Alaska Air (ALK) 10-K 12 Feb 20 2019 FY Annual report Financial data

Cover

Cover - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-8957
Entity Registrant Name	ALASKA AIR GROUP, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	91-1292054
Entity Address, Address Line One	19300 International Boulevard
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98188
City Area Code	206
Local Phone Number	392-5040
Title of 12(b) Security	Common Stock, $0.01 Par Value
Security Exchange Name	NYSE
Trading Symbol	ALK
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		122,913,010
Entity Public Float			$ 7.9
Amendment Flag	false
Document Fiscal Year Focus	2019
Entity Central Index Key	0000766421
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 221	$ 105	$ 194
Marketable securities	1,300	1,131
Total cash and marketable securities	1,521	1,236
Receivables - net	323	366
Inventories and supplies - net	72	60
Prepaid expenses and other current assets	121	125
Total Current Assets	2,037	1,787
Property and Equipment
Aircraft and other flight equipment	8,549	8,221
Other property and equipment	1,306	1,363
Deposits for future flight equipment	533	439
Property and Equipment	10,388	10,023
Less accumulated depreciation and amortization	3,486	3,242
Total Property and Equipment - Net	6,902	6,781
Other Assets
Operating Lease, Right-of-Use Asset	1,711	0
Goodwill	1,943	1,943
Intangible assets - net	122	127
Other noncurrent assets	278	274
Total Other Assets	4,054	2,344
Total Assets	12,993	10,912
Current Liabilities
Accounts payable	146	132
Accrued wages, vacation and payroll taxes	470	415
Air traffic liability	900	788
Other accrued liabilities	431	416
Deferred revenue	750	705
Operating Lease, Liability, Current	269	0
Current portion of long-term debt	235	486
Total Current Liabilities	3,201	2,942
Long-Term Debt, Net of Current Portion	1,264	1,617
Other Liabilities and Credits
Operating Lease, Liability, Noncurrent	1,439	0
Deferred income taxes	715	512
Deferred revenue	1,240	1,169
Obligation for pension and postretirement medical benefits	571	503
Other liabilities	232	418
Total Other Liabilities and Credits	4,197	2,602
Commitments and Contingencies
Shareholders' Equity
Preferred stock, $0.01 par value, Authorized: 5,000,000 shares, none issued or outstanding	0	0
Common stock, $0.01 par value, Authorized: 400,000,000 shares, Issued: 2019 - 131,812,173 shares; 2018 - 130,813,476 shares, Outstanding: 2019 - 123,000,307 shares; 2018 - 123,194,430 shares	1	1
Capital in excess of par value	305	232
Treasury stock (common), at cost: 2019 - 8,811,866 shares; 2018 - 7,619,046 shares	(643)	(568)
Accumulated other comprehensive loss	(465)	(448)
Retained earnings	5,133	4,534
Shareholders' Equity Total	4,331	3,751	$ 3,460	$ 2,744
Total Liabilities and Shareholders' Equity	$ 12,993	$ 10,912

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Total Operating Revenues		$ 8,781	$ 8,264	$ 7,894
Operating Expenses
Wages and benefits		2,370	2,190	1,931
Variable incentive pay		163	147	135
Aircraft fuel, including hedging gains and losses		1,878	1,936	1,447
Aircraft maintenance		437	435	391
Aircraft rent		331	315	274
Landing fees and other rentals		531	499	460
Contracted services		289	306	314
Selling expense		313	326	368
Depreciation and amortization		423	398	372
Cost of Services, Catering		214	211	195
Third-party regional carrier expense		166	154	121
Other operating expenses		559	572	562
Special items - merger-related costs		44	87	116
Special items—other		0	45	0
Total Operating Expenses		7,718	7,621	6,686
Operating Income		1,063	643	1,208
Non-operating Income (Expense)
Interest income		42	38	34
Interest expense		(78)	(91)	(103)
Interest capitalized		15	18	17
Other - net		(26)	(23)	3
Nonoperating Income (Expense) Total		(47)	(58)	(49)
Income before income tax		1,016	585	1,159
Income Tax Expense, Before Tax Cuts and Jobs Act of 2017		247	148	436
Special tax expense (benefit)		0	0	(237)
Income tax expense		247	148	199
Net Income		$ 769	$ 437	$ 960
Basic earnings per share		$ 6.24	$ 3.55	$ 7.79
Diluted earnings per share		$ 6.19	$ 3.52	$ 7.75
Shares used for computation:
Basic		123,279	123,230	123,211
Diluted		124,289	123,975	123,854
Cash dividend declared per share	$ 0.35	$ 1.40
Mileage Plan Services, Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		$ 465	$ 434	$ 418
Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		221	199	175
Passenger Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		8,095	7,631	7,301
Passenger Revenue [Member] | Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		8,095	7,631	7,301
Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		1,169	1,053	959
Mileage Plan Revenue [Member] | Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		704	619	541
Mileage Plan Revenue [Member] | Mileage Plan Services, Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		465	434	418
Cargo and Other Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		221	199	175
Cargo and Other Revenue [Member] | Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax		$ 221	$ 199	$ 175

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 1	$ 1
Shareholders' Equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	131,812,173	130,813,476
Common stock, shares, outstanding	123,000,307	123,194,430
Treasury stock, shares	8,811,866	7,619,046

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income	$ 769	$ 437	$ 960
Related to marketable securities:
Unrealized holding gains (losses) arising during the period	31	(14)	(4)
Reclassification of (gains) losses into Other-net non-operating income (expense)	(5)	8	1
Income tax benefit (expense)	(6)	2	1
Marketable securities, net of tax	20	(4)	(2)
Related to employee benefit plans:
Actuarial losses related to pension and other postretirement benefit plans	(71)	(34)	(123)
Reclassification of net pension expense into Wages and benefits and Other-net non-operating income	32	28	22
Income tax benefit (expense)	10	2	24
Employee benefit plans, net of tax	29	4	77
Related to interest rate derivative instruments:
Unrealized holding gains (losses) arising during the period	(13)	0	1
Reclassification of losses into Aircraft rent	3	3	5
Income tax benefit (expense)	2	(1)	(2)
Interest rate derivative instruments, net of tax	(8)	2	4
Other comprehensive income (loss)	(17)	(6)	(75)
Comprehensive income	$ 752	$ 431	$ 885

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss	Retained Earnings
Stockholders' Equity at Dec. 31, 2016	$ 2,744	$ 1	$ 110	$ (443)	$ (305)	$ 3,381
Common Stock Outstanding at Dec. 31, 2016		123,328,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	960					960
Other comprehensive income (loss)	(75)				(75)
Common stock repurchase (in shares)		(981,000)
Common stock repurchase	(75)		0	(75)
Stock-based compensation	34		34
Cash dividend declared ($1.20 per share)	(148)					(148)
Stock issued for employee stock purchase plan (in shares)		407,000
Stock issued for employee stock purchase plan	24		24
Stock issued under stock plans (in shares)		307,000
Stock issued under stock plans	(4)		(4)
Stockholders' Equity at Dec. 31, 2017	3,460	$ 1	164	(518)	(380)	4,193
Common Stock Outstanding at Dec. 31, 2017		123,061,000
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect	0				(62)	62
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	437					437
Other comprehensive income (loss)	(6)				(6)
Common stock repurchase (in shares)		(776,000)
Common stock repurchase	(50)		0	(50)
Stock-based compensation	36		36
Cash dividend declared ($1.20 per share)	(158)					(158)
Stock issued for employee stock purchase plan (in shares)		632,000
Stock issued for employee stock purchase plan	35		35
Stock issued under stock plans (in shares)		277,000
Stock issued under stock plans	(3)		(3)
Stockholders' Equity at Dec. 31, 2018	$ 3,751	$ 1	232	(568)	(448)	4,534
Common Stock Outstanding at Dec. 31, 2018	123,194,430	123,194,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 769					769
Other comprehensive income (loss)	(17)				(17)
Common stock repurchase (in shares)		(1,193,000)
Common stock repurchase	(75)		0	(75)
Stock-based compensation	36		36
Cash dividend declared ($1.20 per share)	(173)					(173)
Stock issued for employee stock purchase plan (in shares)		785,000
Stock issued for employee stock purchase plan	40		40
Stock issued under stock plans (in shares)		214,000
Stock issued under stock plans	(3)		(3)
Stockholders' Equity at Dec. 31, 2019	$ 4,331	$ 1	$ 305	$ (643)	$ (465)	5,133
Common Stock Outstanding at Dec. 31, 2019	123,000,307	123,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 3					$ 3

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net Income	$ 769	$ 437	$ 960
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	423	398	372
Stock-based compensation and other	29	47	55
Changes in certain assets and liabilities:
Changes in deferred tax provision	209	146	45
(Increase) decrease in accounts receivable	43	(25)	(39)
Increase (decrease) in air traffic liability	112	(18)	45
Increase (decrease) in deferred revenue	116	149	191
Changes in pension and other postretirement benefits	68	52	17
Other - net	18	9	(41)
Net cash provided by operating activities	1,722	1,195	1,590
Property and equipment additions:
Aircraft and aircraft purchase deposits	(356)	(686)	(804)
Other flight equipment	(178)	(105)	(96)
Other property and equipment	(162)	(169)	(126)
Total property and equipment additions	(696)	(960)	(1,026)
Purchases of marketable securities	(1,810)	(834)	(1,569)
Sales and maturities of marketable securities	1,674	1,116	1,388
Proceeds from disposition of assets and changes in restricted deposits	41	47	78
Net cash used in investing activities	(791)	(631)	(1,129)
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of issuance costs	450	339	0
Long-term debt payments	(1,058)	(807)	(397)
Common stock repurchases	(75)	(50)	(75)
Cash dividend paid	(173)	(158)	(148)
Other financing activities	43	29	28
Net cash used in financing activities	(813)	(647)	(592)
Net increase (decrease) in cash, cash equivalents, and restricted cash	118	(83)	(131)
Cash, cash equivalents, and restricted cash at beginning of year	114	197	328
Cash, cash equivalents, and restricted cash at end of year	232	114	197
Cash paid during the year for:
Interest, net of amount capitalized	60	72	84
Income taxes, net of refunds received	31	0	177
Cash and cash equivalents	$ 221	$ 105	$ 194

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of cash, cash equivalents, and restricted cash at end of the period
Cash and cash equivalents	$ 221	$ 105	$ 194
Restricted Cash and Investments, Current	11	9	3
Total cash, cash equivalents, and restricted cash at end of the period	$ 232	$ 114	$ 197

GENERAL AND SUMMARY OF SIGNIFIC

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Basis of Presentation The consolidated financial statements include the accounts of Air Group, or the Company, and its primary subsidiaries, Alaska and Horizon. Our consolidated financial statements also include McGee Air Services, a ground services subsidiary of Alaska. The Company conducts substantially all of its operations through these subsidiaries. All significant intercompany balances and transactions have been eliminated. These financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America and their preparation requires the use of management’s estimates. Actual results may differ from these estimates. Certain reclassifications have been made to prior year financial statements to conform to classifications used in the current year. Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with original maturities of three months or less, such as money market funds, commercial paper and certificates of deposit. They are carried at cost, which approximates market value. The Company reduces cash balances when funds are disbursed. Due to the time delay in funds clearing the banks, the Company normally maintains a negative balance in its cash disbursement accounts, which is reported as a current liability. The amount of the negative cash balance was $7 million and $5 million at December 31, 2019 and 2018, and is included in accounts payable, with the change in the balance during the year included in other financing activities in the consolidated statements of cash flows. The Company's restricted cash balances are not material and are classified as Other noncurrent assets. Restricted cash balances are primarily used to guarantee various letters of credit, self-insurance programs or other contractual rights. They consist of highly liquid securities with original maturities of three months or less. They are carried at cost, which approximates fair value. Marketable Securities Investments with original maturities of greater than three months and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. All cash equivalents and short-term investments are classified as available-for-sale and realized gains and losses are recorded using the specific identification method. Changes in market value, excluding other-than-temporary impairments, are reflected in accumulated other comprehensive loss (AOCL). Investments are considered to be impaired when a decline in fair value is judged to be other-than-temporary. The Company uses a systematic methodology that considers available quantitative and qualitative evidence in evaluating potential impairment. If the cost of an investment exceeds its fair value, management evaluates, among other factors, general market conditions, credit quality of debt instrument issuers, the duration and extent to which the fair value is less than cost, the Company's intent and ability to hold, or plans to sell, the investment. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to Other—net in the consolidated statements of operations and a new cost basis in the investment is established. Inventories and Supplies—net Expendable aircraft parts, materials and supplies are stated at average cost and are included in Inventories and supplies — net. An obsolescence allowance for expendable parts is accrued based on estimated lives of the corresponding fleet type and salvage values. The allowance for expendable inventories was $41 million and $39 million at December 31, 2019 and 2018. Inventory and supplies — net also includes fuel inventory of $28 million and $24 million at December 31, 2019 and 2018. Repairable and rotable aircraft parts inventories are included in flight equipment. Property, Equipment and Depreciation Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives less an estimated salvage value, which are as follows: Estimated Useful Life Estimated Salvage Value Aircraft and other flight equipment: Boeing 737, Airbus A319/A320, and E175 aircraft 20-25 years 10% Bombardier Q400 aircraft 15 years 5% Buildings 25 - 40 years 10% Minor building and land improvements 10 years —% Capitalized leases and leasehold improvements Generally shorter of lease term or —% Computer hardware and software 3-10 years —% Other furniture and equipment 5-10 years —% Near the end of an asset's estimated useful life, management updates the salvage value estimates based on current market conditions and expected use of the asset. Repairable and rotable aircraft parts are included in Aircraft and other flight equipment, and are depreciated over the associated fleet life. Capitalized interest, based on the Company’s weighted-average borrowing rate, is added to the cost of the related asset, and is depreciated over the estimated useful life of the asset. Maintenance and repairs, other than engine maintenance on B737-800 engines, are expensed when incurred. Major modifications that extend the life or improve the usefulness of aircraft are capitalized and depreciated over their estimated period of use. Maintenance on B737-800 engines is covered under a power-by-the-hour agreement with a third party, whereby the Company pays a determinable amount, and transfers risk, to a third party. The Company expenses the contract amounts based on engine usage. The Company evaluates long-lived assets to be held and used for impairment whenever events or changes in circumstances indicate that the total carrying amount of an asset or asset group may not be recoverable. The Company groups assets for purposes of such reviews at the lowest level at which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities, which is generally the fleet level. An impairment loss is considered when estimated future undiscounted cash flows expected to result from the use of the asset or asset group and its eventual disposition are less than its carrying amount. If the asset or asset group is not considered recoverable, a write-down equal to the excess of the carrying amount over the fair value will be recorded. Goodwill Goodwill represents the excess of purchase price over the fair value of the related net assets acquired in the Company's acquisition of Virgin America and is not amortized. The total balance of goodwill is associated with the Mainline reporting unit. The Company reviews goodwill for impairment annually in Q4, or more frequently if events or circumstances indicate than an impairment may exist. If fair value of the reporting unit does not exceed the carrying amount, an impairment charge may be recorded. In 2019, the fair value of the reporting unit with goodwill substantially exceeded its carrying value. Intangible Assets Intangible assets recorded in conjunction with the acquisition of Virgin America consist primarily of indefinite-lived airport slots, finite-lived airport gates and finite-lived customer relationships. Finite-lived intangibles are amortized over their estimated useful lives. Indefinite-lived intangibles are not amortized, but are tested at least annually for impairment using a similar methodology to property, equipment and goodwill, as described above. Aircraft Maintenance Deposits Certain Airbus leases include contractually required maintenance deposit payments to the lessor, which collateralize the lessor for future maintenance events should the Company not perform required maintenance. Most of the lease agreements provide that maintenance deposits are reimbursable upon completion of the major maintenance event in an amount equal to the lesser of (i) the amount qualified for reimbursement from maintenance deposits held by the lessor associated with the specific major maintenance event or (ii) the qualifying costs related to the specific major maintenance event. The Company establishes accounting maintenance deposits based on the anticipated timing and cost of the specific major maintenance events, such that the accounting deposits do not exceed the amount qualified for reimbursement. Aircraft maintenance deposits were $143 million and $90 million as of December 31, 2019 and December 31, 2018. Leased Aircraft Return Costs Cash payments associated with returning leased aircraft are accrued when it is probable that a cash payment will be made and that amount is reasonably estimable, usually no sooner than after the last scheduled maintenance event prior to lease return. Any accrual is based on the time remaining on the lease, planned aircraft usage and the provisions included in the lease agreement, although the actual amount due to any lessor upon return may not be known with certainty until lease termination. As leased aircraft are returned, any payments are charged against the established accrual. The accrual is part of other current and long-term liabilities and was not material as of December 31, 2019 and December 31, 2018. The expense is included in Aircraft maintenance in the consolidated statements of operations. Advertising Expenses The Company's advertising expenses include advertising and promotional costs. Advertising production costs are expensed as incurred. Advertising expense was $72 million, $79 million and $91 million during the years ended December 31, 2019, 2018 and 2017. Derivative Financial Instruments The Company's operations are significantly impacted by changes in aircraft fuel prices and interest rates. In an effort to manage exposure to these risks, the Company periodically enters into fuel and interest rate derivative instruments. These derivative instruments are recognized at fair value on the balance sheet and changes in the fair value are recognized in AOCL or in the consolidated statements of operations, depending on the nature of the instrument. The Company does not apply hedge accounting to its derivative fuel hedge contracts nor does it hold or issue them for trading purposes. For cash flow hedges related to interest rate swaps, the effective portion of the derivative represents the change in fair value of the hedge that offsets the change in fair value of the hedged item. To the extent the change in the fair value of the hedge does not perfectly offset the change in the fair value of the hedged item, the ineffective portion of the hedge is immediately recognized in interest expense. Fair Value Measurements Accounting standards define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The standards also establish a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company has elected not to use the fair value option provided in the accounting standards for non-financial instruments. Accordingly, those assets and liabilities are carried at amortized cost. For financial instruments, the assets and liabilities are carried at fair value, which is determined based on the market approach or income approach, depending upon the level of inputs used. Assets and liabilities recognized or disclosed at fair value on a nonrecurring basis include items such as property, plant and equipment, goodwill, intangible assets and certain other assets and liabilities. The Company determines the fair value of these items using Level 3 inputs, as described in Note 4. Income Taxes The Company uses the asset and liability approach for accounting for and reporting income taxes. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities, and their respective tax bases and for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance would be established, if necessary, for the amount of any tax benefits that, based on available evidence, are not expected to be realized. As of December 31, 2019, there is a partial valuation allowance against net deferred tax assets. The Company accounts for unrecognized tax benefits in accordance with the applicable accounting standards. The Company has substantial federal and state net operating losses (NOLs) for income tax purposes as a result of the acquisition of Virgin America. The Company's ability to utilize Virgin America's NOLs is limited by previous “ownership changes,” as defined in Section 382 of the Internal Revenue Code and similar state provisions, and could be further limited if there is another ownership change. In general terms, an ownership change can occur whenever there is a collective shift in the ownership of a company by more than 50% by one or more “5% stockholders” within a three-year period. The occurrence of such a change generally limits the amount of NOL carryforwards a company could utilize in a given year to the aggregate fair market value of the company's common stock immediately prior to the ownership change, multiplied by the long-term tax-exempt interest rate in effect for the month of the ownership change. The acquisition constituted an ownership change and the potential for further limitations following the acquisition. See Note 7 to the consolidated financial statements for more discussion of the calculation. Stock-Based Compensation Accounting standards require companies to recognize as expense the fair value of stock options and other equity-based compensation issued to employees as of the grant date. These standards apply to all stock awards that the Company grants to employees as well as the Company’s Employee Stock Purchase Plan (ESPP), which features a look-back provision and allows employees to purchase stock at a 15% discount. All stock-based compensation expense is recorded in wages and benefits in the consolidated statements of operations. Earnings Per Share (EPS) Diluted EPS is calculated by dividing net income by the average common shares outstanding plus additional common shares that would have been outstanding assuming the exercise of in-the-money stock options and restricted stock units, using the treasury-stock method. In 2019, 2018, and 2017, anti-dilutive stock options excluded from the calculation of EPS were not material. Recently Adopted Accounting Pronouncements

REVENUE FROM CONTRACTS WITH CUS

REVENUE FROM CONTRACTS WITH CUSTOMERS (Notes)	12 Months Ended
	Dec. 31, 2019
Revenue from Contracts with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUETicket revenue is recorded as Passenger revenue, and represents the primary source of the Company's revenue. Also included in Passenger revenue are passenger ancillary revenues such as bag fees, on-board food and beverage, ticket change fees, and certain revenue from the frequent flyer program. Mileage Plan other revenue includes brand and marketing revenue from our co-branded credit card and other partners and certain interline frequent flyer revenue, net of commissions. Cargo and other revenue includes freight and mail revenue, and to a lesser extent, other ancillary revenue products such as lounge membership and certain commissions. The Company disaggregates revenue by segment in Note 13. The level of detail within the Company’s statements of operations, segment disclosures, and in this footnote depict the nature, amount, timing and uncertainty of revenue and how cash flows are affected by economic and other factors. Passenger Ticket and Ancillary Services Revenue The primary performance obligation on a typical passenger ticket is to provide air travel to the passenger. Ticket revenue is collected in advance of travel and recorded as Air Traffic Liability (ATL) on the consolidated balance sheets. The Company satisfies its performance obligation and recognizes ticket revenue for each flight segment when the transportation is provided. Ancillary passenger revenues relate to items such as checked-bag fees, ticket change fees, and on-board food and beverage sales, all of which are provided at time of flight. As such, the obligation to perform these services is satisfied at the time of travel and is recorded with ticket revenue in Passenger revenue. Revenue is also recognized for tickets that are expected to expire unused, a concept referred to as “passenger ticket breakage.” Passenger ticket breakage is recorded at the flight date using estimates made at the time of sale based on the Company’s historical experience of expired tickets, and other facts such as program changes and modifications. In addition to selling tickets on its own marketed flights, Alaska has interline agreements with partner airlines under which it sells multi-city tickets with one or more segments of the trip flown by a partner airline, or it operates a connecting flight sold by a partner airline. Each segment in a connecting flight represents a separate performance obligation. Revenue on segments sold and operated by the Company is recognized as Passenger revenue in the gross amount of the allocated ticket price when the travel occurs, while the commission paid to the partner airline is recognized as a selling expense when the related transportation is provided. Revenue on segments operated by a partner airline is deferred for the full amount of the consideration received at the time the ticket is sold and, once the segment has been flown the Company records the net amount, after compensating the partner airline, as Cargo and other revenue. A portion of revenue from the Mileage Plan™ program is recorded in Passenger revenue. As members are awarded mileage credits on flown tickets, these credits become a distinct performance obligation to the Company. The Company allocates the transaction price to each performance obligation identified in a passenger ticket contract on a relative standalone selling price basis. The standalone selling price for loyalty mileage credits issued is discussed in the Loyalty Mileage Credits section of this Note below. The amount allocated to the mileage credits is deferred on the balance sheet. Once a member travels using a travel award redeemed with mileage credits on one of the Company's airline carriers, the revenue associated with those mileage credits is recorded as Passenger revenue. Taxes collected from passengers, including transportation excise taxes, airport and security fees and other fees, are recorded on a net basis within passenger revenue in the consolidated statements of operations. Passenger revenue recognized in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Passenger ticket revenue, including ticket breakage and net of taxes and fees $ 6,824 $ 6,482 $ 6,246 Passenger ancillary revenue 567 530 514 Mileage Plan passenger revenue 704 619 541 Total passenger revenue $ 8,095 $ 7,631 $ 7,301 As passenger tickets and related ancillary services are primarily sold via credit cards, certain amounts due from credit card processors are recorded as airline traffic receivables. These credit card receivables and receivables from our affinity credit card partner represent the majority of the receivables balance on the consolidated balance sheets. For performance obligations with performance periods of less than one year, GAAP provides a practical expedient that allows the Company not to disclose the transaction price allocated to remaining performance obligations and the timing of related revenue recognition. As passenger tickets expire one year from ticketing, if unused or not exchanged, the Company elected to apply this practical expedient. Mileage Plan™ Loyalty Program Loyalty mileage credits The Company’s Mileage Plan™ loyalty program provides frequent flyer travel awards to program members based upon accumulated loyalty mileage credits. Mileage credits are earned through travel, purchases using the Mileage Plan™ co-branded credit card and purchases from other participating partners. The program has a 24 month expiration period for unused mileage credits from the month of last account activity. The Company offers redemption of mileage credits through free, discounted or upgraded air travel on flights operated by Alaska and its regional partners or on one of its 17 airline partners, as well as redemption at partner hotels. The Company uses a relative standalone selling price to allocate consideration to material performance obligations in contracts with customers that include loyalty mileage credits. As directly observable selling prices for mileage credits are not available, the Company determines the standalone selling price of mileage credits primarily using actual ticket purchase prices for similar tickets flown, adjusted for the likelihood of redemption, or breakage. In determining similar tickets flown, the Company considers current market prices, class of service, type of award, and other factors. For mileage credits accumulated through travel on partner airlines, the Company uses actual consideration received from the partners. Revenue related to air transportation is deferred in the amount of the relative standalone selling price allocated to the loyalty mileage credits as they are issued. The Company satisfies its performance obligation when the mileage credits are redeemed and the related air transportation is delivered. The Company estimates breakage for the portion of loyalty mileage credits not expected to be redeemed using a statistical analysis of historical data, including actual mileage credits expiring, slow-moving and low-credit accounts, among other factors. The breakage rate for the twelve months ended December 31, 2019 and 2018 was 17.4%. The Company reviews the breakage rate used on an annual basis. Co-brand credit card agreements and other In addition to mileage credits, the co-brand credit card agreements, referred to herein as the Agreements, also include performance obligations for waived bag fees, Companion Fare™ offers to purchase an additional ticket at a discount, marketing, and the use of intellectual property including the brand (unlimited access to the use of the Company’s brand and frequent flyer member lists), which is the predominant element in the Agreement. The co-brand card bank partners are the customer for some elements, including the brand and marketing, while the Mileage Plan™ member is the customer for other elements such as mileage credits, bag waivers, and companion fares. At the inception of the Agreement, management estimated the selling price of each of the performance obligations. The objective was to determine the price at which a sale would be transacted if the product or service was sold on a stand-alone basis. The Company determined its best estimate of selling price for each element by considering multiple inputs and methods including, but not limited to, the estimated selling price of comparable travel, discounted cash flows, brand value, published selling prices, number of miles awarded and number of miles redeemed. The Company estimated the selling prices and volumes over the term of the Agreement in order to determine the allocation of proceeds to each of the multiple deliverables. The estimates of the standalone selling prices of each element do not change subsequent to the original valuation of the contract unless the contract is materially modified, but the allocation between elements may change based upon the actual and updated projected volumes of each element delivered during the term of the contract. Consideration received from the banks is variable and is primarily from consumer spend on the card, among other items. The Company allocates consideration to each of the performance obligations, including mileage credits, waived bag fees, companion fares, and brand and marketing, using their relative standalone selling price. Because the performance obligation related to providing use of intellectual property including the brand is satisfied over time, it is recognized in Mileage Plan TM other revenue in the period that those elements are sold. The Company records passenger revenue related to the air transportation and certificates for discounted companion travel when the transportation is delivered. In contracts with non-bank partners, the Company has identified two performance obligations in most cases - travel and brand. The travel performance obligation is deferred until the transportation is provided in the amount of the estimated standalone selling price of the ticket, less breakage, and the brand performance obligation is recognized using the residual method as commission revenue when the brand element is sold. Mileage credit sales recorded under the residual approach are immaterial to the overall program. Interline loyalty Alaska has interline arrangements with certain airlines whereby its members may earn and redeem Mileage Plan™ credits on those airlines, and members of a partner airline’s loyalty program may earn and redeem frequent flyer program credits on flights operated by Alaska and its regional partners. When a Mileage Plan™ member earns credits on a partner airline, the partner airline remits a contractually-agreed upon fee to the Company which is deferred until credits are redeemed. When a Mileage Plan™ member redeems credits on a partner airline, the Company pays a contractually agreed upon fee to the other airline, which is netted against the revenue recognized associated with the award travel. When a member of a partner airline redeems frequent flyer credits on Alaska, the partner airline remits a contractually-agreed upon amount to the Company, recognized as Passenger revenue upon travel. If the partner airline’s member earns frequent flyer program credits on an Alaska flight, the Company remits a contractually-agreed upon fee to the partner airline and records a commission expense. Mileage Plan revenue included in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Passenger revenue $ 704 $ 619 $ 541 Mileage Plan other revenue 465 434 418 Total Mileage Plan revenue $ 1,169 $ 1,053 $ 959 Mileage Plan other revenue is primarily brand and marketing revenue from our affinity card products. Cargo and Other The Company provides freight and mail services (cargo). The majority of cargo services are provided to commercial businesses and the United States Postal Service. The Company satisfies cargo service performance obligations and recognizes revenue when the shipment arrives at its final destination, or is transferred to a third-party carrier for delivery. The Company also earns other revenue for lounge memberships, hotel and car commissions, and certain other immaterial items not intrinsically tied to providing air travel to passengers. Revenue is recognized when these services are rendered and recorded as Cargo and other revenue. The transaction price for Cargo and other revenue is the price paid by the customer. Cargo and other revenue included in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Cargo revenue $ 133 $ 129 $ 115 Other revenue 88 70 60 Total Cargo and other revenue $ 221 $ 199 $ 175 Air Traffic Liability and Deferred Revenue Passenger ticket and ancillary services liabilities Air traffic liability included on the consolidated balance sheets represents the remaining obligation associated with passenger tickets and ancillary services. The air traffic liability balance fluctuates with seasonal travel patterns. The Company recognized Passenger revenue of $577 million and $583 million from the 2018 and 2017 year-end air traffic liability balance during the twelve months ended December 31, 2019 and 2018. Mileage Plan tm liabilities The total deferred revenue liability included on the consolidated balance sheets represents the remaining transaction price that has been allocated to Mileage Plan TM performance obligations not yet satisfied by the Company. In general, the current amounts will be recognized as revenue within 12 months and the long-term amounts will be recognized as revenue over a period of approximately three to four years. This period of time represents the average time that members have historically taken to earn and redeem miles. The Company records a receivable for amounts due from the affinity card partner and from other partners as mileage credits are sold until the payments are collected. The Company had $105 million and $119 million of such receivables as of December 31, 2019 and December 31, 2018. Mileage credits are combined into one homogeneous pool and are not specifically identifiable. As such, loyalty revenues disclosed earlier in this Note are comprised of miles that were part of the deferred revenue and liabilities balances at the beginning of the period and miles that were issued during the period. The table below presents a roll forward of the total frequent flyer liability (in millions): Twelve Months Ended December 31, 2019 2018 Total Deferred Revenue balance at January 1 $ 1,874 $ 1,725 Travel miles and companion certificate redemption - Passenger revenue (704) (619) Miles redeemed on partner airlines - Other revenue (111) (90) Increase in liability for mileage credits issued 931 858 Total Deferred Revenue balance at December 31 $ 1,990 $ 1,874 Selling Costs Certain costs such as credit card fees, travel agency and other commissions paid, as well as Global Distribution Systems (GDS) booking fees are incurred when the Company sells passenger tickets and ancillary services in advance of the travel date. The Company defers such costs and recognizes them as expenses when the travel occurs. Prepaid expense recorded on the consolidated balance sheets for such costs was $27 million and $23 million as of December 31, 2019 and December 31, 2018. The Company recorded related expense on the consolidated statement of operations of $208 million, $217 million and $238 million for the twelve months ended December 31, 2019, 2018 and 2017.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS AND RISK MANAGEMENT Fuel Hedge Contracts The Company’s operations are inherently dependent upon the price and availability of aircraft fuel. To manage economic risks associated with fluctuations in aircraft fuel prices, the Company periodically enters into call options for crude oil. As of December 31, 2019, the Company had outstanding fuel hedge contracts covering 435 million gallons of crude oil that will be settled from January 2020 to June 2021. Interest Rate Swap Agreements The Company is exposed to market risk from adverse changes in variable interest rates on long-term debt and certain aircraft lease agreements. To manage this risk, the Company periodically enters into interest rate swap agreements. As of December 31, 2019, the Company has outstanding interest rate swap agreements with a third party designed to hedge the volatility of the underlying variable interest rates on lease agreements for six B737-800 aircraft, as well as 13 interest rate swap agreements with third parties designed to hedge the volatility of the underlying variable interest rates on $717 million of debt. All of the interest rate swap agreements stipulate that the Company pay a fixed interest rate and receive a floating interest rate over the term of the underlying contracts. The interest rate swap agreements expire from February 2020 through March 2021, associated with lease terms, and December 2021 through August 2029 to coincide with the debt maturity dates. All significant terms of the swap agreements match the terms of the underlying hedged items and have been designated as qualifying hedging instruments, which are accounted for as cash flow hedges. As qualifying cash flow hedges, the interest rate swaps are recognized at fair value on the balance sheet, and changes in the fair value are recognized in accumulated other comprehensive loss. The effective portion of the derivative represents the change in fair value of the hedge that offsets the change in fair value of the hedged item. To the extent the change in fair value of the hedge does not perfectly offset the change in the fair value of the hedged item, the ineffective portion of the hedge is recognized in interest expense, if material. Fair Values of Derivative Instruments Fair values of derivative instruments on the consolidated balance sheet (in millions): 2019 2018 Fuel hedge contracts (not designated as hedges) Prepaid expenses and other current assets $ 8 $ 2 Other assets 3 2 Interest rate swaps (designated as hedges) Prepaid expenses and other current assets 1 3 Other noncurrent assets 2 7 Other accrued liabilities (5) (3) Other liabilities (5) (4) Losses in accumulated other comprehensive loss (AOCL) (13) (1) The net cash paid for new fuel hedge positions and received from settlements was $19 million, $21 million and $12 million during 2019, 2018, and 2017. Pretax effect of derivative instruments on earnings and AOCL (in millions): 2019 2018 2017 Fuel hedge contracts (not designated as hedges) Gains (losses) recognized in Aircraft fuel $ (10) $ 1 $ (6) Interest rate swaps (designated as hedges) Losses recognized in Aircraft rent (3) (3) (5) Gains (losses) recognized in other comprehensive income (OCI) (13) — 1 The amounts shown as recognized in aircraft rent for cash flow hedges (interest rate swaps) represent the realized losses transferred out of AOCL to aircraft rent. No gains or losses related to interest rate swaps on variable rate debt have been recognized in interest expense during 2019. The amounts shown as recognized in OCI are prior to the losses recognized in aircraft rent during the period. The Company expects $3 million to be reclassified from OCI to aircraft rent and $4 million to interest income within the next twelve months.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments on a Recurring Basis As of December 31, 2019, the total cost basis for marketable securities was $1.3 billion. There were no significant differences between the cost basis and fair value of any individual class of marketable securities. Fair values of financial instruments on the consolidated balance sheet (in millions): December 31, 2019 December 31, 2018 Level 1 Level 2 Total Level 1 Level 2 Total Assets Marketable securities U.S. government and agency securities $ 330 $ — $ 330 $ 293 $ — $ 293 Equity mutual funds 6 — 6 — — — Foreign government bonds — 31 31 — 26 26 Asset-backed securities — 211 211 — 190 190 Mortgage-backed securities — 176 176 — 92 92 Corporate notes and bonds — 523 523 — 520 520 Municipal securities — 23 23 — 10 10 Total Marketable securities 336 964 1,300 293 838 1,131 Derivative instruments Fuel hedge contracts - call options — 11 11 — 4 4 Interest rate swap agreements — 3 3 — 10 10 Total Assets $ 336 $ 978 $ 1,314 $ 293 $ 852 $ 1,145 Liabilities Derivative instruments Interest rate swap agreements — (10) (10) — (7) (7) Total Liabilities $ — $ (10) $ (10) $ — $ (7) $ (7) The Company uses the market and income approach to determine the fair value of marketable securities. U.S. government securities and equity mutual funds are Level 1 as the fair value is based on quoted prices in active markets. The remaining marketable securities instruments are Level 2 as the fair value is based on standard valuation models that calculate values from observable inputs such as quoted interest rates, yield curves, credit ratings of the security and other observable market information. The Company uses the market and income approaches to determine the fair value of derivative instruments. The fair value for fuel hedge call options is determined utilizing an option pricing model that uses inputs that are readily available in active markets or can be derived from information available in active markets. In addition, the fair value considers exposure to credit losses in the event of non-performance by counterparties. Interest rate swap agreements are Level 2 as the fair value of these contracts is determined based on the difference between the fixed interest rate in the agreements and the observable LIBOR-based interest forward rates at period end, multiplied by the total notional value. Activity and Maturities for Marketable Securities Unrealized losses from marketable securities are primarily attributable to changes in interest rates. Management does not believe any remaining losses represent other-than-temporary impairments based on the Company's evaluation of available evidence as of December 31, 2019. Proceeds from sales of marketable securities were $1.7 billion, $1.1 billion and $1.4 billion in 2019, 2018, and 2017. Maturities for marketable securities (in millions): December 31, 2019 Cost Basis Fair Value Due in one year or less $ 164 $ 165 Due after one year through five years 1,102 1,114 Due after five years through 10 years 16 16 Total $ 1,282 $ 1,295 Fair Value of Other Financial Instruments The Company used the following methods and assumptions to determine the fair value of financial instruments that are not recognized at fair value on the consolidated balance sheets. Cash and Cash Equivalents : Carried at amortized costs which approximate fair value. Debt : Debt assumed in the acquisition of Virgin America was subject to a non-recurring fair valuation adjustment as part of purchase price accounting. The adjustment is amortized over the life of the associated debt. All other fixed-rate debt is carried at cost. To estimate the fair value of all fixed-rate debt as of December 31, 2019, the Company uses the income approach by discounting cash flows using borrowing rates for comparable debt over the weighted life of the outstanding debt. The estimated fair value of the fixed-rate debt is Level 3 as certain inputs used are unobservable. Fixed-rate debt on the consolidated balance sheet and the estimated fair value of long-term fixed-rate debt (in millions): December 31, 2019 December 31, 2018 Fixed rate debt at cost $ 473 $ 639 Non-recurring purchase price accounting fair value adjustment 2 3 Total fixed rate debt $ 475 $ 642 Estimated fair value $ 483 $ 641

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT Long-term debt obligations (in millions): 2019 2018 Fixed-rate notes payable due through 2029 $ 475 $ 642 Variable-rate notes payable due through 2029 1,032 1,473 Less debt issuance costs (8) (12) Total debt 1,499 2,103 Less current portion 235 486 Long-term debt, less current portion $ 1,264 $ 1,617 Weighted-average fixed-interest rate 3.3 % 4.1 % Weighted-average variable-interest rate 2.9 % 3.9 % Approximately $717 million of the Company's total variable-rate notes payable are effectively fixed via interest rate swaps at December 31, 2019, bringing the weighted-average interest rate for the full debt portfolio to 3%. During 2019, the Company's total debt decreased $604 million, primarily due to payments of $1.1 billion, including the prepayment of $779 million of debt. These reductions in debt were offset by the addition of secured debt financing from multiple lenders of $450 million. All outstanding debt is secured by aircraft. The Company's variable-rate debt bears interest at a floating rate per annum equal to a margin plus the three or six-month LIBOR in effect at the commencement of each three or six-month period, as applicable. As of December 31, 2019, none of the Company's borrowings were restricted by financial covenants. Long-term debt principal payments for the next five years and thereafter (in millions): Total 2020 $ 235 2021 281 2022 243 2023 173 2024 153 Thereafter 420 Total principal payments $ 1,505 Bank Line of Credit The Company has three credit facilities with availability totaling $516 million. All three facilities have variable interest rates based on LIBOR plus a specified margin. One credit facility for $250 million expires in June 2021 and is secured by aircraft. A second credit facility for $116 million expires in July 2020, with a mechanism for annual renewal, and is secured by aircraft. A third credit facility for $150 million expires in March 2022 and is secured by certain accounts receivable, spare engines, spare parts and ground service equipment. The Company has secured letters of credit against the $116 million facility, but has no plans to borrow using either of the two other facilities. All three credit facilities have a requirement to maintain a minimum unrestricted cash and marketable securities balance of $500 million. The Company was in compliance with this covenant at December 31, 2019.

Leases, Codification Topic 842

Leases, Codification Topic 842	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases of Lessee Disclosure	LEASES In 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," which requires lessees to recognize assets and liabilities for certain operating leases. Under the new standard, a lessee must recognize a liability on the balance sheet representing the lease payments owed, and a lease asset representing its right to use the underlying asset for the lease term. In 2018, the FASB issued ASU 2018-11, "Targeted Improvements - Leases (Topic 842)," which amended Topic 842 to provide a transition method that would not require adjusting comparative period financial information. The Company transitioned to the new lease accounting standard effective January 1, 2019 utilizing the alternative transition method. Upon transition, the Company recorded a cumulative-effect adjustment to the opening balance of retained earnings of $3 million. The new standard eliminated build-to-suit lease accounting guidance and resulted in the derecognition of build-to-suit assets and liabilities of approximately $150 million each. The Company elected certain practical expedients under the standard, including the practical expedient allowing a policy election to exclude from recognition short-term lease assets and lease liabilities for leases with an initial term of 12 months or less. Such expense was not material for the twelve months ended December 31, 2019. Additionally, the Company elected the available package of practical expedients allowing for no reassessment of lease classification for existing leases, no reassessment of expired contracts, and no reassessments of initial direct costs for existing leases. The Company has five asset classes for operating leases: aircraft, capacity purchase arrangements for aircraft operated by third-party carriers (CPA aircraft), airport and terminal facilities, corporate real estate and other equipment. All capitalized lease assets have been recorded on the consolidated balance sheet as of December 31, 2019 as Operating lease assets, with the corresponding liabilities recorded as Operating lease liabilities. Consistent with past accounting, operating rent expense is recognized on a straight-line basis over the term of the lease. At December 31, 2019, the Operating lease assets balance by asset class was as follows (in millions): December 31, 2019 Aircraft $ 1,049 CPA Aircraft 596 Airport and terminal facilities 18 Corporate real estate and other 48 Total Operating lease assets $ 1,711 Aircraft At December 31, 2019, Alaska had operating leases for 10 Boeing 737, 61 Airbus, and Horizon had operating leases for seven Bombardier Q400 aircraft. Remaining lease terms for these aircraft extend up to 12 years, some with options to extend, subject to negotiation at the end of the term. As extension is not certain, and rates are highly likely to be renegotiated, the extended term is only capitalized when it is reasonably determinable. While aircraft rent is primarily fixed, certain leases contain rental adjustments throughout the lease term which would be recognized as variable expense as incurred. Variable lease expense for aircraft was $4 million for the twelve months ended December 31, 2019. Capacity purchase agreements with aircraft (CPA aircraft) At December 31, 2019, Alaska had CPAs with two carriers, including the Company’s wholly-owned subsidiary, Horizon. Horizon sells 100% of its capacity under a CPA with Alaska. Alaska also has a CPA with SkyWest covering 32 E175 aircraft to fly certain routes in the Lower 48 and Canada. Under these agreements, Alaska pays the carriers an amount which is based on a determination of their cost of operating those flights and other factors intended to approximate market rates for those services. As Horizon is a wholly-owned subsidiary, intercompany leases between Alaska and Horizon have not been recognized under the standard. Remaining lease terms for CPA aircraft range from 7.5 years to 11 years. Financial arrangements of the CPAs include a fixed component, representing the costs to operate each aircraft and is capitalized under the new lease accounting standard. CPAs also include variable rent based on actual levels of flying, which is expensed as incurred. Variable lease expense for CPA aircraft for the twelve months ended December 31, 2019 was not material. Airport and terminal facilities The Company leases ticket counters, gates, cargo and baggage space, ground equipment, office space and other support areas at numerous airports. For this asset class, the Company has elected to combine lease and non-lease components. The majority of airport and terminal facility leases are not capitalized because they do not meet the definition of controlled assets under the standard, or because the lease payments are entirely variable. For airports where leased assets are identified, and where the contract includes fixed lease payments, operating lease assets and lease liabilities have been recorded. The Company is also commonly responsible for maintenance, insurance and other facility-related expenses and services under these agreements. These costs are recognized as variable expense in the period incurred. Airport and terminal facilities variable lease expense was $322 million for the twelve months ended December 31, 2019. Starting in 2018, the Company leased 12 airport slots at LaGuardia Airport and eight airport slots at Reagan National Airport to a third party. For these leases, the Company recorded $13 million of lease income during the twelve months ended December 31, 2019. Corporate real estate and other leases Leased corporate real estate is primarily for office space in hub cities, data centers, land leases, and reservation centers. For this asset class, the Company has elected to combine lease and non-lease components under the standard. Other leased assets are comprised of other ancillary contracts and items including leased flight simulators and spare engines. Variable lease expense related to corporate real estate and other leases for the twelve months ended December 31, 2019 was $10 million. Components of Lease Expense The impact of leases, including variable lease cost, on earnings for the twelve months ended December 31, 2019 was as follows (in millions): Classification 2019 Expense Aircraft Aircraft rent $ 246 CPA Aircraft Aircraft rent 79 Airport and terminal facilities Landing fees and other rentals 324 Corporate real estate and other Landing fees and other rentals 19 Total lease expense $ 668 Revenue Lease income Cargo and other revenues (13) Net lease impact $ 655 Supplemental Cash Flow Information During the year ended December 31, 2019, the Company paid $347 million for capitalized operating leases. The Company also acquired $176 million of operating lease assets in exchange for assumption of the same total of operating lease liabilities, inclusive of lease extensions. Lease Term and Discount Rate As most leases do not provide an implicit interest rate, the Company generally utilizes the incremental borrowing rate (IBR) based on information available at the commencement date of the lease to determine the present value of lease payments. The weighted average IBR and weighted average remaining lease term (in years) for all asset classes were as follows at December 31, 2019. Weighted Average IBR Weighted Average Remaining Lease term Aircraft 4.0 % 7.0 CPA Aircraft 4.3 % 9.2 Airports and terminal facilities 4.1 % 10.0 Corporate real estate and other 4.2 % 34.9 Maturities of Lease Liabilities Future minimum lease payments under non-cancellable leases as of December 31, 2019 (in millions): Aircraft CPA Aircraft Airport and Terminal Facilities Corporate Real Estate and Other 2020 $ 245 $ 79 $ 3 $ 8 2021 216 79 2 6 2022 190 79 2 5 2023 133 79 2 5 2024 81 79 2 5 Thereafter 331 329 11 74 Total Lease Payments $ 1,196 $ 724 $ 22 $ 103 Less: Imputed interest (151) (128) (4) (54) Total $ 1,045 $ 596 $ 18 $ 49 Disclosures for Periods Prior to Adoption of Topic 842 As of December 31, 2018, the Company had commitments for aircraft and facility leases. Aircraft lease commitments include future obligations for the Company's operating airlines – Alaska and Horizon – as well as aircraft leases operated by third parties. At December 31, 2018, Alaska had lease contracts for 10 B737 aircraft, 61 Airbus aircraft, 32 E175 aircraft with SkyWest, and Horizon had lease contracts for nine Bombardier Q400 aircraft. Facility lease commitments primarily include airport and terminal facilities and building leases. Total rent expense for aircraft and facility leases was $619 million and $552 million in 2018 and 2017. Future minimum lease payments under noncancelable operating leases were as follows as of December 31, 2018 (in millions): Aircraft Leases Facility Leases 2019 $ 350 $ 133 2020 320 124 2021 286 113 2022 262 94 2023 208 26 Thereafter 847 122 Total $ 2,273 $ 612

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Deferred Income Taxes Deferred income taxes reflect the impact of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and such amounts for tax purposes. The Company has a net deferred tax liability, primarily due to differences in depreciation rates for federal income tax purposes and for financial reporting purposes. Deferred tax (assets) and liabilities comprise the following (in millions): 2019 2018 Excess of tax over book depreciation $ 1,233 $ 1,066 Intangibles - net 16 15 Operating lease liabilities 416 — Other - net 58 43 Deferred tax liabilities 1,723 1,124 Mileage Plan™ (337) (315) Inventory obsolescence (15) (15) Employee benefits (179) (172) Acquired net operating losses (13) (64) Operating lease assets (417) — Other - net (48) (48) Deferred tax assets (1,009) (614) Valuation allowance 1 2 Net deferred tax liabilities $ 715 $ 512 At December 31, 2019, the Company had federal NOLs of approximately $45 million that expire beginning in 2032 and continuing through 2036, and state NOLs of approximately $55 million that expire beginning in 2029 and continuing through 2036. Virgin America experienced multiple “ownership changes” as defined in Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”), the most recent being its acquisition by the Company. Section 382 of the Code imposes an annual limitation on the utilization of pre-ownership change NOLs. Any unused annual limitation may, subject to certain limits, be carried over to later years. The combined Company’s ability to use the NOLs will also depend on the amount of taxable income generated in future periods. Valuation allowances are provided to reduce the related deferred income tax assets to an amount which will, more likely than not, be realized. The valuation allowance was not material at both December 31, 2019 and December 31, 2018. Components of Income Tax Expense The components of income tax expense are as follows (in millions): 2019 2018 2017 Current income tax expense (benefit): Federal $ 26 $ (5) $ 127 State 13 9 35 Total current income tax expense 39 4 162 Deferred income tax expense (benefit): Federal 175 125 (3) State 33 19 40 Total deferred income tax expense (benefit) 208 144 37 Income tax expense $ 247 $ 148 $ 199 Income Tax Rate Reconciliation Income tax expense reconciles to the amount computed by applying the 2019 U.S. federal rate of 21% to income before income tax and for deferred taxes as follows (in millions): 2019 2018 2017 Income before income tax $ 1,016 $ 585 $ 1,159 Expected tax expense 213 123 406 Nondeductible expenses 9 9 5 State income taxes 36 21 28 State income sourcing 1 — 9 Tax law changes (9) (7) (237) Other - net (3) 2 (12) Actual tax expense $ 247 $ 148 $ 199 Effective tax rate 24.3 % 25.3 % 17.2 % As a result of the ASC 606 full retrospective adoption, 2017 tax expense increased by $26 million. As a result of tax changes signed into law during 2017, with final regulations issued in 2019, the Company recorded a deferred tax benefit of $9 million in the current year. In 2017, adjustments were made to the Company's position on income sourcing in various states due to updated guidance from state taxing authorities. The impact of this guidance is reflected as an increase in income tax expense of approximately $9 million for the year ended December 31, 2017. Uncertain Tax Positions The Company has identified its federal tax return and its state tax returns in Alaska, Oregon and California as “major” tax jurisdictions. A summary of the Company's jurisdictions and the periods that are subject to examination are as follows: Jurisdiction Period Federal 2007 to 2018 Alaska 2015 to 2018 California 2007 to 2018 Oregon 2003 to 2018 Certain tax years are open to the extent of net operating loss carryforwards. Changes in the liability for gross unrecognized tax benefits during 2019, 2018 and 2017 are as follows (in millions): 2019 2018 2017 Balance at January 1, $ 40 $ 43 $ 40 Additions related to prior years — 1 16 Releases related to prior years (1) (4) (2) Additions related to current year activity 2 2 2 Releases due to settlements — (1) (11) Releases due to lapse of statute of limitations (1) (1) (2) Balance at December 31, $ 40 $ 40 $ 43 As of December 31, 2019, the Company had $40 million of accrued tax contingencies, of which $34 million, if fully recognized, would decrease the effective tax rate. As of December 31, 2019, 2018 and 2017, the Company has accrued interest and penalties, net of federal income tax benefit, of $7 million, $6 million, and $5 million. In 2019, 2018, and 2017, the

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS Four qualified defined-benefit plans, one non-qualified defined-benefit plan, and seven defined-contribution retirement plans cover various employee groups of Alaska, Horizon and McGee Air Services. The defined-benefit plans provide benefits based on an employee’s term of service and average compensation for a specified period of time before retirement. The qualified defined-benefit pension plans are closed to new entrants. Accounting standards require recognition of the overfunded or underfunded status of an entity’s defined-benefit pension and other postretirement plan as an asset or liability in the consolidated financial statements and requires recognition of the funded status in AOCL. Qualified Defined-Benefit Pension Plans The Company’s four qualified defined-benefit pension plans are funded as required by the Employee Retirement Income Security Act of 1974. The defined-benefit plan assets consist primarily of marketable equity and fixed-income securities. The work groups covered by qualified defined-benefit pension plans include salaried employees, pilots, clerical, office, passenger service employees, mechanics and related craft employees. The Company uses a December 31 measurement date for these plans. All plans are closed to new entrants. Weighted average assumptions used to determine benefit obligations: The rates below vary by plan and related work group. 2019 2018 Discount rates 3.33% to 3.47% 4.37% to 4.46% Rate of compensation increases 2.11% to 5.44% 2.11% to 3.50% Weighted average assumptions used to determine net periodic benefit cost: The rates below vary by plan and related work group. 2019 2018 2017 Discount rates 4.37% to 4.46% 3.69% to 3.78% 4.29% to 4.50% Expected return on plan assets 4.25% to 5.50% 4.25% to 5.50% 5.50% to 6.00% Rate of compensation increases (a) 2.11% to 3.50% 2.11% to 16.51% 2.12% to 2.59% (a) Significant rate of compensation increase in 2018 is due to the new contract with our Mainline pilots, which was executed at the end of 2017. The discount rates are determined using current interest rates earned on high-quality, long-term bonds with maturities that correspond with the estimated cash distributions from the pension plans. At December 31, 2019, the Company selected discount rates for each of the plans using a pool of higher-yielding bonds estimated to be more reflective of settlement rates, as management has taken steps to ultimately terminate or settle plans that are frozen and move toward freezing benefits in active plans in the future. In determining the expected return on plan assets, the Company assesses the current level of expected returns on risk-free investments (primarily government bonds), the historical level of the risk premium associated with the other asset classes in which the portfolio is invested and the expectations for future returns of each asset class. The expected return for each asset class is then weighted based on the target asset allocation to develop the expected long-term rate of return on assets assumption for the portfolio. Plan assets are invested in common commingled trust funds invested in equity and fixed income securities and in certain real estate assets. The target and actual asset allocation of the funds in the qualified defined-benefit plans, by asset category, are as follows: Salaried Plan (a) All other plans Target 2019 2018 Target 2019 2018 Asset category: Domestic equity securities 2% - 12% 7 % 6 % 36% - 46% 41 % 28 % Non-U.S. equity securities 0% - 5% 3 % 3 % 13% - 23% 18 % 12 % Fixed income securities 85% - 95% 90 % 91 % 26% - 46% 35 % 53 % Real estate — % — % — % 0% - 10% 6 % 7 % Plan assets 100 % 100 % 100 % 100 % (a) As our Salaried Plan is frozen and fully funded, our investment strategies differ significantly from that of our other outstanding plans. Investments are in lower-risk securities, with earnings designed to maintain a fully-funded status. The Company’s investment policy focuses on achieving maximum returns at a reasonable risk for pension assets over a full market cycle. The Company determines the strategic allocation between equities, fixed income and real estate based on current funded status and other characteristics of the plans. As the funded status improves, the Company increases the fixed income allocation of the portfolio and decreases the equity allocation. Actual asset allocations are reviewed regularly and periodically rebalanced as appropriate. Plan assets invested in common commingled trust funds are fair valued using the net asset values of these funds to determine fair value as allowed using the practical expedient method outlined in the accounting standards. Fair value estimates for real estate are calculated using the present value of expected future cash flows based on independent appraisals, local market conditions and current and projected operating performance. Plan assets by fund category (in millions): 2019 2018 Fair Value Hierarchy Fund type: U.S. equity market fund $ 773 $ 431 1 Non-U.S. equity fund 344 183 1 Credit bond index fund 1,009 1,135 1 Plan assets in common commingled trusts $ 2,126 $ 1,749 Real estate 102 104 (a) Cash equivalents 11 5 1 Total plan assets $ 2,239 $ 1,858 (a) In accordance with Subtopic 820-10, certain investments that are measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The following table sets forth the status of the qualified defined-benefit pension plans (in millions): 2019 2018 Projected benefit obligation (PBO) Beginning of year $ 2,225 $ 2,387 Service cost 42 48 Interest cost 89 79 Actuarial (gain)/loss 359 (191) Benefits paid (113) (98) End of year $ 2,602 $ 2,225 Plan assets at fair value Beginning of year $ 1,858 $ 2,083 Actual return on plan assets 429 (127) Employer contributions 65 — Benefits paid (113) (98) End of year $ 2,239 $ 1,858 Unfunded status $ (363) $ (367) Percent funded 86 % 84 % The accumulated benefit obligation for the combined qualified defined-benefit pension plans was $2.4 billion and $2.1 billion at December 31, 2019 and 2018. The amounts recognized in the consolidated balance sheets (in millions): 2019 2018 Accrued benefit liability-long term $ 412 $ 392 Plan assets-long term (within Other noncurrent assets) (49) (25) Total liability recognized $ 363 $ 367 The amounts not yet reflected in net periodic benefit cost and included in AOCL (in millions): 2019 2018 Prior service credit $ (6) $ (8) Net loss 595 607 Amount recognized in AOCL (pretax) $ 589 $ 599 The expected amortization of prior service credit and net loss from AOCL in 2020 is $1 million and $35 million for the qualified defined-benefit pension plans. Net pension expense for the qualified defined-benefit plans included the following components (in millions): 2019 2018 2017 Service cost $ 42 $ 48 $ 39 Interest cost 89 79 74 Expected return on assets (95) (107) (106) Amortization of prior service credit (1) (1) (1) Recognized actuarial loss 37 33 26 Net pension expense $ 72 $ 52 $ 32 There are no current statutory funding requirements for the Company’s plans in 2020. Future benefits expected to be paid over the next ten years under the qualified defined-benefit pension plans from the assets of those plans (in millions): Total 2020 $ 115 2021 118 2022 134 2023 137 2024 137 2025– 2029 800 Nonqualified Defined-Benefit Pension Plan Alaska also maintains an unfunded, noncontributory defined-benefit plan for certain elected officers. This plan uses a December 31 measurement date. The assumptions used to determine benefit obligations and the net period benefit cost for the nonqualified defined-benefit pension plan are similar to those used to calculate the qualified defined-benefit pension plan. The plan's unfunded status, PBO and accumulated benefit obligation are immaterial. The net pension expense in prior year and expected future expense is also immaterial. Post-retirement Medical Benefits The Company allows certain retirees to continue their medical, dental and vision benefits by paying all or a portion of the active employee plan premium until eligible for Medicare, currently age 65. This results in a subsidy to retirees, because the premiums received by the Company are less than the actual cost of the retirees’ claims. The accumulated post-retirement benefit obligation for this subsidy is unfunded. The accumulated post-retirement benefit obligation was $129 million and $82 million at December 31, 2019 and 2018. The net periodic benefit cost was not material in 2019 or 2018. Defined-Contribution Plans The seven defined-contribution plans are deferred compensation plans under section 401(k) of the Internal Revenue Code. All of these plans require Company contributions. Total expense for the defined-contribution plans was $132 million, $126 million and $103 million in 2019, 2018, and 2017. The Company also has a noncontributory, unfunded defined-contribution plan for certain elected officers of the Company who are ineligible for the nonqualified defined-benefit pension plan. Amounts recorded as liabilities under the plan are not material to the consolidated balance sheets at December 31, 2019 and 2018. Pilot Long-term Disability Benefits Alaska maintains a long-term disability plan for its pilots. The long-term disability plan does not have a service requirement. Therefore, the liability is calculated based on estimated future benefit payments associated with pilots that were assumed to be disabled on a long-term basis as of December 31, 2019 and does not include any assumptions for future disability. The liability includes the discounted expected future benefit payments and medical costs. The total liability was $45 million and $25 million, which was recorded net of a prefunded trust account of $6 million and $3 million, and included in long-term other liabilities on the consolidated balance sheets as of December 31, 2019 and December 31, 2018. Employee Incentive-Pay Plans The Company has employee incentive plans that pay employees based on certain financial and operational metrics. These metrics are set and approved annually by the Compensation Committee of the Board of Directors. The aggregate expense under these plans in 2019, 2018 and 2017 was $163 million, $147 million and $135 million. The incentive plans are summarized below. • Performance-Based Pay (PBP) is a program that rewards the majority of Alaska and Horizon employees. The program is based on various metrics that adjust periodically, including those related to Air Group profitability, safety, Mileage Plan™ and credit card growth, achievement of unit-cost goals and employee engagement as measured by brand strength. • The Operational Performance Rewards Program entitles the majority of Alaska and Horizon employees to quarterly payouts of up to $450 per person if certain monthly operational and customer service objectives are met.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Future minimum payments for commitments as of December 31, 2019 (in millions): Aircraft Commitments (a) Capacity Purchase Agreements (b) Aircraft Maintenance Deposits 2020 $ 531 $ 145 $ 73 2021 487 166 62 2022 347 174 51 2023 206 179 26 2024 31 184 6 Thereafter 26 880 2 Total $ 1,628 $ 1,728 $ 220 (a) Includes non-cancelable contractual commitments for aircraft and engines, buyer furnished equipment, and aircraft maintenance and parts management. (b) Includes all non-aircraft lease costs associated with capacity purchase agreements. Aircraft Commitments Aircraft purchase commitments include non-cancelable contractual commitments for aircrafts and engines. As of December 31, 2019, Alaska had commitments to purchase 32 Boeing 737 MAX9 aircraft with deliveries in 2020 through 2023. Future minimum contractual payments for these aircraft have been updated to reflect the most current anticipated delivery timing for 737 MAX aircraft, which has been delayed as a result of the grounding order mandated by the FAA on March 13, 2019, and is subject to change. Horizon also has commitments to purchase three E175 aircraft with deliveries in 2023 and has cancelable purchase commitments for 30 Airbus A320neo aircraft with deliveries from 2023 through 2025. In addition, Alaska has options to purchase 37 737 MAX aircraft and Horizon has options to purchase 30 E175 aircraft. Alaska has an option to increase capacity flown by Skywest with eight additional E175 aircraft with deliveries in 2022. The cancelable purchase commitments and option payments are not reflected in the table above. Aircraft Maintenance and Parts Management Through its acquisition of Virgin America, the Company has a separate maintenance-cost-per-hour contract for management and repair of certain rotable parts to support Airbus airframe and engine maintenance and repair. In 2017, Alaska entered into a similar contract for maintenance on its B737-800 aircraft engines. These agreements require monthly payments based upon utilization, such as flight hours, cycles and age of the aircraft, and, in turn, the agreement transfers certain risks to the third-party service provider. There are minimum payments under both agreements, which are reflected in the table above. Accordingly, payments could differ materially based on actual aircraft utilization. Aircraft Maintenance Deposits Certain Airbus leases include contractually required maintenance deposit payments to the lessor, which collateralize the lessor for future maintenance events should the Company not perform required maintenance. Most of the lease agreements provide that maintenance deposits are reimbursable upon completion of the major maintenance event in an amount equal to the lesser of (i) the amount qualified for reimbursement from maintenance deposits held by the lessor associated with the specific major maintenance event or (ii) the qualifying costs related to the specific major maintenance event. Contingencies The Company is a party to routine litigation matters incidental to its business and with respect to which no material liability is expected. Liabilities for litigation related contingencies are recorded when a loss is determined to be probable and estimable. In 2015, three flight attendants filed a class action lawsuit seeking to represent all Virgin America flight attendants for damages based on alleged violations of California and City of San Francisco wage and hour laws. The court certified a class of approximately 1,800 flight attendants in November 2016. The Company believes the claims in this case are without factual and legal merit. In July 2018, the Court granted in part Plaintiffs' motion for summary judgment, finding Virgin America, and Alaska Airlines, as a successor-in-interest to Virgin America, responsible for various damages and penalties sought by the class members. On February 4, 2019, the Court entered final judgment against Virgin America and Alaska Airlines in the amount of approximately $78 million. It did not award injunctive relief against Alaska Airlines. The Company is seeking an appellate court ruling that the California laws on which the judgment is based are invalid as applied to national airlines pursuant to the U.S. Constitution and federal law and for other employment law and improper class certification reasons. The Company remains confident that a higher court will respect the federal preemption principles that were enacted to shield inter-state common carriers from a patchwork of state and local wage and hour regulations such as those at issue in this case and agree with the Company's other bases for appeal. For these reasons, no loss has been accrued.

SHAREHOLDER'S EQUITY

SHAREHOLDER'S EQUITY	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
SHAREHOLDER'S EQUITY	SHAREHOLDERS' EQUITY Dividends During 2019, the Board of Directors declared dividends of $1.40 per share. The Company paid dividends of $173 million, $158 million and $148 million to shareholders of record during 2019, 2018 and 2017. Subsequent to year-end, the Board of Directors declared a quarterly cash dividend of $0.375 per share to be paid in March 2020 to shareholders of record as of February 18, 2020. This is a 7% increase from the most recent quarterly dividend of $0.35 per share. Common Stock Repurchase In August 2015, the Board of Directors authorized a $1 billion share repurchase program. As of December 31, 2019, the Company has repurchased 7.1 million shares for $513 million under this program. At December 31, 2019, the Company held 8,811,866 shares in treasury. Management does not anticipate retiring common shares held in treasury for the foreseeable future. Share repurchase activity (in millions, except shares): 2019 2018 2017 Shares Amount Shares Amount Shares Amount 2015 Repurchase Program – $1 billion 1,192,820 $ 75 776,186 $ 50 981,277 $ 75 Accumulated Other Comprehensive Loss (AOCL) AOCL consisted of the following (in millions, net of tax): 2019 2018 Related to marketable securities $ 9 $ (11) Related to employee benefit plans (469) (440) Related to interest rate derivatives (5) 3 $ (465) $ (448)

SPECIAL ITEMS SPECIAL ITEMS

SPECIAL ITEMS SPECIAL ITEMS	12 Months Ended
	Dec. 31, 2019
SPECIAL ITEMS [Abstract]
Unusual or Infrequent Items Disclosure [Text Block]	SPECIAL ITEMS In 2019, the Company recognized special items of $44 million for merger-related costs associated with its acquisition of Virgin America. Costs classified as merger-related are directly attributable to merger activities. In 2018, the Company recognized $87 million in merger-related costs. The Company incurred a one-time settlement fee of $20 million for the termination of an existing maintenance services agreement and subsequently entered into a new services agreement that provides more flexibility for the timing and scope of engine work. Additionally, the Company incurred $25 million for one-time bonuses paid to employees as a result of tax reform. These charges were recognized as special charges and are included in the Special items - other line on our consolidated statements of operations. In 2017, the Company recognized $116 million in merger-related costs. The Company also recognized a special tax benefit of $237 million due to the remeasurement of net deferred tax liabilities as a result of the Tax Cuts and Jobs Act signed into law on December 22, 2017, partially offset by certain state tax law enactments. The Company has recognized $364 million in merger-related costs since the acquisition of Virgin America in December 2016. The following breaks down merger-related costs incurred in 2019, 2018 and 2017 (in millions): 2019 2018 2017 Consulting and professional services $ 18 $ 45 $ 52 Employee-related costs (a) 15 13 41 Legal and accounting fees 1 1 3 Other merger-related costs (b) 10 28 20 Total Merger-related Costs $ 44 $ 87 $ 116 (a) Employee-related costs consist primarily of vacation balance true-ups, severance, retention bonuses, and training and skill development. (b) Other merger-related costs consist primarily of costs for marketing and advertising, IT, employee appreciation and company sponsored events, moving expenses, supplies, and other immaterial expenses.

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION PLANS	STOCK-BASED COMPENSATION PLANS The Company has various equity incentive plans under which it may grant stock awards to directors, officers and employees. The Company also has an employee stock purchase plan. The table below summarizes the components of total stock-based compensation (in millions): 2019 2018 2017 Stock options $ 3 $ 3 $ 3 Stock awards 21 23 24 Deferred stock awards 1 1 1 Employee stock purchase plan 11 9 6 Stock-based compensation $ 36 $ 36 $ 34 Tax benefit related to stock-based compensation $ 9 $ 9 $ 13 Unrecognized stock-based compensation for non-vested options and awards and the weighted-average period the expense will be recognized (in millions): Amount Weighted-Average Stock options $ 4 1.3 Stock awards 20 1.5 Unrecognized stock-based compensation $ 24 1.5 The Company is authorized to issue 17 million shares of common stock under these plans, of which 8,627,341 shares remain available for future grants of either options or stock awards as of December 31, 2019. Stock Options Stock options to purchase common stock are granted at the fair market value of the stock on the date of grant. The stock options granted have terms of up to ten years. The fair value of each option grant was estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions used for grants: 2019 2018 2017 Expected volatility 30 % 30 % 51 % Expected term 6 years 6 years 6 years Risk-free interest rate 2.41 % 2.61 % 2.04 % Expected dividend yield 2.09 % 1.94 % 1.10 % Weighted-average grant date fair value per share $ 16.84 $ 17.18 $ 41.19 Estimated fair value of options granted (millions) $ 4 $ 1 $ 4 The expected market price volatility and expected term are based on historical results. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of the grant. The expected dividend yield is based on the estimated weighted average dividend yield over the expected term. The expected forfeiture rates are based on historical experience. The tables below summarize stock option activity for the year ended December 31, 2019: Shares Weighted- Weighted- Aggregate Intrinsic Outstanding, December 31, 2018 573,242 $ 57.78 6.6 $ 6 Granted 252,200 66.52 Exercised (21,322) 36.14 Canceled (5,366) 68.94 Forfeited or expired (4,699) 70.98 Outstanding, December 31, 2019 794,055 $ 60.98 6.5 $ 7 Exercisable, December 31, 2019 341,322 $ 50.50 4.3 $ 7 Vested or expected to vest, December 31, 2019 793,684 $ 60.98 6.5 $ 7 (in millions) 2019 2018 2017 Intrinsic value of option exercises $ 1 $ 1 $ 6 Cash received from stock option exercises 1 1 3 Tax benefit related to stock option exercises — — 2 Fair value of options vested 3 2 3 Stock Awards Restricted Stock Units (RSUs) are awarded to eligible employees and entitle the grantee to receive shares of common stock at the end of the vesting period. The fair value of the RSUs is based on the stock price on the date of grant. Generally, RSUs “cliff vest” after three years, or the period from the date of grant to the employee’s retirement eligibility, and expense is recognized accordingly. Performance Share Units (PSUs) are awarded to certain executives to receive shares of common stock if specific performance goals and market conditions are achieved. There are several tranches of PSUs which vest when performance goals and market conditions are met. The following table summarizes information about outstanding stock awards: Number Weighted-Average Grant Date Fair Value Weighted- Aggregate Non-vested, December 31, 2018 511,813 $ 78.75 1.5 $ 31 Granted 402,816 66.35 Vested (270,802) 74.61 Forfeited (102,214) 75.21 Non-vested, December 31, 2019 541,613 $ 71.82 1.4 $ 37 Deferred Stock Awards Deferred Stock Units (DSUs) are awarded to members of the Board of Directors as part of their retainers. The underlying common shares are issued upon retirement from the Board, but require no future service period. As a result, the entire intrinsic value of the awards is expensed on the date of grant. Employee Stock Purchase Plan The ESPP allows employees to purchase common stock at 85% of the stock price on the first day of the offering period or the specified purchase date, whichever is lower. Employees may contribute up to 10% of their base earnings during the offering period to purchase stock. Employees purchased 784,786, 632,145 and 406,628 shares in 2019, 2018 and 2017 under the ESPP.

OPERATING SEGMENT INFORMATION

OPERATING SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Operating Segment Information	OPERATING SEGMENT INFORMATION Alaska Air Group has two operating airlines—Alaska and Horizon. Each is a regulated airline by the U.S. Department of Transportation’s Federal Aviation Administration. Alaska has CPAs for regional capacity with Horizon, as well as with third-party carriers SkyWest and PenAir, under which Alaska receives all passenger revenues. Under U.S. General Accepted Accounting Principles, operating segments are defined as components of a business for which there is discrete financial information that is regularly assessed by the Chief Operating Decision Maker (CODM) in making resource allocation decisions. Financial performance for the operating airlines and CPAs is managed and reviewed by the Company's CODM as part of three reportable operating segments: • Mainline - includes scheduled air transportation on Alaska's Boeing or Airbus jet aircraft for passengers and cargo throughout the U.S., and in parts of Canada, Mexico, and Costa Rica. • Regional - includes Horizon's and other third-party carriers’ scheduled air transportation for passengers across a shorter distance network within the U.S. under CPAs. This segment includes the actual revenues and expenses associated with regional flying, as well as an allocation of corporate overhead incurred by Air Group on behalf of the regional operations. • Horizon - includes the capacity sold to Alaska under CPA. Expenses include those typically borne by regional airlines such as crew costs, ownership costs and maintenance costs. The CODM makes resource allocation decisions for these reporting segments based on flight profitability data, aircraft type, route economics and other financial information. The "Consolidating and Other" column reflects parent company activity, McGee Air Services, consolidating entries and other immaterial business units of the company. The “Air Group Adjusted” column represents a non-GAAP measure that is used by the Company CODM to evaluate performance and allocate resources. Adjustments are further explained below in reconciling to consolidated GAAP results. Operating segment information is as follows (in millions): Year Ended December 31, 2019 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,750 1,345 — — 8,095 — 8,095 CPA revenues — — 450 (450) — — — Mileage Plan other revenue 419 46 — — 465 — 465 Cargo and other 212 3 1 5 221 — 221 Total Operating Revenues 7,381 1,394 451 (445) 8,781 — 8,781 Operating Expenses Non-fuel operating expenses 4,778 1,097 385 (464) 5,796 44 5,840 Fuel expense 1,589 295 — — 1,884 (6) 1,878 Total Operating Expenses 6,367 1,392 385 (464) 7,680 38 7,718 Non-operating Income (Expense) Interest income 66 — — (24) 42 — 42 Interest expense (76) — (28) 26 (78) — (78) Interest capitalized 15 — — — 15 — 15 Other (26) — — — (26) — (26) Total Non-operating Income (Expense) (21) — (28) 2 (47) — (47) Income (Loss) Before Income Tax $ 993 $ 2 $ 38 $ 21 $ 1,054 $ (38) $ 1,016 Year Ended December 31, 2018 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,474 1,157 — — 7,631 — 7,631 CPA revenues — — 508 (508) — — — Mileage Plan other revenue 397 37 — — 434 — 434 Cargo and other 192 3 4 — 199 — 199 Total Operating Revenues 7,063 1,197 512 (508) 8,264 — 8,264 Operating Expenses Non-fuel operating expenses 4,577 1,024 465 (513) 5,553 132 5,685 Fuel expense 1,652 262 — — 1,914 22 1,936 Total Operating Expenses 6,229 1,286 465 (513) 7,467 154 7,621 Non-operating Income (Expense) Interest income 53 — — (15) 38 — 38 Interest expense (82) — (22) 13 (91) — (91) Interest capitalized 16 — 2 — 18 — 18 Other (12) (11) — — (23) — (23) Total Non-operating Income (Expense) (25) (11) (20) (2) (58) — (58) Income (Loss) Before Income Tax $ 809 $ (100) $ 27 $ 3 $ 739 $ (154) $ 585 Year Ended December 31, 2017 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,278 1,023 — — 7,301 — 7,301 CPA revenues — — 426 (426) — — — Mileage Plan other revenue 387 31 — — 418 — 418 Cargo and other 167 4 4 — 175 — 175 Total Operating Revenues 6,832 1,058 430 (426) 7,894 — 7,894 Operating Expenses Non-fuel operating expenses 4,271 852 427 (427) 5,123 116 5,239 Fuel expense 1,282 172 — — 1,454 (7) 1,447 Total Operating Expenses 5,553 1,024 427 (427) 6,577 109 6,686 Non-operating Income (Expense) Interest income 39 — — (5) 34 — 34 Interest expense (92) — (13) 2 (103) — (103) Interest capitalized 15 — 2 — 17 — 17 Other 3 — — — 3 — 3 Total Non-operating Income (Expense) (35) — (11) (3) (49) — (49) Income (Loss) Before Income Tax $ 1,244 $ 34 $ (8) $ (2) $ 1,268 $ (109) $ 1,159 (a) Includes consolidating entries, Parent Company, McGee Air Services, and other immaterial business units. (b) The Air Group Adjusted column represents the financial information that is reviewed by management to assess performance of operations and determine capital allocations and excludes certain income and charges. (c) Includes merger-related costs, mark-to-market fuel-hedge accounting adjustments, and other special items. 2019 2018 2017 Depreciation and amortization: Mainline $ 337 $ 316 $ 308 Horizon 86 82 64 Consolidated $ 423 $ 398 $ 372 Capital expenditures: Mainline $ 605 $ 571 $ 734 Horizon 91 389 292 Consolidated $ 696 $ 960 $ 1,026 Total assets at end of period: Mainline $ 19,207 $ 16,853 Horizon 1,266 1,229 Consolidating & Other (7,480) (7,170) Consolidated $ 12,993 $ 10,912

GENERAL AND SUMMARY OF SIGNIF_2

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Organization and Basis of Accounting, Policy [Policy Text Block]	Organization and Basis of Presentation The consolidated financial statements include the accounts of Air Group, or the Company, and its primary subsidiaries, Alaska and Horizon. Our consolidated financial statements also include McGee Air Services, a ground services subsidiary of Alaska. The Company conducts substantially all of its operations through these subsidiaries. All significant intercompany balances and transactions have been eliminated. These financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America and their preparation requires the use of management’s estimates. Actual results may differ from these estimates. Certain reclassifications have been made to prior year financial statements to conform to classifications used in the current year.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents Cash equivalents consist of highly liquid investments with original maturities of three months or less, such as money market funds, commercial paper and certificates of deposit. They are carried at cost, which approximates market value. The Company reduces cash balances when funds are disbursed. Due to the time delay in funds clearing the banks, the Company normally maintains a negative balance in its cash disbursement accounts, which is reported as a current liability. The amount of the negative cash balance was $7 million and $5 million at December 31, 2019 and 2018, and is included in accounts payable, with the change in the balance during the year included in other financing activities in the consolidated statements of cash flows. The Company's restricted cash balances are not material and are classified as Other noncurrent assets. Restricted cash balances are primarily used to guarantee various letters of credit, self-insurance programs or other contractual rights. They consist of highly liquid securities with original maturities of three months or less. They are carried at cost, which approximates fair value.
Marketable Securities, Policy [Policy Text Block]	Marketable Securities Investments with original maturities of greater than three months and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. All cash equivalents and short-term investments are classified as available-for-sale and realized gains and losses are recorded using the specific identification method. Changes in market value, excluding other-than-temporary impairments, are reflected in accumulated other comprehensive loss (AOCL). Investments are considered to be impaired when a decline in fair value is judged to be other-than-temporary. The Company uses a systematic methodology that considers available quantitative and qualitative evidence in evaluating potential impairment. If the cost of an investment exceeds its fair value, management evaluates, among other factors, general market conditions, credit quality of debt instrument issuers, the duration and extent to which the fair value is less than cost, the Company's intent and ability to hold, or plans to sell, the investment. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to Other—net in the consolidated statements of operations and a new cost basis in the investment is established.
Inventory, Policy [Policy Text Block]	Inventories and Supplies—net Expendable aircraft parts, materials and supplies are stated at average cost and are included in Inventories and supplies — net. An obsolescence allowance for expendable parts is accrued based on estimated lives of the corresponding fleet type and salvage values. The allowance for expendable inventories was $41 million and $39 million at December 31, 2019 and 2018. Inventory and supplies — net also includes fuel inventory of $28 million and $24 million at December 31, 2019 and 2018. Repairable and rotable aircraft parts inventories are included in flight equipment.
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Equipment and Depreciation Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives less an estimated salvage value, which are as follows: Estimated Useful Life Estimated Salvage Value Aircraft and other flight equipment: Boeing 737, Airbus A319/A320, and E175 aircraft 20-25 years 10% Bombardier Q400 aircraft 15 years 5% Buildings 25 - 40 years 10% Minor building and land improvements 10 years —% Capitalized leases and leasehold improvements Generally shorter of lease term or —% Computer hardware and software 3-10 years —% Other furniture and equipment 5-10 years —% Near the end of an asset's estimated useful life, management updates the salvage value estimates based on current market conditions and expected use of the asset. Repairable and rotable aircraft parts are included in Aircraft and other flight equipment, and are depreciated over the associated fleet life. Capitalized interest, based on the Company’s weighted-average borrowing rate, is added to the cost of the related asset, and is depreciated over the estimated useful life of the asset. Maintenance and repairs, other than engine maintenance on B737-800 engines, are expensed when incurred. Major modifications that extend the life or improve the usefulness of aircraft are capitalized and depreciated over their estimated period of use. Maintenance on B737-800 engines is covered under a power-by-the-hour agreement with a third party, whereby the Company pays a determinable amount, and transfers risk, to a third party. The Company expenses the contract amounts based on engine usage. The Company evaluates long-lived assets to be held and used for impairment whenever events or changes in circumstances indicate that the total carrying amount of an asset or asset group may not be recoverable. The Company groups assets for purposes of such reviews at the lowest level at which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities, which is generally the fleet level. An impairment loss is considered when estimated future undiscounted cash flows expected to result from the use of the asset or asset group and its eventual disposition are less than its carrying amount. If the asset or asset group is not considered recoverable, a write-down equal to the excess of the carrying amount over the fair value will be recorded. Goodwill
Goodwill	Goodwill Goodwill represents the excess of purchase price over the fair value of the related net assets acquired in the Company's acquisition of Virgin America and is not amortized. The total balance of goodwill is associated with the Mainline reporting unit. The Company reviews goodwill for impairment annually in Q4, or more frequently if events or circumstances indicate than an impairment may exist. If fair value of the reporting unit does not exceed the carrying amount, an impairment charge may be recorded. In 2019, the fair value of the reporting unit with goodwill substantially exceeded its carrying value.
Intangible Assets	Intangible Assets Intangible assets recorded in conjunction with the acquisition of Virgin America consist primarily of indefinite-lived airport slots, finite-lived airport gates and finite-lived customer relationships. Finite-lived intangibles are amortized over their estimated useful lives. Indefinite-lived intangibles are not amortized, but are tested at least annually for impairment using a similar methodology to property, equipment and goodwill, as described above.
Aircraft Maintenance Deposits	Aircraft Maintenance Deposits Certain Airbus leases include contractually required maintenance deposit payments to the lessor, which collateralize the lessor for future maintenance events should the Company not perform required maintenance. Most of the lease agreements provide that maintenance deposits are reimbursable upon completion of the major maintenance event in an amount equal to the lesser of
Leased Aircraft Return Costs [Policy Text Block]	Leased Aircraft Return Costs Cash payments associated with returning leased aircraft are accrued when it is probable that a cash payment will be made and that amount is reasonably estimable, usually no sooner than after the last scheduled maintenance event prior to lease return. Any accrual is based on the time remaining on the lease, planned aircraft usage and the provisions included in the lease agreement, although the actual amount due to any lessor upon return may not be known with certainty until lease termination. As leased aircraft are returned, any payments are charged against the established accrual. The accrual is part of other current and long-term liabilities and was not material as of December 31, 2019 and December 31, 2018. The expense is included in Aircraft maintenance in the consolidated statements of operations.
Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block]	Advertising Expenses
Derivatives, Policy [Policy Text Block]	Derivative Financial Instruments The Company's operations are significantly impacted by changes in aircraft fuel prices and interest rates. In an effort to manage exposure to these risks, the Company periodically enters into fuel and interest rate derivative instruments. These derivative instruments are recognized at fair value on the balance sheet and changes in the fair value are recognized in AOCL or in the consolidated statements of operations, depending on the nature of the instrument. The Company does not apply hedge accounting to its derivative fuel hedge contracts nor does it hold or issue them for trading purposes. For cash flow hedges related to interest rate swaps, the effective portion of the derivative represents the change in fair value of the hedge that offsets the change in fair value of the hedged item. To the extent the change in the fair value of the hedge does not perfectly offset the change in the fair value of the hedged item, the ineffective portion of the hedge is immediately recognized in interest expense.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value Measurements Accounting standards define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The standards also establish a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company has elected not to use the fair value option provided in the accounting standards for non-financial instruments. Accordingly, those assets and liabilities are carried at amortized cost. For financial instruments, the assets and liabilities are carried at fair value, which is determined based on the market approach or income approach, depending upon the level of inputs used.
Income Tax, Policy [Policy Text Block]	Income Taxes The Company uses the asset and liability approach for accounting for and reporting income taxes. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities, and their respective tax bases and for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance would be established, if necessary, for the amount of any tax benefits that, based on available evidence, are not expected to be realized. As of December 31, 2019, there is a partial valuation allowance against net deferred tax assets. The Company accounts for unrecognized tax benefits in accordance with the applicable accounting standards. The Company has substantial federal and state net operating losses (NOLs) for income tax purposes as a result of the acquisition of Virgin America. The Company's ability to utilize Virgin America's NOLs is limited by previous “ownership changes,” as defined in Section 382 of the Internal Revenue Code and similar state provisions, and could be further limited if there is another ownership change. In general terms, an ownership change can occur whenever there is a collective shift in the ownership of a company by more than 50% by one or more “5% stockholders” within a three-year period. The occurrence of such a change generally limits the amount of NOL carryforwards a company could utilize in a given year to the aggregate fair market value of the company's common stock immediately prior to the ownership change, multiplied by the long-term tax-exempt interest rate in effect for the month of the ownership change. The acquisition constituted an ownership change and the potential for further limitations following the acquisition. See Note 7 to the consolidated financial statements for more discussion of the calculation.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock-Based Compensation Accounting standards require companies to recognize as expense the fair value of stock options and other equity-based compensation issued to employees as of the grant date. These standards apply to all stock awards that the Company grants to employees as well as the Company’s Employee Stock Purchase Plan (ESPP), which features a look-back provision and allows employees to purchase stock at a 15% discount. All stock-based compensation expense is recorded in wages and benefits in the consolidated statements of operations.
Earnings Per Share, Policy [Policy Text Block]	Earnings Per Share (EPS) Diluted EPS is calculated by dividing net income by the average common shares outstanding plus additional common shares that would have been outstanding assuming the exercise of in-the-money stock options and restricted stock units, using the treasury-stock method. In 2019, 2018, and 2017, anti-dilutive stock options excluded from the calculation of EPS were not material.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting PronouncementsIn February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," which requires lessees to recognize assets and liabilities for leases currently classified as operating leases. In July 2018, the FASB issued ASU 2018-11, "Targeted Improvements - Leases (Topic 842)" which amended Topic 842 to provide companies an alternative transition method which would not require adjusting comparative period financial information. The Company elected this transition method upon adoption on January 1, 2019. As a result, the Company recorded a cumulative-effect adjustment to the opening balance of retained earnings upon transition. This adjustment is discussed further in Note 6.

GENERAL AND SUMMARY OF SIGNIF_3

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Property, Plant and Equipment [Table Text Block]	Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives less an estimated salvage value, which are as follows: Estimated Useful Life Estimated Salvage Value Aircraft and other flight equipment: Boeing 737, Airbus A319/A320, and E175 aircraft 20-25 years 10% Bombardier Q400 aircraft 15 years 5% Buildings 25 - 40 years 10% Minor building and land improvements 10 years —% Capitalized leases and leasehold improvements Generally shorter of lease term or —% Computer hardware and software 3-10 years —% Other furniture and equipment 5-10 years —%

CASH, CASH EQUIVALENTS AND MARK

CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2019
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Schedule of Realized Gain (Loss) [Table Text Block]	Proceeds from sales of marketable securities were $1.7 billion, $1.1 billion and $1.4 billion in 2019, 2018, and 2017.
Schedule of Debt Investment Maturities [Table Text Block]	Maturities for marketable securities (in millions): December 31, 2019 Cost Basis Fair Value Due in one year or less $ 164 $ 165 Due after one year through five years 1,102 1,114 Due after five years through 10 years 16 16 Total $ 1,282 $ 1,295

REVENUE FROM CONTRACTS WITH C_2

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contracts with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	Passenger revenue recognized in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Passenger ticket revenue, including ticket breakage and net of taxes and fees $ 6,824 $ 6,482 $ 6,246 Passenger ancillary revenue 567 530 514 Mileage Plan passenger revenue 704 619 541 Total passenger revenue $ 8,095 $ 7,631 $ 7,301 Mileage Plan revenue included in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Passenger revenue $ 704 $ 619 $ 541 Mileage Plan other revenue 465 434 418 Total Mileage Plan revenue $ 1,169 $ 1,053 $ 959 Cargo and other revenue included in the consolidated statements of operations (in millions): Twelve Months Ended December 31, 2019 2018 2017 Cargo revenue $ 133 $ 129 $ 115 Other revenue 88 70 60 Total Cargo and other revenue $ 221 $ 199 $ 175
Contract with Customer, Asset and Liability [Table Text Block]	The table below presents a roll forward of the total frequent flyer liability (in millions): Twelve Months Ended December 31, 2019 2018 Total Deferred Revenue balance at January 1 $ 1,874 $ 1,725 Travel miles and companion certificate redemption - Passenger revenue (704) (619) Miles redeemed on partner airlines - Other revenue (111) (90) Increase in liability for mileage credits issued 931 858 Total Deferred Revenue balance at December 31 $ 1,990 $ 1,874

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	Fair values of derivative instruments on the consolidated balance sheet (in millions): 2019 2018 Fuel hedge contracts (not designated as hedges) Prepaid expenses and other current assets $ 8 $ 2 Other assets 3 2 Interest rate swaps (designated as hedges) Prepaid expenses and other current assets 1 3 Other noncurrent assets 2 7 Other accrued liabilities (5) (3) Other liabilities (5) (4) Losses in accumulated other comprehensive loss (AOCL) (13) (1)
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	Pretax effect of derivative instruments on earnings and AOCL (in millions): 2019 2018 2017 Fuel hedge contracts (not designated as hedges) Gains (losses) recognized in Aircraft fuel $ (10) $ 1 $ (6) Interest rate swaps (designated as hedges) Losses recognized in Aircraft rent (3) (3) (5) Gains (losses) recognized in other comprehensive income (OCI) (13) — 1

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping [Table Text Block]	Fair values of financial instruments on the consolidated balance sheet (in millions): December 31, 2019 December 31, 2018 Level 1 Level 2 Total Level 1 Level 2 Total Assets Marketable securities U.S. government and agency securities $ 330 $ — $ 330 $ 293 $ — $ 293 Equity mutual funds 6 — 6 — — — Foreign government bonds — 31 31 — 26 26 Asset-backed securities — 211 211 — 190 190 Mortgage-backed securities — 176 176 — 92 92 Corporate notes and bonds — 523 523 — 520 520 Municipal securities — 23 23 — 10 10 Total Marketable securities 336 964 1,300 293 838 1,131 Derivative instruments Fuel hedge contracts - call options — 11 11 — 4 4 Interest rate swap agreements — 3 3 — 10 10 Total Assets $ 336 $ 978 $ 1,314 $ 293 $ 852 $ 1,145 Liabilities Derivative instruments Interest rate swap agreements — (10) (10) — (7) (7) Total Liabilities $ — $ (10) $ (10) $ — $ (7) $ (7) Fixed-rate debt on the consolidated balance sheet and the estimated fair value of long-term fixed-rate debt (in millions): December 31, 2019 December 31, 2018 Fixed rate debt at cost $ 473 $ 639 Non-recurring purchase price accounting fair value adjustment 2 3 Total fixed rate debt $ 475 $ 642 Estimated fair value $ 483 $ 641
Schedule of Realized Gain (Loss) [Table Text Block]	Proceeds from sales of marketable securities were $1.7 billion, $1.1 billion and $1.4 billion in 2019, 2018, and 2017.
Schedule of Debt Investment Maturities [Table Text Block]	Maturities for marketable securities (in millions): December 31, 2019 Cost Basis Fair Value Due in one year or less $ 164 $ 165 Due after one year through five years 1,102 1,114 Due after five years through 10 years 16 16 Total $ 1,282 $ 1,295

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	Long-term debt obligations (in millions): 2019 2018 Fixed-rate notes payable due through 2029 $ 475 $ 642 Variable-rate notes payable due through 2029 1,032 1,473 Less debt issuance costs (8) (12) Total debt 1,499 2,103 Less current portion 235 486 Long-term debt, less current portion $ 1,264 $ 1,617 Weighted-average fixed-interest rate 3.3 % 4.1 % Weighted-average variable-interest rate 2.9 % 3.9 %
Schedule of Maturities of Long-term Debt [Table Text Block]	Long-term debt principal payments for the next five years and thereafter (in millions): Total 2020 $ 235 2021 281 2022 243 2023 173 2024 153 Thereafter 420 Total principal payments $ 1,505

Leases, Codification Topic 842

Leases, Codification Topic 842 (Tables)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Schedule of Lease Assets	At December 31, 2019, the Operating lease assets balance by asset class was as follows (in millions): December 31, 2019 Aircraft $ 1,049 CPA Aircraft 596 Airport and terminal facilities 18 Corporate real estate and other 48 Total Operating lease assets $ 1,711
Lease, Cost	The impact of leases, including variable lease cost, on earnings for the twelve months ended December 31, 2019 was as follows (in millions): Classification 2019 Expense Aircraft Aircraft rent $ 246 CPA Aircraft Aircraft rent 79 Airport and terminal facilities Landing fees and other rentals 324 Corporate real estate and other Landing fees and other rentals 19 Total lease expense $ 668 Revenue Lease income Cargo and other revenues (13) Net lease impact $ 655
Lessee, Operating Lease, Liability, Maturity	Future minimum lease payments under non-cancellable leases as of December 31, 2019 (in millions): Aircraft CPA Aircraft Airport and Terminal Facilities Corporate Real Estate and Other 2020 $ 245 $ 79 $ 3 $ 8 2021 216 79 2 6 2022 190 79 2 5 2023 133 79 2 5 2024 81 79 2 5 Thereafter 331 329 11 74 Total Lease Payments $ 1,196 $ 724 $ 22 $ 103 Less: Imputed interest (151) (128) (4) (54) Total $ 1,045 $ 596 $ 18 $ 49
Schedule of Future Minimum Rental Payments for Operating Leases		Future minimum lease payments under noncancelable operating leases were as follows as of December 31, 2018 (in millions): Aircraft Leases Facility Leases 2019 $ 350 $ 133 2020 320 124 2021 286 113 2022 262 94 2023 208 26 Thereafter 847 122 Total $ 2,273 $ 612
Weighted Average Lease Assumptions	The weighted average IBR and weighted average remaining lease term (in years) for all asset classes were as follows at December 31, 2019. Weighted Average IBR Weighted Average Remaining Lease term Aircraft 4.0 % 7.0 CPA Aircraft 4.3 % 9.2 Airports and terminal facilities 4.1 % 10.0 Corporate real estate and other 4.2 % 34.9

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Deferred tax (assets) and liabilities comprise the following (in millions): 2019 2018 Excess of tax over book depreciation $ 1,233 $ 1,066 Intangibles - net 16 15 Operating lease liabilities 416 — Other - net 58 43 Deferred tax liabilities 1,723 1,124 Mileage Plan™ (337) (315) Inventory obsolescence (15) (15) Employee benefits (179) (172) Acquired net operating losses (13) (64) Operating lease assets (417) — Other - net (48) (48) Deferred tax assets (1,009) (614) Valuation allowance 1 2 Net deferred tax liabilities $ 715 $ 512
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The components of income tax expense are as follows (in millions): 2019 2018 2017 Current income tax expense (benefit): Federal $ 26 $ (5) $ 127 State 13 9 35 Total current income tax expense 39 4 162 Deferred income tax expense (benefit): Federal 175 125 (3) State 33 19 40 Total deferred income tax expense (benefit) 208 144 37 Income tax expense $ 247 $ 148 $ 199
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	2019 2018 2017 Income before income tax $ 1,016 $ 585 $ 1,159 Expected tax expense 213 123 406 Nondeductible expenses 9 9 5 State income taxes 36 21 28 State income sourcing 1 — 9 Tax law changes (9) (7) (237) Other - net (3) 2 (12) Actual tax expense $ 247 $ 148 $ 199 Effective tax rate 24.3 % 25.3 % 17.2 %
Summary of Income Tax Contingencies [Table Text Block]	The Company has identified its federal tax return and its state tax returns in Alaska, Oregon and California as “major” tax jurisdictions. A summary of the Company's jurisdictions and the periods that are subject to examination are as follows: Jurisdiction Period Federal 2007 to 2018 Alaska 2015 to 2018 California 2007 to 2018 Oregon 2003 to 2018 Certain tax years are open to the extent of net operating loss carryforwards. Changes in the liability for gross unrecognized tax benefits during 2019, 2018 and 2017 are as follows (in millions): 2019 2018 2017 Balance at January 1, $ 40 $ 43 $ 40 Additions related to prior years — 1 16 Releases related to prior years (1) (4) (2) Additions related to current year activity 2 2 2 Releases due to settlements — (1) (11) Releases due to lapse of statute of limitations (1) (1) (2) Balance at December 31, $ 40 $ 40 $ 43

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables) - Qualified Defined Benefit [Member]	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Assumptions Used [Table Text Block]	Weighted average assumptions used to determine benefit obligations: The rates below vary by plan and related work group. 2019 2018 Discount rates 3.33% to 3.47% 4.37% to 4.46% Rate of compensation increases 2.11% to 5.44% 2.11% to 3.50% Weighted average assumptions used to determine net periodic benefit cost: The rates below vary by plan and related work group. 2019 2018 2017 Discount rates 4.37% to 4.46% 3.69% to 3.78% 4.29% to 4.50% Expected return on plan assets 4.25% to 5.50% 4.25% to 5.50% 5.50% to 6.00% Rate of compensation increases (a) 2.11% to 3.50% 2.11% to 16.51% 2.12% to 2.59%
Schedule of Allocation of Plan Assets [Table Text Block]	The target and actual asset allocation of the funds in the qualified defined-benefit plans, by asset category, are as follows: Salaried Plan (a) All other plans Target 2019 2018 Target 2019 2018 Asset category: Domestic equity securities 2% - 12% 7 % 6 % 36% - 46% 41 % 28 % Non-U.S. equity securities 0% - 5% 3 % 3 % 13% - 23% 18 % 12 % Fixed income securities 85% - 95% 90 % 91 % 26% - 46% 35 % 53 % Real estate — % — % — % 0% - 10% 6 % 7 % Plan assets 100 % 100 % 100 % 100 % (a) As our Salaried Plan is frozen and fully funded, our investment strategies differ significantly from that of our other outstanding plans. Investments are in lower-risk securities, with earnings designed to maintain a fully-funded status. Plan assets by fund category (in millions): 2019 2018 Fair Value Hierarchy Fund type: U.S. equity market fund $ 773 $ 431 1 Non-U.S. equity fund 344 183 1 Credit bond index fund 1,009 1,135 1 Plan assets in common commingled trusts $ 2,126 $ 1,749 Real estate 102 104 (a) Cash equivalents 11 5 1 Total plan assets $ 2,239 $ 1,858
Schedule of Net Funded Status [Table Text Block]	The following table sets forth the status of the qualified defined-benefit pension plans (in millions): 2019 2018 Projected benefit obligation (PBO) Beginning of year $ 2,225 $ 2,387 Service cost 42 48 Interest cost 89 79 Actuarial (gain)/loss 359 (191) Benefits paid (113) (98) End of year $ 2,602 $ 2,225 Plan assets at fair value Beginning of year $ 1,858 $ 2,083 Actual return on plan assets 429 (127) Employer contributions 65 — Benefits paid (113) (98) End of year $ 2,239 $ 1,858 Unfunded status $ (363) $ (367) Percent funded 86 % 84 %
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]	The amounts recognized in the consolidated balance sheets (in millions): 2019 2018 Accrued benefit liability-long term $ 412 $ 392 Plan assets-long term (within Other noncurrent assets) (49) (25) Total liability recognized $ 363 $ 367 The amounts not yet reflected in net periodic benefit cost and included in AOCL (in millions): 2019 2018 Prior service credit $ (6) $ (8) Net loss 595 607 Amount recognized in AOCL (pretax) $ 589 $ 599
Schedule of Net Benefit Costs [Table Text Block]	Net pension expense for the qualified defined-benefit plans included the following components (in millions): 2019 2018 2017 Service cost $ 42 $ 48 $ 39 Interest cost 89 79 74 Expected return on assets (95) (107) (106) Amortization of prior service credit (1) (1) (1) Recognized actuarial loss 37 33 26 Net pension expense $ 72 $ 52 $ 32
Schedule of Expected Benefit Payments [Table Text Block]	Future benefits expected to be paid over the next ten years under the qualified defined-benefit pension plans from the assets of those plans (in millions): Total 2020 $ 115 2021 118 2022 134 2023 137 2024 137 2025– 2029 800

COMMITMENTS AND CONTINGENCIES C

COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases and Unrecorded Unconditional Purchase Obligtaions [Table Text Block]	Future minimum payments for commitments as of December 31, 2019 (in millions): Aircraft Commitments (a) Capacity Purchase Agreements (b) Aircraft Maintenance Deposits 2020 $ 531 $ 145 $ 73 2021 487 166 62 2022 347 174 51 2023 206 179 26 2024 31 184 6 Thereafter 26 880 2 Total $ 1,628 $ 1,728 $ 220

SHAREHOLDER'S EQUITY (Tables)

SHAREHOLDER'S EQUITY (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Treasury Stock by Class [Table Text Block]	Share repurchase activity (in millions, except shares): 2019 2018 2017 Shares Amount Shares Amount Shares Amount 2015 Repurchase Program – $1 billion 1,192,820 $ 75 776,186 $ 50 981,277 $ 75
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	AOCL consisted of the following (in millions, net of tax): 2019 2018 Related to marketable securities $ 9 $ (11) Related to employee benefit plans (469) (440) Related to interest rate derivatives (5) 3 $ (465) $ (448)

SPECIAL ITEMS (Tables)

SPECIAL ITEMS (Tables)	12 Months Ended
	Dec. 31, 2019
Unusual or Infrequent Items, or Both [Abstract]
Merger-related Costs [Table Text Block]	The following breaks down merger-related costs incurred in 2019, 2018 and 2017 (in millions): 2019 2018 2017 Consulting and professional services $ 18 $ 45 $ 52 Employee-related costs (a) 15 13 41 Legal and accounting fees 1 1 3 Other merger-related costs (b) 10 28 20 Total Merger-related Costs $ 44 $ 87 $ 116 (a) Employee-related costs consist primarily of vacation balance true-ups, severance, retention bonuses, and training and skill development. (b) Other merger-related costs consist primarily of costs for marketing and advertising, IT, employee appreciation and company sponsored events, moving expenses, supplies, and other immaterial expenses.

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	The table below summarizes the components of total stock-based compensation (in millions): 2019 2018 2017 Stock options $ 3 $ 3 $ 3 Stock awards 21 23 24 Deferred stock awards 1 1 1 Employee stock purchase plan 11 9 6 Stock-based compensation $ 36 $ 36 $ 34 Tax benefit related to stock-based compensation $ 9 $ 9 $ 13
Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block]	Unrecognized stock-based compensation for non-vested options and awards and the weighted-average period the expense will be recognized (in millions): Amount Weighted-Average Stock options $ 4 1.3 Stock awards 20 1.5 Unrecognized stock-based compensation $ 24 1.5
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The fair value of each option grant was estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions used for grants: 2019 2018 2017 Expected volatility 30 % 30 % 51 % Expected term 6 years 6 years 6 years Risk-free interest rate 2.41 % 2.61 % 2.04 % Expected dividend yield 2.09 % 1.94 % 1.10 % Weighted-average grant date fair value per share $ 16.84 $ 17.18 $ 41.19 Estimated fair value of options granted (millions) $ 4 $ 1 $ 4
Share-based Compensation, Stock Options, Activity [Table Text Block]	The tables below summarize stock option activity for the year ended December 31, 2019: Shares Weighted- Weighted- Aggregate Intrinsic Outstanding, December 31, 2018 573,242 $ 57.78 6.6 $ 6 Granted 252,200 66.52 Exercised (21,322) 36.14 Canceled (5,366) 68.94 Forfeited or expired (4,699) 70.98 Outstanding, December 31, 2019 794,055 $ 60.98 6.5 $ 7 Exercisable, December 31, 2019 341,322 $ 50.50 4.3 $ 7 Vested or expected to vest, December 31, 2019 793,684 $ 60.98 6.5 $ 7 (in millions) 2019 2018 2017 Intrinsic value of option exercises $ 1 $ 1 $ 6 Cash received from stock option exercises 1 1 3 Tax benefit related to stock option exercises — — 2 Fair value of options vested 3 2 3
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	The following table summarizes information about outstanding stock awards: Number Weighted-Average Grant Date Fair Value Weighted- Aggregate Non-vested, December 31, 2018 511,813 $ 78.75 1.5 $ 31 Granted 402,816 66.35 Vested (270,802) 74.61 Forfeited (102,214) 75.21 Non-vested, December 31, 2019 541,613 $ 71.82 1.4 $ 37

OPERATING SEGMENT INFORMATION (

OPERATING SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Schedule of Segment Reporting Information, by Segment	Operating segment information is as follows (in millions): Year Ended December 31, 2019 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,750 1,345 — — 8,095 — 8,095 CPA revenues — — 450 (450) — — — Mileage Plan other revenue 419 46 — — 465 — 465 Cargo and other 212 3 1 5 221 — 221 Total Operating Revenues 7,381 1,394 451 (445) 8,781 — 8,781 Operating Expenses Non-fuel operating expenses 4,778 1,097 385 (464) 5,796 44 5,840 Fuel expense 1,589 295 — — 1,884 (6) 1,878 Total Operating Expenses 6,367 1,392 385 (464) 7,680 38 7,718 Non-operating Income (Expense) Interest income 66 — — (24) 42 — 42 Interest expense (76) — (28) 26 (78) — (78) Interest capitalized 15 — — — 15 — 15 Other (26) — — — (26) — (26) Total Non-operating Income (Expense) (21) — (28) 2 (47) — (47) Income (Loss) Before Income Tax $ 993 $ 2 $ 38 $ 21 $ 1,054 $ (38) $ 1,016 Year Ended December 31, 2018 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,474 1,157 — — 7,631 — 7,631 CPA revenues — — 508 (508) — — — Mileage Plan other revenue 397 37 — — 434 — 434 Cargo and other 192 3 4 — 199 — 199 Total Operating Revenues 7,063 1,197 512 (508) 8,264 — 8,264 Operating Expenses Non-fuel operating expenses 4,577 1,024 465 (513) 5,553 132 5,685 Fuel expense 1,652 262 — — 1,914 22 1,936 Total Operating Expenses 6,229 1,286 465 (513) 7,467 154 7,621 Non-operating Income (Expense) Interest income 53 — — (15) 38 — 38 Interest expense (82) — (22) 13 (91) — (91) Interest capitalized 16 — 2 — 18 — 18 Other (12) (11) — — (23) — (23) Total Non-operating Income (Expense) (25) (11) (20) (2) (58) — (58) Income (Loss) Before Income Tax $ 809 $ (100) $ 27 $ 3 $ 739 $ (154) $ 585 Year Ended December 31, 2017 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,278 1,023 — — 7,301 — 7,301 CPA revenues — — 426 (426) — — — Mileage Plan other revenue 387 31 — — 418 — 418 Cargo and other 167 4 4 — 175 — 175 Total Operating Revenues 6,832 1,058 430 (426) 7,894 — 7,894 Operating Expenses Non-fuel operating expenses 4,271 852 427 (427) 5,123 116 5,239 Fuel expense 1,282 172 — — 1,454 (7) 1,447 Total Operating Expenses 5,553 1,024 427 (427) 6,577 109 6,686 Non-operating Income (Expense) Interest income 39 — — (5) 34 — 34 Interest expense (92) — (13) 2 (103) — (103) Interest capitalized 15 — 2 — 17 — 17 Other 3 — — — 3 — 3 Total Non-operating Income (Expense) (35) — (11) (3) (49) — (49) Income (Loss) Before Income Tax $ 1,244 $ 34 $ (8) $ (2) $ 1,268 $ (109) $ 1,159 (a) Includes consolidating entries, Parent Company, McGee Air Services, and other immaterial business units. (b) The Air Group Adjusted column represents the financial information that is reviewed by management to assess performance of operations and determine capital allocations and excludes certain income and charges. (c) Includes merger-related costs, mark-to-market fuel-hedge accounting adjustments, and other special items. 2019 2018 2017 Depreciation and amortization: Mainline $ 337 $ 316 $ 308 Horizon 86 82 64 Consolidated $ 423 $ 398 $ 372 Capital expenditures: Mainline $ 605 $ 571 $ 734 Horizon 91 389 292 Consolidated $ 696 $ 960 $ 1,026 Total assets at end of period: Mainline $ 19,207 $ 16,853 Horizon 1,266 1,229 Consolidating & Other (7,480) (7,170) Consolidated $ 12,993 $ 10,912

GENERAL AND SUMMARY OF SIGNIF_4

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - CASH AND CASH EQUIVALENTS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Negative cash balance	$ 7	$ 5

GENERAL AND SUMMARY OF SIGNIF_5

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - INVENTORIES AND SUPPLIES - NET (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Allowance for all non-surplus expendable inventories	$ 41	$ 39
Fuel inventory	$ 28	$ 24

GENERAL AND SUMMARY OF SIGNIF_6

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PROPERTY, EQUIPMENT AND DEPRECIATION (Details)	12 Months Ended
	Dec. 31, 2019
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	0.00%
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Minor building and land improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Property, Plant, and Equipment, Salvage Value, Percentage	0.00%
Leaseholds and Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	0.00%
Leaseholds and Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	10.00%
Computer hardware and software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	0.00%
Computer hardware and software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer hardware and software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Other furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	0.00%
Other furniture and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Other furniture and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
B737 | Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	10.00%
B737 | Aircraft [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
B737 | Aircraft [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Airbus [Member] | Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	10.00%
Airbus [Member] | Aircraft [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Airbus [Member] | Aircraft [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
E175 [Member] | Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value, Percentage	10.00%
E175 [Member] | Aircraft [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
E175 [Member] | Aircraft [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Q400 [Member] | Aircraft [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Property, Plant, and Equipment, Salvage Value, Percentage	10.00%

GENERAL AND SUMMARY OF SIGNIF_7

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - ADVERTISING EXPENSES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Advertising Expense	$ 72	$ 79	$ 91

GENERAL AND SUMMARY OF SIGNIF_8

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - STOCK-BASED COMPENSATION (Details)	12 Months Ended
	Dec. 31, 2019
Employee stock purchase plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date	15.00%

GENERAL AND SUMMARY OF SIGNIF_9

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) $ in Millions	Jan. 01, 2019USD ($)
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derecognition of Build-to-suit Accounting	$ 150

GENERAL AND SUMMARY OF SIGNI_10

GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - MAINTENANCE DEPOSITS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Aircraft Maintenance Deposits	$ 143	$ 90

CASH, CASH EQUIVALENTS AND MA_2

CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 221	$ 105	$ 194
Marketable securities	1,282
Marketable securities	1,300	1,131
Total cash and marketable securities	$ 1,521	$ 1,236

CASH, CASH EQUIVALENTS AND MA_3

CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES - MATURITIES (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Cost Basis [Abstract]
Due in one year or less	$ 164
Due after one year through five years	1,102
Due after five years through 10 years	16
Marketable securities	1,282
Fair Value [Abstract]
Due in one year or less	165
Due after one year through five years	1,114
Due after five years through 10 years	16
Marketable securities	$ 1,300	$ 1,131

REVENUE FROM CONTRACTS WITH C_3

REVENUE FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cargo and Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 221	$ 199	$ 175
Passenger Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,095	7,631	7,301
Passenger [Member] | Cargo and Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	133	129	115
Passenger Tickets [Member] | Passenger Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,824	6,482	6,246
Passenger Ancillary Services [Member] | Passenger Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	567	530	514
Mileage Plan Services [Member] | Passenger Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	704	619	541
Mileage Plan Services, Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	465	434	418
Other Services [Member] | Cargo and Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 88	$ 70	$ 60

REVENUE FROM CONTRACTS WITH C_4

REVENUE FROM CONTRACTS WITH CUSTOMERS Contract Liabilities Activity (Details) - Mileage Plan Revenue [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contract with Customer, Liability	$ 1,990	$ 1,874	$ 1,725
Contract with Customer, Liability, Increase From Issuance of Credits	931	858
Mileage Plan Services, Other [Member]
Contract with Customer, Liability, Revenue Recognized	(111)	(90)
Passenger Services [Member]
Contract with Customer, Liability, Revenue Recognized	$ (704)	$ (619)

REVENUE FROM CONTRACTS WITH C_5

REVENUE FROM CONTRACTS WITH CUSTOMERS Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)agreement	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Deferred Revenue Arrangement [Line Items]
Percent of Mileage Breakage	17.40%	17.40%
Contract cost recognized	$ 208	$ 217	$ 238
Receivable	$ 323	366
Number of Partner AIrlines | agreement	17
Prepaid Expenses and Other Current Assets [Member]
Deferred Revenue Arrangement [Line Items]
Capitalized Contract Cost, Net	$ 27	23
Passenger Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Contract with Customer, Liability, Revenue Recognized	577	583
Mileage Plan Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Receivable	$ 105	$ 119

DERIVATIVE INSTRUMENTS - BALANC

DERIVATIVE INSTRUMENTS - BALANCE SHEET CLASSIFICATION (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss	$ (465)	$ (448)
Fuel hedge contracts [Member] | Derivative Instruments Not Designated as Hedges [Member] | Fuel Hedge Contracts, Current [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	8	2
Fuel hedge contracts [Member] | Derivative Instruments Not Designated as Hedges [Member] | Fuel Hedge Contracts, Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Noncurrent	3	2
Interest rate swaps agreements [Member] | Derivative Instruments Designated as Hedges [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	1	3
Interest rate swaps agreements [Member] | Derivative Instruments Designated as Hedges [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Noncurrent	2	7
Interest rate swaps agreements [Member] | Derivative Instruments Designated as Hedges [Member] | Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Current	(5)	(3)
Interest rate swaps agreements [Member] | Derivative Instruments Designated as Hedges [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Noncurrent	(5)	(4)
Interest rate swaps agreements [Member] | Derivative Instruments Designated as Hedges [Member] | Accumulated Other Comprehensive Loss [Member]
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss	$ (13)	$ (1)

DERIVATIVE INSTRUMENTS - INCOME

DERIVATIVE INSTRUMENTS - INCOME STATEMENT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gains (losses) recognized in aircraft rent [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss expected to be reclassified	$ (3)
Gains (losses) recognized in interest income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss expected to be reclassified	(4)
Derivative Instruments Not Designated as Hedges [Member] | Fuel hedge contracts [Member] | Gains (losses) recognized in aircraft fuel expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Losses recognized in income	(10)	$ 1	$ (6)
Cash Flow Hedging [Member] | Derivative Instruments Designated as Hedges [Member] | Interest rate swaps agreements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Losses in accumulated other comprehensive loss	(13)	0	1
Cash Flow Hedging [Member] | Derivative Instruments Designated as Hedges [Member] | Interest rate swaps agreements [Member] | Gains (losses) recognized in aircraft rent [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Losses recognized in income	$ (3)	$ (3)	$ (5)

DERIVATIVE INSTRUMENTS - FAIR V

DERIVATIVE INSTRUMENTS - FAIR VALUE OF HEDGE POSITIONS (Details) gallons in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)gallonsaircraftnumberOfInterestRateSwaps	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Payments for (Proceeds from) Hedge, Investing Activities	$ 19	$ (21)	$ 12
Aircraft Rent [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	3
Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	$ 4
B737-800 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Capital Leased Assets, Number of Units | aircraft	6
Fuel hedge contracts [Member] | Derivative Instruments Not Designated as Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | gallons	435
Interest rate swaps agreements [Member] | Secured Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 717
Number of interest rate swap agreements | numberOfInterestRateSwaps	13

FAIR VALUE MEASUREMENTS - FAIR

FAIR VALUE MEASUREMENTS - FAIR VALUE OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 1,282
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,300	$ 1,131
Derivative instruments, assets	1,314	1,145
Derivative instruments, liabilities	(10)	(7)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	336	293
Derivative instruments, assets	336	293
Derivative instruments, liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	964	838
Derivative instruments, assets	978	852
Derivative instruments, liabilities	(10)	(7)
Fair Value, Measurements, Recurring [Member] | Fuel hedge contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	11	4
Fair Value, Measurements, Recurring [Member] | Fuel hedge contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	0	0
Fair Value, Measurements, Recurring [Member] | Fuel hedge contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	11	4
Fair Value, Measurements, Recurring [Member] | Interest rate swaps agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	3	10
Derivative instruments, liabilities	(10)	(7)
Fair Value, Measurements, Recurring [Member] | Interest rate swaps agreements [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	0	0
Derivative instruments, liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Interest rate swaps agreements [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, assets	3	10
Derivative instruments, liabilities	(10)	(7)
Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	330	293
Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	330	293
Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Debt Security, Government, Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31	26
Fair Value, Measurements, Recurring [Member] | Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Debt Security, Government, Non-US [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31	26
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	211	190
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	211	190
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	176	92
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	176	92
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	523	520
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	523	520
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	23	10
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	23	10
Fair Value, Measurements, Recurring [Member] | Equity funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	6	0
Fair Value, Measurements, Recurring [Member] | Equity funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	6	0
Fair Value, Measurements, Recurring [Member] | Equity funds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 0	$ 0

FAIR VALUE MEASUREMENTS FAIR VA

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS - CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Sales and maturities of marketable securities	$ 1,674	$ 1,116	$ 1,388

FAIR VALUE MEASUREMENTS FAIR _2

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS - CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES - MATURITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Sales and maturities of marketable securities	$ 1,674	$ 1,116	$ 1,388
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Due in one year or less	165
Due after one year through five years	1,114
Due after five years through 10 years	16
Debt Securities, Available-for-sale, Total	1,295
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Due in one year or less	164
Due after one year through five years	1,102
Due after five years through 10 years	16
Marketable securities	$ 1,282

FAIR VALUE MEASUREMENTS - LONG-

FAIR VALUE MEASUREMENTS - LONG-TERM DEBT (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-recurring purchase price accounting fair value adjustment	$ 2	$ 3
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed rate debt at cost	473	639
Long-term debt	475	642
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 483	$ 641

LONG-TERM DEBT - SCHEDULE OF LO

LONG-TERM DEBT - SCHEDULE OF LONG-TERM DEBT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term Debt	$ 1,499	$ 2,103
Less debt issuance costs	(8)	(12)
Less current portion	235	486
Long-term debt, net of current portion	$ 1,264	$ 1,617
Weighted-average fixed-interest rate	3.30%	4.10%
Weighted-average variable-interest rate	2.90%	3.90%
Proceeds from issuance of long-term debt, net of issuance costs	$ 450	$ 339	$ 0
Long-term debt payments	1,058	807	$ 397
Repayments of debt	779
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	235
2021	281
2022	243
2023	173
2024	153
Thereafter	420
Long-term Debt	1,505
Fixed-rate notes payable due through 2029
Debt Instrument [Line Items]
Long-term Debt	475	642
Variable-rate notes payable due through 2029
Debt Instrument [Line Items]
Long-term Debt	$ 1,032	$ 1,473

LONG-TERM DEBT LONG-TERM DEBT -

LONG-TERM DEBT LONG-TERM DEBT - SECURED DEBT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt instrument, increase (decrease)	$ (604)
Long-term Debt	1,499	$ 2,103
Long-term debt payments	1,058	807	$ 397
Repayments of debt	779
Proceeds from Issuance of Debt	450	$ 339	$ 0
Variable Rate debt with interest rate swap [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 717

LONG-TERM DEBT - LINE OF CREDIT

LONG-TERM DEBT - LINE OF CREDIT (Details)	Dec. 31, 2019USD ($)credit_facility	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity	$ 516,000,000
Number of credit facilities | credit_facility	3
Credit Facility 1 [Member]
Line of Credit Facility [Line Items]
Line of credit facility, asset restrictions, unrestricted cash and marketable securities	$ 500,000,000
Credit Facility 1 [Member] | Secured by aircraft [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity			$ 250,000,000
Number of credit facilities | credit_facility	1
Credit Facility 2 [Member] | Secured by other [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity				$ 150,000,000
Credit Facility 3 [Member] | Secured by aircraft [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity		$ 116,000,000
Credit Facilities 1 and 2 [Member]
Line of Credit Facility [Line Items]
Number of credit facilities, no borrowing | credit_facility	2

LEASES - NARRATIVE (Details)

LEASES - NARRATIVE (Details) $ in Millions	Jan. 01, 2019USD ($)	Dec. 31, 2019USD ($)aircraft	Dec. 31, 2018USD ($)aircraft	Dec. 31, 2017USD ($)
Lessee, Lease, Description [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 3
Sublease Income		13
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		176
Operating Lease, Payments		$ 347
Rent expense			$ 619	$ 552
Property Subject to Operating Lease [Member] | Airbus [Member]
Lessee, Lease, Description [Line Items]
Operating leases, number of leased assets (in aircraft) | aircraft		61	61
Property Subject to Operating Lease [Member] | Q400 [Member]
Lessee, Lease, Description [Line Items]
Operating leases, number of leased assets (in aircraft) | aircraft		7	9
Property Subject to Operating Lease [Member] | E175 [Member]
Lessee, Lease, Description [Line Items]
Operating leases, number of leased assets (in aircraft) | aircraft		32	32
Property Subject to Operating Lease [Member] | B737
Lessee, Lease, Description [Line Items]
Operating leases, number of leased assets (in aircraft) | aircraft		10	10
Airport Facilities [Member]
Lessee, Lease, Description [Line Items]
Variable Lease, Cost		$ 322
Aircraft Leases [Member]
Lessee, Lease, Description [Line Items]
Variable Lease, Cost		$ 4
Aircraft Leases [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		12 years
Corporate real estate [Member]
Lessee, Lease, Description [Line Items]
Variable Lease, Cost		$ 10
CPA Aircraft [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		11 years
CPA Aircraft [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		7 years 6 months
Accounting Standards Update 2016-02 [Member]
Lessee, Lease, Description [Line Items]
Derecognition of Build-to-suit Accounting	$ 150
Retained Earnings
Lessee, Lease, Description [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 3

LEASES - Schedule of Leased Ass

LEASES - Schedule of Leased Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	$ 1,711	$ 0
Aircraft Leases [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	1,049
CPA Aircraft [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	596
Airport Facilities [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	18
Corporate real estate [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	$ 48

LEASES - Lease Cost (Details)

LEASES - Lease Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)Rate
Lessee, Lease, Description [Line Items]
Operating Lease, Expense	$ 668
Sublease Income	13
Lease, Cost	655
Aircraft Leases [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 246
Operating Lease, Weighted Average Discount Rate, Percent | Rate	4.00%
Operating Lease, Weighted Average Remaining Lease Term	7 years
CPA Aircraft [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 79
Operating Lease, Weighted Average Discount Rate, Percent | Rate	4.30%
Operating Lease, Weighted Average Remaining Lease Term	9 years 2 months 12 days
Airport Facilities [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 324
Operating Lease, Weighted Average Discount Rate, Percent | Rate	4.10%
Operating Lease, Weighted Average Remaining Lease Term	10 years
Corporate real estate [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 19
Operating Lease, Weighted Average Discount Rate, Percent | Rate	4.20%
Operating Lease, Weighted Average Remaining Lease Term	34 years 10 months 24 days

LEASES - Maturity of Lease Liab

LEASES - Maturity of Lease Liabilities (Details) $ in Millions	Dec. 31, 2019USD ($)
Aircraft Leases [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 245
Lessee, Operating Lease, Liability, Payments, Due Year Two	216
Lessee, Operating Lease, Liability, Payments, Due Year Three	190
Lessee, Operating Lease, Liability, Payments, Due Year Four	133
Lessee, Operating Lease, Liability, Payments, Due Year Five	81
Lessee, Operating Lease, Liability, Payments, Due after Year Five	331
Lessee, Operating Lease, Liability, Payments, Due	1,196
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	151
Operating Lease, Liability	1,045
CPA Aircraft [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	79
Lessee, Operating Lease, Liability, Payments, Due Year Two	79
Lessee, Operating Lease, Liability, Payments, Due Year Three	79
Lessee, Operating Lease, Liability, Payments, Due Year Four	79
Lessee, Operating Lease, Liability, Payments, Due Year Five	79
Lessee, Operating Lease, Liability, Payments, Due after Year Five	329
Lessee, Operating Lease, Liability, Payments, Due	724
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	128
Operating Lease, Liability	596
Airport Facilities [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments, Next Rolling Twelve Months	3
Lessee, Operating Lease, Liability, Payments, Due Year Two	2
Lessee, Operating Lease, Liability, Payments, Due Year Three	2
Lessee, Operating Lease, Liability, Payments, Due Year Four	2
Lessee, Operating Lease, Liability, Payments, Due Year Five	2
Lessee, Operating Lease, Liability, Payments, Due after Year Five	11
Lessee, Operating Lease, Liability, Payments, Due	22
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	4
Operating Lease, Liability	18
Corporate real estate [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments, Next Rolling Twelve Months	8
Lessee, Operating Lease, Liability, Payments, Due Year Two	6
Lessee, Operating Lease, Liability, Payments, Due Year Three	5
Lessee, Operating Lease, Liability, Payments, Due Year Four	5
Lessee, Operating Lease, Liability, Payments, Due Year Five	5
Lessee, Operating Lease, Liability, Payments, Due after Year Five	74
Lessee, Operating Lease, Liability, Payments, Due	103
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	54
Operating Lease, Liability	$ 49

LEASES - Future Minimum Lease P

LEASES - Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2018USD ($)
Aircraft Leases [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 350
Operating Leases, Future Minimum Payments, Due in Rolling Year Two	320
Operating Leases, Future Minimum Payments, Due in Three Years	286
Operating Leases, Future Minimum Payments, Due in Rolling Year Four	262
Operating Leases, Future Minimum Payments, Due in Four Years	208
Thereafter	847
Operating Leases, Future Minimum Payments Due	2,273
Facility Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	133
Operating Leases, Future Minimum Payments, Due in Rolling Year Two	124
Operating Leases, Future Minimum Payments, Due in Three Years	113
Operating Leases, Future Minimum Payments, Due in Rolling Year Four	94
Operating Leases, Future Minimum Payments, Due in Four Years	26
Thereafter	122
Operating Leases, Future Minimum Payments Due	$ 612

INCOME TAXES - DEFERRED TAX ASS

INCOME TAXES - DEFERRED TAX ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Excess of tax over book depreciation	$ 1,233	$ 1,066
Deferred Tax Liabilities, Intangible Assets	16	15
Deferred Tax Liabilities, Other	58	43
Gross deferred tax liabilities	1,723	1,124
Mileage Plan	(337)	(315)
Inventory obsolescence	(15)	(15)
Employee benefits	(179)	(172)
Acquired net operating losses	(13)	(64)
Other - net	(48)	(48)
Deferred tax assets	(1,009)	(614)
Valuation allowance	1	2
Net deferred tax liabilities	715	512
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Other Finite-Lived Assets	416	0
Deferred Tax Assets - Leasing Arrangement	417	$ 0
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss	45
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 55

INCOME TAXES - COMPONENTS OF TA

INCOME TAXES - COMPONENTS OF TAX EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current tax expense (benefit):
Federal	$ 26	$ (5)	$ 127
State	13	9	35
Total current	39	4	162
Deferred tax expense:
Federal	175	125	(3)
State	33	19	40
Total deferred	208	144	37
Income tax expense	$ 247	$ 148	$ 199

INCOME TAXES - EFFECTIVE INCOME

INCOME TAXES - EFFECTIVE INCOME TAX RECONCILIATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
U.S. federal tax rate	21.00%	35.00%	35.00%
Income before income tax	$ 1,016	$ 585	$ 1,159
Expected tax expense	213	123	406
Nondeductible expenses	9	9	5
State income taxes	36	21	28
State income sourcing	1	0	9
Tax law changes	(9)	(7)	(237)
Other—net	(3)	2	(12)
Income tax expense	$ 247	$ 148	$ 199
Effective tax rate	24.30%	25.30%	17.20%

INCOME TAXES INCOME TAXES - UNC

INCOME TAXES INCOME TAXES - UNCERTAIN TAX POSITIONS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 34
Income Tax Examination, Penalties and Interest Accrued	7	$ 6		$ 5
Income Tax Examination, Penalties and Interest Expense	1	1	$ 2
Beginning balance	40	43	40
Additions related to prior years	0	1	16
Releases related to prior years	(1)	(4)	(2)
Additions related to current year activity	2	2	2
Releases due to settlements	0	(1)	(11)
Releases due to lapse of statute of limitations	(1)	(1)	(2)
Ending balance	$ 40	$ 40	$ 43

INCOME TAXES INCOME TAXES NARRA

INCOME TAXES INCOME TAXES NARRATIVE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Description of Prior-period Information Retrospectively Adjusted		26 million
Tax law changes	$ (9)	$ (7)	$ (237)

INCOME TAXES NEW ACCOUNTING STA

INCOME TAXES NEW ACCOUNTING STANDARDS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Other Special Items [Line Items]
Deferred Tax Liabilities, Other	$ 58	$ 43
Deferred income taxes	(715)	(512)
Valuation allowance	$ 1	$ 2

EMPLOYEE BENEFIT PLANS EMPLOYEE

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS - ADDITIONAL INFORMATION (Details)	12 Months Ended
	Dec. 31, 2019plan
Business Acquisition [Line Items]
Number of Qualified Defined Benefit Plans	4
Number of defined benefit plans	1
Number of defined contribution plans	7

EMPLOYEE BENEFIT PLANS - ASSUMP

EMPLOYEE BENEFIT PLANS - ASSUMPTIONS (Details) - Qualified Defined Benefit [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Weighted-average discount rate	3.33%	4.37%	3.69%
Benefit obligations, Rate of compensation increase	2.11%	2.11%	2.11%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Weighted-average discount rate	4.37%	3.69%	4.29%
Net period benefit costs, Weighted-average expected return on assets	4.25%	4.25%	5.50%
Net period benefit costs, Rate of compensation increase	2.11%	2.11%	2.12%
Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit obligations, Weighted-average discount rate	3.47%	4.46%	3.78%
Benefit obligations, Rate of compensation increase	5.44%	3.50%	16.51%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Net period benefit costs, Weighted-average discount rate	4.46%	3.78%	4.50%
Net period benefit costs, Weighted-average expected return on assets	5.50%	5.50%	6.00%
Net period benefit costs, Rate of compensation increase	3.50%	16.51%	2.59%

EMPLOYEE BENEFIT PLANS - PLAN A

EMPLOYEE BENEFIT PLANS - PLAN ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Qualified Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,239	$ 1,858	$ 2,083
Plan asset allocations	100.00%	100.00%
Qualified Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,126	$ 1,749
Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	35.00%	53.00%
Qualified Defined Benefit [Member] | Credit bond index fund [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 1,009	$ 1,135
Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	6.00%	7.00%
Qualified Defined Benefit [Member] | Real Estate [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 102	$ 104
Qualified Defined Benefit [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 11	$ 5
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	41.00%	28.00%
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 773	$ 431
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	18.00%	12.00%
Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 344	$ 183
Qualified Defined Benefit Plan - Salaried [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	100.00%	100.00%
Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	90.00%	91.00%
Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	0.00%	0.00%
Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	7.00%	6.00%
Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	3.00%	3.00%
Minimum [Member] | Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	26
Minimum [Member] | Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Minimum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	36
Minimum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	13
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	86
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	2
Minimum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Maximum [Member] | Qualified Defined Benefit [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	46
Maximum [Member] | Qualified Defined Benefit [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	10
Maximum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	46
Maximum [Member] | Qualified Defined Benefit [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	23
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	95
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	12
Maximum [Member] | Qualified Defined Benefit Plan - Salaried [Member] | Defined Benefit Plan, Equity Securities, Non-US
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	5

EMPLOYEE BENEFIT PLANS - FUNDED

EMPLOYEE BENEFIT PLANS - FUNDED STATUS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Benefit obligation
Beginning of year	$ 2,225	$ 2,387
Service cost	42	48	$ 39
Interest cost	89	79	74
Actuarial (gain) loss	359	(191)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(113)	(98)
End of year	2,602	2,225	2,387
Plan assets at fair value
Beginning of year	1,858	2,083
Actual return on plan assets	429	(127)
Employer contributions	65	0	15
Defined Benefit Plan, Plan Assets, Benefits Paid	(113)	(98)
End of year	2,239	1,858	$ 2,083
Funded status (unfunded)	$ (363)	$ (367)
Percent funded	86.00%	84.00%
Accumulated benefit obligation	$ 2,400	$ 2,100
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 113	$ 98

EMPLOYEE BENEFIT PLANS - AMOUNT

EMPLOYEE BENEFIT PLANS - AMOUNTS RECOGNIZED IN CONSOLIDATED BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Liability, Defined Benefit Plan [Abstract]
Accrued benefit liability-long term	$ 571	$ 503
Qualified Defined Benefit [Member]
Liability, Defined Benefit Plan [Abstract]
Accrued benefit liability-long term	412	392
Plan assets-long term (within Other noncurrent assets)	(49)	(25)
Total liability recognized	363	367
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Prior service credit	(6)	(8)
Net loss	595	607
Amount recognized in AOCL (pretax)	$ 589	$ 599

EMPLOYEE BENEFIT PLANS - EXPECT

EMPLOYEE BENEFIT PLANS - EXPECTED AMORTIZATION FROM AOCI (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	$ 95	$ 107	$ 106
Prior service credit	1
Net loss	$ 35

EMPLOYEE BENEFIT PLANS - NET PE

EMPLOYEE BENEFIT PLANS - NET PENSION EXPENSE (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 42	$ 48	$ 39
Interest cost	89	79	74
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	95	107	106
Amortization of prior service cost	(1)	(1)	(1)
Defined Benefit Plan, Amortization of Gain (Loss)	(37)	(33)	(26)
Net pension expense	$ 72	$ 52	$ 32

EMPLOYEE BENEFIT PLANS - FUTURE

EMPLOYEE BENEFIT PLANS - FUTURE BENEFITS EXPECTED TO BE PAID (Details) - Qualified Defined Benefit [Member] $ in Millions	Dec. 31, 2019USD ($)
Defined Benefit Plan Disclosure [Line Items]
2020	$ 115
2021	118
2022	134
2023	137
2024	137
2025– 2029	$ 800

EMPLOYEE BENEFIT PLANS EMPLOY_2

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS - POSTRETIREMENT MEDICAL BENEFITS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Postretirement Medical Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	$ 129	$ 82

EMPLOYEE BENEFIT PLANS - DEFINE

EMPLOYEE BENEFIT PLANS - DEFINED CONTRIBUTION PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Total expense for the defined-contribution plans	$ 132	$ 126	$ 103

EMPLOYEE BENEFIT PLANS - PILOT

EMPLOYEE BENEFIT PLANS - PILOT LONG-TERM DISABILITY BENEFITS (Details) - Postretirement Health Coverage [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Total liability net of a prefunded trust account	$ 45	$ 25
Prefunded trust account	$ 6	$ 3

EMPLOYEE BENEFIT PLANS - EMPLOY

EMPLOYEE BENEFIT PLANS - EMPLOYEE INCENTIVE-PAY PLANS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Operational Performance Rewards Program entitles all Air Group employees to maximum quarterly payouts (in dollars per quarter)	450
Variable incentive pay	$ 163,000,000	$ 147,000,000	$ 135,000,000

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)aircraft	Dec. 31, 2018USD ($)aircraft	Dec. 31, 2017USD ($)
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Rent expense		$ 619	$ 552
Virgin America Flight Attendants [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Loss Contingency, Damages Sought, Value	$ 78
Loss Contingency, Damages Sought, Value	78
Aircraft Commitments [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2020	531
2021	487
2022	347
2023	206
2024	31
Thereafter	26
Total	1,628
Capacity Purchase Agreements[Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2020	145
2021	166
2022	174
2023	179
2024	184
Thereafter	880
Total	$ 1,728
B737
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) | aircraft	32
Option to purchase additional (in aircraft) | aircraft	37
A-320-Neo [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Option to purchase additional (in aircraft) | aircraft	30
E175 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) | aircraft	3
Option to purchase additional (in aircraft) | aircraft	30
Property Subject to Operating Lease [Member] | B737
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) | aircraft	10	10
Property Subject to Operating Lease [Member] | Q400 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) | aircraft	7	9
Property Subject to Operating Lease [Member] | Airbus [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) | aircraft	61	61
Property Subject to Operating Lease [Member] | E175 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) | aircraft	32	32
Capacity Purchase Agreement with SkyWest [Member] | E175 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Property Subject to or Available for Operating Lease, Number of Optional Additional Units | aircraft	8
Aircraft Maintenance Deposits [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2020	$ 73
2021	62
2022	51
2023	26
2024	6
Thereafter	2
Total	$ 220

SHAREHOLDER'S EQUITY SHAREHOLDE

SHAREHOLDER'S EQUITY SHAREHOLDERS' EQUITY - STOCK CHANGES (Details) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Common stock, shares authorized	400,000,000	400,000,000
Common stock, par value	$ 0.01	$ 0.01

SHAREHOLDER'S EQUITY SHAREHOL_2

SHAREHOLDER'S EQUITY SHAREHOLDERS' EQUITY - DIVIDENDS (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 18, 2020	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Cash dividend declared per share		$ 0.35	$ 1.40
Cash dividend paid			$ 173	$ 158	$ 148
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash dividend declared per share	$ 0.375
Dividend increase	7.00%

SHAREHOLDER'S EQUITY - COMMON S

SHAREHOLDER'S EQUITY - COMMON STOCK REPURCHASE (Details) - USD ($) $ in Millions	12 Months Ended			40 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Aug. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Common stock repurchase	$ 75	$ 50	$ 75
2015 $1 billion Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount					$ 1,000
Common stock repurchase (in shares)	1,192,820	776,186	981,277	7,100,000
Common stock repurchase	$ 75	$ 50	$ 75	$ 513

SHAREHOLDER'S EQUITY SHAREHOL_3

SHAREHOLDER'S EQUITY SHAREHOLDERS' EQUITY - OTHER (Details) - shares	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Treasury stock, shares	8,811,866	7,619,046

SHAREHOLDER'S EQUITY SHAREHOL_4

SHAREHOLDER'S EQUITY SHAREHOLDERS' EQUITY - ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019
Equity [Abstract]
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect	$ 0
Unrealized gain on marketable securities considered available-for-sale	(11)	$ 9
Related to employee benefit plans	(440)	(469)
Related to interest rate derivatives	3	(5)
Accumulated other comprehensive loss	$ (448)	$ (465)

SPECIAL ITEMS SPECIAL ITEMS (De

SPECIAL ITEMS SPECIAL ITEMS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Merger-related Costs [Line Items]
Special items - merger-related costs	$ 44	$ 87	$ 116
Special items—other	0	45	0
Nondeductible expenses	9	9	5
Special tax expense (benefit)	0	0	(237)
Virgin America Inc. [Member]
Merger-related Costs [Line Items]
Special items - merger-related costs	44	$ 87	$ 116
Settlement Fee [Member]
Merger-related Costs [Line Items]
Special items—other	20
One-time Bonus Payment [Member]
Merger-related Costs [Line Items]
Special items—other	$ 25

SPECIAL ITEMS SPECIAL ITEMS - M

SPECIAL ITEMS SPECIAL ITEMS - MERGER-RELATED COSTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Merger-related Costs [Line Items]
Contracted services	$ 289	$ 306	$ 314
Special items—merger-related costs	44	87	116
Virgin America Inc. [Member]
Merger-related Costs [Line Items]
Contracted services	18	45	52
Severance Costs	15	13	41
Legal Fees	1	1	3
Business Acquisition, Transaction Costs	10	28	20
Special items—merger-related costs	$ 44	$ 87	$ 116

SPECIAL ITEMS Other Special Ite

SPECIAL ITEMS Other Special Items (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Special Items [Line Items]
Special items—other	$ 0	$ 45	$ 0
Settlement Fee [Member]
Other Special Items [Line Items]
Special items—other	20
One-time Bonus Payment [Member]
Other Special Items [Line Items]
Special items—other	$ 25

STOCK-BASED COMPENSATION PLAN_2

STOCK-BASED COMPENSATION PLANS (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 36	$ 36	$ 34
Tax benefit related to stock-based compensation	9	9	13
Unrecognized stock-based compensation for non-vested options and awards	$ 24
Unrecognized stock-based compensation awards weighted-average period	1 year 6 months
Shares authorized under stock-based compensation plans (in shares)	17,000,000
Shares remaining available for future grants (shares)	8,627,341
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 3	$ 3	$ 3
Unrecognized stock-based compensation for non-vested options and awards	$ 4
Unrecognized stock-based compensation awards weighted-average period	1 year 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility	30.00%	30.00%	51.00%
Expected term	6 years	6 years	6 years
Risk-free interest rate	2.41%	2.61%	2.04%
Expected dividend yield	2.09%	1.94%	1.10%
Weighted-average grant date fair value per share (in dollars per share)	$ 16.84	$ 17.18	$ 41.19
Estimated fair value of options granted (millions)	$ 4	$ 1	$ 4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares)	573,242
Granted (in Shares)	252,200
Exercised (in shares)	(21,322)
Canceled (in shares)	(5,366)
Forfeited or expired (in shares)	(4,699)
Outstanding, ending balance (in shares)	794,055	573,242
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, beginning balance, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 57.78
Granted, Weighted-Average Exercise Price Per Share (in dollars per share)	66.52
Exercised, Weighted-Average Exercise Price Per Share (in dollars per share)	36.14
Canceled, Weighted-Average Exercise Price Per Share (in dollars per share)	68.94
Fofeited or expired, Weighted-Average Exercise Price Per Share (in dollars per share)	70.98
Outstanding, ending balance, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 60.98	$ 57.78
Outstanding, Weighted-Average Contractual Life	6 years 6 months	6 years 7 months 6 days
Outstanding, Aggregate Intrinsic Value	$ 7	$ 6
Exercisable, Outstanding (in shares)	341,322
Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 50.50
Exercisable, Weighted-Average Contractual Life	4 years 3 months 18 days
Exercisable, Aggregate Intrinsic Value	$ 7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Vested or expected to vest, Shares	793,684
Vested or expected to vest, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 60.98
Vested or expected to vest, Weighted-Average Contractual Life	6 years 6 months
Vested or expected to vest, Aggregate Intrinsic Value	$ 7
Intrinsic value of option exercises	1	1	6
Cash received from stock option exercises	1	1	3
Tax benefit related to stock option exercises	0	0	2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	3	2	3
Stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	21	$ 23	24
Unrecognized stock-based compensation for non-vested options and awards	$ 20
Unrecognized stock-based compensation awards weighted-average period	1 year 6 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	511,813
Granted (in shares)	402,816
Vested (in shares)	(270,802)
Forfeited (in shares)	(102,214)
Non-vested, ending balance (in shares)	541,613	511,813
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Non-vested, beginning balance, Weighted-Average Grant Date Fair Value (in dollars per share)	$ 78.75
Granted, Weighted-Average Grant Date Fair Value (in dollars per share)	66.35
Vested, Weighted-Average Grant Date Fair Value (in dollars per share)	74.61
Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share)	75.21
Non-vested, ending balance, Weighted-Average Price Per Share (in dollars per share)	$ 71.82	$ 78.75
Non-vested, Weighted-Average Contractual Life	1 year 4 months 24 days	1 year 6 months
Non-vested, Total Instrinsic Value (in dollars)	$ 37	$ 31
Deferred stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1	1	1
Employee stock purchase plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 11	$ 9	$ 6
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	784,786	632,145	406,628
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	10.00%

OPERATING SEGMENT INFORMATION_2

OPERATING SEGMENT INFORMATION (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Operating revenues
Total Operating Revenues		$ 8,781	$ 8,264		$ 7,894
Operating expenses
Operating expenses, excluding fuel		5,840	5,685		5,239
Special items - merger-related costs		44	87		116
Economic fuel		1,878	1,936		1,447
Total Operating Expenses		7,718	7,621		6,686
Non-operating Income (Expense)
Interest income		42	38		34
Interest expense		(78)	(91)		(103)
Interest capitalized		15	18		17
Other - net		(26)	(23)		3
Nonoperating Income (Expense) Total		(47)	(58)		(49)
Income (loss) before income tax		1,016	585		1,159
Depreciation		423	398		372
Total property and equipment additions		(696)	(960)		(1,026)
Total assets		12,993	10,912
Air Group Adjusted [Member]
Operating revenues
Total Operating Revenues	[1]	8,781	8,264		7,894
Operating expenses
Operating expenses, excluding fuel	[1]	5,796	5,553		5,123
Economic fuel	[1]	1,884	1,914		1,454
Total Operating Expenses	[1]	7,680	7,467		6,577
Non-operating Income (Expense)
Interest income		42	38		34
Interest expense		(78)	(91)		(103)
Interest capitalized		15	18		17
Other - net		(26)	(23)		3
Nonoperating Income (Expense) Total	[1]	(47)	(58)		(49)
Income (loss) before income tax	[1]	1,054	739		1,268
Horizon [Member]
Operating revenues
Total Operating Revenues		451	512		430
Operating expenses
Operating expenses, excluding fuel		385	465		427
Economic fuel		0	0		0
Total Operating Expenses		385	465		427
Non-operating Income (Expense)
Interest income		0	0		0
Interest expense		(28)	(22)		(13)
Interest capitalized		0	2		2
Other - net		0	0		0
Nonoperating Income (Expense) Total		(28)	(20)		(11)
Income (loss) before income tax		38	27		(8)
Depreciation		86	82		64
Total property and equipment additions		(91)	(389)		(292)
Total assets		1,266	1,229
Parent [Member]
Non-operating Income (Expense)
Total assets		(7,480)	(7,170)
Intersegment Eliminations
Operating revenues
Total Operating Revenues		(445)	(508)		(426)
Operating expenses
Operating expenses, excluding fuel		(464)	(513)		(427)
Economic fuel		0	0		0
Total Operating Expenses		(464)	(513)		(427)
Non-operating Income (Expense)
Interest income		(24)	(15)		(5)
Interest expense		26	13		2
Interest capitalized		0	0		0
Other - net		0	0		0
Nonoperating Income (Expense) Total		2	(2)		(3)
Income (loss) before income tax		21	3		(2)
Special Charges [Member]
Operating revenues
Total Operating Revenues	[2]	0	0		0
Operating expenses
Operating expenses, excluding fuel		44	132	[2]	116	[2]
Economic fuel		(6)	22	[2]	(7)	[2]
Total Operating Expenses	[2]	38	154		109
Non-operating Income (Expense)
Interest income		0	0		0
Interest expense		0	0		0
Interest capitalized		0	0		0
Other - net		0	0		0
Nonoperating Income (Expense) Total	[2]	0	0		0
Income (loss) before income tax	[2]	(38)	(154)		(109)
Alaska Mainline [Member]
Operating revenues
Total Operating Revenues		7,381	7,063		6,832
Operating expenses
Operating expenses, excluding fuel		4,778	4,577		4,271
Economic fuel		1,589	1,652		1,282
Total Operating Expenses		6,367	6,229		5,553
Non-operating Income (Expense)
Interest income		66	53		39
Interest expense		(76)	(82)		(92)
Interest capitalized		15	16		15
Other - net		(26)	(12)		3
Nonoperating Income (Expense) Total		(21)	(25)		(35)
Income (loss) before income tax		993	809		1,244
Depreciation	[3]	337	316		308
Total property and equipment additions	[3]	(605)	(571)		(734)
Total assets	[3]	19,207	16,853
Alaska Regional [Member]
Operating revenues
Total Operating Revenues		1,394	1,197		1,058
Operating expenses
Operating expenses, excluding fuel		1,097	1,024		852
Economic fuel		295	262		172
Total Operating Expenses		1,392	1,286		1,024
Non-operating Income (Expense)
Interest income		0	0		0
Interest expense		0	0		0
Interest capitalized		0	0		0
Other - net		0	(11)		0
Nonoperating Income (Expense) Total		0	(11)		0
Income (loss) before income tax		2	(100)		34
Passenger Revenue [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		8,095	7,631		7,301
Passenger Revenue [Member] | Air Group Adjusted [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	8,095	7,631		7,301
Passenger Revenue [Member] | Horizon [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Passenger Revenue [Member] | Intersegment Eliminations
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Passenger Revenue [Member] | Special Charges [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[2]	0	0		0
Passenger Revenue [Member] | Alaska Mainline [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		6,750	6,474		6,278
Passenger Revenue [Member] | Alaska Regional [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		1,345	1,157		1,023
Capacity Purchase Agreements [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Capacity Purchase Agreements [Member] | Air Group Adjusted [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	0	0		0
Capacity Purchase Agreements [Member] | Horizon [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		450	508		426
Capacity Purchase Agreements [Member] | Intersegment Eliminations
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		(450)	(508)		(426)
Capacity Purchase Agreements [Member] | Special Charges [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[2]	0	0		0
Capacity Purchase Agreements [Member] | Alaska Mainline [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Capacity Purchase Agreements [Member] | Alaska Regional [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Mileage Plan Services, Other [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		465	434		418
Mileage Plan Services, Other [Member] | Air Group Adjusted [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	465	434		418
Mileage Plan Services, Other [Member] | Horizon [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Mileage Plan Services, Other [Member] | Intersegment Eliminations
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		0	0		0
Mileage Plan Services, Other [Member] | Special Charges [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[2]	0	0		0
Mileage Plan Services, Other [Member] | Alaska Mainline [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		419	397		387
Mileage Plan Services, Other [Member] | Alaska Regional [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		46	37		31
Cargo and Freight [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		221	199		175
Cargo and Freight [Member] | Air Group Adjusted [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	221	199		175
Cargo and Freight [Member] | Horizon [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		1	4		4
Cargo and Freight [Member] | Intersegment Eliminations
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		5	0		0
Cargo and Freight [Member] | Special Charges [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax	[2]	0	0		0
Cargo and Freight [Member] | Alaska Mainline [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		212	192		167
Cargo and Freight [Member] | Alaska Regional [Member]
Operating revenues
Revenue from Contract with Customer, Excluding Assessed Tax		$ 3	$ 3		$ 4
[1]	Year Ended December 31, 2017 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,278 1,023 — — 7,301 — 7,301 CPA revenues — — 426 (426) — — — Mileage Plan other revenue 387 31 — — 418 — 418 Cargo and other 167 4 4 — 175 — 175 Total Operating Revenues 6,832 1,058 430 (426) 7,894 — 7,894 Operating Expenses Non-fuel operating expenses 4,271 852 427 (427) 5,123 116 5,239 Fuel expense 1,282 172 — — 1,454 (7) 1,447 Total Operating Expenses 5,553 1,024 427 (427) 6,577 109 6,686 Non-operating Income (Expense) Interest income 39 — — (5) 34 — 34 Interest expense (92) — (13) 2 (103) — (103) Interest capitalized 15 — 2 — 17 — 17 Other 3 — — — 3 — 3 Total Non-operating Income (Expense) (35) — (11) (3) (49) — (49) Income (Loss) Before Income Tax $ 1,244 $ 34 $ (8) $ (2) $ 1,268 $ (109) $ 1,159
[2]	Year Ended December 31, 2017 Mainline Regional Horizon Consolidating & Other (a) Air Group Adjusted (b) Special Items (c) Consolidated Operating Revenues Passenger revenues 6,278 1,023 — — 7,301 — 7,301 CPA revenues — — 426 (426) — — — Mileage Plan other revenue 387 31 — — 418 — 418 Cargo and other 167 4 4 — 175 — 175 Total Operating Revenues 6,832 1,058 430 (426) 7,894 — 7,894 Operating Expenses Non-fuel operating expenses 4,271 852 427 (427) 5,123 116 5,239 Fuel expense 1,282 172 — — 1,454 (7) 1,447 Total Operating Expenses 5,553 1,024 427 (427) 6,577 109 6,686 Non-operating Income (Expense) Interest income 39 — — (5) 34 — 34 Interest expense (92) — (13) 2 (103) — (103) Interest capitalized 15 — 2 — 17 — 17 Other 3 — — — 3 — 3 Total Non-operating Income (Expense) (35) — (11) (3) (49) — (49) Income (Loss) Before Income Tax $ 1,244 $ 34 $ (8) $ (2) $ 1,268 $ (109) $ 1,159
[3]	INCOME TAXES Deferred Income Taxes Deferred income taxes reflect the impact of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and such amounts for tax purposes. The Company has a net deferred tax liability, primarily due to differences in depreciation rates for federal income tax purposes and for financial reporting purposes. Deferred tax (assets) and liabilities comprise the following (in millions): 2019 2018 Excess of tax over book depreciation $ 1,233 $ 1,066 Intangibles - net 16 15 Operating lease liabilities 416 — Other - net 58 43 Deferred tax liabilities 1,723 1,124 Mileage Plan™ (337) (315) Inventory obsolescence (15) (15) Employee benefits (179) (172) Acquired net operating losses (13) (64) Operating lease assets (417) — Other - net (48) (48) Deferred tax assets (1,009) (614) Valuation allowance 1 2 Net deferred tax liabilities $ 715 $ 512 At December 31, 2019, the Company had federal NOLs of approximately $45 million that expire beginning in 2032 and continuing through 2036, and state NOLs of approximately $55 million that expire beginning in 2029 and continuing through 2036. Virgin America experienced multiple “ownership changes” as defined in Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”), the most recent being its acquisition by the Company. Section 382 of the Code imposes an annual limitation on the utilization of pre-ownership change NOLs. Any unused annual limitation may, subject to certain limits, be carried over to later years. The combined Company’s ability to use the NOLs will also depend on the amount of taxable income generated in future periods. Valuation allowances are provided to reduce the related deferred income tax assets to an amount which will, more likely than not, be realized. The valuation allowance was not material at both December 31, 2019 and December 31, 2018. Components of Income Tax Expense The components of income tax expense are as follows (in millions): 2019 2018 2017 Current income tax expense (benefit): Federal $ 26 $ (5) $ 127 State 13 9 35 Total current income tax expense 39 4 162 Deferred income tax expense (benefit): Federal 175 125 (3) State 33 19 40 Total deferred income tax expense (benefit) 208 144 37 Income tax expense $ 247 $ 148 $ 199 Income Tax Rate Reconciliation Income tax expense reconciles to the amount computed by applying the 2019 U.S. federal rate of 21% to income before income tax and for deferred taxes as follows (in millions): 2019 2018 2017 Income before income tax $ 1,016 $ 585 $ 1,159 Expected tax expense 213 123 406 Nondeductible expenses 9 9 5 State income taxes 36 21 28 State income sourcing 1 — 9 Tax law changes (9) (7) (237) Other - net (3) 2 (12) Actual tax expense $ 247 $ 148 $ 199 Effective tax rate 24.3 % 25.3 % 17.2 % As a result of the ASC 606 full retrospective adoption, 2017 tax expense increased by $26 million. As a result of tax changes signed into law during 2017, with final regulations issued in 2019, the Company recorded a deferred tax benefit of $9 million in the current year. In 2017, adjustments were made to the Company's position on income sourcing in various states due to updated guidance from state taxing authorities. The impact of this guidance is reflected as an increase in income tax expense of approximately $9 million for the year ended December 31, 2017. Uncertain Tax Positions The Company has identified its federal tax return and its state tax returns in Alaska, Oregon and California as “major” tax jurisdictions. A summary of the Company's jurisdictions and the periods that are subject to examination are as follows: Jurisdiction Period Federal 2007 to 2018 Alaska 2015 to 2018 California 2007 to 2018 Oregon 2003 to 2018 Certain tax years are open to the extent of net operating loss carryforwards. Changes in the liability for gross unrecognized tax benefits during 2019, 2018 and 2017 are as follows (in millions): 2019 2018 2017 Balance at January 1, $ 40 $ 43 $ 40 Additions related to prior years — 1 16 Releases related to prior years (1) (4) (2) Additions related to current year activity 2 2 2 Releases due to settlements — (1) (11) Releases due to lapse of statute of limitations (1) (1) (2) Balance at December 31, $ 40 $ 40 $ 43 As of December 31, 2019, the Company had $40 million of accrued tax contingencies, of which $34 million, if fully recognized, would decrease the effective tax rate. As of December 31, 2019, 2018 and 2017, the Company has accrued interest and penalties, net of federal income tax benefit, of $7 million, $6 million, and $5 million. In 2019, 2018, and 2017, the