The Proposed Merger with Spirit Airlines, Inc. ("Spirit") (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Business Acquisition [Line Items]
Transaction and merger-related costs	$ 1	$ 11
Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Transaction and merger-related costs	1
Termination fee	69
Spirit Airlines, Inc Merger \| Retention Bonus
Business Acquisition [Line Items]
Transaction and merger-related costs	$ 1	3
Spirit Airlines, Inc Merger \| Legal, Accounting and Other Fees
Business Acquisition [Line Items]
Transaction and merger-related costs		$ 8

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration