Special Charges (Credit) - Narrative (Details) employee in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2017 USD ($) employee	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Cash received under the Payroll Support Program	$ 4,500,000,000			$ 4,500,000,000
Cash received from grants	3,200,000,000			3,200,000,000
Cash received from the issuance of an unsecured loan	1,300,000,000			1,300,000,000
Cash received from the issuance of warrants	57,000,000			57,000,000
Portion of grant recognized as a credit to special charges due to COVID-19	1,589,000,000	$ 0		1,589,000,000	$ 0
Deferred credit	1,508,000,000			1,508,000,000		$ 0
Settlement losses	231,000,000	0		231,000,000	0
Nonoperating credit loss on BRW Term Loan and related guarantee	0	0		697,000,000	0
Nonoperating unrealized losses on investments	(9,000,000)	(34,000,000)		310,000,000	(51,000,000)
Charge for the early termination of several regional aircraft finance leases		6,000,000
Other miscellaneous impairments		8,000,000
Loss recorded for the change in fair value of certain derivative assets		4,000,000			1,000,000
Fair value adjustment for aircraft purchased off lease					8,000,000
Severance and benefit costs	63,000,000	6,000,000		63,000,000	12,000,000
Azul
Restructuring Cost and Reserve [Line Items]
Nonoperating unrealized losses on investments				284,000,000
Gain (loss) for the change in fair value of equity investments	9,000,000	38,000,000		(284,000,000)	52,000,000
AVH Derivative Assets
Restructuring Cost and Reserve [Line Items]
Nonoperating unrealized losses on investments				24,000,000
Management
Restructuring Cost and Reserve [Line Items]
Severance and benefit costs		6,000,000			10,000,000
Voluntary Early-Out Program | International Brotherhood of Teamsters
Restructuring Cost and Reserve [Line Items]
Severance and benefit costs					$ 2,000,000
Number of technicians and related employees that elected to voluntarily separate from the Company | employee			1
Maximum severance payment per employee (up to)			$ 100,000
Term Loan Receivable | BRW
Restructuring Cost and Reserve [Line Items]
Nonoperating credit loss on BRW Term Loan and related guarantee				697,000,000
Routes
Restructuring Cost and Reserve [Line Items]
Fair value of indefinite-lived intangible assets	1,000,000,000.0			1,000,000,000.0
Impairment of intangible assets	$ 80,000,000			$ 130,000,000
Aircraft Engines [Member]
Restructuring Cost and Reserve [Line Items]
Impairment for aircraft engines removed from operations		$ 47,000,000