Miles redeemed for non-air travel and other	(73)	(27)
Current and noncurrent deferred revenue, ending	7,757	7,401
Loyalty program
Loyalty program activity
Current and noncurrent deferred revenue, beginning	$ 7,559	$ 7,182

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130532-203044

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant