Revenue - Roll Forward of Frequent Flyer Deferred Revenue (Details) - Frequent Flyer - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Frequent Flyer Deferred Revenue [Roll Forward]
Total Frequent flyer deferred revenue - beginning balance	$ 6,675	$ 6,282
Total miles awarded	747	477
Travel miles redeemed	(531)	(322)
Non-travel miles redeemed	(31)	(20)
Total Frequent flyer deferred revenue - ending balance	$ 6,860	$ 6,417

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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant