United Airlines (UAL) 10-K20 Feb 152014 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2014	Feb. 10, 2015	Jun. 30, 2014
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	UAL
Entity Registrant Name	United Continental Holdings, Inc.
Entity Central Index Key	100517
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		384,226,369
Entity Public Float			$15,303,043,375
United Airlines, Inc.
Document Information [Line Items]
Entity Registrant Name	United Airlines, Inc.
Entity Central Index Key	319687
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		1,000

Statements_of_Consolidated_Ope

Statements of Consolidated Operations (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating revenue:
Passenger-Mainline	$26,785	$25,997	$25,804
Passenger-Regional	6,977	7,125	6,779
Total passenger revenue	33,762	33,122	32,583
Cargo	938	882	1,018
Other operating revenue	4,201	4,275	3,551
Total revenue	38,901	38,279	37,152
Operating expense:
Aircraft fuel	11,675	12,345	13,138
Salaries and related costs	8,935	8,625	7,945
Regional capacity purchase	2,344	2,419	2,470
Landing fees and other rent	2,274	2,090	1,929
Aircraft maintenance materials and outside repairs	1,779	1,821	1,760
Depreciation and amortization	1,679	1,689	1,522
Distribution expenses	1,373	1,390	1,352
Aircraft rent	883	936	993
Special charges	443	520	1,323
Other operating expenses	5,143	5,195	4,681
Total operating expenses	36,528	37,030	37,113
Operating income	2,373	1,249	39
Nonoperating income (expense):
Interest expense	-735	-783	-835
Interest capitalized	52	49	37
Interest income	22	21	23
Miscellaneous, net	-584	3	12
Total other expense	-1,245	-710	-763
Income (loss) before income taxes	1,128	539	-724
Income tax expense (benefit)	-4	-32	-1
Net income (loss)	1,132	571	-723
Earnings (loss) per share, basic	$3.05	$1.64	($2.18)
Earnings (loss) per share, diluted	$2.93	$1.53	($2.18)
United Airlines, Inc.
Operating revenue:
Passenger-Mainline	26,785	25,997	25,804
Passenger-Regional	6,977	7,125	6,779
Total passenger revenue	33,762	33,122	32,583
Cargo	938	882	1,018
Other operating revenue	4,201	4,283	3,559
Total revenue	38,901	38,287	37,160
Operating expense:
Aircraft fuel	11,675	12,345	13,138
Salaries and related costs	8,935	8,625	7,945
Regional capacity purchase	2,344	2,419	2,470
Landing fees and other rent	2,274	2,090	1,929
Aircraft maintenance materials and outside repairs	1,779	1,821	1,760
Depreciation and amortization	1,679	1,689	1,522
Distribution expenses	1,373	1,390	1,352
Aircraft rent	883	936	993
Special charges	443	520	1,323
Other operating expenses	5,139	5,193	4,677
Total operating expenses	36,524	37,028	37,109
Operating income	2,377	1,259	51
Nonoperating income (expense):
Interest expense	-742	-781	-823
Interest capitalized	52	49	37
Interest income	22	21	23
Miscellaneous, net	-599	89	55
Total other expense	-1,267	-622	-708
Income (loss) before income taxes	1,110	637	-657
Income tax expense (benefit)	-4	-17	4
Net income (loss)	$1,114	$654	($661)

Statements_of_Consolidated_Com

Statements of Consolidated Comprehensive Income (Loss) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Net income (loss)	$1,132		$571		($723)
Other comprehensive income (loss), net change related to:
Employee benefit plans	-1,171		1,626		-730
Fuel derivative financial instruments	-510		21		90
Investments and other	-6		7		11
Comprehensive income (loss) adjustments	-1,687	[1]	1,654	[1]	-629	[1]
Total comprehensive income (loss), net	-555		2,225		-1,352
United Airlines, Inc.
Net income (loss)	1,114		654		-661
Other comprehensive income (loss), net change related to:
Employee benefit plans	-1,171		1,626		-730
Fuel derivative financial instruments	-510		21		90
Investments and other	-6		8		12
Other			6
Comprehensive income (loss) adjustments	-1,687		1,661		-628
Total comprehensive income (loss), net	($573)		$2,315		($1,289)

[1]	UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Current assets:
Cash and cash equivalents	$2,002		$3,220
Short-term investments	2,382		1,901
Total unrestricted cash, cash equivalents and short-term investments	4,384		5,121
Restricted cash	44		31
Receivables, less allowance for doubtful accounts (2014-$22; 2013-$13)	1,146		1,503
Fuel hedge collateral deposits	577
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2014-$169; 2013-$162)	666		667
Deferred income taxes	591		676
Prepaid expenses and other	730		704
Total current assets	8,138		8,702
Operating property and equipment: Owned-
Flight equipment	21,107		18,786
Other property and equipment	4,016		3,687
Operating property and equipment - owned, gross	25,123		22,473
Less-Accumulated depreciation and amortization	-7,079		-6,080
Operating property and equipment - owned, net	18,044		16,393
Purchase deposits for flight equipment	706		706
Capital leases-
Flight equipment	1,272		1,490
Other property and equipment	331		307
Operating property and equipment - capital leases, gross	1,603		1,797
Less-Accumulated amortization	-886		-849
Operating property and equipment - capital leases, net	717		948
Total property, plant, and equipment, net	19,467		18,047
Other assets:
Goodwill	4,523		4,523
Intangibles, less accumulated amortization (2014-$1,049; 2013-$933)	4,284		4,436
Restricted cash	276		364
Other, net	665		740
Other assets total	9,748		10,063
Total assets	37,353		36,812
Current liabilities:
Advance ticket sales	3,701		3,405
Frequent flyer deferred revenue	2,058		2,369
Accounts payable	1,882		2,087
Accrued salaries and benefits	1,818		1,696
Current maturities of long-term debt	1,313		1,368
Current maturities of capital leases	110	[1]	117
Fuel derivative instruments	694
Other	932		1,065
Total current liabilities	12,508		12,107
Long-term debt	10,121		10,171
Long-term obligations under capital leases	571	[1]	753
Other liabilities and deferred credits:
Frequent flyer deferred revenue	2,879		2,535
Postretirement benefit liability	1,933		1,703
Pension liability	2,226		1,650
Advanced purchase of miles	1,217		1,338
Deferred income taxes	1,591		1,662
Lease fair value adjustment, net	466		626
Other	1,445		1,283
Total Other liabilities and deferred credits	11,757		10,797
Commitments and contingencies
Stockholder's equity:
Preferred stock
Common stock	4		4
Additional capital invested	7,721		7,425
Accumulated deficit	-3,883		-5,015
Stock held in treasury, at cost	-367		-38
Accumulated other comprehensive income (loss)	-1,079	[2]	608	[2]
Total stockholders' equity	2,396		2,984
Total liabilities and stockholders' equity (deficit)	37,353		36,812
United Airlines, Inc.
Current assets:
Cash and cash equivalents	1,996		3,214
Short-term investments	2,382		1,901
Total unrestricted cash, cash equivalents and short-term investments	4,378		5,115
Restricted cash	44		31
Receivables, less allowance for doubtful accounts (2014-$22; 2013-$13)	1,146		1,503
Fuel hedge collateral deposits	577
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2014-$169; 2013-$162)	666		667
Deferred income taxes	591		674
Prepaid expenses and other	779		705
Total current assets	8,181		8,695
Operating property and equipment: Owned-
Flight equipment	21,107		18,786
Other property and equipment	4,016		3,687
Operating property and equipment - owned, gross	25,123		22,473
Less-Accumulated depreciation and amortization	-7,079		-6,080
Operating property and equipment - owned, net	18,044		16,393
Purchase deposits for flight equipment	706		706
Capital leases-
Flight equipment	1,272		1,490
Other property and equipment	331		307
Operating property and equipment - capital leases, gross	1,603		1,797
Less-Accumulated amortization	-886		-849
Operating property and equipment - capital leases, net	717		948
Total property, plant, and equipment, net	19,467		18,047
Other assets:
Goodwill	4,523		4,523
Intangibles, less accumulated amortization (2014-$1,049; 2013-$933)	4,284		4,436
Restricted cash	276		364
Other, net	1,377		1,221
Other assets total	10,460		10,544
Total assets	38,108		37,286
Current liabilities:
Advance ticket sales	3,701		3,405
Frequent flyer deferred revenue	2,058		2,369
Accounts payable	1,886		2,092
Accrued salaries and benefits	1,818		1,696
Current maturities of long-term debt	1,313		1,368
Current maturities of capital leases	110		117
Fuel derivative instruments	694
Payables to related parties			114
Other	933		1,064
Total current liabilities	12,513		12,225
Long-term debt	10,120		10,020
Long-term obligations under capital leases	571		753
Other liabilities and deferred credits:
Frequent flyer deferred revenue	2,879		2,535
Postretirement benefit liability	1,933		1,703
Pension liability	2,226		1,650
Advanced purchase of miles	1,217		1,338
Deferred income taxes	1,591		1,661
Lease fair value adjustment, net	466		626
Other	1,957		1,552
Total Other liabilities and deferred credits	12,269		11,065
Commitments and contingencies
Stockholder's equity:
Additional capital invested	7,347		7,590
Accumulated deficit	-3,628		-4,743
Accumulated other comprehensive income (loss)	-1,079		608
Receivable from related parties	-5		-232
Total stockholders' equity	2,635		3,223
Total liabilities and stockholders' equity (deficit)	$38,108		$37,286

[1]	As of December 31, 2014, United's aircraft capital lease minimum payments relate to leases of 37 mainline and 38 regional aircraft as well as to leases of nonaircraft assets. Imputed interest rate ranges are 3.5% to 18.3%.
[2]	UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Receivables, allowance for doubtful accounts	$22	$13
Aircraft fuel, spare parts and supplies, obsolescence allowance	169	162
Intangibles, accumulated amortization	1,049	933
Common stock, par value	$0.01	$0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	374,525,916	362,283,555
United Airlines, Inc.
Receivables, allowance for doubtful accounts	22	13
Aircraft fuel, spare parts and supplies, obsolescence allowance	169	162
Intangibles, accumulated amortization	$1,049	$933
Common stock, par value	$0.01	$0.01
Common shares, authorized	1,000	1,000
Common shares, issued	1,000	1,000
Common shares, outstanding	1,000	1,000

Statements_of_Consolidated_Cas

Statements of Consolidated Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities:
Net income (loss)	$1,132	$571	($723)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities -
Depreciation and amortization	1,679	1,689	1,522
Special charges, non-cash portion	78	50	389
Deferred income taxes	13	-14	13
Other operating activities	-21	18	-115
Changes in operating assets and liabilities -
Increase in fuel hedge collateral	-577
Unrealized (gain) loss on fuel derivatives and change in related pending settlements	436	-56	120
Increase in advance ticket sales	296	45	246
Increase (decrease) in accounts payable	-251	-265	285
(Increase) decrease in receivables	209	-142	-21
Decrease in frequent flyer deferred revenue and advanced purchase of miles	-88	-415	-712
Increase (decrease) in other liabilities	-238	-201	415
(Increase) decrease in other assets	-34	164	-484
Net cash provided by operating activities	2,634	1,444	935
Cash Flows from Investing Activities:
Capital expenditures	-2,005	-2,164	-2,016
Purchases of short-term and other investments	-1,041	-575	-742
Redemptions of short-term and other investments	584	455	497
Proceeds from sale of property and equipment	94	152	183
Decrease in restricted cash, net	75	52	122
Other, net	37	58	-1
Net cash used in investing activities	-2,256	-2,022	-1,957
Cash Flows from Financing Activities:
Payments of long-term debt	-2,503	-2,185	-1,392
Proceeds from issuance of long-term debt	1,432	1,423	1,121
Repurchases of common stock	-312
Principal payments under capital leases	-127	-134	-125
Capitalized financing costs	-104	-103	-71
Proceeds from the exercise of stock options	60	29	17
Other	-42	-2	-4
Net cash used in financing activities	-1,596	-972	-454
Net decrease in cash and cash equivalents	-1,218	-1,550	-1,476
Cash and cash equivalents at beginning of year	3,220	4,770	6,246
Cash and cash equivalents at end of year	2,002	3,220	4,770
United Airlines, Inc.
Cash Flows from Operating Activities:
Net income (loss)	1,114	654	-661
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities -
Depreciation and amortization	1,679	1,689	1,522
Special charges, non-cash portion	78	50	389
Deferred income taxes	13	1	13
Other operating activities	4	-41	-151
Changes in operating assets and liabilities -
Increase in fuel hedge collateral	-577
Unrealized (gain) loss on fuel derivatives and change in related pending settlements	436	-56	120
Increase in advance ticket sales	296	45	246
Increase (decrease) in accounts payable	-251	-265	285
(Increase) decrease in receivables	209	-142	-21
Decrease in frequent flyer deferred revenue and advanced purchase of miles	-88	-415	-712
Increase (decrease) in other liabilities	-236	-203	422
(Increase) decrease in other assets	-34	163	-484
Decrease in intercompany payables	-118	-34	-28
Increase in intercompany receivables		-5	-9
Net cash provided by operating activities	2,525	1,441	931
Cash Flows from Investing Activities:
Capital expenditures	-2,005	-2,164	-2,016
Purchases of short-term and other investments	-1,041	-575	-737
Redemptions of short-term and other investments	584	455	497
Proceeds from sale of property and equipment	94	152	183
Decrease in restricted cash, net	75	52	121
Other, net	37	57
Net cash used in investing activities	-2,256	-2,023	-1,952
Cash Flows from Financing Activities:
Payments of long-term debt	-2,503	-2,185	-1,392
Proceeds from issuance of long-term debt	1,432	1,423	1,121
Dividend to UAL	-212
Principal payments under capital leases	-127	-134	-125
Capitalized financing costs	-104	-103	-71
Proceeds from the exercise of stock options	60	29	17
Other	-33	1	-4
Net cash used in financing activities	-1,487	-969	-454
Net decrease in cash and cash equivalents	-1,218	-1,551	-1,475
Cash and cash equivalents at beginning of year	3,214	4,765	6,240
Cash and cash equivalents at end of year	$1,996	$3,214	$4,765

Statements_of_Consolidated_Sto

Statements of Consolidated Stockholder's Equity (USD $)	Total		United Airlines, Inc.	Common Stock	Additional Capital Invested	Additional Capital Invested	Treasury Stock	Accumulated Deficit	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)	Receivable from Related Parties, Net
In Millions	Total		United Airlines, Inc.	Common Stock	Additional Capital Invested	United Airlines, Inc.	Treasury Stock	Accumulated Deficit	United Airlines, Inc.	Accumulated Other Comprehensive Income (Loss)	United Airlines, Inc.	United Airlines, Inc.
Beginning Balance at Dec. 31, 2011	$1,806		$2,419	$3	$7,114	$7,580	($31)	($4,863)	($4,736)	($417)	($425)
Beginning Balance (in shares) at Dec. 31, 2011				331
Net income (loss)	-723		-661					-723	-661
Other comprehensive income (loss)	-629	[1]	-628							-629	-628
Share-based compensation	14		14		14	14
Proceeds from exercise of stock options (in shares)				1
Proceeds from exercise of stock options	17				17
UAL contribution related to stock plans			17			17
Other	-4						-4
Ending Balance at Dec. 31, 2012	481		1,161	3	7,145	7,611	-35	-5,586	-5,397	-1,046	-1,053
Ending Balance (in shares) at Dec. 31, 2012				332
Net income (loss)	571		654					571	654
Other comprehensive income (loss)	1,654	[1]	1,661							1,654	1,661
Convertible debt redemption (in shares)				28
Convertible debt redemption	241			1	240
Income taxes			-68			-68
Contribution of asset by UAL			7			7
Share-based compensation	11		11		11	11
Proceeds from exercise of stock options (in shares)				2
Proceeds from exercise of stock options	29				29
UAL contribution related to stock plans			29			29
Other	-3		-232				-3					-232
Ending Balance at Dec. 31, 2013	2,984		3,223	4	7,425	7,590	-38	-5,015	-4,743	608	608	-232
Ending Balance (in shares) at Dec. 31, 2013				362
Net income (loss)	1,132		1,114					1,132	1,114
Other comprehensive income (loss)	-1,687	[1]	-1,687							-1,687	-1,687
Convertible debt redemption (in shares)				17
Convertible debt redemption	260		156		260	156
Repurchase of convertible debt	-34				-34
Dividend and other capital distributions to UAL			-236			-469			1			232
Share-based compensation	10		10		10	10
Proceeds from exercise of stock options (in shares)				2
Proceeds from exercise of stock options	60				60
UAL contribution related to stock plans			60			60
Repurchases of common stock	-320						-320
Repurchases of common stock (in shares)				-6
Other	-9		-5				-9					-5
Ending Balance at Dec. 31, 2014	$2,396		$2,635	$4	$7,721	$7,347	($367)	($3,883)	($3,628)	($1,079)	($1,079)	($5)
Ending Balance (in shares) at Dec. 31, 2014				375

[1]	UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.

Significant_Accounting_Policie

Significant Accounting Policies

12 Months Ended

Dec. 31, 2014

Significant Accounting Policies

NOTE 1 - SIGNIFICANT ACCOUNTING POLICIES

(a)

Use of Estimates and Reclassifications—The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in these financial statements and accompanying notes. Actual results could differ from those estimates.

Certain prior years’ cash flows from operating, investing and financing activities have been reclassified to conform to the current year presentation. Within the investing activities section, the change in the short-term and other investments category was further separated between purchases and redemptions. The net effect of this presentation remains unchanged for prior years.

(b)

Revenue Recognition—The value of unused passenger tickets is included in current liabilities as advance ticket sales. The Company records passenger ticket sales and tickets sold by other airlines for use on United as passenger revenue when the transportation is provided or upon estimated breakage. Tickets sold by other airlines are recorded at the estimated values to be billed to the other airlines. Differences between amounts billed and the actual amounts may be rejected and rebilled or written off if the amount recorded was different from the original estimate. When necessary, the Company records a reserve against our interline billings and payables if historical experience indicates that these amounts are different. Non-refundable tickets generally expire on the date of the intended flight, unless the date is extended by notification from the customer on or before the intended flight date.

Fees charged in association with changes or extensions to non-refundable tickets are recorded as other revenue at the time the fee is incurred. The fare on the changed ticket, including any additional collection of fare, is deferred and recognized in accordance with our transportation revenue recognition policy at the time the transportation is provided. Change fees related to non-refundable tickets are considered a separate transaction from the air transportation because they represent a charge for the Company’s additional service to modify a previous sale. Therefore, the pricing of the change fee and the initial customer order are separately determined and represent distinct earnings processes.

The Company records an estimate of breakage revenue on the flight date for tickets that will expire unused. These estimates are based on the evaluation of actual historical results and forecasted trends. Refundable tickets expire after one year from the date of issuance.

The Company recognizes cargo and other revenue as service is provided.

Under our capacity purchase agreements (“CPAs”) with regional carriers, we purchase all of the capacity related to aircraft covered by the contracts and are responsible for selling all of the related seat inventory. We record the passenger revenue and related expenses as separate operating revenue and expense in the consolidated statement of operations.

Accounts receivable primarily consist of amounts due from credit card companies and customers of our aircraft maintenance and cargo transportation services. We provide an allowance for uncollectible accounts equal to the estimated losses expected to be incurred based on historical write-offs and other specific analyses. Bad debt expense and write-offs were not material for the years ended December 31, 2014, 2013 and 2012.

(c)

Frequent Flyer Accounting—United’s MileagePlus program is designed to increase customer loyalty. Program participants earn miles by flying on United and certain other participating airlines. Program participants can also earn miles through purchases from other non-airline partners that participate in United’s loyalty program. We sell miles to these partners, which include credit card issuers, retail merchants, hotels, car rental companies and our participating airline partners. Miles can be redeemed for free (other than taxes and government imposed fees), discounted or upgraded air travel and non-travel awards. The Company records its obligation for future award redemptions using a deferred revenue model.

Miles Earned in Conjunction with Flights

In the case of the sale of air services, the Company recognizes a portion of the ticket sales as revenue when the air transportation occurs and defers a portion of the ticket sale representing the value of the related miles as a multiple-deliverable revenue arrangement. The miles are recorded in frequent flyer deferred revenue on the Company’s balance sheet and recognized into revenue when the transportation is provided.

The Company determines the estimated selling price of air transportation and miles as if each element is sold on a separate basis. The total consideration from each ticket sale is then allocated to each of these elements individually on a pro rata basis. The Company’s estimated selling price of miles prior to April 1, 2014 was based on the price we sell miles to Star Alliance partners in our reciprocal frequent flyer agreements as the best estimate of selling price for these miles.

On March 30, 2014, US Airways exited Star Alliance. Effective with the exit date, the Company updated its estimated selling price for miles to a value based on the equivalent ticket value less fulfillment discount, which incorporates the expected redemption of miles. The equivalent ticket value used as the basis for the estimated selling price of miles is based on the prior 12 months’ weighted average equivalent ticket value of similar fares as those used to settle award redemptions while taking into consideration such factors as redemption pattern, cabin class, loyalty status and geographic region. The estimated selling price of miles is adjusted by a fulfillment discount that considers a number of factors, including redemption patterns of various customer groups. This change in estimate was applied on a prospective basis beginning April 1, 2014. The impact of this change resulted in an increase in consolidated revenue of approximately $95 million (and an increase of approximately $0.26 per UAL basic share and $0.24 per UAL diluted share) in 2014.

Co-branded Credit Card Partner Mileage Sales

United has a significant contract, the Consolidated Amended and Restated Co-Branded Card Marketing Services Agreement (the “Co-Brand Agreement”), to sell MileagePlus miles to its co-branded credit card partner, Chase Bank USA, N.A. (“Chase”). United identified five revenue elements in the Co-Brand Agreement: the air transportation element represented by the value of the mile (generally resulting from its redemption for future air transportation and whose fair value is described above); use of the United brand and access to MileagePlus member lists; advertising; baggage services; and airport lounge usage (together, excluding “the air transportation element,” the “marketing-related deliverables”).

The fair value of the elements is determined using management’s estimated selling price of each element. The objective of using the estimated selling price based methodology is to determine the price at which we would transact a sale if the product or service were sold on a stand-alone basis. Accordingly, we determine our best estimate of selling price by considering multiple inputs and methods including, but not limited to, discounted cash flows, brand value, volume discounts, 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 Co-Brand Agreement in order to determine the allocation of proceeds to each of the multiple elements to be delivered. The method for determining the selling price of the mile component changed March 30, 2014, as described above. We also evaluate volumes on an annual basis, which may result in a change in the allocation of estimated selling price on a prospective basis.

The Company records passenger revenue related to the air transportation element when the transportation is delivered. The other elements are generally recognized as Other operating revenue when earned.

Expiration of Miles

The Company accounts for miles sold and awarded that will never be redeemed by program members, which we refer to as breakage. The Company reviews its breakage estimates annually based upon the latest available information regarding redemption and expiration patterns. Miles expire after 18 months of member account inactivity.

The Company’s estimate of the expected expiration of miles requires significant management judgment. Current and future changes to expiration assumptions or to the expiration policy, or to program rules and program redemption opportunities, may result in material changes to the deferred revenue balance as well as recognized revenues from the programs.

Other Information

The following table provides additional information related to the frequent flyer program (in millions):

Year Ended

Cash Proceeds

Other Revenue

Increase in Frequent

Increase

December 31,

from Miles Sold

Recognized Upon

Flyer Deferred

(Decrease) in

Award of Miles

Revenue for Miles

Advanced

to Third-Party

Awarded (b)

Purchase of

Customers (a)

Miles (c)

2014

2,861

882

2,178

-199

2013

2,903

903

2,174

-174

2012

2,852

816

2,036

—

(a) This amount represents other revenue recognized during the period from the sale of miles to third parties, representing the marketing-related deliverable services component of the sale.

(b) This amount represents the increase to frequent flyer deferred revenue during the period.

(c) This amount represents the net increase (decrease) in the advance purchase of miles obligation due to cash payments for the sale of miles in excess of (less than) miles awarded to customers.

(d)

Cash and Cash Equivalents and Restricted Cash—Highly liquid investments with a maturity of three months or less on their acquisition date are classified as cash and cash equivalents.

Restricted cash primarily includes cash collateral associated with workers’ compensation obligations, reserves for institutions that process credit card ticket sales and cash collateral received from fuel hedge counterparties. Restricted cash is classified as short-term or long-term in the consolidated balance sheets based on the expected timing of return of the assets to the Company. Airline industry practice includes classification of restricted cash flows as either investing cash flows or operating cash flows. Cash flows related to restricted cash activity are classified as investing activities because the Company considers restricted cash arising from these activities similar to an investment.

(e)

Short-term Investments—Short-term investments are classified as available-for-sale and are stated at fair value. Realized gains and losses on sales of investments are reflected in nonoperating income (expense) in the consolidated statements of operations. Unrealized gains and losses on available-for-sale securities are reflected as a component of accumulated other comprehensive income (loss).

(f)

Aircraft Fuel, Spare Parts and Supplies—The Company accounts for aircraft fuel, spare parts and supplies at average cost and provides an obsolescence allowance for aircraft spare parts with an assumed residual value of 10% to 11% of original cost depending on the fleet type.

(g)

Property and Equipment—The Company records additions to owned operating property and equipment at cost when acquired. Property under capital leases and the related obligation for future lease payments are recorded at an amount equal to the initial present value of those lease payments. Modifications that enhance the operating performance or extend the useful lives of airframes or engines are capitalized as property and equipment. It is the Company’s policy to record compensation from delays in delivery of aircraft as a reduction of the cost of the related aircraft.

Depreciation and amortization of owned depreciable assets is based on the straight-line method over the assets’ estimated useful lives. Leasehold improvements are amortized over the remaining term of the lease, including estimated facility renewal options when renewal is reasonably assured at key airports, or the estimated useful life of the related asset, whichever is less. Properties under capital leases are amortized on the straight-line method over the life of the lease or, in the case of certain aircraft, over their estimated useful lives, whichever is shorter. Amortization of capital lease assets is included in depreciation and amortization expense. The estimated useful lives of property and equipment are as follows:

Estimated Useful Life (in years)

Aircraft and related rotable parts

25 to 30

Buildings

25 to 45

Other property and equipment

3 to 15

Computer software

Building improvements

1 to 40

As of December 31, 2014 and 2013, the Company had a carrying value of computer software of $281 million and $290 million, respectively. For the years ended December 31, 2014, 2013 and 2012, the Company’s depreciation expense related to computer software was $81 million, $72 million and $81 million, respectively. Aircraft and aircraft parts were assumed to have residual values with a range of 10% to 11% of original cost, depending on type, and other categories of property and equipment were assumed to have no residual value.

(h)

Maintenance and Repairs—The cost of maintenance and repairs, including the cost of minor replacements, is charged to expense as incurred, except for costs incurred under our power-by-the-hour (“PBTH”) engine maintenance agreements. PBTH contracts transfer certain risk to third-party service providers and fix the amount we pay per flight hour or per cycle to the service provider in exchange for maintenance and repairs under a predefined maintenance program. Under PBTH agreements, the Company recognizes expense at a level rate per engine hour, unless the level of service effort and the related payments during the period are substantially consistent, in which case the Company recognizes expense based on the amounts paid.

(i)

Lease Fair Value Adjustments—Lease fair value adjustments, which arose from recording operating leases at fair value under fresh start or business combination accounting, are amortized on a straight-line basis over the related lease term.

(j)

Regional Capacity Purchase—Payments made to regional carriers under CPAs are reported in Regional capacity purchase in our consolidated statements of operations. As of December 31, 2014, United had 281 call options to purchase regional jet aircraft being operated by certain regional carriers. At December 31, 2014, none of the call options was exercisable because none of the required conditions to make an option exercisable by United was met.

(k)

Advertising—Advertising costs, which are included in Other operating expenses, are expensed as incurred. Advertising expenses were $179 million, $178 million and $154 million for the years ended December 31, 2014, 2013 and 2012, respectively.

(l)

Intangibles—The Company has finite-lived and indefinite-lived intangible assets, including goodwill. Finite-lived intangible assets are amortized over their estimated useful lives. Goodwill and indefinite-lived intangible assets are not amortized but are reviewed for impairment annually or more frequently if events or circumstances indicate that the asset may be impaired. Goodwill and indefinite-lived assets are reviewed for impairment on an annual basis as of October 1, or on an interim basis whenever a triggering event occurs. See Notes 2 and 17 of this report for additional information related to intangibles.

(m)

Long-Lived Asset Impairments—The Company evaluates the carrying value of long-lived assets subject to amortization whenever events or changes in circumstances indicate that an impairment may exist. For purposes of this testing, the Company has generally identified the aircraft fleet type as the lowest level of identifiable cash flows for purposes of testing aircraft for impairment. An impairment charge is recognized when the asset’s carrying value exceeds its net undiscounted future cash flows and its fair market value. The amount of the charge is the difference between the asset’s carrying value and fair market value. See Note 17 of this report for additional information related to asset impairments.

(n)

Share-Based Compensation—The Company measures the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The resulting cost is recognized over the period during which an employee is required to provide service in exchange for the award, usually the vesting period. Obligations for restricted stock units (“RSUs”) are remeasured at fair value throughout the requisite service period on the last day of each reporting period based upon UAL’s stock price. In addition to the service requirement, certain RSUs have performance metrics that must be achieved prior to vesting. These awards are accrued based on the expected level of achievement at each reporting period. A cumulative adjustment is recorded on the last day of each reporting period to adjust compensation expense based on both UAL’s stock price and the then current level of expected performance achievement for the performance-based awards. See Note 5 of this report for additional information on UAL’s share-based compensation plans.

(o)

Ticket Taxes—Certain governmental taxes are imposed on the Company’s ticket sales through a fee included in ticket prices. The Company collects these fees and remits them to the appropriate government agency. These fees are recorded on a net basis (excluded from operating revenue).

(p)

Retirement of Leased Aircraft—The Company accrues for estimated lease costs over the remaining term of the lease at the present value of future minimum lease payments, net of estimated sublease rentals (if any), in the period that aircraft are permanently removed from service. When reasonably estimable and probable, the Company estimates maintenance lease return condition obligations for items such as minimum aircraft and engine conditions specified in leases and accrues these amounts over the lease term while the aircraft are operating, and any remaining unrecognized estimated obligations are accrued in the period that an aircraft is removed from service.

(q)

Uncertain Income Tax Positions—The Company has recorded reserves for income taxes and associated interest that may become payable in future years. Although management believes that its positions taken on income tax matters are reasonable, the Company nevertheless has established tax and interest reserves in recognition that various taxing authorities may challenge certain of the positions taken by the Company, potentially resulting in additional liabilities for taxes and interest. The Company’s uncertain tax position reserves are reviewed periodically and are adjusted as events occur that affect its estimates, such as the availability of new information, the lapsing of applicable statutes of limitation, the conclusion of tax audits, the measurement of additional estimated liability, the identification of new tax matters, the release of administrative tax guidance affecting its estimates of tax liabilities, or the rendering of relevant court decisions. The Company records penalties and interest relating to uncertain tax positions in Other operating expense and Interest expense, respectively, in its consolidated statements of operations. The Company has not recorded any significant expense or liabilities related to interest or penalties in its consolidated financial statements.

(r)

Labor Costs—The Company records expenses associated with amendable labor agreements when the employee group has earned the compensation and the amounts are probable and estimable. These include costs associated with lump sum cash payments that would be made in conjunction with the ratification of labor agreements. To the extent these upfront costs are in lieu of future pay increases, they would be capitalized and amortized over the term of the labor agreements. If not, these amounts would be expensed once earned and when they become probable and estimable.

(s)

Third-Party Business—The Company has third-party business revenue that includes fuel sales, catering, ground handling, maintenance services and frequent flyer award non-air redemptions, and third-party business revenue is recorded in Other operating revenue. The Company also incurs third-party business expenses, such as maintenance, ground handling and catering services for third parties, fuel sales and non-air mileage redemptions, and those third-party business expenses are recorded in Other operating expenses. In addition, the Company previously had a contract to sell aircraft fuel to a third party which was earnings-neutral but resulted in revenue and expense, specifically cost of sales which was unrelated to the operation of the airline. This contract ended in 2014.

(t)

Recently Issued Accounting Standards—In May 2014, the Financial Accounting Standards Board (“FASB”) amended the FASB Accounting Standards Codification and created a new Topic 606, Revenue from Contracts with Customers. This amendment prescribes that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendment supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance throughout the Industry Topics of the Codification. The amendments will become effective for the Company’s annual and interim reporting periods beginning January 1, 2017. Under the new standard, certain airline ancillary fees directly related to passenger revenue tickets, such as airline change fees and baggage fees, are likely to no longer be considered distinct performance obligations separate from the passenger travel component. In addition, the change fees which were previously recognized when incurred, will likely be recognized when transportation is provided. The Company is evaluating other impacts on its consolidated financial statements.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
Goodwill and Other Intangible Assets	Dec. 31, 2014
Goodwill and Other Intangible Assets	NOTE 2 - GOODWILL AND OTHER INTANGIBLE ASSETS
	The following table presents information about the Company’s goodwill and other intangible assets at December 31 (in millions):


			2014				2013
	Item	Asset life (a)	Gross Carrying		Accumulated		Gross Carrying		Accumulated
	Item	Asset life (a)	Amount		Amortization		Amount		Amortization
	Goodwill		$	4,523			$	4,523

	Finite-lived intangible assets
	Airport slots and gates	8	$	97	$	97	$	98	$	88
	Hubs	20		145		67		145		59
	Patents and tradenames	3		108		108		108		108
	Frequent flyer database (b)	22		1,177		624		1,177		536
	Contracts	12		155		86		167		86
	Other	25		109		67		109		56

	Total		$	1,791	$	1,049	$	1,804	$	933

	Indefinite-lived intangible assets
	Airport slots and gates		$	956			$	963
	Route authorities			1,589				1,605
	Tradenames and logos			593				593
	Alliances			404				404

	Total		$	3,542			$	3,565


	(a) Weighted average life expressed in years.
	(b) The frequent flyer database is amortized based on an accelerated amortization schedule to reflect utilization of the assets. Estimated cash flows correlating to the expected attrition rate of customers in the frequent flyer database is considered in the determination of the amortization schedules.
	Amortization expense in 2014, 2013 and 2012 was $128 million, $142 million and $121 million, respectively. Projected amortization expense in 2015, 2016, 2017, 2018 and 2019 is $105 million, $92 million, $81 million, $72 million and $66 million, respectively.
	See Note 17 of this report for additional information related to impairment of intangible assets.

Common_Stockholders_Equity_and

Common Stockholders' Equity and Preferred Securities	12 Months Ended
Common Stockholders' Equity and Preferred Securities	Dec. 31, 2014
Common Stockholders' Equity and Preferred Securities	NOTE 3 - COMMON STOCKHOLDERS’ EQUITY AND PREFERRED SECURITIES

	During 2014, United used $62 million of cash to purchase and retire $28 million aggregate principal amount of United’s 4.5% Convertible Notes due 2015 (the “4.5% Convertible Notes”) in market transactions. UAL and United recorded reductions of additional paid-in capital of $34 million and $62 million, respectively, to record the transactions. At December 31, 2014, the remaining balance of these notes was $202 million. In January 2015, the holders of substantially all of the remaining $202 million principal amount of the 4.5% Convertible Notes exercised their conversion option resulting in the issuance of 11 million shares of UAL common stock.

	United paid a dividend of $212 million to UAL in 2014. United recorded the dividend as a reduction of additional paid-in capital.

	At December 31, 2013, United had receivables from two affiliates, which were wholly-owned subsidiaries of UAL, of $232 million that were classified against stockholder’s equity. UAL transferred all of its equity interest in each of the two subsidiaries to United in 2014, and United reflected the transfers as reductions in additional paid-in capital.

	In 2014, UAL issued approximately 12 million shares of UAL common stock in exchange for, or upon conversion of, $104 million in aggregate principal amount of its 6% Convertible Senior Notes due 2029 (the “6% Convertible Senior Notes”) held by the holders of these notes.



	In January 2014, holders of substantially all of the remaining $156 million outstanding principal amount of the 4.5% Senior Limited-Subordination Convertible Notes due 2021 (the “4.5% Notes”) exercised their right to convert such notes into approximately five million shares of UAL common stock. See Note 11 of this report for additional information related to exercises of rights under the 4.5% Notes.

	On July 24, 2014, UAL announced a $1 billion share repurchase program, which was authorized by UAL’s Board of Directors. UAL may repurchase shares through the open market, privately negotiated transactions, block trades, or accelerated share repurchase transactions from time to time in accordance with applicable securities laws. UAL will repurchase shares of common stock subject to prevailing market conditions, and may discontinue such repurchases at any time.

	On July 24, 2014, pursuant to the $1 billion share repurchase program, UAL entered into two separate agreements to repurchase an aggregate of $200 million of shares of UAL common stock through an accelerated share repurchase program (the “ASR Program”). UAL paid $200 million and received approximately 4.4 million shares. In addition to shares purchased under the ASR Program, UAL spent $120 million on open market repurchases of 2.1 million shares of UAL common stock in 2014.

	At December 31, 2014, approximately 21 million shares of UAL’s common stock were reserved for future issuance related to the conversion of convertible debt securities and the issuance of equity based awards under the Company’s incentive compensation plans.

	As of December 31, 2014, UAL had two shares of junior preferred stock (par value $0.01 per share) outstanding. In addition, UAL is authorized to issue 250 million shares of preferred stock (without par value) under UAL’s amended and restated certificate of incorporation.

Earnings_Loss_Per_Share

Earnings (Loss) Per Share	12 Months Ended
Earnings (Loss) Per Share	Dec. 31, 2014
Earnings (Loss) Per Share	NOTE 4 - EARNINGS (LOSS) PER SHARE
	The computations of UAL’s basic and diluted earnings (loss) per share and the number of securities that have been excluded from the computation of diluted earnings per share amounts because they were antidilutive are set forth below for the years ended December 31 (in millions, except per share amounts):


		2014		2013		2012
	Basic earnings (loss) per share:
	Earnings (loss) available to common stockholders	$	1,132	$	571	$	-723

	Basic weighted-average shares outstanding		371		348		331

	Earnings (loss) per share, basic	$	3.05	$	1.64	$	-2.18


	Diluted earnings (loss) per share:
	Earnings (loss) available to common stockholders	$	1,132	$	571	$	-723
	Effect of dilutive securities		11		26		—

	Earnings (loss) available to common stockholders including the effect of dilutive securities	$	1,143	$	597	$	-723


	Diluted shares outstanding:
	Basic weighted-average shares outstanding		371		348		331
	Effect of convertible notes		18		42		—
	Effect of restricted stock and employee stock options		1		1		—

	Diluted weighted-average shares outstanding		390		391		331

	Earnings (loss) per share, diluted	$	2.93	$	1.53	$	-2.18


	Potentially dilutive shares excluded from diluted per share amounts:
	Restricted stock and stock options		1		3		5
	Convertible notes		3		4		61

			4		7		66

	See Notes 3 and 11 of this report for additional information related to the ASR Program, open market share repurchases, open market purchases of the Company’s convertible debt and exchange of shares for redemption of convertible debt.

ShareBased_Compensation_Plans

Share-Based Compensation Plans	12 Months Ended
Share-Based Compensation Plans	Dec. 31, 2014
Share-Based Compensation Plans	NOTE 5 - SHARE-BASED COMPENSATION PLANS
	UAL maintains several share-based compensation plans. These plans provide for grants of qualified and non-qualified stock options, stock appreciation rights, restricted stock awards, RSUs, performance compensation awards, performance units, cash incentive awards and other types of equity-based and equity-related awards.
	All awards are recorded as equity or a liability in the Company’s consolidated balance sheets. The share-based compensation expense is directly recorded in salaries and related costs or integration-related expense.
	In February 2014, UAL granted share-based compensation awards pursuant to the United Continental Holdings, Inc. 2008 Incentive Compensation Plan. These share-based compensation awards include approximately 0.3 million shares of restricted stock and 0.5 million of RSUs that vest pro-rata over three years on the anniversary of the grant date. The time vested RSUs are cash-settled based on the 20-day average closing price of UAL common stock immediately prior to the vesting date. In addition, UAL granted 0.6 million RSUs that will vest based on UAL’s return on invested capital for the three years ending December 31, 2016. If this performance condition is achieved, cash payments will be made after the end of the performance period based on the 20-day average closing price of UAL common stock immediately prior to the vesting date (subject to a maximum payment valued at two times the closing stock price on the grant date). The Company accounts for the RSUs as liability awards.
	The following table provides information related to UAL’s share-based compensation plan cost for the years ended December 31 (in millions):


		2014		2013		2012
	Compensation cost: (a)
	RSUs	$	104	$	88	$	37
	Restricted stock		10		11		13
	Other		—		1		7

	Total	$	114	$	100	$	57

	(a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million, $9 million and $9 million in 2014, 2013 and 2012, respectively, that was recorded in integration-related costs as a component of special charges.
	The table below summarizes UAL’s unearned compensation and weighted-average remaining period to recognize costs for all outstanding share-based awards that are probable of being achieved for the year ended December 31, 2014 (in millions, except as noted):


		Unearned		Weighted-
		Compensation		Average
				Remaining
				Period (in
				years)
	RSUs	$	55		1.4
	Restricted stock		7		1.4

	Total	$	62

	RSUs and Restricted Stock. All outstanding RSUs are settled in cash. As of December 31, 2014, UAL had recorded a liability of $136 million related to its RSUs. UAL paid $86 million, $29 million and $35 million related to its share-based liabilities during 2014, 2013 and 2012, respectively.

	The table below summarizes UAL’s RSUs and restricted stock activity for the years ended December 31 (shares in millions):


		RSUs		Restricted Stock		Weighted-
						Average
						Grant Price
	Non-vested at December 31, 2011		3.4		1.0	$	23.33
	Granted		2.0		0.5		24.01
	Vested		-0.6		-0.6		23.05
	Surrendered		-0.5		-0.1		24.01

	Non-vested at December 31, 2012		4.3		0.8		23.94
	Granted		1.8		0.5		25.98
	Vested		-0.5		-0.3		23.93
	Surrendered		-0.2		-0.1		24.76

	Non-vested at December 31, 2013		5.4		0.9		25.02
	Granted		0.9		0.3		43.33
	Vested		-2.2		-0.4		24.66
	Surrendered		-0.3		-0.1		28.88

	Non-vested at December 31, 2014		3.8		0.7		32.55

	The fair value of RSUs and restricted stock vested in 2014, 2013 and 2012 was $97 million, $22 million and $27 million, respectively. The fair value of the restricted stock awards was primarily based upon the UAL common stock price on the date of grant. These awards are accounted for as equity awards. The fair value of the RSUs was based on the UAL common stock price as of the last day preceding the settlement date. These awards were accounted for as liability awards. Restricted stock vesting and the recognition of the expense is similar to the stock option vesting described below.
	Stock Options. UAL has not granted any stock options since 2010. Historically, stock options were awarded with exercise prices equal to the fair market value of UAL’s common stock on the date of grant. UAL stock options generally vested over a period of either three or four years and have a contractual life of 10 years. Expense related to each portion of an option grant was recognized on a straight-line basis over the specific vesting period for those options. The Company determined the fair value of stock options at the grant date using a Black Scholes option pricing model. As of December 31, 2014, there were approximately 1 million outstanding stock option awards, all of which were exercisable, with a weighted-average exercise price of $29.73.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
Accumulated Other Comprehensive Income (Loss)	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss)	NOTE 6 - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	The tables below present the components of the Company’s accumulated other comprehensive income (loss) (“AOCI”), net of tax (in millions):


	UAL (a)	Pension and			Unrealized		Investments		Total
		Other			Gains (Losses)		and Other
		Postretirement			on Derivatives
		Unrecognized
		Actuarial
		Gains (Losses)
		and Prior
		Service Cost
	Balance at December 31, 2011	$	-312		$	-100	$	-5	$	-417

	Other comprehensive loss before reclassifications		-747	(b)		-51		11		-787
	Amounts reclassified from accumulated other comprehensive income		17			141		—		158

	Net current-period other comprehensive income (loss)		-730			90		11		-629

	Balance at December 31, 2012	$	-1,042		$	-10	$	6	$	(1,046)

	Other comprehensive income before reclassifications		1,584	(b)		39		7		1,630
	Amounts reclassified from accumulated other comprehensive income		42			-18		—		24

	Net current-period other comprehensive income (loss)		1,626			21		7		1,654

	Balance at December 31, 2013	$	584		$	11	$	13	$	608

	Other comprehensive income before reclassifications		-1,106	(b)		-599		—		-1,705
	Amounts reclassified from accumulated other comprehensive income		-65			89		-6		18

	Net current-period other comprehensive income (loss)		-1,171			-510		-6		-1,687

	Balance at December 31, 2014	$	-587		$	-499	$	7	$	-1,079



	Details about AOCI Components	Amount Reclassified from AOCI to							Affected Line Item in
		Income							the Statement Where
									Net Income is Presented
		Year Ended December 31,
		2014			2013		2012
	Derivatives designated as cash flow hedges
	Fuel contracts-reclassifications of (gains) losses into earnings (c)	$	89		$	-18	$	141	Aircraft fuel
	Amortization of pension and post-retirement items
	Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (c) (d)		-65			42		17	Salaries and related costs
	Investments and other
	Available for sale securities—reclassifications of gains into earnings (c)		-6			—		—	Miscellaneous, net


	(a) UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.
	(b) For 2014, prior service credits increased by $3 million and actuarial losses increased by approximately $1.1 billion. For 2013, prior service credits increased by $331 million and actuarial gains increased by approximately $1.3 billion. The amount for 2012 was not material.
	(c) Income tax expense for these items was offset by the Company’s valuation allowance.
	(d) This accumulated other comprehensive income component is included in the computation of net periodic pension and other postretirement costs (see Note 8 of this report for additional information).

Income_Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2014
Income Taxes	NOTE 7 - INCOME TAXES

	The significant components of the income tax expense (benefit) are as follows (in millions):



	2014		UAL			United
	Current		$	-17		$	-17
	Deferred			13			13

			$	-4		$	-4


	2013
	Current		$	-18		$	-18
	Deferred			-14			1

			$	-32		$	-17


	2012
	Current		$	-14		$	-9
	Deferred			13			13

			$	-1		$	4




	The income tax provision differed from amounts computed at the statutory federal income tax rate, as follows (in millions):



	UAL		2014			2013			2012
	Income tax provision at statutory rate		$	395		$	189		$	-253
	State income taxes, net of federal income tax			16			5			-15
	Foreign income taxes			2			3			7
	Nondeductible employee meals			15			15			12
	Nondeductible interest expense			—			—			19
	State rate change			—			-33			—
	Valuation allowance			-441			-219			234
	Other, net			9			8			-5

			$	-4		$	-32		$	-1


	United		2014			2013			2012
	Income tax provision at statutory rate		$	388		$	223		$	-230
	State income taxes, net of federal income tax			15			5			-7
	Foreign income taxes			2			3			7
	Nondeductible employee meals			15			15			12
	Nondeductible interest expense			—			—			19
	Derivative market adjustment			-7			-24			-15
	State rate change			—			-33			—
	Valuation allowance			-426			-229			223
	Other, net			9			23			-5

			$	-4		$	-17		$	4




	Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows (in millions):



		UAL						United
		December 31,						December 31,
		2014			2013			2014			2013
Deferred income tax asset (liability):
Federal and state net operating loss (“NOL”) carryforwards		$	3,491		$	4,006		$	3,423		$	3,943
Frequent flyer deferred revenue			2,287			2,254			2,287			2,254
Employee benefits, including pension, postretirement and medical			1,943			1,701			1,943			1,701
Alternative minimum tax credit carryforwards			214			233			214			233
Other			657			340			659			340
Less: Valuation allowance			-4,751			-4,591			-4,721			-4,561

Total deferred tax assets		$	3,841		$	3,943		$	3,805		$	3,910


Depreciation, capitalized interest and other		$	-3,212		$	-3,201		$	-3,212		$	-3,201
Intangibles			-1,545			-1,585			-1,545			-1,585
Other			-84			-144			-48			-111

Total deferred tax liabilities		$	-4,841		$	-4,930		$	-4,805		$	-4,897

Net deferred tax liability		$	-1,000		$	-987		$	-1,000		$	-987


United and its domestic consolidated subsidiaries file a consolidated federal income tax return with UAL. Under an intercompany tax allocation policy, United and its subsidiaries compute, record and pay UAL for their own tax liability as if they were separate companies filing separate returns. In determining their own tax liabilities, United and each of its subsidiaries take into account all tax credits or benefits generated and utilized as separate companies and they are each compensated for the aforementioned tax benefits only if they would be able to use those benefits on a separate company basis.

The federal and state NOL carryforwards relate to prior years’ NOLs, which may be used to reduce tax liabilities in future years. These tax benefits are mostly attributable to federal pre-tax NOL carryforwards of $9.6 billion for UAL. If not utilized these federal pre-tax NOLs will expire as follows (in billions): $1.1 in 2024, $2.5 in 2025, $2.0 in 2026 and $4.0 after 2026. In addition, the majority of tax benefits of the state net operating losses of $111 million for UAL will expire over a five to 20-year period.

Our effective tax rates are lower than the federal statutory rate of 35% primarily because of the impact of changes to existing valuation allowances. We continue to provide a valuation allowance for our deferred tax assets in excess of deferred tax liabilities because we have concluded that it is more likely than not that such deferred tax assets will ultimately not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income (including the reversals of deferred tax liabilities) during the periods in which those deferred tax assets will become deductible. The Company’s management assesses available positive and negative evidence regarding the Company’s ability to realize its deferred tax assets and records a valuation allowance when it is more likely than not that deferred tax assets will not be realized. To form a conclusion, management considers positive evidence in the form of reversing temporary differences, projections of future taxable income and tax planning strategies and negative evidence such as historical losses. Although the Company was not in a three-year cumulative loss position at the end of 2014, management determined that the low level of cumulative pretax income, combined with uncertainty about forecasted results, supports the conclusion that the valuation allowance is still necessary. Management will continue to evaluate future financial performance to determine whether such performance is both sustained and significant enough to provide sufficient evidence to support reversal of the valuation allowance.

The December 31, 2014 valuation allowances of $4.8 billion and $4.7 billion for UAL and United, respectively, if reversed in future years will reduce income tax expense. The current valuation allowance reflects increases from December 31, 2013 of $160 million, for both UAL and United, including amounts charged directly to other comprehensive income.

The Company’s unrecognized tax benefits related to uncertain tax positions were $9 million, $14 million and $19 million at 2014, 2013 and 2012, respectively. Included in the ending balance at 2014 is $7 million that would affect the Company’s effective tax rate if recognized. The Company does not expect significant increases or decreases in their unrecognized tax benefits within the next twelve months.

There are no significant amounts included in the balance at December 31, 2014 for tax positions for which the ultimate deductibility is highly certain but for which there is uncertainty about the timing of such deductibility.

The following is a reconciliation of the beginning and ending amount of unrecognized tax benefits related to the Company’s uncertain tax positions (in millions):



		2014			2013			2012
Balance at January 1,		$	14		$	19		$	24
Decrease in unrecognized tax benefits relating to settlements with taxing authorities			-5			—			-12
Increase in unrecognized tax benefits as a result of tax positions taken during a prior period			—			—			8
Decrease in unrecognized tax benefits relating from a lapse of the statute of limitations			—			-5			-1

Balance at December 31,		$	9		$	14		$	19


The Company’s federal income tax returns for tax years after 2002 remain subject to examination by the Internal Revenue Service (“IRS”) and state taxing jurisdictions. Currently, there are no ongoing examinations of the Company’s prior year tax returns being conducted by the IRS.

Pension_and_Other_Postretireme

Pension and Other Postretirement Plans	12 Months Ended
Pension and Other Postretirement Plans	Dec. 31, 2014
Pension and Other Postretirement Plans	NOTE 8 - PENSION AND OTHER POSTRETIREMENT PLANS
	The following summarizes the significant pension and other postretirement plans of United:
	Pension Plans
	United maintains two primary defined benefit pension plans, one covering certain pilot employees and another covering certain U.S. non-pilot employees. Each of these plans provide benefits based on a combination of years of benefit accruals service and an employee’s final average compensation. Additional benefit accruals were frozen under the plan covering certain pilot employees during 2005 and management and administrative employees as of December 31, 2013 at which time any existing accrued benefits for those employees were preserved. Benefit accruals for certain non-pilot employees under its other primary defined benefit pension plan continue. United maintains additional defined benefit pension plans, which cover certain international employees.
	Other Postretirement Plans
	We maintain postretirement medical programs which provide medical benefits to certain retirees and eligible dependents, as well as life insurance benefits to certain retirees participating in the plan. Benefits provided are subject to applicable contributions, co-payments, deductible and other limits as described in the specific plan documentation.

	Changes in benefits that either qualified as curtailments (which reduced prior actuarial losses) or negative plan amendments are detailed in the tables below. Actuarial assumption changes are reflected as a component of the net actuarial gains/(losses) during 2014 and 2013. These amounts will be amortized over the average remaining service life of the covered active employees or the average life expectancy of inactive participants and will impact 2014 and 2013 pension and retiree medical expense as described below.
	The following table sets forth the reconciliation of the beginning and ending balances of the benefit obligation and plan assets, the funded status and the amounts recognized in these financial statements for the defined benefit and other postretirement plans (in millions):


			Pension Benefits
			Year Ended			Year Ended
			December 31, 2014			December 31, 2013
	Accumulated benefit obligation:		$	4,068		$	3,383


	Change in projected benefit obligation:
	Projected benefit obligation at beginning of year		$	4,000		$	4,526
	Service cost			98			121
	Interest cost			201			191
	Actuarial (gain) loss			807			-464
	Gross benefits paid and settlements			-281			-269
	Curtailments			—			-84
	Other			-22			-21

	Projected benefit obligation at end of year		$	4,803		$	4,000


	Change in plan assets:
	Fair value of plan assets at beginning of year		$	2,397		$	2,157
	Actual gain on plan assets			151			239
	Employer contributions			307			277
	Gross benefits paid and settlements			-281			-269
	Other			-12			-7

	Fair value of plan assets at end of year		$	2,562		$	2,397

	Funded status—Net amount recognized		$	-2,241		$	-1,603



			Pension Benefits
			December 31, 2014			December 31, 2013
	Amounts recognized in the consolidated balance sheets consist of:
	Noncurrent asset		$	2		$	49
	Current liability			-17			-2
	Noncurrent liability			-2,226			-1,650

	Total liability		$	-2,241		$	-1,603

	Amounts recognized in accumulated other comprehensive loss consist of:
	Net actuarial loss		$	-982		$	-162
	Prior service loss			-1			—

	Total accumulated other comprehensive loss		$	-983		$	-162



			Other Postretirement Benefits
			Year Ended			Year Ended
			December 31, 2014			December 31, 2013
	Change in benefit obligation:
	Benefit obligation at beginning of year		$	1,819		$	2,743
Service cost			19			52
Interest cost			88			110
Plan participants’ contributions			67			67
Actuarial (gain) loss			262			-640
Federal subsidy			4			7
Plan amendments			-3			-331
Curtailments			8			8
Gross benefits paid			-212			-197

Benefit obligation at end of year		$	2,052		$	1,819

Change in plan assets:
Fair value of plan assets at beginning of year		$	57		$	58
Actual return on plan assets			1			1
Employer contributions			144			128
Plan participants’ contributions			67			67
Benefits paid			-212			-197
Fair value of plan assets at end of year			57			57

Funded status—Net amount recognized		$	-1,995		$	-1,762



		Other Postretirement Benefits
		December 31, 2014			December 31, 2013
Amounts recognized in the consolidated balance sheets consist of:
Current liability		$	-62		$	-59
Noncurrent liability			-1,933			-1,703

Total liability		$	-1,995		$	-1,762

Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial gain		$	233		$	555
Prior service credit			278			306

Total accumulated other comprehensive income		$	511		$	861

The following information relates to all pension plans with an accumulated benefit obligation and a projected benefit obligation in excess of plan assets at December 31 (in millions):


		2014			2013
Projected benefit obligation		$	4,625		$	3,820
Accumulated benefit obligation			3,930			3,245
Fair value of plan assets			2,387			2,176

Net periodic benefit cost for the years ended December 31 included the following components (in millions):


		2014						2013				2012
		Pension			Other			Pension		Other		Pension				Other
		Benefits			Postretirement			Benefits		Postretirement		Benefits				Postretirement
					Benefits					Benefits						Benefits
Service cost		$	98		$	19		$	121	$	52	$	99			$	50
Interest cost			201			88			191		110		184				124
Expected return on plan assets			-180			-2			-163		-2		-138				-2
Curtailment loss			—			—			2		2		—				—
Amortization of prior service credits			—			-31			—		-3		-1				—
Settlement (gain) loss			1			—			-10		—		1				—
Amortization of unrecognized actuarial (gain) loss			12			-47			48		3		21				-3

Net periodic benefit cost		$	132		$	27		$	189	$	162	$	166			$	169

The estimated amounts that will be amortized in 2015 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions):


		Pension			Other
		Benefits			Postretirement
					Benefits
Actuarial (gain) loss		$	87		$	-22
Prior service credit			—			-32
The assumptions used for the benefit plans were as follows:


			Pension Benefits
Assumptions used to determine benefit obligations			2014			2013
Discount rate			4.20%			5.09%
Rate of compensation increase			3.66%			3.49%

Assumptions used to determine net expense
Discount rate			5.10%			4.48%
Expected return on plan assets			7.36%			7.56%
Rate of compensation increase			3.50%			2.48%


		Other Postretirement Benefits
Assumptions used to determine benefit obligations		2014			2013
Discount rate			4.07%			4.94%

Assumptions used to determine net expense
Discount rate			4.94%			4.12%
Expected return on plan assets			4.00%			4.00%
Health care cost trend rate assumed for next year			7.00%			7.25%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023)			5.00%			5.00%
During 2014, the Company experienced changes in its benefit obligations related to changes in discount rates and mortality tables in its pension plans and other postretirement benefit plans. The Company used the Society of Actuaries’ 2014 mortality tables, modified to reflect the Social Security Administration Trustee’s Report on current projections regarding expected longevity improvements.
The Company selected the 2014 discount rate for most of its plans by using a hypothetical portfolio of high quality bonds at December 31, 2014, that would provide the necessary cash flows to match projected benefit payments.
We develop our expected long-term rate of return assumption for such plans based on historical experience and by evaluating input from the trustee managing the plans’ assets. Our expected long-term rate of return on plan assets for these plans is based on a target allocation of assets, which is based on our goal of earning the highest rate of return while maintaining risk at acceptable levels. The plans strive to have assets sufficiently diversified so that adverse or unexpected results from one security class will not have an unduly detrimental impact on the entire portfolio. Plan fiduciaries regularly review our actual asset allocation and the pension plans’ investments are periodically rebalanced to our targeted allocation when considered appropriate. United’s plan assets are allocated within the following guidelines:


		Percent of Total		Expected Long-Term
		Percent of Total		Rate of Return

Equity securities		40-54 %		10 %
Fixed-income securities		26-34		4
Alternatives		14-20		7
Other		8-Apr		6
One-hundred percent of other postretirement plan assets are invested in a deposit administration fund.
Assumed health care cost trend rates have a significant effect on the amounts reported for the other postretirement plans. A 1% change in the assumed health care trend rate for the Company would have the following additional effects (in millions):


		1% Increase			1% Decrease
Effect on total service and interest cost for the year ended December 31, 2014		$	13		$	-11
Effect on postretirement benefit obligation at December 31, 2014			254			-220
A one percentage point decrease in the weighted average discount rate would increase the postretirement benefit liability by approximately $247 million and increase the estimated 2014 benefits expense by approximately $10 million.

Fair Value Information. Accounting standards require us to use valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs are prioritized as follows:


Level 1		Unadjusted quoted prices in active markets for assets or liabilities identical to those to be reported at fair value
Level 2		Other inputs that are observable directly or indirectly, such as quoted prices for similar assets or liabilities or market-corroborated inputs
Level 3		Unobservable inputs for which there is little or no market data and which require us to develop our own assumptions about how market participants would price the assets or liabilities
Assets and liabilities measured at fair value are based on the valuation techniques identified in the tables below. The valuation techniques are as follows:
(a) Market approach. Prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities; and
(b) Income approach. Techniques to convert future amounts to a single current value based on market expectations (including present value techniques, option-pricing and excess earnings models).
The following tables present information about United’s pension and other postretirement plan assets at December 31 (in millions):


		2014												2013
Pension Plan Assets:		Total			Level 1			Level 2		Level 3				Total				Level 1		Level 2		Level 3
Equity securities funds		$	1,181		$	388		$	793	$	—			$	1,158			$	389	$	769	$	—
Fixed-income securities			813			—			813		—				702				—		698		4
Alternatives			359			—			148		211				405				—		199		206
Insurance contract			21			—			—		21				26				—		—		26
Other investments			188			—			165		23				106				—		106		—

Total		$	2,562		$	388		$	1,919	$	255			$	2,397			$	389	$	1,772	$	236

Other Postretirement Benefit Plan Assets:
Deposit administration fund		$	57		$	—		$	—	$	57			$	57			$	—	$	—	$	57

Equity and Fixed-Income Securities. Equity securities include investments in both developed market and emerging market equity securities. Fixed-income securities include primarily U.S. and non-U.S. government fixed-income securities and U.S. and non-U.S corporate fixed-income securities.
Insurance Contract and Deposit Administration Fund. Each of these investments are stable value investment products structured to provide investment income.
Alternatives. Alternative investments consist primarily of investments in hedge funds, real estate and private equity interests.
Other investments. Other investments consist primarily of investments in currency and commodity commingled funds.

The reconciliation of United’s defined benefit plan assets measured at fair value using unobservable inputs (Level 3) for the years ended December 31, 2014 and 2013 is as follows (in millions):


		2014			2013
Balance at beginning of year		$	293		$	256
Actual return on plan assets:
Sold during the year			7			15
Held at year end			6			7
Purchases, sales, issuances and settlements (net)			6			15

Balance at end of year		$	312		$	293

Funding requirements for tax-qualified defined benefit pension plans are determined by government regulations. United’s contributions reflected above have satisfied its required contributions through the 2014 calendar year. In 2015, employer anticipated contributions to all of United’s pension and postretirement plans are at least $400 million and approximately $120 million, respectively.
The estimated future benefit payments, net of expected participant contributions, in United’s pension plans and other postretirement benefit plans as of December 31, 2014 are as follows (in millions):


		Pension			Other			Other Postretirement—
		Pension			Postretirement			subsidy receipts
2015		$	299		$	125		$	6
2016			283			126			7
2017			294			129			8
2018			291			132			9
2019			293			135			9
Years 2020 – 2024			1,581			732			56
Defined Contribution Plans
Depending upon the employee group, employer contributions consist of matching contributions and/or non-elective employer contributions. United’s employer contribution percentages vary from 1% to 16% of eligible earnings depending on the terms of each plan. United recorded contributions to its defined contribution plans of $503 million, $433 million and $330 million in the years ended December 31, 2014, 2013 and 2012, respectively.

Multi-Employer Plans
United’s participation in the IAM National Pension Plan (“IAM Plan”) for the annual period ended December 31, 2014 is outlined in the table below. There have been no significant changes that affect the comparability 2014 and 2013 contributions. The risks of participating in these multi-employer plans are different from single-employer plans, as United may be subject to additional risks that others do not meet their obligations, which in certain circumstances could revert to United. The IAM Plan reported $368 million in employers’ contributions for the year ended December 31, 2013. For 2013, the Company’s contributions to the IAM Plan represented more than 5% of total contributions to the IAM Plan.


Pension Fund		IAM National Pension Fund
EIN/ Pension Plan Number		51-6031295 - 002
Pension Protection Act Zone Status (2014 and 2013)		Green Zone. Plans in the green zone are at least 80 percent funded.
FIP/RP Status Pending/Implemented		No
United’s Contributions		$39 million, $38 million and $36 million in the years ended December 31, 2014, 2013 and 2012, respectively
Surcharge Imposed		No
Expiration Date of Collective Bargaining Agreement		N/A
At the date the financial statements were issued, Forms 5500 were not available for the plan year ending in 2014.
Profit Sharing
Substantially all employees participated in profit sharing, which depending on the work group and the Company’s earnings thresholds, determines profit sharing payments based on receiving a portion of 5% to 20% of total pre-tax earnings, excluding special items, profit sharing expense and share-based compensation expense, to eligible employees. Eligible U.S. co-workers in each participating work group received a profit sharing payout using a formula based on the ratio of each qualified co-worker’s annual eligible earnings to the eligible earnings of all qualified co-workers in all domestic work groups. The international profit sharing plan paid eligible non-U.S. co-workers based on the calculation under the U.S. profit sharing plan for management and administrative employees. The Company recorded profit sharing and related payroll tax expense of $235 million, $190 million and $119 million in 2014, 2013 and 2012, respectively. Profit sharing expense is recorded as a component of Salaries and related costs in the Company’s consolidated statements of operations.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2014
Fair Value Measurements	NOTE 9 - FAIR VALUE MEASUREMENTS

	Fair Value Information. Accounting standards require us to use valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs are prioritized as follows:



	Level 1		Unadjusted quoted prices in active markets for assets or liabilities identical to those to be reported at fair value
	Level 2		Other inputs that are observable directly or indirectly, such as quoted prices for similar assets or liabilities or market-corroborated inputs
	Level 3		Unobservable inputs for which there is little or no market data and which require us to develop our own assumptions about how market participants would price the assets or liabilities



	The table below presents disclosures about the fair value of financial assets and financial liabilities measured at fair value on a recurring basis in the Company’s financial statements as of December 31 (in millions):



			2014												2013
			Total			Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3
			UAL
	Cash and cash equivalents			$2,002		$	2,002		$	—		$	—		$	3,220		$	3,220		$	—		$	—
	Short-term investments:
	Asset-backed securities			901			—			901			—			694			—			694			—
	Corporate debt			876			—			876			—			685			—			685			—
	Certificates of deposit placed through an account registry service (“CDARS”)			256			—			256			—			301			—			301			—
	U.S. government and agency notes			68			—			68			—			38			—			38			—
	Auction rate securities			26			—			—			26			105			—			—			105
	Other fixed income securities			255			—			255			—			78			—			78			—
	Enhanced equipment trust certificates (“EETC”)			28			—			—			28			61			—			—			61
	Fuel derivatives asset (liability), net			-717			—			-717			—			104			—			104			—
	Foreign currency derivatives			2			—			2			—			1			—			1			—
	Restricted cash			320			320			—			—			395			395			—			—

			United
	Cash and cash equivalents		$	1,996		$	1,996		$	—		$	—		$	3,214		$	3,214		$	—		$	—
	Short-term investments:
	Asset-backed securities			901			—			901			—			694			—			694			—
	Corporate debt			876			—			876			—			685			—			685			—
	CDARS			256			—			256			—			301			—			301			—
	U.S. government and agency notes			68			—			68			—			38			—			38			—
	Auction rate securities			26			—			—			26			105			—			—			105
	Other fixed income securities			255			—			255			—			78			—			78			—
	EETC			28			—			—			28			61			—			—			61
	Fuel derivatives asset (liability), net			-717			—			-717			—			104			—			104			—
	Foreign currency derivatives			2			—			2			—			1			—			1			—
	Restricted cash			320			320			—			—			395			395			—			—
	Convertible debt derivative asset			712			—			—			712			480			—			—			480
	Convertible debt option liability			-511			—			—			-511			-270			—			—			-270



	Available-for-sale investment maturities—The short-term investments shown in the table above are classified as available-for-sale. As of December 31, 2014, asset-backed securities have remaining maturities of less than one year to approximately 40 years, corporate debt securities have remaining maturities of less than one year to approximately six years and CDARS have maturities of less than one year. U.S. government and other securities have maturities of less than one year to approximately four years.

	The tables below present disclosures about the activity for “Level 3” financial assets and financial liabilities for the year ended December 31 (in millions):



			2014												2013
			UAL and United						United						UAL and United						United
			Student			EETC			Convertible			Convertible			Student			EETC			Convertible			Convertible
			Loan-Related						Debt			Debt			Loan-Related						Debt			Debt
			Auction Rate						Supplemental			Conversion			Auction Rate						Supplemental			Conversion
			Securities						Derivative			Option			Securities						Derivative			Option
									Asset			Liability									Asset			Liability

Balance at January 1		$	105		$	61		$	480		$	-270		$	116		$	63		$	268		$	-128
Purchases, (sales), issuances and settlements (net)			-84			-33			-62			34			-19			-4			—			—
Gains and (losses):
Reported in earnings:
Realized			10			1			-5			5			3			—			—			—
Unrealized			—			—			299			-280			1			—			212			-142
Reported in other comprehensive income (loss)			-5			-1			—			—			4			2			—			—

Balance at December 31		$	26		$	28		$	712		$	-511		$	105		$	61		$	480		$	-270


United’s debt-related derivatives presented in the tables above relate to (a) supplemental indentures that provide that United’s convertible debt is convertible into shares of UAL common stock upon the terms and conditions specified in the indentures, and (b) the embedded conversion options in United’s convertible debt that are required to be separated and accounted for as though they are free-standing derivatives as a result of the United debt becoming convertible into the common stock of a different reporting entity. The derivatives described above relate to the 6% Convertible Junior Subordinated Debentures due 2030 (the “6% Convertible Debentures”) and the 4.5% Convertible Notes. Gains (losses) on these derivatives are recorded in Nonoperating income (expense): Miscellaneous, net in United’s Statements of Consolidated Operations. These derivatives along with their gains (losses) are reported in United’s separate financial statements and are eliminated in consolidation for UAL.

In October 2014, United used cash to retire, at par, the entire $248 million principal balance of the 6% Convertible Debentures. In January 2015, the holders of substantially all of the remaining $202 million principal amount of the 4.5% Convertible Notes exercised their conversion options. The derivative assets and liabilities associated with the 6% Convertible Debentures and the 4.5% Convertible Notes were settled in connection with the retirement of the related convertible debt. See Note 11 of this report for additional information related to the 6% Convertible Debentures and the 4.5% Convertible Notes.



Derivative instruments and investments presented in the tables above have the same fair value as their carrying value. The table below presents the carrying values and estimated fair values of financial instruments not presented in the tables above as of December 31 (in millions):



		Fair Value of Debt by Fair Value Hierarchy Level
		2014															2013
		Carrying			Fair Value												Carrying			Fair Value
		Amount			Fair Value												Amount			Fair Value
					Total			Level 1			Level 2			Level 3						Total			Level 1			Level 2		Level 3
UAL debt		$	11,434		$	12,386		$	—		$	8,568		$	3,818		$	11,539		$	12,695		$	—		$	8,829	$	3,866
United debt			11,433			12,386			—			8,568			3,818			11,388			12,249			—			8,383		3,866

Quantitative Information About Level 3 Fair Value Measurements as of December 31, 2014 ($ in millions)



Item		Fair Value at			Valuation Technique		Unobservable Input	Input Value
Item		December 31, 2014			Valuation Technique		Unobservable Input	Input Value
Auction rate securities		$	26		Valuation Service / Broker Quotes		Broker quotes (a)	NA
EETC			28		Discounted Cash Flows		Structure credit risk (b)	4%
Convertible debt derivative asset			712		Binomial Lattice Model		Expected volatility (c)	40%
Convertible debt derivative asset			712		Binomial Lattice Model		Own credit risk (d)	5%
Convertible debt option liability			-511		Binomial Lattice Model		Expected volatility (c)	40%
Convertible debt option liability			-511		Binomial Lattice Model		Own credit risk (d)	5%



(a) Broker quotes obtained by a third-party valuation service.

(b) Represents the credit risk premium of the EETC structure above the risk-free rate that the Company has determined market participants would use when pricing the instruments.

(c) Represents the volatility estimate that the Company has determined market participants would use when pricing the instruments.

(d) Represents the Company-specific risk adjustment that the Company has determined market participants would use as a model input.

Valuation Processes - Level 3 Measurements - Depending on the instrument, the Company utilizes broker quotes obtained from third-party valuation services, discounted cash flow methods, or option pricing methods, as indicated above. Valuations using discounted cash flow methods are generally conducted by the Company. Valuations using option pricing models are generally provided to the Company by third-party valuation experts. Each reporting period, the Company reviews the unobservable inputs used by third-party valuation experts for reasonableness utilizing relevant information available to the Company from other sources.

The Company uses broker quotes obtained from a valuation service (in replacement of a discounted cash flows method) for valuing auction rate securities. This approach provides the best available information.

Sensitivity Analysis - Level 3 Measurements - Changes in the structure credit risk would be unlikely to cause material changes in the fair value of the EETCs.

The significant unobservable inputs used in the fair value measurement of the United convertible debt derivative assets and liabilities are the expected volatility in UAL common stock and the Company’s own credit risk. Significant increases (decreases) in expected stock volatility would result in a higher (lower) fair value measurement. Significant increases (decreases) in the Company’s own credit risk would result in a lower (higher) fair value measurement. A change in one of the inputs would not necessarily result in a directionally similar change in the other.



Fair value of the financial instruments included in the tables above was determined as follows:



Description		Fair Value Methodology
Cash and cash equivalents		The carrying amounts approximate fair value because of the short-term maturity of these assets.

Short-term investments and Restricted cash		Fair value is based on (a) the trading prices of the investment or similar instruments, (b) an income approach, which uses valuation techniques to convert future amounts into a single present amount based on current market expectations about those future amounts when observable trading prices are not available, (c) internally-developed models of the expected future cash flows related to the securities, or (d) broker quotes obtained by third-party valuation services.

Fuel derivatives		Derivative contracts are privately negotiated contracts and are not exchange traded. Fair value measurements are estimated with option pricing models that employ observable inputs. Inputs to the valuation models include contractual terms, market prices, yield curves, fuel price curves and measures of volatility, among others.

Foreign currency derivatives		Fair value is determined with a formula utilizing observable inputs. Significant inputs to the valuation models include contractual terms, risk-free interest rates and forward exchange rates.

Debt		Fair values were based on either market prices or the discounted amount of future cash flows using our current incremental rate of borrowing for similar liabilities.

Convertible debt derivative asset and option liability		United used a binomial lattice model to value the conversion options and the supplemental derivative assets. Significant binomial model inputs that are not objectively determinable include volatility and the Company’s credit risk component of the discount rate.

NOTE 10 - HEDGING ACTIVITIES

Hedging_Activities

Hedging Activities	12 Months Ended
Hedging Activities	Dec. 31, 2014
Hedging Activities	NOTE 10 - HEDGING ACTIVITIES
	Fuel Derivatives
	The Company routinely hedges a portion of its future fuel requirements. As of December 31, 2014, the Company had hedged approximately 22% and 1% of its projected fuel requirements (859 million and 35 million gallons, respectively) for 2015 and 2016, respectively, with commonly used financial hedge instruments based on aircraft fuel or crude oil. As of December 31, 2014, the Company had fuel hedges expiring through March 2016. The Company does not enter into derivative instruments for non-risk management purposes.
	As required, the Company assesses the effectiveness of each of its individual hedges on a quarterly basis. The Company also examines the effectiveness of its entire hedging program on a quarterly basis utilizing statistical analysis. This analysis involves utilizing regression and other statistical analyses that compare changes in the price of aircraft fuel to changes in the prices of the commodities used for hedging purposes.
	Upon proper qualification, the Company accounts for certain fuel derivative instruments as cash flow hedges. All derivatives designated as hedges that meet certain requirements are granted hedge accounting treatment. The types of instruments the Company utilizes that qualify for special hedge accounting treatment typically include swaps, call options, collars (which consist of a purchased call option and a sold put option) and four-way collars (a collar with a higher strike sold call option and a lower strike purchased put option). Generally, utilizing hedge accounting, all periodic changes in fair value of the derivatives designated as hedges that are considered to be effective are recorded in AOCI until the underlying fuel is consumed and recorded in fuel expense. The Company is exposed to the risk that its hedges may not be effective in offsetting changes in the cost of fuel and that its hedges may not continue to qualify for hedge accounting. Hedge ineffectiveness results when the change in the fair value of the derivative instrument exceeds the change in the value of the Company’s expected future cash outlay to purchase and consume fuel. To the extent that the periodic changes in the fair value of the derivatives are not effective, that ineffectiveness is classified as Nonoperating income (expense): Miscellaneous, net in the statements of consolidated operations.
	The Company also utilizes certain derivative instruments that are economic hedges but do not qualify for hedge accounting under U.S. GAAP. As with derivatives that qualify for hedge accounting, the purpose of these economic hedges is to mitigate the adverse financial impact of potential increases in the price of fuel. Currently, the only such economic hedges in the Company’s hedging portfolio are three-way collars (a collar with a higher strike sold call option). The Company records changes in the fair value of three-way collars to Nonoperating income (expense): Miscellaneous, net in the statements of consolidated operations.
	If the Company settles a derivative prior to its contractual settlement date, then the cumulative gain or loss recognized in AOCI at the termination date remains in AOCI until the forecasted transaction occurs. In a situation where it becomes probable that a hedged forecasted transaction will not occur, any gains and/or losses that have been recorded to AOCI would be required to be immediately reclassified into earnings. All cash flows associated with purchasing and settling derivatives are classified as operating cash flows in the statements of consolidated cash flows.
	The Company records each derivative instrument as a derivative asset or liability (on a gross basis) in its consolidated balance sheets, and, accordingly, records any related collateral on a gross basis. The table below presents the fair value amounts of fuel derivative assets and liabilities and the location of amounts recognized in the Company’s financial statements.

	At December 31, the Company’s derivatives were reported in its consolidated balance sheets as follows (in millions):


	Classification		Balance Sheet Location		2014				2013
	Derivatives designated as cash flow hedges
	Assets:
	Fuel contracts due within one year		Receivables		$	—			$	19
	Fuel contracts with maturities greater than one year		Other assets: Other, net			—				6

	Total assets				$	—			$	25

	Liabilities:
	Fuel contracts due within one year		Fuel derivative instruments		$	450			$	—
	Fuel contracts with maturities greater than one year		Other liabilities and deferred credits: Other			27				—

					$	477			$	—

	Derivatives not designated for hedge accounting
	Assets:
	Fuel contracts due within one year		Receivables		$	6			$	70
	Fuel contracts with maturities greater than one year		Other assets: Other, net			—				9

	Total assets				$	6			$	79

	Liabilities:
	Fuel contracts due within one year		Fuel derivative instruments		$	244			$	—
	Fuel contracts with maturities greater than one year		Other liabilities and deferred credits: Other			2				—

	Total liabilities				$	246			$	—

	Total derivatives
	Assets:
	Fuel contracts due within one year		Receivables		$	6			$	89
	Fuel contracts with maturities greater than one year		Other assets: Other, net			—				15

	Total assets				$	6			$	104

	Liabilities:
	Fuel contracts due within one year		Fuel derivative instruments		$	694			$	—
	Fuel contracts with maturities greater than one year		Other liabilities and deferred credits: Other			29				—

	Total liabilities				$	723			$	—

	Derivative Credit Risk and Fair Value
	The Company is exposed to credit losses in the event of nonperformance by counterparties to its derivative instruments. While the Company records derivative instruments on a gross basis, the Company monitors its net derivative position with each counterparty to monitor credit risk. Based on the fair value of our fuel derivative instruments, our counterparties may require us to post collateral when the price of the underlying commodity decreases, and we may require our counterparties to provide us with collateral when the price of the underlying commodity increases. The Company posted $577 million of collateral with fuel derivative counterparties as of December 31, 2014. The collateral is recorded as Fuel hedge collateral deposits on the Company’s balance sheet. The Company did not post or hold collateral as of December 31, 2013.

	We have master trading agreements with all of our fuel hedging counterparties that allow us to net our fuel hedge derivative positions. We have elected not to net the fair value positions and collateral recorded on our consolidated balance sheets. The following table shows the potential net fair value positions (including fuel derivatives and related collateral) had we elected to offset. The table reflects offset at the counterparty level (in millions):


			December 31, 2014				December 31, 2013
	Receivables		$	—			$	89
	Other assets: Other, net			—				15
	Current liabilities: Other			-209				—
	Other liabilities and deferred credits: Other			-30				—

Hedge derivatives assets (liabilities), net		$	-239			$	104

The following tables present the fuel hedge gains (losses) recognized during the periods presented and their classification in the financial statements (in millions):
Derivatives designated as cash flow hedges


		Amount of Gain (Loss)								Gain (Loss)				Amount of Gain (Loss)
		Recognized								Reclassified from				Recognized in
		in AOCI on Derivatives								AOCI into Income				Nonoperating income
		(Effective Portion)								(Fuel Expense)				(expense): Miscellaneous, net
										(Effective Portion)				(Ineffective Portion)
		2014				2013				2014		2013		2014		2013
Fuel contracts		$	-599			$	39			$	-89	$	18	$	-3	$	5
Derivatives not designated for hedge accounting


		Amount of Gain (Loss) Recognized
		in Nonoperating income (expense):
		Miscellaneous, net
		2014				2013				2012
Fuel contracts		$	-462			$	79			$	38

Debt

Debt	12 Months Ended
Debt	Dec. 31, 2014
Debt

	NOTE 11 - DEBT



	(In millions)		At December 31,
			2014			2013
	United:
	Secured
	Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.86% as of December 31, 2014), payable through 2026		$	7,464		$	6,279
	Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 5.46%, payable through 2026			1,151			1,243
	Term loan, LIBOR subject to a 0.75% floor, plus 2.75%, or alternative rate based on certain market rates plus 1.75%, due 2019			884			893
	Term loan, LIBOR subject to a 0.75% floor, plus 3.00%, or alternative rate based on certain market rates plus 2%, due 2021			499			—
	6.75% Senior Secured Notes due 2015			—			800
	Unsecured
	6% Notes due 2026 to 2028 (a)			632			652
	6% Senior Notes due 2020 (a)			300			300
	6.375% Senior Notes due 2018 (a)			300			300
	4.5% Convertible Notes due 2015			202			230
	8% Notes due 2024 (a)			—			400
	6% Convertible Junior Subordinated Debentures due 2030			—			248
	4.5% Senior Limited-Subordination Convertible Notes due 2021 (a)			—			156
	Other			101			103

				11,533			11,604

	Less: unamortized debt discount			-99			-169
	Less: current portion of long-term debt—United			-1,313			-1,368

	Long-term debt, net—United (b)		$	10,121		$	10,067


	UAL:
	6% Convertible Senior Notes due 2029		$	—		$	104

	Long-term debt, net—UAL		$	10,121		$	10,171




	(a) UAL is the issuer of this debt. United is a guarantor.

	(b) As further described below under “Convertible Debt Securities and Derivatives,” there is a basis difference between UAL and United debt values, because we applied different accounting methodologies. The United debt presented above does not agree to United’s balance sheet by the amount of this adjustment.

	The table below presents the Company’s contractual principal payments at December 31, 2014 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions):



			UAL and United
	2015		$	1,313
	2016			1,195
	2017			755
	2018			1,269
	2019			1,721
	After 2019			5,280

			$	11,533




	As of December 31, 2014, a substantial portion of the Company’s assets, principally aircraft, route authorities and certain other intangible assets, were pledged under various loan and other agreements. As of December 31, 2014, UAL and United were in compliance with their respective debt covenants. Continued compliance depends on many factors, some of which are beyond the Company’s control, including the overall industry revenue environment and the level of fuel costs.

United secured debt

2013 Credit and Guaranty Agreement. On March 27, 2013, United and UAL entered into the Credit and Guaranty Agreement (the “Credit Agreement”) as the borrower and guarantor, respectively. The Company’s Credit Agreement originally consisted of a $900 million term loan due April 1, 2019 and a $1.0 billion revolving credit facility available for drawing until April 1, 2018.

On March 27, 2013, the Company used $900 million from the Credit Agreement, together with approximately $300 million of cash, to retire the entire principal balance of a $1.2 billion term loan due 2014 that was outstanding under United’s Amended and Restated Revolving Credit, Term Loan and Guaranty Agreement, dated as of February 2, 2007 (the “Amended Credit Facility”). The Amended Credit Facility was terminated concurrently with the repayment of the term loan.

In March 2014, United amended the Credit Agreement to reduce the interest rate payable on the existing $893 million term loan from LIBOR plus a margin of 3.0% per annum to LIBOR plus a margin of 2.75% per annum, subject to a 0.75% floor. Borrowings under the revolving credit facility under the Credit Agreement bear interest at a variable rate equal to LIBOR plus a margin of 3.0% per annum, or another rate based on certain market interest rates, plus a margin of 2.0% per annum. The principal amount of the term loan must be repaid in consecutive quarterly installments of 0.25% of the original principal amount thereof, commencing on June 30, 2013, with any unpaid balance due on April 1, 2019. United may prepay all or a portion of the loan from time to time, at par plus accrued and unpaid interest. United pays a commitment fee equal to 0.75% per-annum on the undrawn amount available under the revolving credit facility.

The Credit Agreement requires United to repay the term loan and any other outstanding borrowings under the Credit Agreement at par plus accrued and unpaid interest if certain changes of control of UAL occur.

In September 2014, United borrowed a $500 million term loan under the Credit Agreement, of which $499 million is outstanding. The loan is due September 2021 and bears interest at LIBOR plus a margin of 3.0% per annum, subject to a 0.75% floor. The $500 million term loan ranks pari passu with the $900 million term loan that United originally borrowed under the Credit Agreement, of which $884 million is outstanding. Also in September 2014, UAL amended its revolving credit facility under the Credit Agreement increasing the capacity from $1.0 billion to $1.35 billion and establishing the maturity date for $1.315 billion in lender commitments as January 2, 2019.

As of December 31, 2014, United had its entire capacity of $1.35 billion available under the revolving credit facility of the Company’s Credit Agreement.

As of December 31, 2014, United had cash collateralized $74 million of letters of credit. United also had $410 million of performance bonds and letters of credit relating to various real estate, customs and aircraft financing obligations at December 31, 2014. Most of the letters of credit have evergreen clauses and are expected to be renewed on an annual basis and the performance bonds have expiration dates through 2019.

6.75% Senior Secured Notes due 2015. In September 2014, United retired, at par, the entire $800 million principal balance of its 6.75% Senior Secured Notes due 2015, which had originally been issued in August 2010.

EETCs. United has $7.2 billion principal amount of equipment notes outstanding issued under EETC financings included in notes payable in the table of outstanding debt above. Generally, the structure of these EETC financings consist of pass-through trusts created by United to issue pass-through certificates, which represent fractional undivided interests in the respective pass-through trusts and are not obligations of United. The proceeds of the issuance of the pass-through certificates are used to purchase equipment notes which are issued by United and secured by its aircraft. The payment obligations under the equipment notes are those of United. Proceeds received from the sale of pass-through certificates are initially held by a depositary in escrow for the benefit of the certificate holders until United issues equipment notes to the trust, which purchases such notes with a portion of the escrowed funds. These escrowed funds are not guaranteed by United and are not reported as debt on United’s consolidated balance sheet because the proceeds held by the depositary are not United’s assets.

In August 2014, April 2014 and August 2013, United created separate EETC pass-through trusts, each of which issued pass-through certificates. The proceeds of the issuance of the pass-through certificates are used to purchase equipment notes issued by United and secured by its aircraft. The Company records the debt obligation upon issuance of the equipment notes rather than upon the initial issuance of the pass-through certificates. United expects to receive all proceeds from these pass-through trusts by the end of 2015. Certain details of the pass-through trusts with proceeds received from issuance of debt in 2014 are as follows (in millions, except stated interest rate):



EETC Date		Class		Principal			Final	Stated		Total debt		Proceeds		Remaining
							expected	interest		recorded		received from		proceeds from
							distribution	rate		as of December 31,		issuance of		issuance of debt
							date			2014		debt during		to be received
												2014		in future
														periods
Aug-14		A		$	823		September 2026		3.75%	$	112	$	112	$	711
Aug-14		B			238		Sep-22		4.63%		32		32		206
Apr-14		A			736		Apr-26		4.00%		736		736		—
Apr-14		B			213		Apr-22		4.75%		213		213		—
Aug-13		A			720		Aug-25		4.30%		720		567		—
Aug-13		B			209		Aug-21		5.38%		209		165		—

				$	2,939					$	2,022	$	1,825	$	917


United unsecured debt

6% Senior Notes due 2020. In November 2013, UAL issued $300 million aggregate principal amount of 6% Senior Notes due December 1, 2020 (the “6% Senior Notes”). The notes are fully and unconditionally guaranteed and recorded by United on its balance sheet as debt. The indenture for the 6% Senior Notes requires UAL to offer to repurchase the notes for cash if certain changes of control of UAL occur at a purchase price equal to 101% of the aggregate principal amount of notes repurchased plus accrued and unpaid interest.

6.375% Senior Notes due 2018. In May 2013, UAL issued $300 million aggregate principal amount of 6.375% Senior Notes due June 1, 2018 (the “6.375% Senior Notes”). The notes are fully and unconditionally guaranteed and recorded by United on its balance sheet as debt. The indenture for the 6.375% Senior Notes includes the same change of control covenant as the indenture for the 6% Senior Notes.

4.5% Convertible Notes due 2015. The 4.5% Convertible Notes were convertible by holders into shares of UAL common stock at a conversion price of approximately $18.93 per share. During 2014, United used $62 million of cash to purchase and retire $28 million aggregate principal amount of its 4.5% Convertible Notes in market transactions. UAL recorded $34 million of the repurchase cost as a reduction of additional paid-in capital. At December 31, 2014, the remaining balance of these notes was $202 million. In January 2015, the holders of substantially all of the remaining $202 million principal amount of the 4.5% Convertible Notes exercised their conversion option resulting in the issuance of 11 million shares of UAL common stock.

8% Notes due 2024. UAL redeemed in cash at par value all $400 million aggregate principal amount of the 8% Notes due 2024 (the “8% Notes”) on January 17, 2014. The 8% Notes were recorded in current liabilities as of December 31, 2013.

6% Convertible Junior Subordinated Debentures due 2030. In October 2014, United used cash to retire, at par, the entire $248 million principal balance of the 6% Convertible Debentures and the 6% Convertible Preferred Securities, Term Income Deferrable Equity Securities (TIDES). UAL accounted for this debt extinguishment in Nonoperating income (expense): Miscellaneous, net for approximately $64 million in the fourth quarter of 2014.



4.5% Senior Limited-Subordination Convertible Notes due 2021. On January 10, 2014, UAL called all of the 4.5% Notes that remained outstanding for redemption on February 10, 2014. As a result, holders of substantially all of the remaining $156 million outstanding principal amount of the 4.5% Notes exercised their right to convert such notes into approximately five million shares of UAL common stock at a conversion rate of 30.6419 shares of UAL common stock per $1,000 principal amount of 4.5% Notes.

Convertible Debt Securities and Derivatives. UAL, United and the trustee for the 6% Convertible Debentures and the 4.5% Convertible Notes were parties to supplemental indentures that made United’s convertible debt convertible into shares of UAL common stock. For purposes of United separate-entity reporting, as a result of the remaining outstanding debt having been convertible into the stock of a non-consolidated entity, the embedded conversion options in United’s convertible debt are required to be separated and accounted for as though they are free-standing derivatives. As a result, the carrying value of United’s debt, net of current maturities, on a separate-entity reporting basis as of December 31, 2014 and December 31, 2013 was $1 million and $47 million, respectively, lower than the consolidated UAL carrying value on those dates.

In addition, UAL’s contractual commitment to provide common stock to satisfy United’s obligation upon conversion of the debt is an embedded call option on UAL common stock that was also required to be separated and accounted for as though it were a free-standing derivative. The fair value of the indenture derivatives on a separate-entity reporting basis as of December 31, 2014 and December 31, 2013 was an asset of $712 million and $480 million, respectively. The fair value of the embedded conversion options as of December 31, 2014 and December 31, 2013, was a liability of $511 million and $270 million, respectively. The 2013 balances of the indenture derivatives and conversion options included amounts related to the 6% Convertible Debentures and the 4.5% Convertible Notes. The 6% Convertible Debentures and their related indenture derivative and conversion options were retired in 2014. The initial contribution of the indenture derivatives to United by UAL is accounted for as additional paid-in capital in United’s separate-entity financial statements. Changes in fair value of both the indenture derivatives and the embedded conversion options subsequent to October 1, 2010 are recognized in Nonoperating income (expense).

UAL

6% Convertible Senior Notes due 2029. During 2013, UAL issued approximately 28 million shares of UAL common stock pursuant to agreements that UAL entered into with certain holders of its 6% Convertible Senior Notes in exchange for approximately $240 million in aggregate principal amount of these notes held by such securityholders. The Company retired the 6% Convertible Senior Notes acquired in the exchange. In 2014, UAL issued approximately 12 million shares of UAL common stock in exchange for, or upon conversion of, $104 million in aggregate principal amount of UAL’s outstanding 6% Convertible Senior Notes held by the holders of these notes. The Company retired the 6% Convertible Senior Notes acquired in the exchange.



The collateral, covenants and cross default provisions of the Company’s principal debt instruments that contain such provisions are summarized in the table below:



Debt Instrument		Collateral, Covenants and Cross Default Provisions
Credit Agreement		Secured by certain of United’s international route authorities, specified take-off and landing slots at certain airports and certain other assets.

		The Credit Agreement requires the Company to maintain at least $3.0 billion of unrestricted liquidity at all times, which includes unrestricted cash, short-term investments and any undrawn amounts under any revolving credit facility, and to maintain a minimum ratio of appraised value of collateral to the outstanding obligations under the Credit Agreement of 1.67 to 1.0 at all times. The Credit Agreement contains covenants that, among other things, restrict the ability of UAL and its restricted subsidiaries (as defined in the Credit Agreement) to incur additional indebtedness and to pay dividends on or repurchase stock.

		The Credit Agreement contains events of default customary for this type of financing, including a cross default and cross acceleration provision to certain other material indebtedness of the Company.
6% Notes due 2026		The amended and restated indenture for these notes, which are unsecured, contains covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock.

6% Notes due 2028		These covenants cease to be in effect when the indenture covering the 6.375% Senior Notes due 2018 is discharged.

		The indenture contains events of default that are customary for similar financings.
6.375% Senior Notes due 2018		The indentures for these notes, which are unsecured, contain covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock.

6% Senior Notes due 2020		The indentures contain events of default that are customary for similar financings.

Advanced_Purchase_of_Miles

Advanced Purchase of Miles	12 Months Ended
Advanced Purchase of Miles	Dec. 31, 2014
Advanced Purchase of Miles	NOTE 12 - ADVANCED PURCHASE OF MILES
	United previously sold MileagePlus miles to Chase which United recorded as Advanced Purchase of Miles. United has the right, but is not required, to repurchase the pre-purchased miles from Chase during the term of the agreement. The balance of pre-purchased miles is eligible to be allocated by Chase to MileagePlus members’ accounts by a maximum of $224 million in 2015, $249 million in 2016 and the remainder in 2017. The Co-Brand Agreement contains termination penalties that may require United to make certain payments and repurchase outstanding pre-purchased miles in cases such as United’s insolvency, bankruptcy or other material breaches. The Company has recorded these amounts as advanced purchase of miles in the liabilities section of the Company’s consolidated balance sheets.
	The obligations of UAL, United and Mileage Plus Holdings, LLC to Chase under the Co-Brand Agreement are joint and several. Certain of United’s obligations under the Co-Brand Agreement are secured by a junior lien in all collateral pledged by United under the Credit Agreement. United also provides a first priority lien to Chase on its MileagePlus assets to secure certain of its obligations under the Co-Brand Agreement and its obligations under the new combined credit card processing agreement among United, Paymentech, LLC and JPMorgan Chase.

Leases_and_Capacity_Purchase_A

Leases and Capacity Purchase Agreements	12 Months Ended
Leases and Capacity Purchase Agreements	Dec. 31, 2014
Leases and Capacity Purchase Agreements	NOTE 13 - LEASES AND CAPACITY PURCHASE AGREEMENTS
	United leases aircraft, airport passenger terminal space, aircraft hangars and related maintenance facilities, cargo terminals, other airport facilities, other commercial real estate, office and computer equipment and vehicles.
	At December 31, 2014, United’s scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year, aircraft leases, including aircraft rent under CPAs and capital leases (substantially all of which are for aircraft) were as follows (in millions):


		Capital Leases (a)		Facility and Other		Aircraft Operating
		Capital Leases (a)		Operating Leases (b)		Leases (c)
	2015	$	168	$	1,283	$	1,446
	2016		154		1,123		1,247
	2017		115		1,089		1,147
	2018		104		842		908
	2019		38		766		682
	After 2019		495		7,919		1,910

	Minimum lease payments	$	1,074	$	13,022	$	7,340

	Imputed interest		-393

	Present value of minimum lease payments		681
	Current portion		-110

	Long-term obligations under capital leases	$	571

	(a) As of December 31, 2014, United’s aircraft capital lease minimum payments relate to leases of 37 mainline and 38 regional aircraft as well as to leases of nonaircraft assets. Imputed interest rate ranges are 3.5% to 18.3%.
	(b) See Note 17 of this report for additional information related to facility and other operating leases at Hopkins International Airport (“Cleveland”).
	(c) The operating lease payments presented above include future payments of $72 million related to 21 nonoperating aircraft as of December 31, 2014.
	Aircraft operating leases have initial terms of six to twenty-eight years, with expiration dates ranging from 2015 through 2024. Under the terms of most leases, United has the right to purchase the aircraft at the end of the lease term, in some cases at fair market value, and in others, at fair market value or a percentage of cost. United has facility operating leases that extend to 2041.
	United is the lessee of real property under long-term operating leases at a number of airports where we are also the guarantor of approximately $1.5 billion of underlying debt and interest thereon as of December 31, 2014. These leases are typically with municipalities or other governmental entities, which are excluded from the consolidation requirements concerning a variable interest entity (“VIE”). To the extent United’s leases and related guarantees are with a separate legal entity other than a governmental entity, United is not the primary beneficiary because the lease terms are consistent with market terms at the inception of the lease and the lease does not include a residual value guarantee, fixed-price purchase option, or similar feature.

	In September 2014, United entered into a 10-year lease extension through 2035 with the City and County of Denver to continue its use of the airport terminal space at Denver International Airport. This extension is expected to result in annual cost savings through 2025 for the Company.
	In November 2013, United signed a lease amendment with the City of Los Angeles and Los Angeles World Airports (“LAWA”) to its terminal facilities lease at Los Angeles International Airport (“LAX”). The amendment allows United to make approximately $450 million in renovations at LAX that we expect to complete in late 2017. United will fund the cost of these renovations and LAWA will acquire the improvements at the end of each designated construction phase through a cash payment at the construction cost. United expects to be considered the owner of the property during and after the construction period for accounting purposes. As a result, the construction project will be included on the Company’s balance sheet as operating property and equipment and with the construction obligation under other liabilities.
	United’s nonaircraft rent expense was approximately $1.4 billion, $1.3 billion and $1.3 billion for the years ended December 31, 2014, 2013 and 2012, respectively.
	In addition to nonaircraft rent and aircraft rent, which is separately presented in the consolidated statements of operations, United had aircraft rent related to regional aircraft operating leases, which is included as part of regional capacity purchase expense in United’s consolidated statement of operations, of $442 million, $428 million and $463 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	In connection with UAL Corporation’s and United Air Lines, Inc.’s fresh-start reporting requirements upon their exit from Chapter 11 bankruptcy protection in 2006 and the Company’s acquisition accounting adjustments related to the Company’s merger transaction in 2010, lease valuation adjustments for operating leases were initially recorded in the consolidated balance sheet, representing the net present value of the differences between contractual lease rates and the fair market lease rates for similar leased assets at the time. An asset (liability) results when the contractual lease rates are more (less) favorable than market lease terms at the valuation date. The lease valuation adjustment is amortized on a straight-line basis as an increase (decrease) to rent expense over the individual applicable remaining lease terms, resulting in recognition of rent expense as if United had entered into the leases at market rates. The related remaining lease terms are one to ten years for United. The lease valuation adjustments are classified within other noncurrent liabilities and the net accretion amounts are $160 million, $173 million and $240 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Regional CPAs
	United has CPAs with certain regional carriers. We purchase all of the capacity from the flights covered by the CPA at a negotiated price. We pay the regional carrier a pre-determined rate, subject to annual inflation adjustments, primarily for block hours flown (the hours from gate departure to gate arrival) and other operating factors and reimburse the regional carrier for various pass-through expenses related to the flights. Under the CPAs, we are responsible for the cost of providing fuel for all flights and for paying aircraft rent for all of the aircraft covered by the CPAs. Generally, the CPAs contain incentive bonus and rebate provisions based upon each regional carrier’s operational performance. United’s CPAs are for 566 regional aircraft, and the CPAs have terms expiring through 2029. Aircraft operated under CPAs include aircraft leased directly from the regional carriers and those owned by United or leased from third-party lessors and operated by the regional carriers.
	In September 2014, United entered into an amendment to a contract with Shuttle America Corporation (“Shuttle America”), a wholly-owned subsidiary of Republic Airways Holdings, for Shuttle America to operate 50 new Embraer S.A. (“Embraer”) 175 aircraft under the United Express brand and extend the term of 38 existing Embraer 170 aircraft operating under the United Express brand. Shuttle America will acquire fifty 76-seat Embraer E175 aircraft with deliveries from 2015 through 2017, although United has the right to acquire the aircraft under certain circumstances and lease the aircraft to Shuttle America. These 50 aircraft are in addition to United’s other 70 Embraer E175 aircraft that are currently being operated or will in the future be operated by different United Express carriers under CPAs. In a separate but related amendment with Republic Airways Holdings Inc. and its subsidiary, Republic Airline Inc. (“Republic”), United and Republic agreed to remove 31 Q400 aircraft from United Express service in 2015 and 2016.

	In May 2013, United entered into a CPA with SkyWest Airlines, Inc. (“SkyWest”), a wholly-owned subsidiary of SkyWest, Inc. to operate 40 Embraer E175 aircraft under the United Express brand. As of December 31, 2014, SkyWest is operating 19 of these aircraft and expects to bring into service the remaining 21 aircraft in 2015.
	In April 2013, United agreed to purchase 30 Embraer E175 aircraft. In August 2013, United entered into a CPA with Mesa Air Group, Inc. and Mesa Airlines, Inc. (“Mesa”), a wholly-owned subsidiary of Mesa Air Group, Inc., for Mesa to operate these 30 Embraer E175 aircraft under the United Express brand. As of December 31, 2014, Mesa is operating 14 of these aircraft with the remaining aircraft to be brought into service in 2015.
	Our future commitments under our CPAs are dependent on numerous variables, and are therefore difficult to predict. The most important of these variables is the number of scheduled block hours. Although we are not required to purchase a minimum number of block hours under certain of our CPAs, we have set forth below estimates of our future payments under the CPAs based on our assumptions. United’s estimates of its future payments under all of the CPAs do not include the portion of the underlying obligation for any aircraft leased to ExpressJet or deemed to be leased from other regional carriers and facility rent that are disclosed as part of aircraft and nonaircraft operating leases. For purposes of calculating these estimates, we have assumed (1) the number of block hours flown is based on our anticipated level of flight activity or at any contractual minimum utilization levels if applicable, whichever is higher, (2) that we will reduce the fleet as rapidly as contractually allowed under each CPA, (3) that aircraft utilization, stage length and load factors will remain constant, (4) that each carrier’s operational performance will remain at historic levels and (5) an annual projected inflation rate. These amounts exclude variable pass-through costs such as fuel and landing fees, among others. Based on these assumptions as of December 31, 2014, our future payments through the end of the terms of our CPAs are presented in the table below (in millions):


	2015	$	1,893
	2016		1,760
	2017		1,653
	2018		1,301
	2019		973
	After 2019		3,497

		$	11,077

	It is important to note that the actual amounts we pay to our regional operators under CPAs could differ materially from these estimates. For example, a 10% increase or decrease in scheduled block hours for all of United’s regional operators (whether as a result of changes in average daily utilization or otherwise) in 2015 would result in a corresponding change in annual cash obligations under the CPAs of approximately $152 million (8.0%).

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
Variable Interest Entities	Dec. 31, 2014
Variable Interest Entities	NOTE 14 - VARIABLE INTEREST ENTITIES
	Variable interests are contractual, ownership or other monetary interests in an entity that change with fluctuations in the fair value of the entity’s net assets exclusive of variable interests. A VIE can arise from items such as lease agreements, loan arrangements, guarantees or service contracts. An entity is a VIE if (a) the entity lacks sufficient equity or (b) the entity’s equity holders lack power or the obligation and right as equity holders to absorb the entity’s expected losses or to receive its expected residual returns. Therefore, if the equity owners as a group do not have the power to direct the entity’s activities that most significantly impact its economic performance, the entity is a VIE.
	If an entity is determined to be a VIE, the entity must be consolidated by the primary beneficiary. The primary beneficiary is the holder of the variable interests that has the power to direct the activities of a VIE that (i) most significantly impact the VIE’s economic performance and (ii) has the obligation to absorb losses of or the right to receive benefits from the VIE that could potentially be significant to the VIE. Therefore, the Company must identify which activities most significantly impact the VIE’s economic performance and determine whether it, or another party, has the power to direct those activities.
	The Company’s evaluation of its association with VIEs is described below:
	Aircraft Leases. We are the lessee in a number of operating leases covering the majority of our leased aircraft. The lessors are trusts established specifically to purchase, finance and lease aircraft to us. These leasing entities meet the criteria for VIEs. We are generally not the primary beneficiary of the leasing entities if the lease terms are consistent with market terms at the inception of the lease and do not include a residual value guarantee, fixed-price purchase option or similar feature that obligates us to absorb decreases in value or entitles us to participate in increases in the value of the aircraft. This is the case for many of our operating leases; however, leases of approximately 60 mainline jet aircraft contain a fixed-price purchase option that allow United to purchase the aircraft at predetermined prices on specified dates during the lease term. Additionally, leases covering approximately 239 leased regional jet aircraft contain an option to purchase the aircraft at the end of the lease term at prices that, depending on market conditions, could be below fair value. United has not consolidated the related trusts because, even taking into consideration these purchase options, United is still not the primary beneficiary. United’s maximum exposure under these leases is the remaining lease payments, which are reflected in future lease commitments in Note 13 of this report.
	EETCs. United evaluated whether the pass-through trusts formed for its EETC financings, treated as either debt or aircraft operating leases, are VIEs required to be consolidated by United under applicable accounting guidance, and determined that the pass-through trusts are VIEs. Based on United’s analysis as described below, United determined that it does not have a variable interest in the pass-through trusts.
	The primary risk of the pass-through trusts is credit risk (i.e. the risk that United, the issuer of the equipment notes, may be unable to make its principal and interest payments). The primary purpose of the pass-through trust structure is to enhance the credit worthiness of United’s debt obligation through certain bankruptcy protection provisions, a liquidity facility (in certain of the EETC structures) and improved loan-to-value ratios for more senior debt classes. These credit enhancements lower United’s total borrowing cost. Pass-through trusts are established to receive principal and interest payments on the equipment notes purchased by the pass-through trusts from United and remit these proceeds to the pass-through trusts’ certificate holders.
	United does not invest in or obtain a financial interest in the pass-through trusts. Rather, United has an obligation to make interest and principal payments on its equipment notes held by the pass-through trusts. United did not intend to have any voting or non-voting equity interest in the pass-through trusts or to absorb variability from the pass-through trusts. Based on this analysis, the Company determined that it is not required to consolidate the pass-through trusts.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2014
Commitments and Contingencies	NOTE 15 - COMMITMENTS AND CONTINGENCIES
	Commitments. As of December 31, 2014, United had firm commitments to purchase aircraft from The Boeing Company (“Boeing”), Embraer and Airbus S.A.S. (“Airbus”) presented in the table below:


	Aircraft Type	Number of Firm
	Aircraft Type	Commitments (a) (b)
	Airbus A350-1000		35
	Boeing 737-900ER		34
	Boeing 737 MAX 9		100
	Boeing 787-9/-10		51
	Embraer E175		11
	(a) United also has options and purchase rights for additional aircraft.
	(b) United also has committed to purchase two used 737-700 aircraft in 2015.

	The aircraft listed in the table above are scheduled for delivery from 2015 through 2025.
	The table below summarizes United’s commitments as of December 31, 2014 (including those assigned from UAL), which primarily relate to the acquisition of aircraft and related spare engines, aircraft improvements and include other commitments primarily to acquire information technology services and assets for the years ended December 31 (in billions):


	2015	$	3.2
	2016		2.3
	2017		1.3
	2018		2.2
	2019		3.3
	After 2019		10.7

		$	23.0

	Any incremental firm aircraft orders, including through the exercise of purchase options and purchase rights, will increase the total future capital commitments of the Company.
	As of December 31, 2014, United has arranged for EETC financing for 20 of our 2015 aircraft deliveries, including 11 Boeing 737-900ER aircraft, four Boeing 787-9 aircraft and five Embraer E175 aircraft. In addition, United has secured backstop financing commitments from certain of its aircraft manufacturers for a limited number of its future aircraft deliveries, subject to certain customary conditions. Financing will be necessary to satisfy the Company’s capital commitments for its firm order aircraft and other related capital expenditures.
	Legal and Environmental. The Company has certain contingencies resulting from litigation and claims incident to the ordinary course of business. Management believes, after considering a number of factors, including (but not limited to) the information currently available, the views of legal counsel, the nature of contingencies to which the Company is subject and prior experience, that the ultimate disposition of the litigation and claims will not materially affect the Company’s consolidated financial position or results of operations. The Company records liabilities for legal and environmental claims when a loss is probable and reasonably estimable. These amounts are recorded based on the Company’s assessments of the likelihood of their eventual disposition.
	Guarantees and Indemnifications. In the normal course of business, the Company enters into numerous real estate leasing and aircraft financing arrangements that have various guarantees included in the contracts. These guarantees are primarily in the form of indemnities under which the Company typically indemnifies the lessors and any tax/financing parties against tort liabilities that arise out of the use, occupancy, operation or maintenance of the leased premises or financed aircraft. Currently, the Company believes that any future payments required under these guarantees or indemnities would be immaterial, as most tort liabilities and related indemnities are covered by insurance (subject to deductibles). Additionally, certain leased premises such as fueling stations or storage facilities include indemnities of such parties for any environmental liability that may arise out of or relate to the use of the leased premises.
	As of December 31, 2014, United is the guarantor of approximately $1.8 billion in aggregate principal amount of tax-exempt special facilities revenue bonds and interest thereon. These bonds, issued by various airport municipalities, are payable solely from rentals paid under long-term agreements with the respective governing bodies. The leasing arrangements associated with $1.5 billion of these obligations are accounted for as operating leases with the associated expense recorded on a straight-line basis resulting in ratable accrual of the lease obligation over the expected lease term. These tax-exempt special facilities revenue bonds are included in our lease commitments disclosed in Note 13 of this report. The leasing arrangements associated with $290 million of these obligations are accounted for as capital leases. All of these bonds are due between 2015 and 2038.
	In United’s financing transactions that include loans, United typically agrees to reimburse lenders for any reduced returns with respect to the loans due to any change in capital requirements and, in the case of loans in which the interest rate is based on LIBOR, for certain other increased costs that the lenders incur in carrying these loans as a result of any change in law, subject in most cases to obligations of the lenders to take certain limited steps to mitigate the requirement for, or the amount of, such increased costs. At December 31, 2014, the Company had $2.5 billion of floating rate debt and $159 million of fixed rate debt, with remaining terms of up to twelve years, that are subject to these increased cost provisions. In several financing transactions involving loans or leases from non-U.S. entities, with remaining terms of up to twelve years and an aggregate balance of $2.7 billion, the Company bears the risk of any change in tax laws that would subject loan or lease payments thereunder to non-U.S. entities to withholding taxes, subject to customary exclusions.
	Fuel Consortia. United participates in numerous fuel consortia with other air carriers at major airports to reduce the costs of fuel distribution and storage. Interline agreements govern the rights and responsibilities of the consortia members and provide for the allocation of the overall costs to operate the consortia based on usage. The consortia (and in limited cases, the participating carriers) have entered into long-term agreements to lease certain airport fuel storage and distribution facilities that are typically financed through tax-exempt bonds (either special facilities lease revenue bonds or general airport revenue bonds), issued by various local municipalities. In general, each consortium lease agreement requires the consortium to make lease payments in amounts sufficient to pay the maturing principal and interest payments on the bonds. As of December 31, 2014, approximately $1.4 billion principal amount of such bonds were secured by significant fuel facility leases in which United participates, as to which United and each of the signatory airlines has provided indirect guarantees of the debt. As of December 31, 2014, the Company’s contingent exposure was approximately $239 million principal amount of such bonds based on its recent consortia participation. The Company’s contingent exposure could increase if the participation of other air carriers decreases. The guarantees will expire when the tax-exempt bonds are paid in full, which ranges from 2015 to 2041. The Company did not record a liability at the time these indirect guarantees were made.
	Credit Card Processing Agreements. United has agreements with financial institutions that process customer credit card transactions for the sale of air travel and other services. Under certain of United’s credit card processing agreements, the financial institutions either require, or under certain circumstances have the right to require, that United maintains a reserve equal to a portion of advance ticket sales that has been processed by that financial institution, but for which United has not yet provided the air transportation. Such financial institutions may require additional cash or other collateral reserves to be established or additional withholding of payments related to receivables collected if United does not maintain certain minimum levels of unrestricted cash, cash equivalents and short term investments. United’s current level of unrestricted cash, cash equivalents and short term investments is substantially in excess of these minimum levels.
	Labor Negotiations. As of December 31, 2014, United, including its subsidiaries, had approximately 84,000 employees. Approximately 80% of United’s employees were represented by various U.S. labor organizations as of December 31, 2014. During 2014, United’s maintenance instructor, load planner, fleet technical instructor, security officer and dispatcher work groups ratified new joint labor agreements. We are in the process of negotiating joint collective bargaining agreements with our technicians and flight attendants.

Statement_of_Consolidated_Cash

Statement of Consolidated Cash Flows - Supplemental Disclosures	12 Months Ended
	Dec. 31, 2014
Statement of Consolidated Cash Flows - Supplemental Disclosures	NOTE 16 - STATEMENT OF CONSOLIDATED CASH FLOWS - SUPPLEMENTAL DISCLOSURES
	Supplemental disclosures of cash flow information and non-cash investing and financing activities for the years ended December 31 are as follows (in millions):


	2014	UAL		United
	Cash paid (refunded) during the period for:
	Interest (net of amounts capitalized)	$	748	$	748
	Income taxes		-16		-16
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	1,114	$	1,114
	Airport construction financing		14		14
	Exchanges of certain 4.5% Notes and 6% Convertible Senior Notes for common stock		260		156
	Transfer of UAL subsidiaries to United		—		186

	2013
	Cash paid (refunded) during the period for:
	Interest (net of amounts capitalized)	$	752	$	752
	Income taxes		-20		-15
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	229	$	229
	Airport construction financing		40		40
	Exchanges of certain 6% Convertible Senior Notes for common stock		240		—

	2012
	Cash paid during the period for:
	Interest (net of amounts capitalized)	$	766	$	766
	Income taxes		2		4
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	544	$	544
	8% Contingent Senior Notes and 6% Senior Notes due 2031, net of discount		357		357
	Special facility payment financing		101		101
	Airport construction financing		50		50

IntegrationRelated_Costs_and_S

Integration-Related Costs and Special Items	12 Months Ended
Integration-Related Costs and Special Items	Dec. 31, 2014
Integration-Related Costs and Special Items	NOTE 17 - INTEGRATION-RELATED COSTS AND SPECIAL ITEMS
	Integration-related costs and special items classified as special charges in the statements of consolidated operations consisted of the following for the years ended December 31 (in millions):


	Operating:	2014		2013		2012
	Severance and benefit costs	$	199	$	105	$	125
	Integration-related costs		96		205		739
	Costs associated with permanently grounding Embraer ERJ 135 aircraft		66		—		—
	Impairment of assets		49		33		30
	Labor agreement costs		—		127		475
	(Gains) losses on sale of assets and other special (gains) losses, net		33		50		-46

	Special charges	$	443	$	520	$	1,323
	Nonoperating:
	Loss on extinguishment of debt and other, net	$	74	$	—	$	—
	Income tax benefit		-10		-7		-11

	Total operating and nonoperating special charges, net of income taxes	$	507	$	513	$	1,312

	2014
	The Company recorded $141 million of severance and benefit costs related primarily to a voluntary early-out program for its flight attendants. More than 2,500 participants elected a one-time opportunity to voluntarily separate from the Company and will receive a severance payment, with a maximum value of $100,000 per participant, based on years of service, with retirement dates from November 30, 2014 through the end of 2015. The Company will record approximately $100 million of additional expense associated with this program through 2015 over the remaining required service periods. In addition, the Company recorded $58 million of severance and benefits primarily related to reductions of management and front-line employees, including from Cleveland, as part of its cost savings initiatives. The Company is currently evaluating its options regarding its long-term contractual lease commitments at Cleveland. The capacity reductions at Cleveland may result in further special charges, which could be significant, related to our contractual commitments.
	Integration-related costs include compensation costs related to systems integration, training, severance and relocation for employees.
	The Company recorded $66 million for the permanent grounding of 21 of the Company’s Embraer ERJ 135 regional aircraft under lease through 2018, which includes an accrual for remaining lease payments and an amount for maintenance return conditions. As a result of fuel prices, new Embraer E175 regional jet deliveries and impact of pilot shortages at regional carriers, the Company decided to permanently ground these 21 Embraer ERJ 135 aircraft. The Company continues to operate nine Embraer ERJ 135 aircraft and will assess the possibility of grounding those aircraft when the term of the current capacity purchase contract ends in 2015.
	The Company recorded a charge of $16 million ($10 million net of related income tax benefits) related to its annual assessment of impairment of its indefinite-lived intangible assets (certain international Pacific routes). In addition, the Company recorded $33 million for charges related primarily to impairment of its flight equipment held for disposal associated with its Boeing 737-300 and 737-500 fleets.

	United used cash to retire, at par, the entire $248 million principal balance of the 6% Convertible Debentures and the 6% Convertible Preferred Securities, Term Income Deferrable Equity Securities (TIDES) and incurred $74 million of expense primarily associated with the write-off of the related non-cash debt discounts recorded due to purchase accounting during the Company’s merger transaction in 2010.
	2013
	The Company offered a voluntary retirement program for its fleet service, passenger service, storekeeper and pilot work groups. Approximately 1,200 employees volunteered under the program during the fourth quarter of 2013 and United recorded approximately $64 million of severance and benefit costs for the programs. The Company also offered voluntary leave of absence programs which allowed for continued medical coverage for flight attendants who volunteered during the leave of absence period, resulting in a charge of approximately $26 million. The remaining $15 million of severance and benefit costs was related to involuntary severance programs associated with flight attendants and other work groups.
	Integration-related costs included compensation costs related to systems integration and training, branding activities, new uniforms, write-off or acceleration of depreciation on systems and facilities that were no longer used or planned to be used for significantly shorter periods, relocation for employees and severance primarily associated with administrative headcount reductions.
	The Company recorded $32 million of impairment charges of its flight equipment held for disposal associated with its Boeing 737-300 and 737-500 fleets and $1 million on an intangible asset for a route to Manila in order to reflect the estimated fair value of this asset as part of the Company’s annual impairment test of indefinite-lived intangible assets.
	The fleet service, passenger service and storekeeper employees represented by the International Association of Machinists ratified a joint collective bargaining agreement with the Company during 2013. The Company recorded a $127 million special charge for lump sum payments made in conjunction with the ratification. The lump sum payments were not in lieu of future pay increases. The Company completed substantially all cash payments in 2013.
	The Company recorded $18 million associated with the temporary grounding of its Boeing 787 aircraft. The charges were comprised of aircraft depreciation expense and dedicated personnel costs that the Company incurred while the aircraft were grounded. The aircraft returned to service in May 2013. In addition, the Company adjusted its reserves for certain legal matters by $29 million and recorded approximately $11 million in accruals for future rent associated with the early retirement of four leased Boeing 757-200 aircraft. Additionally, the Company recorded a $5 million gain related to a contract termination and $3 million in gains on the sale of assets.
	2012
	The Company recorded $125 million of severance and benefits associated with various voluntary retirement and leave of absence programs for its various employee groups. During the first quarter of 2012, approximately 400 mechanics offered to retire early in exchange for a cash severance payment that was based on the number of years of service each employee had accumulated. The expense for this voluntary program was approximately $32 million. The Company also offered a voluntary leave of absence program that approximately 1,800 flight attendants accepted, which allowed for continued medical coverage during the leave of absence period. The expense for this voluntary program was approximately $17 million. During the second quarter of 2012, as part of the recently amended collective bargaining agreement with the Association of Flight Attendants, the Company offered a voluntary program for flight attendants to retire early in exchange for a cash severance payment. The payments are dependent on the number of years of service each employee has accumulated. Approximately 1,300 flight attendants accepted this program and the expense for this voluntary program was approximately $76 million.
	Integration-related costs included compensation costs related to systems integration and training, branding activities, write-off or acceleration of depreciation on systems and facilities that are either no longer used or planned to be used for significantly shorter periods, as well as relocation for employees and severance primarily associated with administrative headcount reductions.
	On December 31, 2012, UAL and United Air Lines, Inc. entered into an agreement with the Pension Benefit Guaranty Corporation (“PBGC”) that reduced the aggregate amount of 8% Contingent Senior Notes to be issued by UAL, and eliminated the contingent nature of such obligation by replacing the $188 million principal amount of 8% Contingent Senior Notes incurred as of December 31, 2012 and the obligation to issue any additional 8% Contingent Senior Notes with $400 million principal amount of new 8% Notes. In addition, UAL agreed to replace the $652 million principal amount outstanding of 6% Senior Notes due 2031 with $326 million principal amount of new 6% Notes due 2026 and $326 million principal amount of 6% Notes due 2028 (collectively, the “New 6% Notes” and together with the 8% Notes, the “New PBGC Notes”). The Company did not receive any cash proceeds in connection with the issuance of the New PBGC Notes. The Company accounted for this agreement as a debt extinguishment, resulting in a charge of $309 million in 2012 that represented the fair value of $212 million of 8% Notes that it agreed to issue and the change in the fair value of the New 6% Notes and the $188 million of 8% Notes versus their previous carrying values. The Company classified the expense as a component of special charges within integration-related costs because the note restructuring would not have occurred if it were not for the Company’s merger transaction in 2010.
	The Company recorded impairment charges of $30 million on an intangible asset for European take-off and landing slots in order to reflect the estimated fair value of these assets as part of its annual impairment test of indefinite-lived intangible assets.
	In December 2012, the pilots represented by the Air Line Pilots Association, International ratified a new joint collective bargaining agreement with the Company. The Company recorded $475 million of expense associated with lump sum cash payments that would be made in conjunction with the ratification of the contract and the completion of the integrated pilot seniority list. This charge also includes $80 million associated with changes to existing pilot disability plans negotiated in connection with the agreement. The lump sum payments are not in lieu of future pay increases. The Company completed substantially all cash payments in 2013.
	The Company recorded net gains of $46 million related to gains and losses on the disposal of aircraft and related parts and other assets.
	Accrual Activity
	Activity related to the accruals for severance and medical costs and future lease payments on permanently grounded aircraft is as follows (in millions):


		Severance/		Permanently
		Medical Costs		Grounded Aircraft
	Balance at December 31, 2011	$	55	$	31
	Accrual		170		-1
	Payments		-160		-25

	Balance at December 31, 2012		65		5
	Accrual		120		10
	Payments		-94		-4

	Balance at December 31, 2013		91		11
	Accrual		199		102
	Payments		-181		-11

	Balance at December 31, 2014	$	109	$	102

	The Company’s accrual and payment activity is primarily related to severance and other compensation expense associated with voluntary employee programs and the Company’s merger transaction in 2010, respectively.

Segment_Information

Segment Information	12 Months Ended
Segment Information	Dec. 31, 2014
Segment Information	NOTE 18 - SEGMENT INFORMATION
	Operating segments are defined as components of an enterprise with separate financial information, which are evaluated regularly by the chief operating decision maker and are used in resource allocation and performance assessments.
	The Company deploys its aircraft across its route network through a single route scheduling system to maximize its value. When making resource allocation decisions, the Company’s chief operating decision maker evaluates flight profitability data, which considers aircraft type and route economics. The Company’s chief operating decision maker makes resource allocation decisions to maximize the Company’s consolidated financial results. Managing the Company as one segment allows management the opportunity to maximize the value of its route network.
	The Company’s operating revenue by principal geographic region (as defined by the U.S. Department of Transportation) for the years ended December 31 is presented in the table below (in millions):


	2014	UAL		United
	Domestic (U.S. and Canada)	$	22,320	$	22,320
	Pacific		5,767		5,767
	Atlantic		7,321		7,321
	Latin America		3,493		3,493

	Total	$	38,901	$	38,901

	2013
	Domestic (U.S. and Canada)	$	22,092	$	22,100
	Pacific		5,794		5,794
	Atlantic		7,132		7,132
	Latin America		3,261		3,261

	Total	$	38,279	$	38,287

	2012
	Domestic (U.S. and Canada)	$	21,276	$	21,284
	Pacific		6,040		6,040
	Atlantic		6,582		6,582
	Latin America		3,254		3,254

	Total	$	37,152	$	37,160

	The Company attributes revenue among the geographic areas based upon the origin and destination of each flight segment. The Company’s operations involve an insignificant level of dedicated revenue-producing assets in geographic regions as the overwhelming majority of the Company’s revenue producing assets (primarily U.S. registered aircraft) can be deployed in any of its geographic regions.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
Selected Quarterly Financial Data	Dec. 31, 2014
Selected Quarterly Financial Data	NOTE 19 - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)


	UAL	Quarter Ended
	(In millions, except per share amounts)	March 31		June 30		September 30		December 31
	2014
	Operating revenue	$	8,696	$	10,329	$	10,563	$	9,313
	Income (loss) from operations		-349		906		1,191		625
	Net income (loss)		-609		789		924		28
	Basic earnings (loss) per share		-1.66		2.11		2.49		0.08
	Diluted earnings (loss) per share		-1.66		2.01		2.37		0.07
	2013
	Operating revenue	$	8,721	$	10,001	$	10,228	$	9,329
	Income (loss) from operations		-264		770		508		235
	Net income (loss)		-417		469		379		140
	Basic earnings (loss) per share		-1.26		1.37		1.06		0.39
	Diluted earnings (loss) per share		-1.26		1.21		0.98		0.37

	UAL’s quarterly financial data is subject to seasonal fluctuations and historically its second and third quarter financial results, which reflect higher travel demand, are better than its first and fourth quarter financial results. UAL’s quarterly results were impacted by the following significant items (in millions):


		Quarter Ended
		March 31		June 30		September 30		December 31
	2014
	Operating:
	Severance and benefit costs	$	14	$	38	$	6	$	141
	Integration-related costs		34		17		28		17
	Costs associated with permanently grounding Embraer ERJ 135 aircraft		—		66		—		—
	Impairment of assets		1		32		—		16
	Losses on sale of assets and other special (gains) losses, net		3		16		9		5

	Special charges		52		169		43		179
	Nonoperating:
	Loss on extinguishment of debt and other, net		21		—		—		53
	Income tax benefit		-1		—		-3		-6

	Total operating and nonoperating special charges, net of income taxes	$	72	$	169	$	40	$	226

	2013
	Special charges (income):
	Severance and benefit costs	$	14	$	—	$	—	$	91
	Integration-related costs		70		45		50		40
	Labor agreement costs		—		—		127		—
	Impairment of assets		—		—		—		33
	(Gains) losses on sale of assets and other special (gains) losses, net		8		7		34		1

	Total special items		92		52		211		165

	Income tax benefit		—		—		—		-7

	Total special items, net of tax	$	92	$	52	$	211	$	158

	See Note 17 of this report for additional information of these items.

Schedule_II_Valuation_and_Qual

Schedule II Valuation and Qualifying Accounts	12 Months Ended
Schedule II Valuation and Qualifying Accounts	Dec. 31, 2014
Schedule II Valuation and Qualifying Accounts	Schedule II
	Valuation and Qualifying Accounts
	For the Years Ended December 31, 2014, 2013 and 2012


	(In millions)	Balance at		Additions		Deductions		Other		Balance at
		Beginning of		Charged to		(a)		(b)		End of
	Description	Period		Costs and						Period
				Expenses
	Allowance for doubtful accounts - UAL and United:
	2014	$	13	$	45	$	36	$	—	$	22
	2013		13		35		35		—		13
	2012		7		12		6		—		13
	Obsolescence allowance—spare parts - UAL and United:
	2014	$	162	$	35	$	28	$	—	$	169
	2013		125		38		1		—		162
	2012		89		40		4		—		125
	Valuation allowance for deferred tax assets - UAL:
	2014	$	4,591	$	156	$	—	$	4	$	4,751
	2013		5,388		7		888		84		4,591
	2012		4,922		487		21		—		5,388
	Valuation allowance for deferred tax assets - United:
	2014	$	4,561	$	167	$	—	$	-7	$	4,721
	2013		5,288		8		898		163		4,561
	2012		4,833		661		206		—		5,288

	(a) Deduction from reserve for purpose for which reserve was created.
	(b) See Note 7 to the financial statements included in Part II, Item 8 of this report for additional information related to other valuation allowance adjustments.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2014

Use of Estimates and Reclassifications

(a)

Revenue Recognition

(b)

The Company recognizes cargo and other revenue as service is provided.

Frequent Flyer Accounting

(c)

Miles Earned in Conjunction with Flights

Co-branded Credit Card Partner Mileage Sales

Expiration of Miles

Other Information

The following table provides additional information related to the frequent flyer program (in millions):

Year Ended

Cash Proceeds

Other Revenue

Increase in Frequent

Increase

December 31,

from Miles Sold

Recognized Upon

Flyer Deferred

(Decrease) in

Award of Miles

Revenue for Miles

Advanced

to Third-Party

Awarded (b)

Purchase of

Customers (a)

Miles (c)

2014

2,861

882

2,178

-199

2013

2,903

903

2,174

-174

2012

2,852

816

2,036

—

(a) This amount represents other revenue recognized during the period from the sale of miles to third parties, representing the marketing-related deliverable services component of the sale.

(b) This amount represents the increase to frequent flyer deferred revenue during the period.

(c) This amount represents the net increase (decrease) in the advance purchase of miles obligation due to cash payments for the sale of miles in excess of (less than) miles awarded to customers.

Cash and Cash Equivalents and Restricted Cash

(d)

Cash and Cash Equivalents and Restricted Cash—Highly liquid investments with a maturity of three months or less on their acquisition date are classified as cash and cash equivalents.

Short-term Investments

(e)

Aircraft Fuel, Spare Parts and Supplies

(f)

Property and Equipment

(g)

Estimated Useful Life (in years)

Aircraft and related rotable parts

25 to 30

Buildings

25 to 45

Other property and equipment

3 to 15

Computer software

Building improvements

1 to 40

Maintenance and Repairs

(h)

Lease Fair Value Adjustments

(i)

Regional Capacity Purchase

(j)

Advertising

(k)

Intangibles

(l)

Long-Lived Asset Impairments

(m)

Share-Based Compensation

(n)

Ticket Taxes

(o)

Retirement of Leased Aircraft

(p)

Uncertain Income Tax Positions

(q)

Labor Costs

(r)

Third-Party Business

(s)

Recently Issued Accounting Standards

(t)

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Schedule of Information Related to Amounts Recorded Related to Frequent Flyer Programs

The following table provides additional information related to the frequent flyer program (in millions):

Year Ended

Cash Proceeds

Other Revenue

Increase in Frequent

Increase

December 31,

from Miles Sold

Recognized Upon

Flyer Deferred

(Decrease) in

Award of Miles

Revenue for Miles

Advanced

to Third-Party

Awarded (b)

Purchase of

Customers (a)

Miles (c)

2014

2,861

882

2,178

-199

2013

2,903

903

2,174

-174

2012

2,852

816

2,036

—

(a) This amount represents other revenue recognized during the period from the sale of miles to third parties, representing the marketing-related deliverable services component of the sale.

(b) This amount represents the increase to frequent flyer deferred revenue during the period.

(c) This amount represents the net increase (decrease) in the advance purchase of miles obligation due to cash payments for the sale of miles in excess of (less than) miles awarded to customers.

Estimated Useful Lives of Property and Equipment

The estimated useful lives of property and equipment are as follows:

Estimated Useful Life (in years)

Aircraft and related rotable parts

25 to 30

Buildings

25 to 45

Other property and equipment

3 to 15

Computer software

Building improvements

1 to 40

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
Goodwill and Other Intangible Assets (Tables)	Dec. 31, 2014
Goodwill and Other Intangible Assets	The following table presents information about the Company’s goodwill and other intangible assets at December 31 (in millions):


			2014				2013
	Item	Asset life (a)	Gross Carrying		Accumulated		Gross Carrying		Accumulated
	Item	Asset life (a)	Amount		Amortization		Amount		Amortization
	Goodwill		$	4,523			$	4,523

	Finite-lived intangible assets
	Airport slots and gates	8	$	97	$	97	$	98	$	88
	Hubs	20		145		67		145		59
	Patents and tradenames	3		108		108		108		108
	Frequent flyer database (b)	22		1,177		624		1,177		536
	Contracts	12		155		86		167		86
	Other	25		109		67		109		56

	Total		$	1,791	$	1,049	$	1,804	$	933

	Indefinite-lived intangible assets
	Airport slots and gates		$	956			$	963
	Route authorities			1,589				1,605
	Tradenames and logos			593				593
	Alliances			404				404

	Total		$	3,542			$	3,565


	(a) Weighted average life expressed in years.
	(b) The frequent flyer database is amortized based on an accelerated amortization schedule to reflect utilization of the assets. Estimated cash flows correlating to the expected attrition rate of customers in the frequent flyer database is considered in the determination of the amortization schedules.

Earnings_Loss_Per_Share_Tables

Earnings (Loss) Per Share (Tables)	12 Months Ended
Earnings (Loss) Per Share (Tables)	Dec. 31, 2014
Computation of Earnings Per Share (Loss)	The computations of UAL’s basic and diluted earnings (loss) per share and the number of securities that have been excluded from the computation of diluted earnings per share amounts because they were antidilutive are set forth below for the years ended December 31 (in millions, except per share amounts):


		2014		2013		2012
	Basic earnings (loss) per share:
	Earnings (loss) available to common stockholders	$	1,132	$	571	$	-723

	Basic weighted-average shares outstanding		371		348		331

	Earnings (loss) per share, basic	$	3.05	$	1.64	$	-2.18


	Diluted earnings (loss) per share:
	Earnings (loss) available to common stockholders	$	1,132	$	571	$	-723
	Effect of dilutive securities		11		26		—

	Earnings (loss) available to common stockholders including the effect of dilutive securities	$	1,143	$	597	$	-723


	Diluted shares outstanding:
	Basic weighted-average shares outstanding		371		348		331
	Effect of convertible notes		18		42		—
	Effect of restricted stock and employee stock options		1		1		—

	Diluted weighted-average shares outstanding		390		391		331

	Earnings (loss) per share, diluted	$	2.93	$	1.53	$	-2.18


	Potentially dilutive shares excluded from diluted per share amounts:
	Restricted stock and stock options		1		3		5
	Convertible notes		3		4		61

			4		7		66

ShareBased_Compensation_Plans_

Share-Based Compensation Plans (Tables)	12 Months Ended
Share-Based Compensation Plans (Tables)	Dec. 31, 2014
Schedule of Share-Based Compensation Plan Cost	The following table provides information related to UAL’s share-based compensation plan cost for the years ended December 31 (in millions):


		2014		2013		2012
	Compensation cost: (a)
	RSUs	$	104	$	88	$	37
	Restricted stock		10		11		13
	Other		—		1		7

	Total	$	114	$	100	$	57

	(a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million, $9 million and $9 million in 2014, 2013 and 2012, respectively, that was recorded in integration-related costs as a component of special charges.
Schedule of Unearned Compensation and Weighted Average Remaining Period for Outstanding Share-Based Awards	The table below summarizes UAL’s unearned compensation and weighted-average remaining period to recognize costs for all outstanding share-based awards that are probable of being achieved for the year ended December 31, 2014 (in millions, except as noted):


		Unearned		Weighted-
		Compensation		Average
				Remaining
				Period (in
				years)
	RSUs	$	55		1.4
	Restricted stock		7		1.4

	Total	$	62

Schedule Of Restricted Stock Unit and Restricted Stock Activity	The table below summarizes UAL’s RSUs and restricted stock activity for the years ended December 31 (shares in millions):


		RSUs		Restricted Stock		Weighted-
						Average
						Grant Price
	Non-vested at December 31, 2011		3.4		1.0	$	23.33
	Granted		2.0		0.5		24.01
	Vested		-0.6		-0.6		23.05
	Surrendered		-0.5		-0.1		24.01

	Non-vested at December 31, 2012		4.3		0.8		23.94
	Granted		1.8		0.5		25.98
	Vested		-0.5		-0.3		23.93
	Surrendered		-0.2		-0.1		24.76

	Non-vested at December 31, 2013		5.4		0.9		25.02
	Granted		0.9		0.3		43.33
	Vested		-2.2		-0.4		24.66
	Surrendered		-0.3		-0.1		28.88

	Non-vested at December 31, 2014		3.8		0.7		32.55

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
Accumulated Other Comprehensive Income (Loss) (Tables)	Dec. 31, 2014
Components of Accumulated Other Comprehensive Income (Loss), Net of Tax	The tables below present the components of the Company’s accumulated other comprehensive income (loss) (“AOCI”), net of tax (in millions):


	UAL (a)	Pension and			Unrealized		Investments		Total
		Other			Gains (Losses)		and Other
		Postretirement			on Derivatives
		Unrecognized
		Actuarial
		Gains (Losses)
		and Prior
		Service Cost
	Balance at December 31, 2011	$	-312		$	-100	$	-5	$	-417

	Other comprehensive loss before reclassifications		-747	(b)		-51		11		-787
	Amounts reclassified from accumulated other comprehensive income		17			141		—		158

	Net current-period other comprehensive income (loss)		-730			90		11		-629

	Balance at December 31, 2012	$	-1,042		$	-10	$	6	$	(1,046)

	Other comprehensive income before reclassifications		1,584	(b)		39		7		1,630
	Amounts reclassified from accumulated other comprehensive income		42			-18		—		24

	Net current-period other comprehensive income (loss)		1,626			21		7		1,654

	Balance at December 31, 2013	$	584		$	11	$	13	$	608

	Other comprehensive income before reclassifications		-1,106	(b)		-599		—		-1,705
	Amounts reclassified from accumulated other comprehensive income		-65			89		-6		18

	Net current-period other comprehensive income (loss)		-1,171			-510		-6		-1,687

	Balance at December 31, 2014	$	-587		$	-499	$	7	$	-1,079



	Details about AOCI Components	Amount Reclassified from AOCI to							Affected Line Item in
		Income							the Statement Where
									Net Income is Presented
		Year Ended December 31,
		2014			2013		2012
	Derivatives designated as cash flow hedges
	Fuel contracts-reclassifications of (gains) losses into earnings (c)	$	89		$	-18	$	141	Aircraft fuel
	Amortization of pension and post-retirement items
	Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (c) (d)		-65			42		17	Salaries and related costs
	Investments and other
	Available for sale securities—reclassifications of gains into earnings (c)		-6			—		—	Miscellaneous, net


	(a) UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.
	(b) For 2014, prior service credits increased by $3 million and actuarial losses increased by approximately $1.1 billion. For 2013, prior service credits increased by $331 million and actuarial gains increased by approximately $1.3 billion. The amount for 2012 was not material.
	(c) Income tax expense for these items was offset by the Company’s valuation allowance.
	(d) This accumulated other comprehensive income component is included in the computation of net periodic pension and other postretirement costs (see Note 8 of this report for additional information).

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2014
Components of Income Tax Expense (Benefit)	The significant components of the income tax expense (benefit) are as follows (in millions):


	2014	UAL		United
	Current	$	-17	$	-17
	Deferred		13		13

		$	-4	$	-4


	2013
	Current	$	-18	$	-18
	Deferred		-14		1

		$	-32	$	-17


	2012
	Current	$	-14	$	-9
	Deferred		13		13

		$	-1	$	4

Income Tax Provision Differed from Amounts Computed at Statutory Federal Income Tax Rate	The income tax provision differed from amounts computed at the statutory federal income tax rate, as follows (in millions):



	UAL	2014		2013		2012
	Income tax provision at statutory rate	$	395	$	189	$	-253
	State income taxes, net of federal income tax		16		5		-15
	Foreign income taxes		2		3		7
	Nondeductible employee meals		15		15		12
	Nondeductible interest expense		—		—		19
	State rate change		—		-33		—
	Valuation allowance		-441		-219		234
	Other, net		9		8		-5

		$	-4	$	-32	$	-1


	United	2014		2013		2012
	Income tax provision at statutory rate	$	388	$	223	$	-230
	State income taxes, net of federal income tax		15		5		-7
	Foreign income taxes		2		3		7
	Nondeductible employee meals		15		15		12
	Nondeductible interest expense		—		—		19
	Derivative market adjustment		-7		-24		-15
	State rate change		—		-33		—
	Valuation allowance		-426		-229		223
	Other, net		9		23		-5

		$	-4	$	-17	$	4

Components of Deferred Tax Assets and Liabilities	Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows (in millions):


		UAL				United
		December 31,				December 31,
		2014		2013		2014		2013
	Deferred income tax asset (liability):
	Federal and state net operating loss (“NOL”) carryforwards	$	3,491	$	4,006	$	3,423	$	3,943
	Frequent flyer deferred revenue		2,287		2,254		2,287		2,254
	Employee benefits, including pension, postretirement and medical		1,943		1,701		1,943		1,701
	Alternative minimum tax credit carryforwards		214		233		214		233
	Other		657		340		659		340
	Less: Valuation allowance		-4,751		-4,591		-4,721		-4,561

	Total deferred tax assets	$	3,841	$	3,943	$	3,805	$	3,910


	Depreciation, capitalized interest and other	$	-3,212	$	-3,201	$	-3,212	$	-3,201
	Intangibles		-1,545		-1,585		-1,545		-1,585
	Other		-84		-144		-48		-111

	Total deferred tax liabilities	$	-4,841	$	-4,930	$	-4,805	$	-4,897

	Net deferred tax liability	$	-1,000	$	-987	$	-1,000	$	-987

Reconciliation of Unrecognized Tax Benefits	The following is a reconciliation of the beginning and ending amount of unrecognized tax benefits related to the Company’s uncertain tax positions (in millions):


		2014		2013		2012
	Balance at January 1,	$	14	$	19	$	24
	Decrease in unrecognized tax benefits relating to settlements with taxing authorities		-5		—		-12
	Increase in unrecognized tax benefits as a result of tax positions taken during a prior period		—		—		8
	Decrease in unrecognized tax benefits relating from a lapse of the statute of limitations		—		-5		-1

	Balance at December 31,	$	9	$	14	$	19

Pension_and_Other_Postretireme1

Pension and Other Postretirement Plans (Tables)	12 Months Ended
Pension and Other Postretirement Plans (Tables)	Dec. 31, 2014
Reconciliation of Change in Projected Benefit Obligation and Plan Assets	The following table sets forth the reconciliation of the beginning and ending balances of the benefit obligation and plan assets, the funded status and the amounts recognized in these financial statements for the defined benefit and other postretirement plans (in millions):


			Pension Benefits
			Year Ended			Year Ended
			December 31, 2014			December 31, 2013
	Accumulated benefit obligation:		$	4,068		$	3,383


	Change in projected benefit obligation:
	Projected benefit obligation at beginning of year		$	4,000		$	4,526
	Service cost			98			121
	Interest cost			201			191
	Actuarial (gain) loss			807			-464
	Gross benefits paid and settlements			-281			-269
	Curtailments			—			-84
	Other			-22			-21

	Projected benefit obligation at end of year		$	4,803		$	4,000


	Change in plan assets:
	Fair value of plan assets at beginning of year		$	2,397		$	2,157
	Actual gain on plan assets			151			239
	Employer contributions			307			277
	Gross benefits paid and settlements			-281			-269
	Other			-12			-7

	Fair value of plan assets at end of year		$	2,562		$	2,397

	Funded status—Net amount recognized		$	-2,241		$	-1,603




			Other Postretirement Benefits
			Year Ended			Year Ended
			December 31, 2014			December 31, 2013
	Change in benefit obligation:
	Benefit obligation at beginning of year		$	1,819		$	2,743
	Service cost			19			52
	Interest cost			88			110
	Plan participants’ contributions			67			67
	Actuarial (gain) loss			262			-640
	Federal subsidy			4			7
	Plan amendments			-3			-331
	Curtailments			8			8
	Gross benefits paid			-212			-197

	Benefit obligation at end of year		$	2,052		$	1,819

	Change in plan assets:
	Fair value of plan assets at beginning of year		$	57		$	58
	Actual return on plan assets			1			1
	Employer contributions			144			128
	Plan participants’ contributions			67			67
	Benefits paid			-212			-197
	Fair value of plan assets at end of year			57			57

	Funded status—Net amount recognized		$	-1,995		$	-1,762

Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss)		Pension Benefits
			December 31, 2014			December 31, 2013
	Amounts recognized in the consolidated balance sheets consist of:
	Noncurrent asset		$	2		$	49
	Current liability			-17			-2
	Noncurrent liability			-2,226			-1,650

	Total liability		$	-2,241		$	-1,603

	Amounts recognized in accumulated other comprehensive loss consist of:
	Net actuarial loss		$	-982		$	-162
	Prior service loss			-1			—

	Total accumulated other comprehensive loss		$	-983		$	-162




			Other Postretirement Benefits
			December 31, 2014			December 31, 2013
	Amounts recognized in the consolidated balance sheets consist of:
	Current liability		$	-62		$	-59
	Noncurrent liability			-1,933			-1,703

	Total liability		$	-1,995		$	-1,762

	Amounts recognized in accumulated other comprehensive income consist of:
	Net actuarial gain		$	233		$	555
	Prior service credit			278			306

	Total accumulated other comprehensive income		$	511		$	861

Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets	The following information relates to all pension plans with an accumulated benefit obligation and a projected benefit obligation in excess of plan assets at December 31 (in millions):


			2014			2013
	Projected benefit obligation		$	4,625		$	3,820
	Accumulated benefit obligation			3,930			3,245
	Fair value of plan assets			2,387			2,176
Components Of Net Periodic Benefit Cost	Net periodic benefit cost for the years ended December 31 included the following components (in millions):


			2014					2013				2012
			Pension			Other		Pension		Other		Pension				Other
			Benefits			Postretirement		Benefits		Postretirement		Benefits				Postretirement
						Benefits				Benefits						Benefits
	Service cost		$	98		$	19	$	121	$	52	$	99			$	50
	Interest cost			201			88		191		110		184				124
	Expected return on plan assets			-180			-2		-163		-2		-138				-2
	Curtailment loss			—			—		2		2		—				—
	Amortization of prior service credits			—			-31		—		-3		-1				—
	Settlement (gain) loss			1			—		-10		—		1				—
	Amortization of unrecognized actuarial (gain) loss			12			-47		48		3		21				-3

	Net periodic benefit cost		$	132		$	27	$	189	$	162	$	166			$	169

Amortized Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost	The estimated amounts that will be amortized in 2015 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions):


			Pension			Other
			Benefits			Postretirement
						Benefits
	Actuarial (gain) loss		$	87		$	-22
	Prior service credit			—			-32
Assumptions Used for Benefit Plans	The assumptions used for the benefit plans were as follows:


				Pension Benefits
	Assumptions used to determine benefit obligations			2014			2013
	Discount rate			4.20%			5.09%
	Rate of compensation increase			3.66%			3.49%

	Assumptions used to determine net expense
	Discount rate			5.10%			4.48%
	Expected return on plan assets			7.36%			7.56%
	Rate of compensation increase			3.50%			2.48%


			Other Postretirement Benefits
	Assumptions used to determine benefit obligations		2014			2013
	Discount rate			4.07%			4.94%

	Assumptions used to determine net expense
	Discount rate			4.94%			4.12%
	Expected return on plan assets			4.00%			4.00%
	Health care cost trend rate assumed for next year			7.00%			7.25%
	Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023)			5.00%			5.00%
Allocation of Plan Asset	United’s plan assets are allocated within the following guidelines:


			Percent of Total		Expected Long-Term
			Percent of Total		Rate of Return

	Equity securities		40-54 %		10 %
	Fixed-income securities		26-34		4
	Alternatives		14-20		7
	Other		8-Apr		6
Effect of One-Percentage-Point Change in Assumed Health Care Trend Rate	A 1% change in the assumed health care trend rate for the Company would have the following additional effects (in millions):


			1% Increase			1% Decrease
	Effect on total service and interest cost for the year ended December 31, 2014		$	13		$	-11
	Effect on postretirement benefit obligation at December 31, 2014			254			-220
Pension and Other Postretirement Plan Assets	The following tables present information about United’s pension and other postretirement plan assets at December 31 (in millions):


			2014											2013
	Pension Plan Assets:		Total			Level 1		Level 2		Level 3				Total				Level 1		Level 2		Level 3
	Equity securities funds		$	1,181		$	388	$	793	$	—			$	1,158			$	389	$	769	$	—
	Fixed-income securities			813			—		813		—				702				—		698		4
	Alternatives			359			—		148		211				405				—		199		206
	Insurance contract			21			—		—		21				26				—		—		26
	Other investments			188			—		165		23				106				—		106		—

	Total		$	2,562		$	388	$	1,919	$	255			$	2,397			$	389	$	1,772	$	236

	Other Postretirement Benefit Plan Assets:
	Deposit administration fund		$	57		$	—	$	—	$	57			$	57			$	—	$	—	$	57

Defined Benefit Plan Assets Measured at Fair Value Using Unobservable Inputs (Level Three)	The reconciliation of United’s defined benefit plan assets measured at fair value using unobservable inputs (Level 3) for the years ended December 31, 2014 and 2013 is as follows (in millions):


			2014			2013
	Balance at beginning of year		$	293		$	256
	Actual return on plan assets:
	Sold during the year			7			15
	Held at year end			6			7
	Purchases, sales, issuances and settlements (net)			6			15

	Balance at end of year		$	312		$	293

Estimated Future Benefit Payments	The estimated future benefit payments, net of expected participant contributions, in United’s pension plans and other postretirement benefit plans as of December 31, 2014 are as follows (in millions):


			Pension			Other		Other Postretirement—
			Pension			Postretirement		subsidy receipts
	2015		$	299		$	125	$	6
	2016			283			126		7
	2017			294			129		8
	2018			291			132		9
	2019			293			135		9
	Years 2020 – 2024			1,581			732		56
Multi-Employer Plans
	Pension Fund		IAM National Pension Fund
	EIN/ Pension Plan Number		51-6031295 - 002
	Pension Protection Act Zone Status (2014 and 2013)		Green Zone. Plans in the green zone are at least 80 percent funded.
	FIP/RP Status Pending/Implemented		No
	United’s Contributions		$39 million, $38 million and $36 million in the years ended December 31, 2014, 2013 and 2012, respectively
	Surcharge Imposed		No
	Expiration Date of Collective Bargaining Agreement		N/A

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2014
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The table below presents disclosures about the fair value of financial assets and financial liabilities measured at fair value on a recurring basis in the Company’s financial statements as of December 31 (in millions):


		2014									2013
		Total		Level 1			Level 2		Level 3		Total		Level 1		Level 2		Level 3
		UAL
	Cash and cash equivalents		$2,002	$	2,002		$	—	$	—	$	3,220	$	3,220	$	—	$	—
	Short-term investments:
	Asset-backed securities		901		—			901		—		694		—		694		—
	Corporate debt		876		—			876		—		685		—		685		—
	Certificates of deposit placed through an account registry service (“CDARS”)		256		—			256		—		301		—		301		—
	U.S. government and agency notes		68		—			68		—		38		—		38		—
	Auction rate securities		26		—			—		26		105		—		—		105
	Other fixed income securities		255		—			255		—		78		—		78		—
	Enhanced equipment trust certificates (“EETC”)		28		—			—		28		61		—		—		61
	Fuel derivatives asset (liability), net		-717		—			-717		—		104		—		104		—
	Foreign currency derivatives		2		—			2		—		1		—		1		—
	Restricted cash		320		320			—		—		395		395		—		—

		United
	Cash and cash equivalents	$	1,996	$	1,996		$	—	$	—	$	3,214	$	3,214	$	—	$	—
	Short-term investments:
	Asset-backed securities		901		—			901		—		694		—		694		—
	Corporate debt		876		—			876		—		685		—		685		—
	CDARS		256		—			256		—		301		—		301		—
	U.S. government and agency notes		68		—			68		—		38		—		38		—
	Auction rate securities		26		—			—		26		105		—		—		105
	Other fixed income securities		255		—			255		—		78		—		78		—
	EETC		28		—			—		28		61		—		—		61
	Fuel derivatives asset (liability), net		-717		—			-717		—		104		—		104		—
	Foreign currency derivatives		2		—			2		—		1		—		1		—
	Restricted cash		320		320			—		—		395		395		—		—
	Convertible debt derivative asset		712		—			—		712		480		—		—		480
	Convertible debt option liability		-511		—			—		-511		-270		—		—		-270
Activity for "Level Three" Financial Assets and Financial Liabilities	The tables below present disclosures about the activity for “Level 3” financial assets and financial liabilities for the year ended December 31 (in millions):


		2014									2013
		UAL and United					United				UAL and United				United
		Student		EETC			Convertible		Convertible		Student		EETC		Convertible		Convertible
		Loan-Related					Debt		Debt		Loan-Related				Debt		Debt
		Auction Rate					Supplemental		Conversion		Auction Rate				Supplemental		Conversion
		Securities					Derivative		Option		Securities				Derivative		Option
							Asset		Liability						Asset		Liability

	Balance at January 1	$	105	$	61		$	480	$	-270	$	116	$	63	$	268	$	-128
	Purchases, (sales), issuances and settlements (net)		-84		-33			-62		34		-19		-4		—		—
	Gains and (losses):
	Reported in earnings:
	Realized		10		1			-5		5		3		—		—		—
	Unrealized		—		—			299		-280		1		—		212		-142
	Reported in other comprehensive income (loss)		-5		-1			—		—		4		2		—		—

	Balance at December 31	$	26	$	28		$	712	$	-511	$	105	$	61	$	480	$	-270

Carrying Values and Estimated Fair Values of Financial Instruments	The table below presents the carrying values and estimated fair values of financial instruments not presented in the tables above as of December 31 (in millions):


		Fair Value of Debt by Fair Value Hierarchy Level
		2014											2013
		Carrying		Fair Value									Carrying		Fair Value
		Amount		Fair Value									Amount		Fair Value
				Total			Level 1		Level 2		Level 3				Total		Level 1		Level 2		Level 3
	UAL debt	$	11,434	$	12,386		$	—	$	8,568	$	3,818	$	11,539	$	12,695	$	—	$	8,829	$	3,866
	United debt		11,433		12,386			—		8,568		3,818		11,388		12,249		—		8,383		3,866
Fair Value Methodology for Financial Instruments	Fair value of the financial instruments included in the tables above was determined as follows:


	Description	Fair Value Methodology
	Cash and cash equivalents	The carrying amounts approximate fair value because of the short-term maturity of these assets.

	Short-term investments and Restricted cash	Fair value is based on (a) the trading prices of the investment or similar instruments, (b) an income approach, which uses valuation techniques to convert future amounts into a single present amount based on current market expectations about those future amounts when observable trading prices are not available, (c) internally-developed models of the expected future cash flows related to the securities, or (d) broker quotes obtained by third-party valuation services.

	Fuel derivatives	Derivative contracts are privately negotiated contracts and are not exchange traded. Fair value measurements are estimated with option pricing models that employ observable inputs. Inputs to the valuation models include contractual terms, market prices, yield curves, fuel price curves and measures of volatility, among others.

	Foreign currency derivatives	Fair value is determined with a formula utilizing observable inputs. Significant inputs to the valuation models include contractual terms, risk-free interest rates and forward exchange rates.

	Debt	Fair values were based on either market prices or the discounted amount of future cash flows using our current incremental rate of borrowing for similar liabilities.

	Convertible debt derivative asset and option liability	United used a binomial lattice model to value the conversion options and the supplemental derivative assets. Significant binomial model inputs that are not objectively determinable include volatility and the Company’s credit risk component of the discount rate.
Level 3
Fair Value Methodology for Financial Instruments	Quantitative Information About Level 3 Fair Value Measurements as of December 31, 2014 ($ in millions)


	Item	Fair Value at		Valuation Technique		Unobservable Input	Input Value
	Item	December 31, 2014		Valuation Technique		Unobservable Input	Input Value
	Auction rate securities	$	26	Valuation Service / Broker Quotes		Broker quotes (a)	NA
	EETC		28	Discounted Cash Flows		Structure credit risk (b)	4%
	Convertible debt derivative asset		712	Binomial Lattice Model		Expected volatility (c)	40%
	Convertible debt derivative asset		712	Binomial Lattice Model		Own credit risk (d)	5%
	Convertible debt option liability		-511	Binomial Lattice Model		Expected volatility (c)	40%
	Convertible debt option liability		-511	Binomial Lattice Model		Own credit risk (d)	5%

	(a) Broker quotes obtained by a third-party valuation service.
	(b) Represents the credit risk premium of the EETC structure above the risk-free rate that the Company has determined market participants would use when pricing the instruments.
	(c) Represents the volatility estimate that the Company has determined market participants would use when pricing the instruments.
	(d) Represents the Company-specific risk adjustment that the Company has determined market participants would use as a model input.

Hedging_Activities_Tables

Hedging Activities (Tables)	12 Months Ended
Hedging Activities (Tables)	Dec. 31, 2014
Description of Derivative Instruments	At December 31, the Company’s derivatives were reported in its consolidated balance sheets as follows (in millions):


	Classification	Balance Sheet Location		2014				2013
	Derivatives designated as cash flow hedges
	Assets:
	Fuel contracts due within one year	Receivables		$	—			$	19
	Fuel contracts with maturities greater than one year	Other assets: Other, net			—				6

	Total assets			$	—			$	25

	Liabilities:
	Fuel contracts due within one year	Fuel derivative instruments		$	450			$	—
	Fuel contracts with maturities greater than one year	Other liabilities and deferred credits: Other			27				—

				$	477			$	—

	Derivatives not designated for hedge accounting
	Assets:
	Fuel contracts due within one year	Receivables		$	6			$	70
	Fuel contracts with maturities greater than one year	Other assets: Other, net			—				9

	Total assets			$	6			$	79

	Liabilities:
	Fuel contracts due within one year	Fuel derivative instruments		$	244			$	—
	Fuel contracts with maturities greater than one year	Other liabilities and deferred credits: Other			2				—

	Total liabilities			$	246			$	—

	Total derivatives
	Assets:
	Fuel contracts due within one year	Receivables		$	6			$	89
	Fuel contracts with maturities greater than one year	Other assets: Other, net			—				15

	Total assets			$	6			$	104

	Liabilities:
	Fuel contracts due within one year	Fuel derivative instruments		$	694			$	—
	Fuel contracts with maturities greater than one year	Other liabilities and deferred credits: Other			29				—

	Total liabilities			$	723			$	—

Offsetting Assets and Liabilities	The following table shows the potential net fair value positions (including fuel derivatives and related collateral) had we elected to offset. The table reflects offset at the counterparty level (in millions):


		December 31, 2014				December 31, 2013
	Receivables	$	—			$	89
	Other assets: Other, net		—				15
	Current liabilities: Other		-209				—
	Other liabilities and deferred credits: Other		-30				—

	Hedge derivatives assets (liabilities), net	$	-239			$	104

Schedule of Gains (Losses) on Derivative Instruments	The following tables present the fuel hedge gains (losses) recognized during the periods presented and their classification in the financial statements (in millions):
	Derivatives designated as cash flow hedges


		Amount of Gain (Loss)								Gain (Loss)				Amount of Gain (Loss)
		Recognized								Reclassified from				Recognized in
		in AOCI on Derivatives								AOCI into Income				Nonoperating income
		(Effective Portion)								(Fuel Expense)				(expense): Miscellaneous, net
										(Effective Portion)				(Ineffective Portion)
		2014				2013				2014		2013		2014		2013
	Fuel contracts	$	-599			$	39			$	-89	$	18	$	-3	$	5
Schedule of Derivative Instruments not Designated as Hedges Gains (Losses)	Derivatives not designated for hedge accounting


		Amount of Gain (Loss) Recognized
		in Nonoperating income (expense):
		Miscellaneous, net
		2014				2013				2012
	Fuel contracts	$	-462			$	79			$	38

Debt_Tables

Debt (Tables)	12 Months Ended
Debt (Tables)	Dec. 31, 2014
Debt
	(In millions)	At December 31,
		2014				2013
	United:
	Secured
	Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.86% as of December 31, 2014), payable through 2026	$	7,464			$	6,279
	Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 5.46%, payable through 2026		1,151				1,243
	Term loan, LIBOR subject to a 0.75% floor, plus 2.75%, or alternative rate based on certain market rates plus 1.75%, due 2019		884				893
	Term loan, LIBOR subject to a 0.75% floor, plus 3.00%, or alternative rate based on certain market rates plus 2%, due 2021		499				—
	6.75% Senior Secured Notes due 2015		—				800
	Unsecured
	6% Notes due 2026 to 2028 (a)		632				652
	6% Senior Notes due 2020 (a)		300				300
	6.375% Senior Notes due 2018 (a)		300				300
	4.5% Convertible Notes due 2015		202				230
	8% Notes due 2024 (a)		—				400
	6% Convertible Junior Subordinated Debentures due 2030		—				248
	4.5% Senior Limited-Subordination Convertible Notes due 2021 (a)		—				156
	Other		101				103

			11,533				11,604

	Less: unamortized debt discount		-99				-169
	Less: current portion of long-term debt—United		-1,313				-1,368

	Long-term debt, net—United (b)	$	10,121			$	10,067


	UAL:
	6% Convertible Senior Notes due 2029	$	—			$	104

	Long-term debt, net—UAL	$	10,121			$	10,171


	(a) UAL is the issuer of this debt. United is a guarantor.
	(b) As further described below under “Convertible Debt Securities and Derivatives,” there is a basis difference between UAL and United debt values, because we applied different accounting methodologies. The United debt presented above does not agree to United’s balance sheet by the amount of this adjustment.
Contractual Principal Payments	The table below presents the Company’s contractual principal payments at December 31, 2014 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions):


		UAL and United
	2015	$	1,313
	2016		1,195
	2017		755
	2018		1,269
	2019		1,721
	After 2019		5,280

		$	11,533

Details of Pass Through Trusts	Certain details of the pass-through trusts with proceeds received from issuance of debt in 2014 are as follows (in millions, except stated interest rate):


	EETC Date	Class		Principal				Final	Stated		Total debt		Proceeds		Remaining
								expected	interest		recorded		received from		proceeds from
								distribution	rate		as of December 31,		issuance of		issuance of debt
								date			2014		debt during		to be received
													2014		in future
															periods
	Aug-14	A		$	823			September 2026		3.75%	$	112	$	112	$	711
	Aug-14	B			238			Sep-22		4.63%		32		32		206
	Apr-14	A			736			Apr-26		4.00%		736		736		—
	Apr-14	B			213			Apr-22		4.75%		213		213		—
	Aug-13	A			720			Aug-25		4.30%		720		567		—
	Aug-13	B			209			Aug-21		5.38%		209		165		—

				$	2,939						$	2,022	$	1,825	$	917

Summary of Collateral Covenants and Cross Default Provisions	The collateral, covenants and cross default provisions of the Company’s principal debt instruments that contain such provisions are summarized in the table below:


	Debt Instrument	Collateral, Covenants and Cross Default Provisions
	Credit Agreement	Secured by certain of United’s international route authorities, specified take-off and landing slots at certain airports and certain other assets.

		The Credit Agreement requires the Company to maintain at least $3.0 billion of unrestricted liquidity at all times, which includes unrestricted cash, short-term investments and any undrawn amounts under any revolving credit facility, and to maintain a minimum ratio of appraised value of collateral to the outstanding obligations under the Credit Agreement of 1.67 to 1.0 at all times. The Credit Agreement contains covenants that, among other things, restrict the ability of UAL and its restricted subsidiaries (as defined in the Credit Agreement) to incur additional indebtedness and to pay dividends on or repurchase stock.

		The Credit Agreement contains events of default customary for this type of financing, including a cross default and cross acceleration provision to certain other material indebtedness of the Company.
	6% Notes due 2026	The amended and restated indenture for these notes, which are unsecured, contains covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock.

	6% Notes due 2028	These covenants cease to be in effect when the indenture covering the 6.375% Senior Notes due 2018 is discharged.

		The indenture contains events of default that are customary for similar financings.
	6.375% Senior Notes due 2018	The indentures for these notes, which are unsecured, contain covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock.

	6% Senior Notes due 2020	The indentures contain events of default that are customary for similar financings.

Leases_and_Capacity_Purchase_A1

Leases and Capacity Purchase Agreements (Tables)	12 Months Ended
Leases and Capacity Purchase Agreements (Tables)	Dec. 31, 2014
Future Minimum Lease Payments for Capital and Operating Leases	At December 31, 2014, United’s scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year, aircraft leases, including aircraft rent under CPAs and capital leases (substantially all of which are for aircraft) were as follows (in millions):


		Capital Leases (a)		Facility and Other		Aircraft Operating
		Capital Leases (a)		Operating Leases (b)		Leases (c)
	2015	$	168	$	1,283	$	1,446
	2016		154		1,123		1,247
	2017		115		1,089		1,147
	2018		104		842		908
	2019		38		766		682
	After 2019		495		7,919		1,910

	Minimum lease payments	$	1,074	$	13,022	$	7,340

	Imputed interest		-393

	Present value of minimum lease payments		681
	Current portion		-110

	Long-term obligations under capital leases	$	571

Future Lease Payment Under Terms of Capacity Purchase Agreement	Based on these assumptions as of December 31, 2014, our future payments through the end of the terms of our CPAs are presented in the table below (in millions):


	2015	$	1,893
	2016		1,760
	2017		1,653
	2018		1,301
	2019		973
	After 2019		3,497

		$	11,077

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2014
Firm Commitments to Purchase Aircraft	As of December 31, 2014, United had firm commitments to purchase aircraft from The Boeing Company (“Boeing”), Embraer and Airbus S.A.S. (“Airbus”) presented in the table below:


	Aircraft Type	Number of Firm
	Aircraft Type	Commitments (a) (b)
	Airbus A350-1000		35
	Boeing 737-900ER		34
	Boeing 737 MAX 9		100
	Boeing 787-9/-10		51
	Embraer E175		11
	(a) United also has options and purchase rights for additional aircraft.
	(b) United also has committed to purchase two used 737-700 aircraft in 2015.
Schedule of Acquisition of Aircrafts and Related Spare Engines	The table below summarizes United’s commitments as of December 31, 2014 (including those assigned from UAL), which primarily relate to the acquisition of aircraft and related spare engines, aircraft improvements and include other commitments primarily to acquire information technology services and assets for the years ended December 31 (in billions):


	2015	$	3.2
	2016		2.3
	2017		1.3
	2018		2.2
	2019		3.3
	After 2019		10.7

		$	23.0

Statement_of_Consolidated_Cash1

Statement of Consolidated Cash Flows - Supplemental Disclosures (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Disclosures of Cash Flow Information and Non-Cash Investing and Financing Activities	Supplemental disclosures of cash flow information and non-cash investing and financing activities for the years ended December 31 are as follows (in millions):


	2014	UAL		United
	Cash paid (refunded) during the period for:
	Interest (net of amounts capitalized)	$	748	$	748
	Income taxes		-16		-16
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	1,114	$	1,114
	Airport construction financing		14		14
	Exchanges of certain 4.5% Notes and 6% Convertible Senior Notes for common stock		260		156
	Transfer of UAL subsidiaries to United		—		186

	2013
	Cash paid (refunded) during the period for:
	Interest (net of amounts capitalized)	$	752	$	752
	Income taxes		-20		-15
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	229	$	229
	Airport construction financing		40		40
	Exchanges of certain 6% Convertible Senior Notes for common stock		240		—

	2012
	Cash paid during the period for:
	Interest (net of amounts capitalized)	$	766	$	766
	Income taxes		2		4
	Non-cash transactions:
	Net property and equipment acquired through issuance of debt	$	544	$	544
	8% Contingent Senior Notes and 6% Senior Notes due 2031, net of discount		357		357
	Special facility payment financing		101		101
	Airport construction financing		50		50

IntegrationRelated_Costs_and_S1

Integration-Related Costs and Special Items (Tables)	12 Months Ended
Integration-Related Costs and Special Items (Tables)	Dec. 31, 2014
Components of Integration-Related Costs and Special Items	Integration-related costs and special items classified as special charges in the statements of consolidated operations consisted of the following for the years ended December 31 (in millions):


	Operating:	2014		2013		2012
	Severance and benefit costs	$	199	$	105	$	125
	Integration-related costs		96		205		739
	Costs associated with permanently grounding Embraer ERJ 135 aircraft		66		—		—
	Impairment of assets		49		33		30
	Labor agreement costs		—		127		475
	(Gains) losses on sale of assets and other special (gains) losses, net		33		50		-46

	Special charges	$	443	$	520	$	1,323
	Nonoperating:
	Loss on extinguishment of debt and other, net	$	74	$	—	$	—
	Income tax benefit		-10		-7		-11

	Total operating and nonoperating special charges, net of income taxes	$	507	$	513	$	1,312

Accrual Activity	Activity related to the accruals for severance and medical costs and future lease payments on permanently grounded aircraft is as follows (in millions):


		Severance/		Permanently
		Medical Costs		Grounded Aircraft
	Balance at December 31, 2011	$	55	$	31
	Accrual		170		-1
	Payments		-160		-25

	Balance at December 31, 2012		65		5
	Accrual		120		10
	Payments		-94		-4

	Balance at December 31, 2013		91		11
	Accrual		199		102
	Payments		-181		-11

	Balance at December 31, 2014	$	109	$	102

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
Segment Information (Tables)	Dec. 31, 2014
Operating Revenue by Principle Geographic Region	The Company’s operating revenue by principal geographic region (as defined by the U.S. Department of Transportation) for the years ended December 31 is presented in the table below (in millions):


	2014	UAL		United
	Domestic (U.S. and Canada)	$	22,320	$	22,320
	Pacific		5,767		5,767
	Atlantic		7,321		7,321
	Latin America		3,493		3,493

	Total	$	38,901	$	38,901

	2013
	Domestic (U.S. and Canada)	$	22,092	$	22,100
	Pacific		5,794		5,794
	Atlantic		7,132		7,132
	Latin America		3,261		3,261

	Total	$	38,279	$	38,287

	2012
	Domestic (U.S. and Canada)	$	21,276	$	21,284
	Pacific		6,040		6,040
	Atlantic		6,582		6,582
	Latin America		3,254		3,254

	Total	$	37,152	$	37,160

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
Selected Quarterly Financial Data (Tables)	Dec. 31, 2014
Schedule of Selected Quarterly Financial Data
	UAL	Quarter Ended
	(In millions, except per share amounts)	March 31		June 30		September 30		December 31
	2014
	Operating revenue	$	8,696	$	10,329	$	10,563	$	9,313
	Income (loss) from operations		-349		906		1,191		625
	Net income (loss)		-609		789		924		28
	Basic earnings (loss) per share		-1.66		2.11		2.49		0.08
	Diluted earnings (loss) per share		-1.66		2.01		2.37		0.07
	2013
	Operating revenue	$	8,721	$	10,001	$	10,228	$	9,329
	Income (loss) from operations		-264		770		508		235
	Net income (loss)		-417		469		379		140
	Basic earnings (loss) per share		-1.26		1.37		1.06		0.39
	Diluted earnings (loss) per share		-1.26		1.21		0.98		0.37
Schedule of Effect of Four Quarters Events	UAL’s quarterly results were impacted by the following significant items (in millions):


		Quarter Ended
		March 31		June 30		September 30		December 31
	2014
	Operating:
	Severance and benefit costs	$	14	$	38	$	6	$	141
	Integration-related costs		34		17		28		17
	Costs associated with permanently grounding Embraer ERJ 135 aircraft		—		66		—		—
	Impairment of assets		1		32		—		16
	Losses on sale of assets and other special (gains) losses, net		3		16		9		5

	Special charges		52		169		43		179
	Nonoperating:
	Loss on extinguishment of debt and other, net		21		—		—		53
	Income tax benefit		-1		—		-3		-6

	Total operating and nonoperating special charges, net of income taxes	$	72	$	169	$	40	$	226

	2013
	Special charges (income):
	Severance and benefit costs	$	14	$	—	$	—	$	91
	Integration-related costs		70		45		50		40
	Labor agreement costs		—		—		127		—
	Impairment of assets		—		—		—		33
	(Gains) losses on sale of assets and other special (gains) losses, net		8		7		34		1

	Total special items		92		52		211		165

	Income tax benefit		—		—		—		-7

	Total special items, net of tax	$	92	$	52	$	211	$	158

Significant_Accounting_Policie3

Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Option	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Carrying value of computer software	$281	$290
Number of call options to purchase regional jet aircraft	281
Advertising expense	179	178	154
Co-Brand Agreement
Significant Accounting Policies [Line Items]
Number of elements identified in agreement	5
Frequent Flyer
Significant Accounting Policies [Line Items]
Estimated impact of change on consolidated revenue	95
Impact of change resulted in increase in consolidated revenue basic share	$0.26
Impact of change resulted in increase in consolidated revenue diluted share	$0.24
Minimum
Significant Accounting Policies [Line Items]
Refundable tickets expiration period	1 year
Residual value	10.00%
Maximum
Significant Accounting Policies [Line Items]
Residual value	11.00%
Computer software
Significant Accounting Policies [Line Items]
Depreciation expense related to computer software	$81	$72	$81
Aircraft and related rotable parts \| Minimum
Significant Accounting Policies [Line Items]
Residual value	10.00%
Aircraft and related rotable parts \| Maximum
Significant Accounting Policies [Line Items]
Residual value	11.00%

Schedule_of_Information_Relate

Schedule of Information Related to Amounts Recorded Related to Frequent Flyer Program (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Significant Accounting Policies [Line Items]
Cash Proceeds from Miles Sold	$2,861		$2,903		$2,852
Other Revenue Recognized Upon Award of Miles to Third-Party Customers	882	[1]	903	[1]	816	[1]
Increase in Frequent Flyer Deferred Revenue for Miles Awarded	2,178	[2]	2,174	[2]	2,036	[2]
Increase (Decrease) in Advanced Purchase of Miles	($199)	[3]	($174)	[3]

[1]	This amount represents other revenue recognized during the period from the sale of miles to third parties, representing the marketing-related deliverable services component of the sale.
[2]	This amount represents the increase to frequent flyer deferred revenue during the period.
[3]	This amount represents the net increase (decrease) in the advance purchase of miles obligation due to cash payments for the sale of miles in excess of (less than) miles awarded to customers.

Estimated_Useful_Lives_of_Prop

Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
Estimated Useful Lives of Property and Equipment (Detail)	Dec. 31, 2014
Aircraft and related rotable parts \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	25 years
Aircraft and related rotable parts \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	30 years
Buildings \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	25 years
Buildings \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	45 years
Other property and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Other property and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Computer software
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Building improvements \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	1 year
Building improvements \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	40 years

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Goodwill And Intangible Assets [Line Items]
Goodwill	$4,523		$4,523
Finite-lived intangible assets, Gross Carrying Amount	1,791		1,804
Finite-lived intangible assets, Accumulated Amortization	1,049		933
Indefinite-lived intangible assets, Gross Carrying Amount	3,542		3,565
Hubs
Goodwill And Intangible Assets [Line Items]
Asset life	20 years	[1]
Finite-lived intangible assets, Gross Carrying Amount	145		145
Finite-lived intangible assets, Accumulated Amortization	67		59
Patents And Trade Names
Goodwill And Intangible Assets [Line Items]
Asset life	3 years	[1]
Finite-lived intangible assets, Gross Carrying Amount	108		108
Finite-lived intangible assets, Accumulated Amortization	108		108
Frequent Flyer Database
Goodwill And Intangible Assets [Line Items]
Asset life	22 years	[1],[2]
Finite-lived intangible assets, Gross Carrying Amount	1,177	[2]	1,177	[2]
Finite-lived intangible assets, Accumulated Amortization	624	[2]	536	[2]
Contracts
Goodwill And Intangible Assets [Line Items]
Asset life	12 years	[1]
Finite-lived intangible assets, Gross Carrying Amount	155		167
Finite-lived intangible assets, Accumulated Amortization	86		86
Other Intangible Assets
Goodwill And Intangible Assets [Line Items]
Asset life	25 years	[1]
Finite-lived intangible assets, Gross Carrying Amount	109		109
Finite-lived intangible assets, Accumulated Amortization	67		56
Route Authorities
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount	1,589		1,605
Tradenames And Logos
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount	593		593
Alliances
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount	404		404
Airport Slots And Gates
Goodwill And Intangible Assets [Line Items]
Asset life	8 years	[1]
Finite-lived intangible assets, Gross Carrying Amount	97		98
Finite-lived intangible assets, Accumulated Amortization	97		88
Indefinite-lived intangible assets, Gross Carrying Amount	$956		$963

[1]	Weighted average life expressed in years.
[2]	The frequent flyer database is amortized based on an accelerated amortization schedule to reflect utilization of the assets. Estimated cash flows correlating to the expected attrition rate of customers in the frequent flyer database is considered in the determination of the amortization schedules.

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Actual and Estimated Amortization Expense [Line Items]
Actual amortization	$128	$142	$121
Projected amortization in 2015	105
Projected amortization in 2016	92
Projected amortization in 2017	81
Projected amortization in 2018	72
Projected amortization in 2019	$66

Common_Stockholders_Equity_and1

Common Stockholders' Equity and Preferred Securities - Additional Information (Detail) (USD $)	12 Months Ended		0 Months Ended	12 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2012	Jul. 24, 2014	Dec. 31, 2013	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2015
Schedule Of Stockholders Equity [Line Items]
Debt purchased and retired		$212,000,000
Long-term Debt, Gross	248,000,000
Share repurchase program authorized amount			1,000,000,000
Number of accelerated shares repurchase programs			2
Agreement to repurchase through an accelerated share repurchase program			200,000,000
Payments for repurchases of common stock	312,000,000
Common stock reserved for future issuance	21,000,000
Junior preferred stock outstanding	2
Junior preferred stock par value per share	$0.01
Preferred stock authorized to issue	250,000,000
Accelerated Share Repurchase Program
Schedule Of Stockholders Equity [Line Items]
Payments for repurchases of common stock			200,000,000
Number of shares repurchased			4,400,000
Open Market Repurchases
Schedule Of Stockholders Equity [Line Items]
Payments for repurchases of common stock	120,000,000
Number of shares repurchased	2,100,000
6% Convertible Senior Notes
Schedule Of Stockholders Equity [Line Items]
Debt instrument stated interest rate	6.00%			6.00%
Common stock issued in exchange for conversion notes	12,000,000			28,000,000
Debt instrument maturity year	2029			2029
Debt instrument converted amount	104,000,000
4.5% Convertible Notes Due 2015
Schedule Of Stockholders Equity [Line Items]
Debt instrument stated interest rate	4.50%
United Airlines, Inc.
Schedule Of Stockholders Equity [Line Items]
Long-term Debt, Gross	11,533,000,000			11,604,000,000
Dividend paid	212,000,000
Receivable from related parties	5,000,000			232,000,000
Number of affiliates				2
Unsecured Debt
Schedule Of Stockholders Equity [Line Items]
Debt instrument stated interest rate					4.50%
Common stock issued in exchange for conversion notes					5,000,000
Debt instrument maturity year					2021
Debt instrument converted amount					156,000,000
Unsecured Debt \| 4.5% Convertible Notes Due 2015
Schedule Of Stockholders Equity [Line Items]
Debt purchased and retired	28,000,000
Debt instrument conversion rate	18.93
Payment to extinguish debt	62,000,000
Debt instrument stated interest rate	4.50%
Long-term Debt, Gross	202,000,000
Adjustment to additional paid in capital upon debt redemption	34,000,000
Debt instrument maturity year	2015
Unsecured Debt \| 4.5% Convertible Notes Due 2015 \| Subsequent Event
Schedule Of Stockholders Equity [Line Items]
Debt instrument stated interest rate						4.50%	4.50%
Long-term Debt, Gross						202,000,000	202,000,000
Common stock issued in exchange for conversion notes							11,000,000
Debt instrument converted amount						202,000,000
Unsecured Debt \| United Airlines, Inc. \| 4.5% Convertible Notes Due 2015
Schedule Of Stockholders Equity [Line Items]
Debt instrument stated interest rate	4.50%			4.50%
Long-term Debt, Gross	202,000,000			230,000,000
Adjustment to additional paid in capital upon debt redemption	$62,000,000
Debt instrument maturity year	2015			2015

Computation_of_Earnings_Loss_P

Computation of Earnings (Loss) Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic earnings (loss) per share:
Earnings (loss) available to common stockholders									$1,132	$571	($723)
Basic weighted-average shares outstanding									371	348	331
Earnings (loss) per share, basic	$0.08	$2.49	$2.11	($1.66)	$0.39	$1.06	$1.37	($1.26)	$3.05	$1.64	($2.18)
Diluted earnings (loss) per share:
Earnings (loss) available to common stockholders									1,132	571	-723
Effect of dilutive securities									11	26
Earnings (loss) available to common stockholders including the effect of dilutive securities									$1,143	$597	($723)
Diluted shares outstanding:
Basic weighted-average shares outstanding									371	348	331
Effect of convertible notes									18	42
Effect of restricted stock and employee stock options									1	1
Diluted weighted-average shares outstanding									390	391	331
Earnings (loss) per share, diluted	$0.07	$2.37	$2.01	($1.66)	$0.37	$0.98	$1.21	($1.26)	$2.93	$1.53	($2.18)
Potentially dilutive shares excluded from diluted per share amounts:
Potentially dilutive shares excluded from diluted per share amounts									4	7	66
Restricted Stock And Stock Options
Potentially dilutive shares excluded from diluted per share amounts:
Potentially dilutive shares excluded from diluted per share amounts									1	3	5
Convertible Notes
Potentially dilutive shares excluded from diluted per share amounts:
Potentially dilutive shares excluded from diluted per share amounts									3	4	61

ShareBased_Compensation_Plans_1

Share-Based Compensation Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of days used to compute performance period average closing price of restricted stock units	20 days
Outstanding stock option awards	1
Outstanding weighted average exercise price	$29.73
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, award granted	0.5
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, award granted	0.9	1.8	2
Liabilities related to share based payments	$136
Payment related to share-based liabilities	86	29	35
Equity awards fair value	$97	$22	$27
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term, years	10 years
Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, vesting period	3 years
Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, vesting period	4 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, award granted	0.3
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, award granted	0.3	0.5	0.5
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, award granted	0.6
Share-Based Compensation, vesting date	31-Dec-16

Schedule_of_ShareBased_Compens

Schedule of Share-Based Compensation Plan Cost (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$114	[1]	$100	[1]	$57	[1]
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	104	[1]	88	[1]	37	[1]
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	10	[1]	11	[1]	13	[1]
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost			$1	[1]	$7	[1]

[1]	All compensation cost is recorded to Salaries and related costs, with the exception of $3 million, $9 million and $9 million in 2014, 2013 and 2012, respectively, that was recorded in integration-related costs as a component of special charges.

Schedule_of_ShareBased_Compens1

Schedule of Share-Based Compensation Plan Cost (Parenthetical) (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs	$17	$28	$17	$34	$40	$50	$45	$70	$96	$205	$739
Special Charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs									$3	$9	$9

Schedule_of_Unearned_Compensat

Schedule of Unearned Compensation and Weighted Average Remaining Period for Outstanding Share-Based Awards (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$62
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	55
Weighted-Average Remaining Period (in years)	1 year 4 months 24 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$7
Weighted-Average Remaining Period (in years)	1 year 4 months 24 days

Schedule_of_Restricted_Stock_U

Schedule of Restricted Stock Unit and Restricted Stock Activity (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	0.9	0.8	1
Granted, Stock	0.3	0.5	0.5
Vested, Stock	-0.4	-0.3	-0.6
Surrendered, Stock	-0.1	-0.1	-0.1
Non-vested at end of year, Stock	0.7	0.9	0.8
Weighted-Average Grant Price at beginning of year	$25.02	$23.94	$23.33
Granted, Weighted-Average Grant Price	$43.33	$25.98	$24.01
Vested, Weighted-Average Grant Price	$24.66	$23.93	$23.05
Surrendered, Weighted-Average Grant Price	$28.88	$24.76	$24.01
Non-vested at end of year, Weighted-Average Grant Price	$32.55	$25.02	$23.94
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	5.4	4.3	3.4
Granted, Stock	0.9	1.8	2
Vested, Stock	-2.2	-0.5	-0.6
Surrendered, Stock	-0.3	-0.2	-0.5
Non-vested at end of year, Stock	3.8	5.4	4.3

Components_of_Accumulated_Othe

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$608	[1]	($1,046)	[1]	($417)	[1]
Other comprehensive income (loss) before reclassifications	-1,705	[1]	1,630	[1]	-787	[1]
Amounts reclassified from accumulated other comprehensive income	18	[1]	24	[1]	158	[1]
Comprehensive income (loss) adjustments	-1,687	[1]	1,654	[1]	-629	[1]
Ending Balance	-1,079	[1]	608	[1]	-1,046	[1]
Pension and Other Postretirement Liabilities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	584	[1]	-1,042	[1]	-312	[1]
Other comprehensive income (loss) before reclassifications	-1,106	[1],[2]	1,584	[1],[2]	-747	[1],[2]
Amounts reclassified from accumulated other comprehensive income	-65	[1]	42	[1]	17	[1]
Comprehensive income (loss) adjustments	-1,171	[1]	1,626	[1]	-730	[1]
Ending Balance	-587	[1]	584	[1]	-1,042	[1]
Derivative Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	11	[1]	-10	[1]	-100	[1]
Other comprehensive income (loss) before reclassifications	-599	[1]	39	[1]	-51	[1]
Amounts reclassified from accumulated other comprehensive income	89	[1]	-18	[1]	141	[1]
Comprehensive income (loss) adjustments	-510	[1]	21	[1]	90	[1]
Ending Balance	-499	[1]	11	[1]	-10	[1]
Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	13	[1]	6	[1]	-5	[1]
Other comprehensive income (loss) before reclassifications			7	[1]	11	[1]
Amounts reclassified from accumulated other comprehensive income	-6	[1]
Comprehensive income (loss) adjustments	-6	[1]	7	[1]	11	[1]
Ending Balance	$7	[1]	$13	[1]	$6	[1]

[1]	UAL and United amounts are substantially the same except for an additional $6 million of income tax benefit at United in 2013. In addition, United had additional gains related to investments and other of $1 million in both 2012 and 2013.
[2]	For 2014, prior service credits increased by $3 million and actuarial losses increased by approximately $1.1 billion. For 2013, prior service credits increased by $331 million and actuarial gains increased by approximately $1.3 billion. The amount for 2012 was not material.

Details_about_Accumulated_Othe

Details about Accumulated Other Comprehensive Income Components (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Salaries And Related Costs
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements	($65)	[1],[2]	$42	[1],[2]	$17	[1],[2]
Miscellaneous, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Available for sale securities-reclassifications of gains into earnings	-6	[1]
Fuel Oil Contract \| Cash Flow Hedging \| Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of (gains) losses into earnings	$89	[1]	($18)	[1]	$141	[1]

[1]	Income tax expense for these items was offset by the Company's valuation allowance.
[2]	This accumulated other comprehensive income component is included in the computation of net periodic pension and other postretirement costs (see Note 8 of this report for additional information).

Components_of_Accumulated_Othe1

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Increase in prior service credits	$3,000,000	$331,000,000
Increase in actuarial gains (losses)	-1,100,000,000	1,300,000,000
United Airlines, Inc.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax (expense) benefit		6,000,000
Additional (losses) gains related to investments and other		$1,000,000	$1,000,000

Components_of_Income_Tax_Expen

Components of Income Tax Expense (Benefit) (Detail) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components Of Income Tax Expense Benefit [Line Items]
Current					($17)	($18)	($14)
Deferred					13	-14	13
Income tax expense (benefit)	-6	-3	-1	-7	-4	-32	-1
United Airlines, Inc.
Components Of Income Tax Expense Benefit [Line Items]
Current					-17	-18	-9
Deferred					13	1	13
Income tax expense (benefit)					($4)	($17)	$4

Income_Tax_Provision_Differed_

Income Tax Provision Differed from Amounts Computed at Statutory Federal Income Tax Rate (Detail) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Income tax provision at statutory rate					$395	$189	($253)
State income taxes, net of federal income tax					16	5	-15
Foreign income taxes					2	3	7
Nondeductible employee meals					15	15	12
Nondeductible interest expense							19
State rate change						-33
Valuation allowance					-441	-219	234
Other, net					9	8	-5
Income tax expense (benefit)	-6	-3	-1	-7	-4	-32	-1
United Airlines, Inc.
Income Taxes [Line Items]
Income tax provision at statutory rate					388	223	-230
State income taxes, net of federal income tax					15	5	-7
Foreign income taxes					2	3	7
Nondeductible employee meals					15	15	12
Nondeductible interest expense							19
Derivative market adjustment					-7	-24	-15
State rate change						-33
Valuation allowance					-426	-229	223
Other, net					9	23	-5
Income tax expense (benefit)					($4)	($17)	$4

Components_of_Deferred_Tax_Ass

Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	$3,491	$4,006
Frequent flyer deferred revenue	2,287	2,254
Employee benefits, including pension, postretirement and medical	1,943	1,701
Alternative minimum tax credit carryforwards	214	233
Other	657	340
Less: Valuation allowance	-4,751	-4,591
Total deferred tax assets	3,841	3,943
Depreciation, capitalized interest and other	-3,212	-3,201
Intangibles	-1,545	-1,585
Other	-84	-144
Total deferred tax liabilities	-4,841	-4,930
Net deferred tax liability	-1,000	-987
United Airlines, Inc.
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	3,423	3,943
Frequent flyer deferred revenue	2,287	2,254
Employee benefits, including pension, postretirement and medical	1,943	1,701
Alternative minimum tax credit carryforwards	214	233
Other	659	340
Less: Valuation allowance	-4,721	-4,561
Total deferred tax assets	3,805	3,910
Depreciation, capitalized interest and other	-3,212	-3,201
Intangibles	-1,545	-1,585
Other	-48	-111
Total deferred tax liabilities	-4,805	-4,897
Net deferred tax liability	($1,000)	($987)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Federal pre-tax NOL carry forwards	$9,600,000,000
State tax benefits	111,000,000
Federal statutory income tax rate	35.00%
Cumulative loss position at the end of 2014	3 years
Current valuation allowances	4,751,000,000	4,591,000,000
Increase (decrease) in current valuation allowances	160,000,000
Unrecognized tax benefits	9,000,000	14,000,000	19,000,000	24,000,000
Unrecognized tax benefits that would impact effective tax rate if recognized	7,000,000
United Airlines, Inc.
Income Taxes [Line Items]
Current valuation allowances	4,721,000,000	4,561,000,000
Increase (decrease) in current valuation allowances	160,000,000
2024
Income Taxes [Line Items]
Net operating loss expiration amount	1,100,000,000
2025
Income Taxes [Line Items]
Net operating loss expiration amount	2,500,000,000
2026
Income Taxes [Line Items]
Net operating loss expiration amount	2,000,000,000
Thereafter
Income Taxes [Line Items]
Net operating loss expiration amount	$4,000,000,000
Minimum
Income Taxes [Line Items]
State tax benefits of the NOL carry forwards expiration period, years	5 years
Maximum
Income Taxes [Line Items]
State tax benefits of the NOL carry forwards expiration period, years	20 years

Reconciliation_of_Unrecognized

Reconciliation of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Balance at January 1,	$14	$19	$24
Decrease in unrecognized tax benefits relating to settlements with taxing authorities	-5		-12
Increase in unrecognized tax benefits as a result of tax positions taken during a prior period			8
Decrease in unrecognized tax benefits relating from a lapse of the statute of limitations		-5	-1
Balance at December 31,	$9	$14	$19

Reconciliation_of_Change_in_Pr

Reconciliation of Change in Projected Benefit Obligation and Plan Assets (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Balance at end of year	$312	$293	$256
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation:	4,068	3,383
Benefit obligation at beginning of year	4,000	4,526
Service cost	98	121	99
Interest cost	201	191	184
Actuarial (gain) loss	807	-464
Gross benefits paid and settlements	-281	-269
Curtailments		-84
Other	-22	-21
Benefit obligation at end of year	4,803	4,000	4,526
Balance at beginning of year	2,397	2,157
Actual return on plan assets	151	239
Employer contributions	307	277
Gross benefits paid and settlements	-281	-269
Other	-12	-7
Balance at end of year	2,562	2,397	2,157
Funded status-Net amount recognized	-2,241	-1,603
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,819	2,743
Service cost	19	52	50
Interest cost	88	110	124
Plan participants' contributions	67	67
Actuarial (gain) loss	262	-640
Federal subsidy	4	7
Plan amendments	-3	-331
Curtailments	8	8
Gross benefits paid	-212	-197
Benefit obligation at end of year	2,052	1,819	2,743
Balance at beginning of year	57	58
Actual return on plan assets	1	1
Employer contributions	144	128
Plan participants' contributions	67	67
Benefits paid	-212	-197
Balance at end of year	57	57	58
Funded status-Net amount recognized	($1,995)	($1,762)

Amounts_Recognized_in_Consolid

Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent asset	$2	$49
Current liability	-17	-2
Noncurrent liability	-2,226	-1,650
Total liability	-2,241	-1,603
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	-982	-162
Prior service credit (loss)	-1
Total accumulated other comprehensive income (loss)	-983	-162
Other Postretirement Benefits
Amounts recognized in the consolidated balance sheets consist of:
Current liability	-62	-59
Noncurrent liability	-1,933	-1,703
Total liability	-1,995	-1,762
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	233	555
Prior service credit (loss)	278	306
Total accumulated other comprehensive income (loss)	$511	$861

Accumulated_Benefit_Obligation

Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$4,625	$3,820
Accumulated benefit obligation	3,930	3,245
Fair value of plan assets	$2,387	$2,176

Components_of_Net_Periodic_Ben

Components of Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$98	$121	$99
Interest cost	201	191	184
Expected return on plan assets	-180	-163	-138
Curtailment loss		2
Amortization of prior service credits			-1
Settlement (gain) loss	1	-10	1
Amortization of unrecognized actuarial (gain) loss	12	48	21
Net periodic benefit cost	132	189	166
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	19	52	50
Interest cost	88	110	124
Expected return on plan assets	-2	-2	-2
Curtailment loss		2
Amortization of prior service credits	-31	-3
Amortization of unrecognized actuarial (gain) loss	-47	3	-3
Net periodic benefit cost	$27	$162	$169

Amortized_Accumulated_Other_Co

Amortized Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$87
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	-22
Prior service credit	($32)

Assumptions_Used_for_Benefit_P

Assumptions Used for Benefit Plans (Detail)	12 Months Ended
Assumptions Used for Benefit Plans (Detail)	Dec. 31, 2014	Dec. 31, 2013
Other Postretirement Benefits
Assumptions used to determine benefit obligations
Discount rate	4.07%	4.94%
Assumptions used to determine net expense
Discount rate	4.94%	4.12%
Expected return on plan assets	4.00%	4.00%
Health care cost trend rate assumed for next year	7.00%	7.25%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023)	5.00%	5.00%
Pension Benefits
Assumptions used to determine benefit obligations
Discount rate	4.20%	5.09%
Rate of compensation increase	3.66%	3.49%
Assumptions used to determine net expense
Discount rate	5.10%	4.48%
Expected return on plan assets	7.36%	7.56%
Rate of compensation increase	3.50%	2.48%

Allocation_of_Plan_Asset_Detai

Allocation of Plan Asset (Detail) (United Airlines, Inc.)	12 Months Ended
Allocation of Plan Asset (Detail) (United Airlines, Inc.)	Dec. 31, 2014
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	40.00%
Percent of Total, Maximum	54.00%
Expected Long-Term Rate of Return	10.00%
Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	26.00%
Percent of Total, Maximum	34.00%
Expected Long-Term Rate of Return	4.00%
Alternatives
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	14.00%
Percent of Total, Maximum	20.00%
Expected Long-Term Rate of Return	7.00%
Other Investments
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	4.00%
Percent of Total, Maximum	8.00%
Expected Long-Term Rate of Return	6.00%

Pension_and_Other_Postretireme2

Pension and Other Postretirement Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Effect on post retirement benefit obligation, 1% Decrease	$247
Effect on total service and interest cost, 1% Decrease	10
Profit sharing and payroll tax expense	235	190	119
Multiemployer Plans, Pension \| IAM National Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan contributions		368
Minimum
Defined Benefit Plan Disclosure [Line Items]
Percentage of pre-tax earnings paid for profit sharing plan	5.00%
Minimum \| Multiemployer Plans, Pension \| IAM National Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Percent of company's contribution to plan		5.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Percentage of pre-tax earnings paid for profit sharing plan	20.00%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Effect on post retirement benefit obligation, 1% Decrease	-220
Effect on total service and interest cost, 1% Decrease	-11
Employer contributions	144	128
Other Postretirement Benefits \| Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets	100.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	307	277
United Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	503	433	330
United Airlines, Inc. \| Multiemployer Plans, Pension \| IAM National Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan contributions	39	38	36
United Airlines, Inc. \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution, percentage	1.00%
United Airlines, Inc. \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution, percentage	16.00%
United Airlines, Inc. \| Other Postretirement Benefits \| Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Employer contributions				120
United Airlines, Inc. \| Pension Benefits \| Minimum \| Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Employer contributions				$400

Effect_of_OnePercentagePoint_C

Effect of One-Percentage-Point Change in Assumed Health Care Trend Rate (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest cost,1% Decrease	$10
Effect on post retirement benefit obligation, 1% Decrease	247
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest cost, 1% Increase	13
Effect on post retirement benefit obligation, 1% Increase	254
Effect on total service and interest cost,1% Decrease	-11
Effect on post retirement benefit obligation, 1% Decrease	($220)

Pension_and_Other_Postretireme3

Pension and Other Postretirement Plan Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	$312	$293	$256
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	2,562	2,397	2,157
Pension Benefits \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,181	1,158
Pension Benefits \| Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	813	702
Pension Benefits \| Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	359	405
Pension Benefits \| Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	21	26
Pension Benefits \| Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	188	106
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	57	57	58
Other Postretirement Benefits \| Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	57	57
Level 1 \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	388	389
Level 1 \| Pension Benefits \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	388	389
Level 2 \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,919	1,772
Level 2 \| Pension Benefits \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	793	769
Level 2 \| Pension Benefits \| Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	813	698
Level 2 \| Pension Benefits \| Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	148	199
Level 2 \| Pension Benefits \| Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	165	106
Level 3 \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	255	236
Level 3 \| Pension Benefits \| Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		4
Level 3 \| Pension Benefits \| Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	211	206
Level 3 \| Pension Benefits \| Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	21	26
Level 3 \| Pension Benefits \| Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	23
Level 3 \| Other Postretirement Benefits \| Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	$57	$57

Defined_Benefit_Plan_Assets_Me

Defined Benefit Plan Assets Measured at Fair Value Using Unobservable Inputs (Level Three) (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	$293	$256
Actual return on plan assets, Sold during the year	7	15
Actual return on plan assets, Held at year end	6	7
Purchases, sales, issuances and settlements (net)	6	15
Balance at end of year	$312	$293

Estimated_Future_Benefit_Payme

Estimated Future Benefit Payments (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2015	$299
2016	283
2017	294
2018	291
2019	293
Years 2020 - 2024	1,581
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2015	125
2016	126
2017	129
2018	132
2019	135
Years 2020 - 2024	732
Other Postretirement-Subsidy Receipts
Defined Benefit Plan Disclosure [Line Items]
2015	6
2016	7
2017	8
2018	9
2019	9
Years 2020 - 2024	$56

MultiEmployer_Plans_Detail

Multi-Employer Plans (Detail) (Multiemployer Plans, Pension, IAM National Pension Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Multiemployer Plans [Line Items]
EIN/ Pension Plan Number	51-6031295 - 002
Pension Protection Act Zone Status (2014 and 2013)	Green	[1]
FIP/RP Status Pending/Implemented	No
United's Contributions			$368
Surcharge Imposed	No
United Airlines, Inc.
Multiemployer Plans [Line Items]
United's Contributions	$39		$38	$36

[1]	Plans in the green zone are at least 80 percent funded.

MultiEmployer_Plans_Parentheti

Multi-Employer Plans (Parenthetical) (Detail) (Minimum, Multiemployer Plans, Pension, IAM National Pension Plan)	Dec. 31, 2014
Minimum \| Multiemployer Plans, Pension \| IAM National Pension Plan
Multiemployer Plans [Line Items]
Green zone funded percentage	80.00%

Financial_Assets_and_Liabiliti

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Convertible Debt Derivative Asset \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative asset	$712	$480
Convertible Debt Option Liability \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt option liability	-511	-270
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	2,002	3,220
Restricted cash	320	395
Fair Value, Measurements, Recurring \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,996	3,214
Restricted cash	320	395
Fair Value, Measurements, Recurring \| Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	901	694
Fair Value, Measurements, Recurring \| Asset-backed Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	901	694
Fair Value, Measurements, Recurring \| Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	876	685
Fair Value, Measurements, Recurring \| Corporate Debt \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	876	685
Fair Value, Measurements, Recurring \| CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	256	301
Fair Value, Measurements, Recurring \| CDARS \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	256	301
Fair Value, Measurements, Recurring \| U.S. Government and Agency Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	68	38
Fair Value, Measurements, Recurring \| U.S. Government and Agency Notes \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	68	38
Fair Value, Measurements, Recurring \| Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	26	105
Fair Value, Measurements, Recurring \| Auction Rate Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	26	105
Fair Value, Measurements, Recurring \| Other Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	255	78
Fair Value, Measurements, Recurring \| Other Fixed Income Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	255	78
Fair Value, Measurements, Recurring \| EETC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	28	61
Fair Value, Measurements, Recurring \| EETC \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	28	61
Fair Value, Measurements, Recurring \| Fuel derivatives asset (liability), net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	-717	104
Fair Value, Measurements, Recurring \| Fuel derivatives asset (liability), net \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	-717	104
Fair Value, Measurements, Recurring \| Foreign Currency Derivatives, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	2	1
Fair Value, Measurements, Recurring \| Foreign Currency Derivatives, Net \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	2	1
Fair Value, Measurements, Recurring \| Convertible Debt Derivative Asset \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative asset	712	480
Fair Value, Measurements, Recurring \| Convertible Debt Option Liability \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt option liability	-511	-270
Fair Value, Measurements, Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	2,002	3,220
Restricted cash	320	395
Fair Value, Measurements, Recurring \| Level 1 \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,996	3,214
Restricted cash	320	395
Fair Value, Measurements, Recurring \| Level 2 \| Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	901	694
Fair Value, Measurements, Recurring \| Level 2 \| Asset-backed Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	901	694
Fair Value, Measurements, Recurring \| Level 2 \| Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	876	685
Fair Value, Measurements, Recurring \| Level 2 \| Corporate Debt \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	876	685
Fair Value, Measurements, Recurring \| Level 2 \| CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	256	301
Fair Value, Measurements, Recurring \| Level 2 \| CDARS \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	256	301
Fair Value, Measurements, Recurring \| Level 2 \| U.S. Government and Agency Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	68	38
Fair Value, Measurements, Recurring \| Level 2 \| U.S. Government and Agency Notes \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	68	38
Fair Value, Measurements, Recurring \| Level 2 \| Other Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	255	78
Fair Value, Measurements, Recurring \| Level 2 \| Other Fixed Income Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	255	78
Fair Value, Measurements, Recurring \| Level 2 \| Fuel derivatives asset (liability), net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	-717	104
Fair Value, Measurements, Recurring \| Level 2 \| Fuel derivatives asset (liability), net \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	-717	104
Fair Value, Measurements, Recurring \| Level 2 \| Foreign Currency Derivatives, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	2	1
Fair Value, Measurements, Recurring \| Level 2 \| Foreign Currency Derivatives, Net \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	2	1
Fair Value, Measurements, Recurring \| Level 3 \| Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	26	105
Fair Value, Measurements, Recurring \| Level 3 \| Auction Rate Securities \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	26	105
Fair Value, Measurements, Recurring \| Level 3 \| EETC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	28	61
Fair Value, Measurements, Recurring \| Level 3 \| EETC \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	28	61
Fair Value, Measurements, Recurring \| Level 3 \| Convertible Debt Derivative Asset \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative asset	712	480
Fair Value, Measurements, Recurring \| Level 3 \| Convertible Debt Option Liability \| United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt option liability	($511)	($270)

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Jan. 31, 2014	Dec. 31, 2014	Oct. 10, 2014	Dec. 31, 2013	Jan. 31, 2015
Fair Value [Line Items]
Debt purchased and retired	$212
Unsecured Debt
Fair Value [Line Items]
Debt instrument convertible stated interest rate		4.50%
Debt instrument maturity year		2021
Debt instument converted amount		156
Asset-backed Securities \| Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			1 year
Asset-backed Securities \| Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			40 years
Corporate Debt \| Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			1 year
Corporate Debt \| Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			6 years
CDARS \| Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			1 year
U.S. Government and Other Securities \| Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			1 year
U.S. Government and Other Securities \| Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities			4 years
6% Convertible Junior Subordinated Debentures due 2030
Fair Value [Line Items]
Debt instrument convertible stated interest rate			6.00%
Debt instrument maturity year			2030
6% Convertible Junior Subordinated Debentures due 2030 \| United Airlines, Inc. \| Unsecured Debt
Fair Value [Line Items]
Debt instrument convertible stated interest rate			6.00%	6.00%	6.00%
Debt instrument maturity year			2030		2030
Debt purchased and retired				248
4.5% Convertible Notes Due 2015
Fair Value [Line Items]
Debt instrument convertible stated interest rate			4.50%
4.5% Convertible Notes Due 2015 \| Unsecured Debt
Fair Value [Line Items]
Debt instrument convertible stated interest rate			4.50%
Debt instrument maturity year			2015
Debt purchased and retired			28
4.5% Convertible Notes Due 2015 \| Subsequent Event \| Unsecured Debt
Fair Value [Line Items]
Debt instrument convertible stated interest rate						4.50%
Debt instument converted amount						$202
4.5% Convertible Notes Due 2015 \| United Airlines, Inc. \| Unsecured Debt
Fair Value [Line Items]
Debt instrument convertible stated interest rate			4.50%		4.50%
Debt instrument maturity year			2015		2015

Activity_for_Level_Three_Finan

Activity for "Level Three" Financial Assets and Financial Liabilities (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
United Airlines, Inc. \| Convertible Debt Option Liability
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	($270)	($128)
Purchases, (sales), issuances and settlements (net)	34
Realized	5
Unrealized	-280	-142
Reported in other comprehensive income (loss)	0	0
Ending Balance	-511	-270
United Airlines, Inc. \| Convertible Debt Derivative Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	480	268
Purchases, (sales), issuances and settlements (net)	-62
Realized	-5
Unrealized	299	212
Ending Balance	712	480
UAL and United \| Auction Rate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	105	116
Purchases, (sales), issuances and settlements (net)	-84	-19
Realized	10	3
Unrealized		1
Reported in other comprehensive income (loss)	-5	4
Ending Balance	26	105
UAL and United \| EETC
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	61	63
Purchases, (sales), issuances and settlements (net)	-33	-4
Realized	1
Reported in other comprehensive income (loss)	-1	2
Ending Balance	$28	$61

Carrying_Values_and_Estimated_

Carrying Values and Estimated Fair Values of Financial Instruments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Carrying (Reported) Amount, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$11,434	$11,539
Carrying (Reported) Amount, Fair Value Disclosure \| United Airlines, Inc.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	11,433	11,388
Estimate of Fair Value, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	12,386	12,695
Estimate of Fair Value, Fair Value Disclosure \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,568	8,829
Estimate of Fair Value, Fair Value Disclosure \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,818	3,866
Estimate of Fair Value, Fair Value Disclosure \| United Airlines, Inc.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	12,386	12,249
Estimate of Fair Value, Fair Value Disclosure \| United Airlines, Inc. \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,568	8,383
Estimate of Fair Value, Fair Value Disclosure \| United Airlines, Inc. \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$3,818	$3,866

Quantitative_Information_about

Quantitative Information about Level 3 Fair Value Measurements (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
EETC
Fair Value Measurements [Line Items]
Level 3 Financial Instruments, asset	$28
Valuation Technique	Discounted Cash Flows
Unobservable Input	Structure credit risk	[1]
EETC \| Structure Credit Risk
Fair Value Measurements [Line Items]
Level 3 fair value measurements, input value percentage	4.00%
Convertible Debt Derivative Asset
Fair Value Measurements [Line Items]
Level 3 Financial Instruments, asset	712
Valuation Technique	Binomial Lattice Model
Convertible Debt Derivative Asset \| Expected Volatility
Fair Value Measurements [Line Items]
Unobservable Input	Expected volatility	[2]
Level 3 fair value measurements, input value percentage	40.00%
Convertible Debt Derivative Asset \| Own Credit Risk
Fair Value Measurements [Line Items]
Unobservable Input	Own credit risk	[3]
Level 3 fair value measurements, input value percentage	5.00%
Convertible Debt Option Liability
Fair Value Measurements [Line Items]
Level 3 Financial Instruments, liability	-511
Valuation Technique	Binomial Lattice Model
Convertible Debt Option Liability \| Expected Volatility
Fair Value Measurements [Line Items]
Unobservable Input	Expected volatility	[2]
Level 3 fair value measurements, input value percentage	40.00%
Convertible Debt Option Liability \| Own Credit Risk
Fair Value Measurements [Line Items]
Unobservable Input	Own credit risk	[3]
Level 3 fair value measurements, input value percentage	5.00%
Auction Rate Securities
Fair Value Measurements [Line Items]
Level 3 Financial Instruments, asset	$26
Valuation Technique	Valuation Service / Broker Quotes
Unobservable Input	Broker quotes	[4]

[1]	Represents the credit risk premium of the EETC structure above the risk-free rate that the Company has determined market participants would use when pricing the instruments.
[2]	Represents the volatility estimate that the Company has determined market participants would use when pricing the instruments.
[3]	Represents the Company-specific risk adjustment that the Company has determined market participants would use as a model input.
[4]	Broker quotes obtained by a third-party valuation service.

Hedging_Activities_Additional_

Hedging Activities - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivatives And Hedging Activities [Line Items]
Fuel hedges expiration date	2016-03
Collateral fuel derivative	$577
2015 Projected
Derivatives And Hedging Activities [Line Items]
Percentage of projected fuel requirements	22.00%
Volume of fuel hedging	859,000,000
2016 Projected
Derivatives And Hedging Activities [Line Items]
Percentage of projected fuel requirements	1.00%
Volume of fuel hedging	35,000,000
Fuel Derivative Instruments
Derivatives And Hedging Activities [Line Items]
Collateral fuel derivative	$577	$0

Description_of_Derivative_Inst

Description of Derivative Instruments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Fuel contracts, assets	$6	$104
Fuel contracts, liabilities	723
Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	694
Receivables
Derivatives, Fair Value [Line Items]
Fuel contracts, assets	6	89
Other Assets
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		15
Other liabilities and deferred credits: Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	29
Designated as Hedging Instrument \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		25
Fuel contracts, liabilities	477
Designated as Hedging Instrument \| Cash Flow Hedging \| Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	450
Designated as Hedging Instrument \| Cash Flow Hedging \| Receivables
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		19
Designated as Hedging Instrument \| Cash Flow Hedging \| Other Assets
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		6
Designated as Hedging Instrument \| Cash Flow Hedging \| Other liabilities and deferred credits: Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	27
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fuel contracts, assets	6	79
Fuel contracts, liabilities	246
Not Designated as Hedging Instrument \| Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	244
Not Designated as Hedging Instrument \| Receivables
Derivatives, Fair Value [Line Items]
Fuel contracts, assets	6	70
Not Designated as Hedging Instrument \| Other Assets
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		9
Not Designated as Hedging Instrument \| Other liabilities and deferred credits: Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	$2

Offsetting_Assets_and_Liabilit

Offsetting Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset	($239)	$104
Receivables
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset		89
Other Assets
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset		15
Current liabilities: Other
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset	-209
Other liabilities and deferred credits: Other
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset	($30)

Schedule_of_Gains_Losses_on_De

Schedule of Gains (Losses) on Derivative Instruments (Detail) (Designated as Hedging Instrument, Cash Flow Hedging, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Designated as Hedging Instrument \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	($599)	$39
Gain (Loss) Reclassified from AOCI into Income (Fuel Expense) (Effective Portion)	-89	18
Amount of Gain (Loss) Recognized in Nonoperating income (expense): Miscellaneous, net (Ineffective Portion)	($3)	$5

Schedule_of_Derivative_Instrum

Schedule of Derivative Instruments not Designated as Hedges Gains (Losses) (Detail) (Not Designated as Hedging Instrument, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Nonoperating income (expense): Miscellaneous, net	($462)	$79	$38

Debt_Detail

Debt (Detail) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Gross	$248
Less: current portion of long-term debt-United	-1,313		-1,368
Long-term debt, net	10,121		10,171
United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	11,533		11,604
Less: unamortized debt discount	-99		-169
Less: current portion of long-term debt-United	-1,313		-1,368
Long-term debt, net	10,120		10,020
6% convertible senior notes due 2029
Debt Instrument [Line Items]
Long-term Debt, Gross			104
Secured Debt \| Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.88% as of December 31, 2014), payable through 2026 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	7,464		6,279
Secured Debt \| Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 5.46%, payable through 2026 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	1,151		1,243
Secured Debt \| Term Loan \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	884		893
Secured Debt \| Term Loan, due 2021 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	499
Secured Debt \| 6.75% senior secured notes due 2015 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross			800
Unsecured Debt \| Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	632	[1]	652	[1]
Unsecured Debt \| Senior Notes 6% Due 2020 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	300	[1]	300	[1]
Unsecured Debt \| 6.375% Senior Notes due 2018 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	300	[1]	300	[1]
Unsecured Debt \| 4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Long-term Debt, Gross	202
Unsecured Debt \| 4.5% Convertible Notes Due 2015 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	202		230
Unsecured Debt \| 8% Notes due 2024 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross			400	[1]
Unsecured Debt \| 6% Convertible Junior Subordinated Debentures due 2030 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross			248
Unsecured Debt \| 4.5% Senior Limited-Subordination Convertible Notes Due 2021 \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross			156
Unsecured Debt \| Other Debt \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	101		103
Adjusted For Embedded Conversion Options \| United Airlines, Inc.
Debt Instrument [Line Items]
Long-term debt, net	$10,121	[2]	$10,067	[2]

[1]	UAL is the issuer of this debt. United is a guarantor.
[2]	As further described below under "Convertible Debt Securities and Derivatives," there is a basis difference between UAL and United debt values, because we applied different accounting methodologies. The United debt presented above does not agree to United's balance sheet by the amount of this adjustment.

Debt_Parenthetical_Detail

Debt (Parenthetical) (Detail)	12 Months Ended				1 Months Ended	3 Months Ended
Debt (Parenthetical) (Detail)	Dec. 31, 2014		Dec. 31, 2013		Jan. 31, 2014	Mar. 31, 2014	Sep. 30, 2014	Nov. 30, 2013	31-May-13	Oct. 10, 2014
Senior Notes 6% Due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.38%
4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.50%
6% Convertible Junior Subordinated Debentures due 2030
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument, maturity date	2030
6% convertible senior notes due 2029
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%		6.00%
Debt instrument, maturity date	2029		2029
Secured Debt \| Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.88% as of December 31, 2014), payable through 2026 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate, minimum	1.42%		1.42%
Debt instrument stated interest rate, maximum	12.00%		12.00%
Weighted average interest rate	5.86%		5.86%
Debt instrument, maturity date	2026		2026
Secured Debt \| Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 5.46%, payable through 2026 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	2026		2026
Secured Debt \| Term Loan \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	2019		2019
Secured Debt \| Term Loan \| United Airlines, Inc. \| LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.75%		2.75%
Secured Debt \| Term Loan \| United Airlines, Inc. \| Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%		0.75%
Secured Debt \| Term Loan \| United Airlines, Inc. \| Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%		1.75%
Secured Debt \| Term Loan, due 2021 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	2021		2021
Secured Debt \| Term Loan, due 2021 \| United Airlines, Inc. \| LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	3.00%		3.00%
Secured Debt \| Term Loan, due 2021 \| United Airlines, Inc. \| Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%		0.75%
Secured Debt \| Term Loan, due 2021 \| United Airlines, Inc. \| Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.00%		2.00%
Secured Debt \| 6.75% senior secured notes due 2015 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.75%		6.75%				6.75%
Debt instrument, maturity date	2015		2015
Unsecured Debt
Debt Instrument [Line Items]
Debt instrument stated interest rate					4.50%
Debt instrument, maturity date					2021
Unsecured Debt \| Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%	[1]	6.00%	[1]
Unsecured Debt \| Senior Notes 6% Due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate								6.00%
Unsecured Debt \| Senior Notes 6% Due 2020 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%	[1]	6.00%	[1]
Debt instrument, maturity date	2020	[1]	2020	[1]
Unsecured Debt \| 6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate									6.38%
Unsecured Debt \| 6.375% Senior Notes due 2018 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.38%	[1]	6.38%	[1]
Debt instrument, maturity date	2018	[1]	2018	[1]
Unsecured Debt \| 4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.50%
Debt instrument, maturity date	2015
Unsecured Debt \| 4.5% Convertible Notes Due 2015 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.50%		4.50%
Debt instrument, maturity date	2015		2015
Unsecured Debt \| 8% Notes due 2024 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	8.00%	[1]	8.00%	[1]
Debt instrument, maturity date	2024	[1]	2024	[1]
Unsecured Debt \| 6% Convertible Junior Subordinated Debentures due 2030 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%		6.00%							6.00%
Debt instrument, maturity date	2030		2030
Unsecured Debt \| 4.5% Senior Limited-Subordination Convertible Notes Due 2021
Debt Instrument [Line Items]
Debt instrument stated interest rate						4.50%
Debt instrument, maturity date						2021
Unsecured Debt \| 4.5% Senior Limited-Subordination Convertible Notes Due 2021 \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.50%	[1]	4.50%	[1]
Debt instrument, maturity date	2021	[1]	2021	[1]
Minimum \| Secured Debt \| Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 5.46%, payable through 2026 \| United Airlines, Inc. \| LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.20%		0.20%
Minimum \| Unsecured Debt \| Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	2026	[1]	2026	[1]
Maximum \| Secured Debt \| Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 5.46%, payable through 2026 \| United Airlines, Inc. \| LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	5.46%		5.46%
Maximum \| Unsecured Debt \| Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight \| United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	2028	[1]	2028	[1]

[1]	UAL is the issuer of this debt. United is a guarantor.

Contractual_Principal_Payments

Contractual Principal Payments (Detail) (UAL and United, USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
UAL and United
Debt Instrument [Line Items]
2015	$1,313
2016	1,195
2017	755
2018	1,269
2019	1,721
After 2019	5,280
Long-term debt	$11,533

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

Share data in Millions, unless otherwise specified

Dec. 31, 2014

Mar. 31, 2014

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Jan. 31, 2014

Nov. 30, 2013

31-May-13

Jan. 31, 2015

Mar. 27, 2013

Sep. 30, 2014

Oct. 10, 2014

Mar. 31, 2014

Jan. 17, 2014

Debt Instrument [Line Items]

Debt purchased and retired

$212,000,000

Long-term Debt, Gross

248,000,000

Debt extinguishment charge

53,000,000

21,000,000

74,000,000

309,000,000

Aggregate principal amount of convertible senior notes exchanged

240,000,000

Senior Notes 6% Due 2020

Debt Instrument [Line Items]

Debt instrument stated interest rate

6.00%

6.375% Senior Notes due 2018

Debt Instrument [Line Items]

Debt instrument stated interest rate

6.38%

4.5% Convertible Notes Due 2015

Debt Instrument [Line Items]

Debt instrument stated interest rate

4.50%

6% Convertible Junior Subordinated Debentures due 2030

Debt Instrument [Line Items]

Debt instrument maturity year

2030

Debt instrument stated interest rate

6.00%

6% Convertible Senior Notes

Debt Instrument [Line Items]

Debt instrument maturity year

2029

Debt instrument stated interest rate

6.00%

Common stock issued in exchange for convertible notes

Debt instrument converted amount

104,000,000

Aggregate principal amount of convertible senior notes exchanged

104,000,000

240,000,000

Unsecured Debt

Debt Instrument [Line Items]

Debt instrument maturity year

2021

Debt instrument stated interest rate

4.50%

Common stock issued in exchange for convertible notes

Debt extinguishment charge

74,000,000

Debt instrument converted amount

156,000,000

Unsecured Debt | Senior Notes 6% Due 2020

Debt Instrument [Line Items]

Debt instrument maturity date

1-Dec-20

Debt instrument stated interest rate

6.00%

Aggregate principal amount

300,000,000

Debt instrument redemption percentage

101.00%

Unsecured Debt | 6.375% Senior Notes due 2018

Debt Instrument [Line Items]

Debt instrument maturity date

1-Jun-18

Debt instrument stated interest rate

6.38%

Aggregate principal amount

300,000,000

Unsecured Debt | 4.5% Convertible Notes Due 2015

Debt Instrument [Line Items]

Debt purchased and retired

28,000,000

Debt instrument maturity year

2015

Long-term Debt, Gross

202,000,000

Debt instrument stated interest rate

4.50%

Debt instrument conversion rate

18.93

Adjustment to additional paid in capital upon debt redemption

34,000,000

Unsecured Debt | 4.5% Convertible Notes Due 2015 | Subsequent Event

Debt Instrument [Line Items]

Long-term Debt, Gross

202,000,000

Debt instrument stated interest rate

4.50%

Common stock issued in exchange for convertible notes

Debt instrument converted amount

202,000,000

Unsecured Debt | 8% Notes due 2024

Debt Instrument [Line Items]

Aggregate principal amount of debt redeemed

400,000,000

Unsecured Debt | 4.5% Senior Limited-Subordination Convertible Notes Due 2021

Debt Instrument [Line Items]

Debt instrument maturity year

2021

Debt instrument stated interest rate

4.50%

Debt instrument conversion rate

30.6419

Debt instrument converted amount

156,000,000

Debt instrument converted shares issued

Term Loan Facility | Secured Debt

Debt Instrument [Line Items]

Credit Agreement

900,000,000

Debt instrument maturity date

1-Apr-19

Amount utilized to repay term loan

900,000,000

Revolving Credit Facility | Secured Debt

Debt Instrument [Line Items]

Credit Agreement

1,000,000,000

1,315,000,000

Debt instrument maturity date

2-Jan-19

Revolving credit facility available for drawing date

1-Apr-18

Revolving Credit Facility | Secured Debt | Before amendment

Debt Instrument [Line Items]

Credit Agreement

1,000,000,000

Revolving Credit Facility | Secured Debt | After amendment

Debt Instrument [Line Items]

Credit Agreement

1,350,000,000

Amended Credit Facility | Secured Debt

Debt Instrument [Line Items]

Cash utilized to repay term loan

300,000,000

Debt purchased and retired

1,200,000,000

Debt instrument maturity year

2014

Performance Bonds | Secured Debt

Debt Instrument [Line Items]

Credit facility expiration year

2019

United Airlines, Inc.

Debt Instrument [Line Items]

Long-term Debt, Gross

11,533,000,000

11,604,000,000

Difference in long term debt noncurrent

1,000,000

47,000,000

United Airlines, Inc. | Convertible Debt Derivative Asset

Debt Instrument [Line Items]

Convertible debt derivative asset

712,000,000

480,000,000

United Airlines, Inc. | Convertible Debt Option Liability

Debt Instrument [Line Items]

Convertible debt option liability

511,000,000

270,000,000

United Airlines, Inc. | Pass-through certificates

Debt Instrument [Line Items]

Long term debt

7,200,000,000

United Airlines, Inc. | Secured Debt | 6.75% senior secured notes due 2015

Debt Instrument [Line Items]

Debt purchased and retired

800,000,000

Debt instrument maturity year

2015

Long-term Debt, Gross

800,000,000

Debt instrument stated interest rate

6.75%

United Airlines, Inc. | Unsecured Debt | Senior Notes 6% Due 2020

Debt Instrument [Line Items]

Debt instrument maturity year

2020

[1]

2020

[1]

Long-term Debt, Gross

300,000,000

[1]

300,000,000

[1]

300,000,000

[1]

Debt instrument stated interest rate

6.00%

[1]

6.00%

[1]

6.00%

[1]

United Airlines, Inc. | Unsecured Debt | 6.375% Senior Notes due 2018

Debt Instrument [Line Items]

Debt instrument maturity year

2018

[1]

2018

[1]

Long-term Debt, Gross

300,000,000

[1]

300,000,000

[1]

300,000,000

[1]

Debt instrument stated interest rate

6.38%

[1]

6.38%

[1]

6.38%

[1]

United Airlines, Inc. | Unsecured Debt | 4.5% Convertible Notes Due 2015

Debt Instrument [Line Items]

Debt instrument maturity year

2015

Long-term Debt, Gross

202,000,000

230,000,000

Debt instrument stated interest rate

4.50%

Adjustment to additional paid in capital upon debt redemption

62,000,000

Debt instrument convertible effective interest rate

4.50%

United Airlines, Inc. | Unsecured Debt | 8% Notes due 2024

Debt Instrument [Line Items]

Debt instrument maturity year

2024

[1]

2024

[1]

Long-term Debt, Gross

400,000,000

[1]

Debt instrument stated interest rate

8.00%

[1]

8.00%

[1]

8.00%

[1]

United Airlines, Inc. | Unsecured Debt | 6% Convertible Junior Subordinated Debentures due 2030

Debt Instrument [Line Items]

Debt purchased and retired

248,000,000

Debt instrument maturity year

2030

Long-term Debt, Gross

248,000,000

Debt instrument stated interest rate

6.00%

Debt extinguishment charge

64,000,000

United Airlines, Inc. | Unsecured Debt | 4.5% Senior Limited-Subordination Convertible Notes Due 2021

Debt Instrument [Line Items]

Debt instrument maturity year

2021

[1]

2021

[1]

Long-term Debt, Gross

156,000,000

Debt instrument stated interest rate

4.50%

[1]

4.50%

[1]

4.50%

[1]

United Airlines, Inc. | Term Loan Facility

Debt Instrument [Line Items]

Credit Agreement

900,000,000

500,000,000

Credit agreement, outstanding

884,000,000

499,000,000

Debt instrument maturity date

2021-09

United Airlines, Inc. | Term Loan Facility | LIBOR

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

3.00%

United Airlines, Inc. | Term Loan Facility | Interest Rate Floor

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

0.75%

United Airlines, Inc. | Revolving Credit Facility

Debt Instrument [Line Items]

Commitment fee percentage

0.75%

United Airlines, Inc. | Revolving Credit Facility | LIBOR

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

3.00%

United Airlines, Inc. | Revolving Credit Facility | Certain Market Interest Rates

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

2.00%

United Airlines, Inc. | Revolving Credit Facility | Secured Debt

Debt Instrument [Line Items]

Available under revolving credit facility

1,350,000,000

United Airlines, Inc. | Term Loan | Secured Debt

Debt Instrument [Line Items]

Debt instrument maturity date

1-Apr-19

Long-term Debt, Gross

893,000,000

Quarterly principal repayment amount

0.25%

Commencement date of installment payment

30-Jun-13

United Airlines, Inc. | Term Loan | Secured Debt | LIBOR | Before amendment

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

3.00%

United Airlines, Inc. | Term Loan | Secured Debt | LIBOR | After amendment

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

2.75%

United Airlines, Inc. | Term Loan | Secured Debt | Interest Rate Floor

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

0.75%

United Airlines, Inc. | Letters of credit | Cash Collateralized Letters of Credit

Debt Instrument [Line Items]

Credit agreement, outstanding

74,000,000

United Airlines, Inc. | Letter of Credit and Performance Bonds

Debt Instrument [Line Items]

Credit agreement, outstanding

$410,000,000

[1]

UAL is the issuer of this debt. United is a guarantor.

Details_of_Pass_Through_Trusts

Details of Pass Through Trusts (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Total debt recorded	$248
Proceeds received from issuance of debt	1,432	1,423	1,121
United Airlines, Inc.
Debt Instrument [Line Items]
Total debt recorded	11,533	11,604
Proceeds received from issuance of debt	1,432	1,423	1,121
United Airlines, Inc. \| Class A Pass Through Certificates \| August 2014
Debt Instrument [Line Items]
Principal	823
Final expected distribution date	2026-09
Stated interest rate	3.75%
Total debt recorded	112
Proceeds received from issuance of debt	112
Remaining proceeds from issuance of debt to be received in future periods	711
United Airlines, Inc. \| Class A Pass Through Certificates \| April 2014
Debt Instrument [Line Items]
Principal	736
Final expected distribution date	2026-04
Stated interest rate	4.00%
Total debt recorded	736
Proceeds received from issuance of debt	736
United Airlines, Inc. \| Class A Pass Through Certificates \| August 2013
Debt Instrument [Line Items]
Principal	720
Final expected distribution date	2025-08
Stated interest rate	4.30%
Total debt recorded	720
Proceeds received from issuance of debt	567
United Airlines, Inc. \| Class B Pass Through Certificates \| August 2014
Debt Instrument [Line Items]
Principal	238
Final expected distribution date	2022-09
Stated interest rate	4.63%
Total debt recorded	32
Proceeds received from issuance of debt	32
Remaining proceeds from issuance of debt to be received in future periods	206
United Airlines, Inc. \| Class B Pass Through Certificates \| April 2014
Debt Instrument [Line Items]
Principal	213
Final expected distribution date	2022-04
Stated interest rate	4.75%
Total debt recorded	213
Proceeds received from issuance of debt	213
United Airlines, Inc. \| Class B Pass Through Certificates \| August 2013
Debt Instrument [Line Items]
Principal	209
Final expected distribution date	2021-08
Stated interest rate	5.38%
Total debt recorded	209
Proceeds received from issuance of debt	165
United Airlines, Inc. \| EETC
Debt Instrument [Line Items]
Principal	2,939
Total debt recorded	2,022
Proceeds received from issuance of debt	1,825
Remaining proceeds from issuance of debt to be received in future periods	$917

Summary_of_Collateral_Covenant

Summary of Collateral Covenants and Cross Default Provisions (Detail)	12 Months Ended
	Dec. 31, 2014
Credit Agreement
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	Secured by certain of United's international route authorities, specified take-off and landing slots at certain airports and certain other assets. The Credit Agreement requires the Company to maintain at least $3.0 billion of unrestricted liquidity at all times, which includes unrestricted cash, short-term investments and any undrawn amounts under any revolving credit facility and to maintain a minimum ratio of appraised value of collateral to the outstanding obligations under the Credit Agreement of 1.67 to 1.0 at all times. The Credit Agreement contains covenants that, among other things, restrict the ability of UAL and its restricted subsidiaries (as defined in the Credit Agreement) to incur additional indebtedness and to pay dividends on or repurchase stock. The Credit Agreement contains events of default customary for this type of financing, including a cross default and cross acceleration provision to certain other material indebtedness of the Company.
United Air Lines 6% Notes Due 2026
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	The amended and restated indenture for these notes, which are unsecured, contains covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock. These covenants cease to be in effect when the indenture covering the 6.375% Senior Notes due 2018 is discharged. The indenture contains events of default that are customary for similar financings.
United Air Lines 6% Notes Due 2028
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	The amended and restated indenture for these notes, which are unsecured, contains covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock. These covenants cease to be in effect when the indenture covering the 6.375% Senior Notes due 2018 is discharged. The indenture contains events of default that are customary for similar financings.
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	The indentures for these notes, which are unsecured, contain covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock. The indentures contain events of default that are customary for similar financings.
Senior Notes 6% Due 2020
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	The indentures for these notes, which are unsecured, contain covenants that, among other things, restrict the ability of the Company and its restricted subsidiaries (as defined in the indenture) to incur additional indebtedness and pay dividends on or repurchase stock. The indentures contain events of default that are customary for similar financings.

Summary_of_Collateral_Covenant1

Summary of Collateral Covenants and Cross Default Provisions (Parenthetical) (Detail) (USD $)	12 Months Ended
In Billions, unless otherwise specified	Dec. 31, 2014
Credit Agreement
Debt Instrument [Line Items]
Unrestricted liquidity required for credit agreement	3
Minimum ratio of appraised value of collateral for Credit Agreement	1.67
United Air Lines 6% Notes Due 2026
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2026
United Air Lines 6% Notes Due 2028
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2028
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.38%
Debt instrument maturity year	2018
Senior Notes 6% Due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2020

Advanced_Purchase_of_Miles_Add

Advanced Purchase of Miles - Additional Information (Detail) (United Airlines, Inc., Co-Brand Agreement, Maximum, Advanced Purchase of Miles, USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
United Airlines, Inc. \| Co-Brand Agreement \| Maximum \| Advanced Purchase of Miles
Airline Products and Services [Line Items]
Repurchase of pre-purchased miles from Chase in 2015	$224
Repurchase of pre-purchased miles from Chase in 2016	$249

Future_Minimum_Lease_Payments_

Future Minimum Lease Payments for Capital and Operating Leases (Detail) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Capital Leases
2015	$168	[1]
2016	154	[1]
2017	115	[1]
2018	104	[1]
2019	38	[1]
After 2019	495	[1]
Minimum lease payments	1,074	[1]
Imputed interest	-393	[1]
Present value of minimum lease payments	681	[1]
Current portion	-110	[1]	-117
Long-term obligations under capital leases	571	[1]	753
Present value of minimum lease payments	681	[1]
Facility and Other Operating Leases
Operating Leases
2015	1,283	[2]
2016	1,123	[2]
2017	1,089	[2]
2018	842	[2]
2019	766	[2]
After 2019	7,919	[2]
Minimum lease payments	13,022	[2]
Aircraft Operating Leases
Operating Leases
2015	1,446	[3]
2016	1,247	[3]
2017	1,147	[3]
2018	908	[3]
2019	682	[3]
After 2019	1,910	[3]
Minimum lease payments	$7,340	[3]

[1]	As of December 31, 2014, United's aircraft capital lease minimum payments relate to leases of 37 mainline and 38 regional aircraft as well as to leases of nonaircraft assets. Imputed interest rate ranges are 3.5% to 18.3%.
[2]	See Note 17 of this report for additional information related to facility and other operating leases at Hopkins International Airport ("Cleveland").
[3]	The operating lease payments presented above include future payments of $72 million related to 21 nonoperating aircraft as of December 31, 2014.

Future_Minimum_Lease_Payments_1

Future Minimum Lease Payments for Capital and Operating Leases (Parenthetical) (Detail) (United Airlines, Inc., USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Mainline
Capital Leases And Operating Leases [Line Items]
Number of assets subject to lease	37
Regional Carrier
Capital Leases And Operating Leases [Line Items]
Number of assets subject to lease	38
Nonoperating Aircraft
Capital Leases And Operating Leases [Line Items]
Operating lease future payments	72
Number of assets subject to lease	21
Minimum
Capital Leases And Operating Leases [Line Items]
Imputed interest rate	3.50%
Maximum
Capital Leases And Operating Leases [Line Items]
Imputed interest rate	18.30%

Leases_and_Capacity_Purchase_A2

Leases and Capacity Purchase Agreements - Additional Information (Detail) (USD $)	12 Months Ended				1 Months Ended	3 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Apr. 30, 2013	Dec. 31, 2014		31-May-13	Dec. 31, 2015	Sep. 30, 2014	Nov. 30, 2013
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Aircraft	Aircraft		Aircraft	Aircraft	Aircraft	Nov. 30, 2013
Operating Leased Assets [Line Items]
Regional capacity purchase expense	$2,344,000,000		$2,419,000,000	$2,470,000,000
Scenario Forecast \| Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Scheduled block hours increase (decrease) percentage	10.00%
Change in cash obligation	152,000,000
Cash obligation increase (decrease) percentage	8.00%
United Airlines, Inc.
Operating Leased Assets [Line Items]
Nonaircraft rent expense	1,400,000,000		1,300,000,000	1,300,000,000
Regional capacity purchase expense	2,344,000,000		2,419,000,000	2,470,000,000
United Airlines, Inc. \| Revaluation of Liabilities
Operating Leased Assets [Line Items]
Net accretion amounts	160,000,000		173,000,000	240,000,000		160,000,000
United Airlines, Inc. \| Variable Interest Entity, Not Primary Beneficiary
Operating Leased Assets [Line Items]
Operating leases obligations	1,500,000,000					1,500,000,000
United Airlines, Inc. \| Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Number of aircraft operated	566				30	14
Airline capacity purchase arrangements, expiration year	2029
Number of aircraft purchase					30
United Airlines, Inc. \| Regional Aircraft
Operating Leased Assets [Line Items]
Regional capacity purchase expense	442,000,000		428,000,000	463,000,000
United Airlines, Inc. \| Minimum
Operating Leased Assets [Line Items]
Lease Fair Value Adjustment, Remaining Lease Term	1 year
United Airlines, Inc. \| Maximum
Operating Leased Assets [Line Items]
Lease Fair Value Adjustment, Remaining Lease Term	10 years
SkyWest \| Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Number of aircraft operated	19
Number of aircraft to operate								40
SkyWest \| Scenario Forecast \| Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Number of aircraft operated									21
Aircraft Operating Leases
Operating Leased Assets [Line Items]
Operating leases obligations	7,340,000,000	[1]				7,340,000,000	[1]
Aircraft Operating Leases \| Minimum
Operating Leased Assets [Line Items]
Operating lease term	6 years
Operating lease expiration date, in years	2015
Aircraft Operating Leases \| Maximum
Operating Leased Assets [Line Items]
Operating lease term	28 years
Operating lease expiration date, in years	2024
Aircraft Operating Leases \| United Airlines, Inc.
Operating Leased Assets [Line Items]
Number of aircraft operated										70
Aircraft Operating Leases \| United Airlines, Inc. \| Embraer E175 Aircraft \| New Lease Arrangement
Operating Leased Assets [Line Items]
Number of aircraft operated										50
Aircraft Operating Leases \| United Airlines, Inc. \| Embraer E175 Aircraft \| Extension of Term
Operating Leased Assets [Line Items]
Number of aircraft operated										38
Aircraft Operating Leases \| United Airlines, Inc. \| Q400 Aircraft
Operating Leased Assets [Line Items]
Number of aircraft operated										31
Facility and Other Operating Leases
Operating Leased Assets [Line Items]
Operating lease extended expiration year	2041
Operating leases obligations	13,022,000,000	[2]				13,022,000,000	[2]
Facility and Other Operating Leases \| Denver International Airport
Operating Leased Assets [Line Items]
Operating lease term										10 years
Operating lease original expiration year										2025
Aircraft Leases \| United Airlines, Inc. \| Embraer E175 Aircraft
Operating Leased Assets [Line Items]
Number of aircraft right to acquire										50
Lease Amendment \| United Airlines, Inc.
Operating Leased Assets [Line Items]
Additional investment commitments											$450,000,000

[1]	The operating lease payments presented above include future payments of $72 million related to 21 nonoperating aircraft as of December 31, 2014.
[2]	See Note 17 of this report for additional information related to facility and other operating leases at Hopkins International Airport ("Cleveland").

Future_Lease_Payment_Under_Ter

Future Lease Payment Under Terms of Capacity Purchase Agreement (Detail) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
2015	$1,893
2016	1,760
2017	1,653
2018	1,301
2019	973
After 2019	3,497
Contractual Obligation, Total	$11,077

Variable_Interest_Entities_Add

Variable Interest Entities - Additional Information (Detail) (Variable Interest Entity, Not Primary Beneficiary)	Dec. 31, 2014
	Aircraft
Mainline
Variable Interest Entity [Line Items]
Aircraft under operating lease, fixed purchase options	60
Regional Carrier
Variable Interest Entity [Line Items]
Aircraft under operating lease	239

Firm_Commitments_to_Purchase_A

Firm Commitments to Purchase Aircraft (Detail) (United Airlines, Inc., Capital Addition Purchase Commitments)	Dec. 31, 2014
	Aircraft
Airbus A350-1000 Aircraft
Commitments [Line Items]
Number of new aircraft committed to purchase	35	[1],[2]
Boeing 737-900ER aircraft
Commitments [Line Items]
Number of new aircraft committed to purchase	34	[1],[2]
Boeing 737 MAX 9 Aircraft
Commitments [Line Items]
Number of new aircraft committed to purchase	100	[1],[2]
Boeing 787-9/-10 Aircraft
Commitments [Line Items]
Number of new aircraft committed to purchase	51	[1],[2]
Embraer E175 Aircraft
Commitments [Line Items]
Number of new aircraft committed to purchase	11	[1],[2]

[1]	United also has options and purchase rights for additional aircraft.
[2]	United also has committed to purchase two used 737-700 aircraft in 2015.

Firm_Commitments_to_Purchase_A1

Firm Commitments to Purchase Aircraft (Parenthetical) (Detail) (737-700 aircraft)	Dec. 31, 2014
	Aircraft
737-700 aircraft
Commitments [Line Items]
Number of aircrafts committed to purchase in 2015	2

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	Employee	Dec. 31, 2013
Commitments and Contingencies [Line Items]
Debt instrument principal amount	$248,000,000
Floating Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	2,500,000,000
Fixed Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	159,000,000
Loans And Leases From Non-U.S Entities
Commitments and Contingencies [Line Items]
Debt instrument principal amount	2,700,000,000
Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	1,800,000,000
Operating leases obligations	1,500,000,000
Capital leases obligations	290,000,000
Tax-exempt special facilities revenue bonds \| Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	1,400,000,000
Contingent liabilities based on participation	239,000,000
Minimum \| Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2015
Minimum \| Tax-exempt special facilities revenue bonds \| Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2015
Maximum
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms (years)	12 years
Maximum \| Loans And Leases From Non-U.S Entities
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms (years)	12 years
Maximum \| Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2038
Maximum \| Tax-exempt special facilities revenue bonds \| Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2041
United Airlines, Inc.
Commitments and Contingencies [Line Items]
Debt instrument principal amount	$11,533,000,000	$11,604,000,000
Number of employees	84,000
Percentage of employees represented by various U.S. labor organizations	80.00%
Capital Addition Purchase Commitments \| United Airlines, Inc.
Commitments and Contingencies [Line Items]
Number of aircraft under financing arrangement expected to be delivered	20
Capital Addition Purchase Commitments \| United Airlines, Inc. \| Boeing 787-9 aircraft
Commitments and Contingencies [Line Items]
Number of aircraft under financing arrangement expected to be delivered	4
Capital Addition Purchase Commitments \| United Airlines, Inc. \| Embraer E175 Aircraft
Commitments and Contingencies [Line Items]
Number of aircraft under financing arrangement expected to be delivered	5
Capital Addition Purchase Commitments \| United Airlines, Inc. \| Boeing 737-900ER aircraft
Commitments and Contingencies [Line Items]
Number of aircraft under financing arrangement expected to be delivered	11
Capital Addition Purchase Commitments \| United Airlines, Inc. \| Minimum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date	2015
Capital Addition Purchase Commitments \| United Airlines, Inc. \| Maximum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date	2025

Schedule_of_Acquisition_of_Air

Schedule of Acquisition of Aircrafts and Related Spare Engines (Detail) (USD $)	Dec. 31, 2014
In Billions, unless otherwise specified	Dec. 31, 2014
Unrecorded Unconditional Purchase Obligation [Line Items]
2015	$3.20
2016	2.3
2017	1.3
2018	2.2
2019	3.3
After 2019	10.7
Total commitments	$23

Supplemental_Disclosures_of_Ca

Supplemental Disclosures of Cash Flow Information and Non-Cash Investing and Financing Activities (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash paid (refunded) during the period for:
Interest (net of amounts capitalized)	$748	$752	$766
Income taxes	-16	-20	2
Non-cash transactions:
Net property and equipment acquired through issuance of debt	1,114	229	544
8% Contingent Senior Notes and 6% Senior Notes due 2031, net of discount			357
Special facility payment financing			101
Airport construction financing	14	40	50
Exchanges of certain 4.5% Note and 6% Convertible Senior Notes for common stock		240
UAL 4.5% and 6% Senior Convertible Notes
Non-cash transactions:
Exchanges of certain 4.5% Note and 6% Convertible Senior Notes for common stock	260
United Airlines, Inc.
Cash paid (refunded) during the period for:
Interest (net of amounts capitalized)	748	752	766
Income taxes	-16	-15	4
Non-cash transactions:
Net property and equipment acquired through issuance of debt	1,114	229	544
8% Contingent Senior Notes and 6% Senior Notes due 2031, net of discount			357
Special facility payment financing			101
Airport construction financing	14	40	50
Transfer of UAL subsidiaries to United	186
United Airlines, Inc. \| UAL 4.5% and 6% Senior Convertible Notes
Non-cash transactions:
Exchanges of certain 4.5% Note and 6% Convertible Senior Notes for common stock	$156

Supplemental_Disclosures_of_Ca1

Supplemental Disclosures of Cash Flow Information and Non-Cash Investing and Financing Activities (Parenthetical) (Detail)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
UAL 6% Senior Convertible Notes
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate	6.00%	6.00%	6.00%
UAL 6% Senior Convertible Notes \| United Airlines, Inc.
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate	6.00%	6.00%	6.00%
UAL 4.5% Senior Convertible Notes
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate	4.50%
UAL 4.5% Senior Convertible Notes \| United Airlines, Inc.
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate	4.50%
UAL 8% Contingent Senior Notes
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate			8.00%
UAL 8% Contingent Senior Notes \| United Airlines, Inc.
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument stated interest rate			8.00%

Components_of_Special_Charges_

Components of Special Charges (Detail) (USD $)	3 Months Ended									12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating:
Severance and benefit costs	$141	$6	$38	$14	$91			$14	$76	$199	$105	$125
Integration-related costs	17	28	17	34	40	50	45	70		96	205	739
Impairment of assets	16		32	1	33					49	33	30
Labor agreement costs						127					127	475
(Gains) losses on sale of assets and other special (gains) losses, net	5	9	16	3	1	34	7	8		33	50	-46
Special charges	179	43	169	52						443	520	1,323
Nonoperating:
Loss on extinguishment of debt and other, net	53			21						74		309
Income tax benefit										-10	-7	-11
Total operating and nonoperating special charges, net of income taxes	226	40	169	72						507	513	1,312
Permanently grounded Embraer ERJ 135 aircraft
Operating:
Costs associated with permanently grounding Embraer ERJ 135 aircraft			$66							$66

IntegrationRelated_Costs_and_S2

Integration-Related Costs and Special Items - Additional Information (Detail) (USD $)	3 Months Ended									12 Months Ended			1 Months Ended	3 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2014	Mar. 31, 2012
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Attendant	Dec. 31, 2014	Employee	Dec. 31, 2012	Jan. 31, 2014	Attendant
Special Charges [Line Items]
Severance and benefits	$141,000,000	$6,000,000	$38,000,000	$14,000,000	$91,000,000			$14,000,000	$76,000,000	$199,000,000	$105,000,000	$125,000,000
Number of positions eliminated									1,300		1,200
Impairment charges of equipment held for disposal										33,000,000
Impairment of indefinite-lived intangible assets, net of tax benefits										10,000,000
Impairment of indefinite-lived intangible assets										16,000,000	1,000,000	30,000,000
Debt instrument principal amount	248,000,000									248,000,000
Debt extinguishment charge	53,000,000			21,000,000						74,000,000		309,000,000
Labor agreement costs						127,000,000					127,000,000	475,000,000
Adjustment of reserves for certain legal matters											29,000,000
Gain related to contract termination											5,000,000
Loss on sale of asset											3,000,000
Fair value of liabilities extinguished												212,000,000
Aircraft-related charges (gains), net	-5,000,000	-9,000,000	-16,000,000	-3,000,000	-1,000,000	-34,000,000	-7,000,000	-8,000,000		-33,000,000	-50,000,000	46,000,000
International Association of Machinists
Special Charges [Line Items]
Labor agreement costs											127,000,000
Unsecured Debt
Special Charges [Line Items]
Debt instrument stated interest rate													4.50%
Debt extinguishment charge										74,000,000
Debt instrument maturity year													2021
6% Convertible Junior Subordinated Debentures
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%									6.00%
6% Convertible preferred securities
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%									6.00%
UAL 8% Contingent Senior Notes
Special Charges [Line Items]
Debt instrument stated interest rate												8.00%
Debt instrument convertible effective interest rate												8.00%
Principal amount of senior notes												188,000,000
United Air Lines 8% Senior Notes Due 2024
Special Charges [Line Items]
Debt instrument convertible effective interest rate												8.00%
Principal amount of senior notes												400,000,000
UAL 6% Senior Convertible Notes
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%				6.00%					6.00%	6.00%	6.00%
Debt instrument convertible effective interest rate												6.00%
Principal amount of senior notes												652,000,000
Debt instrument maturity year												2031
United Air Lines 6% Notes Due 2026
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%									6.00%
Debt instrument convertible effective interest rate												6.00%
Principal amount of senior notes												326,000,000
Debt instrument maturity year												2026
United Air Lines 6% Notes Due 2028
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%									6.00%
Debt instrument convertible effective interest rate												6.00%
Principal amount of senior notes												326,000,000
Debt instrument maturity year												2028
Permanently grounded Embraer ERJ 135 aircraft
Special Charges [Line Items]
Costs associated with aircraft			66,000,000							66,000,000
Number of leased aircraft										21
Lease expiry year										2018
Number of aircraft in operation										9
Boeing 737-300 and 737-500 fleets
Special Charges [Line Items]
Impairment charges of equipment held for disposal											32,000,000
Temporarily grounded Boeing 787 aircraft
Special Charges [Line Items]
Costs associated with aircraft											18,000,000
Cleveland [Member]
Special Charges [Line Items]
Severance and benefits										58,000,000
Voluntary early out program
Special Charges [Line Items]
Severance and benefits										141,000,000
Number of positions eliminated										2,500
Voluntary early out program \| Scenario Forecast
Special Charges [Line Items]
Severance and benefits										100,000,000
Voluntary early out program \| Maximum
Special Charges [Line Items]
Severance payment per participant	100,000									100,000
Voluntary retirement program
Special Charges [Line Items]
Severance and benefits											64,000,000			32,000,000
Number of positions eliminated														400
Number of leased aircraft											4
Accruals for future rent					11,000,000						11,000,000
Voluntary leave of absence program
Special Charges [Line Items]
Severance and benefits											26,000,000			17,000,000
Number of positions eliminated														1,800
Involuntary severance programs
Special Charges [Line Items]
Severance and benefits											15,000,000
United Continental Holdings Inc
Special Charges [Line Items]
Labor agreement costs												475,000,000
United Continental Holdings Inc \| Pilot Disability Plan
Special Charges [Line Items]
Labor agreement costs												80,000,000
United Airlines, Inc.
Special Charges [Line Items]
Debt instrument principal amount	11,533,000,000				11,604,000,000					11,533,000,000	11,604,000,000
Aircraft-related charges (gains), net												$46,000,000
United Airlines, Inc. \| UAL 8% Contingent Senior Notes
Special Charges [Line Items]
Debt instrument stated interest rate												8.00%
United Airlines, Inc. \| UAL 6% Senior Convertible Notes
Special Charges [Line Items]
Debt instrument stated interest rate	6.00%				6.00%					6.00%	6.00%	6.00%

Accrual_Activity_Detail

Accrual Activity (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Severance/ Medical Costs
Schedule Of Accrual Activity [Line Items]
Beginning Balance	$91	$65	$55
Accrual	199	120	170
Payments	-181	-94	-160
Ending Balance	109	91	65
Permanently Grounded Aircraft
Schedule Of Accrual Activity [Line Items]
Beginning Balance	11	5	31
Accrual	102	10	-1
Payments	-11	-4	-25
Ending Balance	$102	$11	$5

Segment_Information_Additional

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Segment
Segment Reporting Information [Line Items]
Number of Operating Segments	1

Operating_Revenue_by_Principle

Operating Revenue by Principle Geographic Region (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total revenues	$9,313	$10,563	$10,329	$8,696	$9,329	$10,228	$10,001	$8,721	$38,901	$38,279	$37,152
Domestic (U.S. and Canada)
Segment Reporting Information [Line Items]
Total revenues									22,320	22,092	21,276
Pacific
Segment Reporting Information [Line Items]
Total revenues									5,767	5,794	6,040
Atlantic
Segment Reporting Information [Line Items]
Total revenues									7,321	7,132	6,582
Latin America
Segment Reporting Information [Line Items]
Total revenues									3,493	3,261	3,254
United Airlines, Inc.
Segment Reporting Information [Line Items]
Total revenues									38,901	38,287	37,160
United Airlines, Inc. \| Domestic (U.S. and Canada)
Segment Reporting Information [Line Items]
Total revenues									22,320	22,100	21,284
United Airlines, Inc. \| Pacific
Segment Reporting Information [Line Items]
Total revenues									5,767	5,794	6,040
United Airlines, Inc. \| Atlantic
Segment Reporting Information [Line Items]
Total revenues									7,321	7,132	6,582
United Airlines, Inc. \| Latin America
Segment Reporting Information [Line Items]
Total revenues									$3,493	$3,261	$3,254

Schedule_of_Selected_Quarterly

Schedule of Selected Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Data [Line Items]
Operating revenue	$9,313	$10,563	$10,329	$8,696	$9,329	$10,228	$10,001	$8,721	$38,901	$38,279	$37,152
Income (loss) from operations	625	1,191	906	-349	235	508	770	-264	2,373	1,249	39
Net income (loss)	$28	$924	$789	($609)	$140	$379	$469	($417)	$1,132	$571	($723)
Basic earnings (loss) per share	$0.08	$2.49	$2.11	($1.66)	$0.39	$1.06	$1.37	($1.26)	$3.05	$1.64	($2.18)
Diluted earnings (loss) per share	$0.07	$2.37	$2.01	($1.66)	$0.37	$0.98	$1.21	($1.26)	$2.93	$1.53	($2.18)

Schedule_of_Effect_of_Four_Qua

Schedule of Effect of Four Quarters Events (Detail) (USD $)	3 Months Ended									12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Data [Line Items]
Severance and benefit costs	$141	$6	$38	$14	$91			$14	$76	$199	$105	$125
Integration-related costs	17	28	17	34	40	50	45	70		96	205	739
Labor agreement costs						127					127	475
Impairment of assets	16		32	1	33					49	33	30
(Gains) losses on sale of assets and other special (gains) losses, net	5	9	16	3	1	34	7	8		33	50	-46
Total special items					165	211	52	92
Income tax benefit	-6	-3		-1	-7					-4	-32	-1
Total special items, net of tax					158	211	52	92
Special charges	179	43	169	52						443	520	1,323
Loss on extinguishment of debt and other, net	53			21						74		309
Total operating and nonoperating special charges, net of income taxes	226	40	169	72						507	513	1,312
Permanently grounded Embraer ERJ 135 aircraft
Selected Quarterly Financial Data [Line Items]
Costs associated with permanently grounding Embraer ERJ 135 aircraft			$66							$66

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$4,591		$5,388		$4,922
Additions Charged to Costs and Expenses	156		7		487
Deductions			888	[1]	21	[1]
Other	4	[2]	84	[2]
Balance at End of Period	4,751		4,591		5,388
UAL and United \| Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	13		13		7
Additions Charged to Costs and Expenses	45		35		12
Deductions	36	[1]	35	[1]	6	[1]
Balance at End of Period	22		13		13
UAL and United \| Obsolescence allowance-spare parts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	162		125		89
Additions Charged to Costs and Expenses	35		38		40
Deductions	28	[1]	1	[1]	4	[1]
Balance at End of Period	169		162		125
United Airlines, Inc. \| Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	4,561		5,288		4,833
Additions Charged to Costs and Expenses	167		8		661
Deductions			898	[1]	206	[1]
Other	-7	[2]	163	[2]
Balance at End of Period	$4,721		$4,561		$5,288

[1]	Deduction from reserve for purpose for which reserve was created.
[2]	See Note 7 to the financial statements included in Part II, Item 8 of this report for additional information related to other valuation allowance adjustments.