Operating Leases - Lessor Concessions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Increase (decrease) in deferrals related to leases	$ (22)	$ 33
Aircraft Rental
Lessee, Lease, Description [Line Items]
Deferrals related to leases	(31)	31
Station Operations
Lessee, Lease, Description [Line Items]
Deferrals related to leases	$ 9	$ 2

The increase (decrease) during the reporting period in the book value of deferred leasing fees. Amortization of these fees over the terms of the leases reduces deferred leasing fees. Originating new leases increases the balance of deferred leasing fees.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInDeferredLeasingFees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration