United Airlines (UAL) 10-K 18 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 09, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	UAL
Entity Registrant Name	United Continental Holdings, Inc.
Entity Central Index Key	100,517
Current Fiscal Year End Date	--12-31
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		359,484,808
Entity Public Float			$ 20,035,996,479
United Airlines, Inc.
Document Information [Line Items]
Entity Registrant Name	United Airlines, Inc.
Entity Central Index Key	319,687
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		1,000

Statements of Consolidated Oper

Statements of Consolidated Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating revenue:
Passenger-Mainline	$ 26,333	$ 26,785	$ 25,997
Passenger-Regional	6,452	6,977	7,125
Total passenger revenue	32,785	33,762	33,122
Cargo	937	938	882
Other operating revenue	4,142	4,201	4,275
Total revenue	37,864	38,901	38,279	[1]
Operating expense:
Salaries and related costs	9,713	8,935	8,625
Aircraft fuel	7,522	11,675	12,345
Regional capacity purchase	2,290	2,344	2,419
Landing fees and other rent	2,203	2,274	2,090
Depreciation and amortization	1,819	1,679	1,689
Aircraft maintenance materials and outside repairs	1,651	1,779	1,821
Distribution expenses	1,342	1,373	1,390
Aircraft rent	754	883	936
Special charges (Note 16)	326	443	520
Other operating expenses	5,078	5,143	5,195
Total operating expenses	32,698	36,528	37,030
Operating income	5,166	2,373	1,249
Nonoperating income (expense):
Interest expense	(669)	(735)	(783)
Interest capitalized	49	52	49
Interest income	25	22	21
Miscellaneous, net (Note 16)	(352)	(584)	3
Total other expense	(947)	(1,245)	(710)
Income before income taxes	4,219	1,128	539
Income tax benefit	(3,121)	(4)	(32)
Net income	$ 7,340	$ 1,132	$ 571
Earnings per share, basic	$ 19.52	$ 3.05	$ 1.64
Earnings per share, diluted	$ 19.47	$ 2.93	$ 1.53
United Airlines, Inc.
Operating revenue:
Passenger-Mainline	$ 26,333	$ 26,785	$ 25,997
Passenger-Regional	6,452	6,977	7,125
Total passenger revenue	32,785	33,762	33,122
Cargo	937	938	882
Other operating revenue	4,142	4,201	4,283
Total revenue	37,864	38,901	38,287
Operating expense:
Salaries and related costs	9,713	8,935	8,625
Aircraft fuel	7,522	11,675	12,345
Regional capacity purchase	2,290	2,344	2,419
Landing fees and other rent	2,203	2,274	2,090
Depreciation and amortization	1,819	1,679	1,689
Aircraft maintenance materials and outside repairs	1,651	1,779	1,821
Distribution expenses	1,342	1,373	1,390
Aircraft rent	754	883	936
Special charges (Note 16)	326	443	520
Other operating expenses	5,076	5,139	5,193
Total operating expenses	32,696	36,524	37,028
Operating income	5,168	2,377	1,259
Nonoperating income (expense):
Interest expense	(670)	(742)	(781)
Interest capitalized	49	52	49
Interest income	25	22	21
Miscellaneous, net (Note 16)	(351)	(599)	89
Total other expense	(947)	(1,267)	(622)
Income before income taxes	4,221	1,110	637
Income tax benefit	(3,080)	(4)	(17)
Net income	$ 7,301	$ 1,114	$ 654
[1]	UAL and United amounts are substantially the same.

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income		$ 7,340	$ 1,132	$ 571
Other comprehensive income (loss), net change related to:
Employee benefit plans		70	(1,171)	1,626
Fuel derivative financial instruments		182	(510)	21
Investments and other		(4)	(6)	7
Comprehensive income (loss) adjustments	[1]	248	(1,687)	1,654
Total comprehensive income (loss), net		7,588	(555)	2,225
United Airlines, Inc.
Net income		7,301	1,114	654
Other comprehensive income (loss), net change related to:
Employee benefit plans		70	(1,171)	1,626
Fuel derivative financial instruments		182	(510)	21
Investments and other		(4)	(6)	8
Other				6
Comprehensive income (loss) adjustments		248	(1,687)	1,661
Total comprehensive income (loss), net		$ 7,549	$ (573)	$ 2,315
[1]	UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents		$ 3,006	$ 2,002
Short-term investments		2,190	2,382
Receivables, less allowance for doubtful accounts (2015-$18; 2014-$22)		1,128	1,146
Fuel hedge collateral deposits		26	577
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2015-$235; 2014-$169)		738	666
Prepaid expenses and other		740	774
Total current assets		7,828	7,547
Operating property and equipment: Owned-
Flight equipment		23,728	21,107
Other property and equipment		4,542	4,016
Operating property and equipment - owned, gross		28,270	25,123
Less-Accumulated depreciation and amortization		(8,339)	(7,079)
Operating property and equipment - owned, net		19,931	18,044
Purchase deposits for flight equipment		788	706
Capital leases-
Flight equipment		1,527	1,272
Other property and equipment		332	331
Operating property and equipment - capital leases, gross		1,859	1,603
Less-Accumulated amortization		(998)	(886)
Operating property and equipment - capital leases, net		861	717
Total property, plant, and equipment, net		21,580	19,467
Other assets:
Goodwill		4,523	4,523
Intangibles, less accumulated amortization (2015-$1,144; 2014-$1,049)		4,136	4,284
Deferred income taxes		2,037
Restricted cash		204	276
Other, net		553	498
Other assets total		11,453	9,581
Total assets		40,861	36,595
Current liabilities:
Advance ticket sales		3,753	3,701
Frequent flyer deferred revenue		2,117	2,058
Accounts payable		1,869	1,882
Accrued salaries and benefits		2,350	1,818
Current maturities of long-term debt		1,224	1,313
Current maturities of capital leases		135	110
Fuel derivative instruments		124	694
Other		842	932
Total current liabilities		12,414	12,508
Long-term debt		9,673	9,953
Long-term obligations under capital leases		727	571
Other liabilities and deferred credits:
Frequent flyer deferred revenue		2,826	2,879
Postretirement benefit liability		1,882	1,933
Pension liability		1,488	2,226
Advanced purchase of miles		1,010	1,217
Deferred income taxes			1,000
Lease fair value adjustment, net		359	466
Other		1,516	1,446
Total Other liabilities and deferred credits		$ 9,081	$ 11,167
Commitments and contingencies
Stockholder's equity:
Preferred stock
Common stock		$ 4	$ 4
Additional capital invested		7,946	7,721
Retained earnings (accumulated deficit)		3,457	(3,883)
Stock held in treasury, at cost		(1,610)	(367)
Accumulated other comprehensive loss	[1]	(831)	(1,079)
Total stockholders' equity		8,966	2,396
Total liabilities and stockholders' equity (deficit)		40,861	36,595
United Airlines, Inc.
Current assets:
Cash and cash equivalents		3,000	1,996
Short-term investments		2,190	2,382
Receivables, less allowance for doubtful accounts (2015-$18; 2014-$22)		1,128	1,146
Fuel hedge collateral deposits		26	577
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2015-$235; 2014-$169)		738	666
Prepaid expenses and other		787	823
Total current assets		7,869	7,590
Operating property and equipment: Owned-
Flight equipment		23,728	21,107
Other property and equipment		4,542	4,016
Operating property and equipment - owned, gross		28,270	25,123
Less-Accumulated depreciation and amortization		(8,339)	(7,079)
Operating property and equipment - owned, net		19,931	18,044
Purchase deposits for flight equipment		788	706
Capital leases-
Flight equipment		1,527	1,272
Other property and equipment		332	331
Operating property and equipment - capital leases, gross		1,859	1,603
Less-Accumulated amortization		(998)	(886)
Operating property and equipment - capital leases, net		861	717
Total property, plant, and equipment, net		21,580	19,467
Other assets:
Goodwill		4,523	4,523
Intangibles, less accumulated amortization (2015-$1,144; 2014-$1,049)		4,136	4,284
Deferred income taxes		1,995
Restricted cash		204	276
Other, net		554	1,210
Other assets total		11,412	10,293
Total assets		40,861	37,350
Current liabilities:
Advance ticket sales		3,753	3,701
Frequent flyer deferred revenue		2,117	2,058
Accounts payable		1,874	1,886
Accrued salaries and benefits		2,350	1,818
Current maturities of long-term debt		1,224	1,313
Current maturities of capital leases		135	110
Fuel derivative instruments		124	694
Other		840	933
Total current liabilities		12,417	12,513
Long-term debt		9,673	9,953
Long-term obligations under capital leases		727	571
Other liabilities and deferred credits:
Frequent flyer deferred revenue		2,826	2,879
Postretirement benefit liability		1,882	1,933
Pension liability		1,488	2,226
Advanced purchase of miles		1,010	1,217
Deferred income taxes			1,000
Lease fair value adjustment, net		359	466
Other		1,516	1,957
Total Other liabilities and deferred credits		$ 9,081	$ 11,678
Commitments and contingencies
Stockholder's equity:
Additional capital invested		$ 6,138	$ 7,347
Retained earnings (accumulated deficit)		3,673	(3,628)
Accumulated other comprehensive loss		(831)	(1,079)
Receivable from related parties		(17)	(5)
Total stockholders' equity		8,963	2,635
Total liabilities and stockholders' equity (deficit)		$ 40,861	$ 37,350
[1]	UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Receivables, allowance for doubtful accounts	$ 18	$ 22
Aircraft fuel, spare parts and supplies, obsolescence allowance	235	169
Intangibles, accumulated amortization	$ 1,144	$ 1,049
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	364,609,108	374,525,916
United Airlines, Inc.
Receivables, allowance for doubtful accounts	$ 18	$ 22
Aircraft fuel, spare parts and supplies, obsolescence allowance	235	169
Intangibles, accumulated amortization	$ 1,144	$ 1,049
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 Cash

Statements of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows from Operating Activities:
Net income	$ 7,340	$ 1,132	$ 571
Adjustments to reconcile net income to net cash provided by operating activities -
Deferred income taxes	(3,177)	13	(14)
Depreciation and amortization	1,819	1,679	1,689
Special charges, non-cash portion	247	78	50
Other operating activities	115	(21)	18
Changes in operating assets and liabilities -
(Increase) decrease in fuel hedge collateral	551	(577)
Unrealized (gain) loss on fuel derivatives	(305)	436	(56)
Decrease in other liabilities	(198)	(238)	(201)
Decrease in frequent flyer deferred revenue and advanced purchase of miles	(200)	(88)	(415)
(Increase) decrease in other assets	(160)	(34)	164
Decrease in accounts payable	(77)	(251)	(265)
Increase in advance ticket sales	52	296	45
(Increase) decrease in receivables	(15)	209	(142)
Net cash provided by operating activities	5,992	2,634	1,444
Cash Flows from Investing Activities:
Capital expenditures	(2,747)	(2,005)	(2,164)
Proceeds from sale of short-term and other investments	2,707	3,112	2,827
Purchases of short-term and other investments	(2,517)	(3,569)	(2,947)
Proceeds from sale of property and equipment	86	94	152
Other, net	(22)	112	110
Net cash used in investing activities	(2,493)	(2,256)	(2,022)
Cash Flows from Financing Activities:
Payments of long-term debt	(2,178)	(2,503)	(2,185)
Repurchases of common stock	(1,233)	(312)
Proceeds from issuance of long-term debt	1,073	1,432	1,423
Principal payments under capital leases	(123)	(127)	(134)
Capitalized financing costs	(37)	(104)	(103)
Proceeds from the exercise of stock options	16	60	29
Other	(13)	(42)	(2)
Net cash used in financing activities	(2,495)	(1,596)	(972)
Net increase (decrease) in cash and cash equivalents	1,004	(1,218)	(1,550)
Cash and cash equivalents at beginning of year	2,002	3,220	4,770
Cash and cash equivalents at end of year	3,006	2,002	3,220
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	866	1,114	229
Operating lease conversions to capital lease	285
Airport construction financing	17	14	40
Exchange of convertible notes for common stock	202	260	240
Cash Paid (Refunded) During the Period for:
Interest (net of amounts capitalized)	660	748	752
Income taxes	15	(16)	(20)
United Airlines, Inc.
Cash Flows from Operating Activities:
Net income	7,301	1,114	654
Adjustments to reconcile net income to net cash provided by operating activities -
Deferred income taxes	(3,136)	13	1
Depreciation and amortization	1,819	1,679	1,689
Special charges, non-cash portion	247	78	50
Other operating activities	115	4	(41)
Changes in operating assets and liabilities -
(Increase) decrease in fuel hedge collateral	551	(577)
Unrealized (gain) loss on fuel derivatives	(305)	436	(56)
Decrease in other liabilities	(199)	(236)	(203)
Decrease in frequent flyer deferred revenue and advanced purchase of miles	(200)	(88)	(415)
(Increase) decrease in other assets	(160)	(34)	163
Decrease in accounts payable	(77)	(251)	(265)
Increase in advance ticket sales	52	296	45
(Increase) decrease in receivables	(15)	209	(142)
Increase in intercompany receivables	(12)		(5)
Decrease in intercompany payables		(118)	(34)
Net cash provided by operating activities	5,981	2,525	1,441
Cash Flows from Investing Activities:
Capital expenditures	(2,747)	(2,005)	(2,164)
Proceeds from sale of short-term and other investments	2,707	3,112	2,827
Purchases of short-term and other investments	(2,517)	(3,569)	(2,947)
Proceeds from sale of property and equipment	86	94	152
Other, net	(22)	112	109
Net cash used in investing activities	(2,493)	(2,256)	(2,023)
Cash Flows from Financing Activities:
Payments of long-term debt	(2,178)	(2,503)	(2,185)
Dividend to UAL	(1,233)	(212)
Proceeds from issuance of long-term debt	1,073	1,432	1,423
Principal payments under capital leases	(123)	(127)	(134)
Capitalized financing costs	(37)	(104)	(103)
Proceeds from the exercise of stock options	16	60	29
Other	(2)	(33)	1
Net cash used in financing activities	(2,484)	(1,487)	(969)
Net increase (decrease) in cash and cash equivalents	1,004	(1,218)	(1,551)
Cash and cash equivalents at beginning of year	1,996	3,214	4,765
Cash and cash equivalents at end of year	3,000	1,996	3,214
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	866	1,114	229
Operating lease conversions to capital lease	285
Airport construction financing	17	14	40
Transfer of UAL subsidiaries to United		186
Exchange of convertible notes for common stock		156
Cash Paid (Refunded) During the Period for:
Interest (net of amounts capitalized)	660	748	752
Income taxes	$ 15	$ (16)	$ (15)

Statements of Consolidated Stoc

Statements of Consolidated Stockholder's Equity - USD ($) shares in Millions, $ in Millions	Total		United Airlines, Inc.	Common Stock	Additional Capital Invested	Additional Capital InvestedUnited Airlines, Inc.	Treasury Stock	Accumulated Deficit	Accumulated DeficitUnited Airlines, Inc.	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)United Airlines, Inc.	Receivable from Related Parties, NetUnited Airlines, Inc.
Beginning Balance (in shares) at Dec. 31, 2012				332
Beginning Balance at Dec. 31, 2012	$ 481		$ 1,161	$ 3	$ 7,145	$ 7,611	$ (35)	$ (5,586)	$ (5,397)	$ (1,046)	$ (1,053)
Net income	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 (in shares) at Dec. 31, 2013				362
Ending Balance at Dec. 31, 2013	2,984		3,223	$ 4	7,425	7,590	(38)	(5,015)	(4,743)	608	608	(232)
Net income	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 (in shares) at Dec. 31, 2014				375
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)
Net income	7,340		7,301					7,340	7,301
Other comprehensive income (loss)	248	[1]	248							248	248
Convertible debt redemption (in shares)				11
Convertible debt redemption	202				202
Dividend and other capital distributions to UAL			(1,232)			(1,232)
Share-based compensation	7		7		7	7
Proceeds from exercise of stock options	16				16
UAL contribution related to stock plans			16			16
Repurchases of common stock	(1,232)						(1,232)
Repurchases of common stock (in shares)				(21)
Other	(11)		(12)				(11)					(12)
Ending Balance (in shares) at Dec. 31, 2015				365
Ending Balance at Dec. 31, 2015	$ 8,966		$ 8,963	$ 4	$ 7,946	$ 6,138	$ (1,610)	$ 3,457	$ 3,673	$ (831)	$ (831)	$ (17)
[1]	UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Significant Accounting Policies	NOTE 1 - SIGNIFICANT ACCOUNTING POLICIES (a) Use of Estimates— (b) Revenue Recognition— 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, 2015, 2014 and 2013. (c) Frequent Flyer Accounting— 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 consolidated 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 is based on an equivalent ticket value less fulfillment discount, which incorporates the expected redemption of miles, as the best estimate of selling price for these miles. The equivalent ticket value 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. 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 the following significant 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; and other travel related benefits. 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. 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 December 31, Cash Proceeds Other Revenue Increase in Frequent Increase 2015 $ 2,999 $ 1,050 $ 2,173 $ (224) 2014 2,861 882 2,178 (199) 2013 2,903 903 2,174 (174) (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— 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. The Company’s net cash inflows associated with its restricted cash balances for the years ended December 31, 2015, 2014 and 2013 were $114 million, $75 million and $52 million, respectively. (e) Short-term Investments— (f) Aircraft Fuel, Spare Parts and Supplies— (g) Property and Equipment— 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 5 Building improvements 1 to 40 As of December 31, 2015 and 2014, the Company had a carrying value of computer software of $279 million and $281 million, respectively. For the years ended December 31, 2015, 2014 and 2013, the Company’s depreciation expense related to computer software was $93 million, $81 million and $72 million, respectively. Aircraft and aircraft spare parts were assumed to have residual values of approximately 10% of original cost, and other categories of property and equipment were assumed to have no residual value. (h) Maintenance and Repairs— (i) Lease Fair Value Adjustments— (j) Regional Capacity Purchase— (k) Advertising— (l) Intangibles— (m) Long-Lived Asset Impairments— (n) Share-Based Compensation— (o) Ticket Taxes— (p) Retirement of Leased Aircraft— (q) Uncertain Income Tax Positions— (r) Labor Costs— (s) Third-Party Business— (t) Recently Issued Accounting Standards— Revenue from Contracts with Customers. Revenue Recognition The FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The FASB issued Accounting Standards Update No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). The FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 Item Asset life (a) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Goodwill $ 4,523 $ 4,523 Finite-lived intangible assets Frequent flyer database (b) 22 $ 1,177 $ 702 $ 1,177 $ 624 Hubs 20 145 74 145 67 Contracts 12 135 86 155 86 Patents and tradenames 3 108 108 108 108 Airport slots and gates 8 97 97 97 97 Other 25 109 77 109 67 Total $ 1,771 $ 1,144 $ 1,791 $ 1,049 Indefinite-lived intangible assets Route authorities $ 1,570 $ 1,589 Airport slots and gates 942 956 Tradenames and logos 593 593 Alliances 404 404 Total $ 3,509 $ 3,542 (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 2015, 2014 and 2013 was $105 million, $128 million and $142 million, respectively. Projected amortization expense in 2016, 2017, 2018, 2019 and 2020 is $90 million, $79 million, $70 million, $64 million and $58 million, respectively. See Note 16 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
	Dec. 31, 2015
Common Stockholders' Equity and Preferred Securities	NOTE 3 - COMMON STOCKHOLDERS’ EQUITY AND PREFERRED SECURITIES In 2014, UAL’s Board of Directors authorized a share repurchase program to acquire up to $1 billion of UAL’s common stock (the “2014 Program”). On July 21, 2015, UAL’s Board of Directors authorized a $3 billion share repurchase program, which the Company expects to complete substantially earlier than its original expected completion date of December 31, 2017 (the “2015 Program”). Under the programs, 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. In October 2015, pursuant to the 2015 Program, the Company entered into agreements to repurchase approximately $300 million of shares of UAL common stock through an accelerated share repurchase program (the “ASR Program”). The ASR Program was completed in November 2015 and in total, United purchased approximately 5 million shares at an average price of $58.14 under the program. The aggregate number of shares repurchased by UAL under the ASR Program was based on the volume-weighted average price per share of UAL’s common stock during the calculation period, less a discount. In addition to the ASR Program, UAL spent $932 million to repurchase approximately 16 million shares of UAL common stock in open market transactions in the year ended December 31, 2015. As of December 31, 2015, the Company had completed purchases under the 2014 Program and had $2.4 billion remaining to spend under the 2015 Program. See Part II, Item 5, “Market for registrant’s common equity, related stockholder matters and issuer purchases of equity securities” of this report for additional information. At December 31, 2015, approximately 8 million shares of UAL’s common stock were reserved for future issuance related to the issuance of equity-based awards under the Company’s incentive compensation plans. As of December 31, 2015, 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 Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share	NOTE 4 - EARNINGS PER SHARE The computations of UAL’s basic and diluted earnings per share are set forth below for the years ended December 31 (in millions, except per share amounts): 2015 2014 2013 Basic earnings per share: Earnings available to common stockholders $ 7,340 $ 1,132 $ 571 Basic weighted-average shares outstanding 376 371 348 Earnings per share, basic $ 19.52 $ 3.05 $ 1.64 Diluted earnings per share: Earnings available to common stockholders $ 7,340 $ 1,132 $ 571 Effect of dilutive securities — 11 26 Earnings available to common stockholders including the effect of dilutive securities $ 7,340 $ 1,143 $ 597 Diluted shares outstanding: Basic weighted-average shares outstanding 376 371 348 Effect of convertible notes — 18 42 Effect of employee stock awards 1 1 1 Diluted weighted-average shares outstanding 377 390 391 Earnings per share, diluted $ 19.47 $ 2.93 $ 1.53 The number of antidilutive securities excluded from the computation of diluted earnings per share amounts were not material. 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.

Share-Based Compensation Plans

Share-Based Compensation Plans	12 Months Ended
	Dec. 31, 2015
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. The Company generally grants incentive compensation awards, including long-term equity-based awards, during the first quarter of the calendar year. In the first quarter of 2015, UAL granted share-based compensation awards pursuant to the United Continental Holdings, Inc. 2008 Incentive Compensation Plan. These share-based compensation awards include approximately 0.2 million shares of restricted stock and 0.3 million of time-vested 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 performance-based RSUs that will vest based on UAL’s return on invested capital and the Company’s relative improvement in pre-tax margin for the three years ending December 31, 2017. If these performance conditions are 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. 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): 2015 2014 2013 Compensation cost (a): RSUs $ 52 $ 104 $ 88 Restricted stock 6 10 11 Other — — 1 Total $ 58 $ 114 $ 100 (a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million and $9 million in 2014 and 2013, respectively, that was recorded in integration-related costs as a component of special items. 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, 2015 (in millions, except as noted): Unearned Weighted- Average Remaining (in years) RSUs $ 37 1.5 Restricted stock 4 1.4 Total $ 41 RSUs and Restricted Stock The table below summarizes UAL’s RSUs and restricted stock activity for the years ended December 31 (shares in millions): RSUs Restricted Stock Weighted- 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 Forfeited (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 Forfeited (0.3) (0.1) 28.88 Non-vested at December 31, 2014 3.8 0.7 32.55 Granted 1.0 0.2 66.53 Vested (1.6) (0.4) 31.14 Forfeited (0.6) (0.2) 46.23 Non-vested at December 31, 2015 2.6 0.3 48.68 The fair value of RSUs and restricted stock that vested in 2015, 2014 and 2013 was $92 million, $97 million and $22 million, respectively. The fair value of the restricted stock awards was 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

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2015
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): Deferred Taxes UAL (a) Pension and Unrealized Gains (Losses) on Derivatives Investments Pension and Derivative Total Balance at December 31, 2012 $ (927) $ (10) $ 6 $ (115) $ — (d) $ (1,046) Other comprehensive income before reclassifications (b) 1,584 (c) 39 7 — — 1,630 Amounts reclassified from accumulated other comprehensive income (b) 42 (18) — — — 24 Net current-period other comprehensive income (loss) 1,626 21 7 — — 1,654 Balance at December 31, 2013 $ 699 $ 11 $ 13 $ (115) $ — (d) $ 608 Other comprehensive loss before reclassifications (b) (1,106) (c) (599) — — — (1,705) Amounts reclassified from accumulated other comprehensive income (b) (65) 89 (6) — — 18 Net current-period other comprehensive income (loss) (1,171) (510) (6) — — (1,687) Balance at December 31, 2014 $ (472) $ (499) $ 7 $ (115) $ — (d) $ (1,079) Other comprehensive income (loss) before reclassifications 78 (c) (320) (4) (28) 115 (159) Amounts reclassified from accumulated other comprehensive income 31 604 — (11) (217) 407 Net current-period other comprehensive income (loss) 109 284 (4) (39) (102) 248 Balance at December 31, 2015 $ (363) $ (215) $ 3 $ (154) $ (102) $ (831) Details about AOCI Components Amount Reclassified from AOCI to Affected Line Item in Year Ended December 31, 2015 2014 2013 Derivatives designated as cash flow hedges Fuel contracts-reclassifications of (gains) losses into earnings $ 604 $ 89 $ (18) Aircraft fuel Amortization of pension and postretirement items Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (e) 31 (65) 42 Salaries and related costs Investments and other Available-for-sale securities—reclassifications of gains into earnings — (6) — Miscellaneous, net (a) UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013. (b) Income tax expense for these items was offset by the Company’s valuation allowance. (c) Prior service credits increased by $0 million, $3 million and $331 million and actuarial gains (losses) increased by approximately $78 million, $(1.1) billion and $1.3 billion for 2015, 2014 and 2013, respectively. (d) Deferred tax balance was offset by the Company’s valuation allowance. (e) 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
	Dec. 31, 2015
Income Taxes	NOTE 7 - INCOME TAXES The significant components of the income tax expense (benefit) are as follows (in millions): 2015 UAL United Current $ 56 $ 56 Deferred (3,177) (3,136) $ (3,121) $ (3,080) 2014 Current $ (17) $ (17) Deferred 13 13 $ (4) $ (4) 2013 Current $ (18) $ (18) Deferred (14) 1 $ (32) $ (17) The income tax provision differed from amounts computed at the statutory federal income tax rate, as follows (in millions): UAL 2015 2014 2013 Income tax provision at statutory rate $ 1,477 $ 395 $ 189 State income taxes, net of federal income tax 60 16 5 Foreign income taxes 4 2 3 Nondeductible employee meals 15 15 15 State rate change — — (33) Valuation allowance (4,684) (441) (219) Other, net 7 9 8 $ (3,121) $ (4) $ (32) United 2015 2014 2013 Income tax provision at statutory rate $ 1,477 $ 388 $ 223 State income taxes, net of federal income tax 60 15 5 Foreign income taxes 4 2 3 Nondeductible employee meals 15 15 15 Derivative market adjustment — (7) (24) State rate change — — (33) Valuation allowance (4,643) (426) (229) Other, net 7 9 23 $ (3,080) $ (4) $ (17) Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2015 and 2014 were as follows (in millions): UAL United December 31, December 31, 2015 2014 2015 2014 Deferred income tax asset (liability): Federal and state net operating loss (“NOL”) carryforwards $ 2,897 $ 3,491 $ 2,855 $ 3,423 Deferred revenue 2,160 2,287 2,160 2,287 Employee benefits, including pension, postretirement and medical 1,662 1,943 1,662 1,943 Alternative minimum tax (“AMT”) credit carryforwards 232 214 232 214 Other 566 657 566 659 Less: Valuation allowance (48) (4,751) (48) (4,721) Total deferred tax assets $ 7,469 $ 3,841 $ 7,427 $ 3,805 Depreciation, capitalized interest and other $ (3,921) $ (3,212) $ (3,921) $ (3,212) Intangibles (1,511) (1,545) (1,511) (1,545) Other — (84) — (48) Total deferred tax liabilities $ (5,432) $ (4,841) $ (5,432) $ (4,805) Net deferred tax asset (liability) $ 2,037 $ (1,000) $ 1,995 $ (1,000) 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 $8.0 billion for UAL. If not utilized these federal pre-tax NOLs will expire as follows (in billions): $2.1 in 2025, $2.0 in 2026, $1.4 in 2027 and $2.5 after 2028. In addition, the majority of tax benefits of the state net operating losses of $103 million for UAL will expire over a five to 20-year period. Additionally, the Company has $232 million of AMT credit carryforwards which do not expire. The Company’s income tax benefit was $3.1 billion for the year ended December 31, 2015. A discrete tax benefit of $3.1 billion for the reduction to the U.S. net federal and state deferred tax asset valuation allowance was included in the income tax benefit for the year ended December 31, 2015. During 2015, after considering all positive and negative evidence and the four sources of taxable income, the Company concluded that its deferred income tax assets are more likely than not to be realized. In evaluating the likelihood of utilizing the Company’s net federal and state deferred tax assets, the significant relevant factors that the Company considered are: (1) its recent history and forecasted profitability; (2) growth in the U.S. and global economies; and (3) future impact of taxable temporary differences. Although the Company was not in a three-year cumulative loss position at December 31, 2014, management concluded that the low level of cumulative pre-tax income, coupled with the Company’s history of operating losses resulted in a determination that a valuation allowance was still necessary. We considered past profitability and future expectations of profitability to determine whether it is more likely than not that we will generate sufficient taxable income to realize our net deferred tax assets. Management placed significant weight on past performance (i.e., losses or near break-even results in 2009 to 2013) as it is more objectively verifiable than projections of future taxable income. However, during 2015, the Company’s pre-tax profit of $4.2 billion benefited from lower oil prices and improved efficiency that resulted in significant taxable income. Additionally, based upon current projection of future earnings, the Company evaluated the NOLs expiration periods and change in ownership limitations under Section 382 of the Internal Revenue Code of 1986, as amended, and determined the NOLs would be realized before expiring beginning in 2025. Therefore, the Company released almost all of its valuation allowance in 2015, resulting in a $3.1 billion benefit in its provision for income taxes. The valuation allowance recorded in AOCI in prior years was released through the income statement and resulted in remaining debits within AOCI of $285 million and $180 million related to pension and derivatives, respectively, which will not be recognized into income tax expense until either the plans are exited or the Company no longer has any outstanding derivatives. The Company has retained a valuation allowance of $48 million against certain state and local NOLs and credit carryforwards at the end of 2015. The Company expects these NOLs and credits will expire unused due to limited carryforward periods. The ability to utilize these state NOLs and credits will be evaluated on a quarterly basis to determine if there are any significant events or any prudent and feasible tax planning strategies that would affect the Company’s ability to realize these deferred tax assets. The Company’s effective tax rates differ from the federal statutory rate of 35% primarily because of the impact of changes to existing valuation allowances. The change in the effective tax rate each period is impacted by a number of factors, including the relative mix of domestic and state income tax expense in the U.S., adjustments to the valuation allowances and discrete items. During 2015, the Company reversed a significant portion of valuation allowances. Of the $4.7 billion reversed, $1.5 billion relates to current year income. The Company’s unrecognized tax benefits related to uncertain tax positions were $24 million, $9 million and $14 million at 2015, 2014 and 2013, respectively. Included in the ending balance at 2015 is $21 million that would affect the Company’s effective tax rate if recognized. The changes in unrecognized tax benefits relating to settlements with taxing authorities, unrecognized tax benefits as a result of tax positions taken during a prior period and unrecognized tax benefits relating from a lapse of the statute of limitations were immaterial during 2015, 2014 and 2013. The Company does not expect significant increases or decreases in their unrecognized tax benefits within the next 12 months. There are no significant amounts included in the balance at December 31, 2015 for tax positions for which the ultimate deductibility is highly certain but for which there is uncertainty about the timing of such deductibility. 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 Postretiremen

Pension and Other Postretirement Plans	12 Months Ended
	Dec. 31, 2015
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, deductibles 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 2015 and 2014. 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 2015 and 2014 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 Accumulated benefit obligation: $ 3,795 $ 4,068 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 4,803 $ 4,000 Service cost 124 98 Interest cost 200 201 Actuarial (gain) loss (298) 807 Gross benefits paid and settlements (343) (281) Other (13) (22) Projected benefit obligation at end of year $ 4,473 $ 4,803 Change in plan assets: Fair value of plan assets at beginning of year $ 2,562 $ 2,397 Actual gain (loss) on plan assets (59) 151 Employer contributions 824 307 Gross benefits paid and settlements (343) (281) Other (9) (12) Fair value of plan assets at end of year $ 2,975 $ 2,562 Funded status—Net amount recognized $ (1,498) $ (2,241) Pension Benefits December 31, 2015 December 31, 2014 Amounts recognized in the consolidated balance sheets consist of: Noncurrent asset $ 2 $ 2 Current liability (12) (17) Noncurrent liability (1,488) (2,226) Total liability $ (1,498) $ (2,241) Amounts recognized in accumulated other comprehensive loss consist of: Net actuarial loss $ (844) $ (982) Prior service loss (1) (1) Total accumulated other comprehensive loss $ (845) $ (983) Other Postretirement Benefits Year Ended Year Ended Change in benefit obligation: Benefit obligation at beginning of year $ 2,052 $ 1,819 Service cost 21 19 Interest cost 82 88 Plan participants’ contributions 68 67 Benefits paid (205) (212) Actuarial (gain) loss (22) 262 Other 6 9 Benefit obligation at end of year $ 2,002 $ 2,052 Change in plan assets: Fair value of plan assets at beginning of year $ 57 $ 57 Actual return on plan assets 1 1 Employer contributions 135 144 Plan participants’ contributions 68 67 Benefits paid (205) (212) Fair value of plan assets at end of year 56 57 Funded status—Net amount recognized $ (1,946) $ (1,995) Other Postretirement Benefits December 31, 2015 December 31, 2014 Amounts recognized in the consolidated balance sheets consist of: Current liability $ (64) $ (62) Noncurrent liability (1,882) (1,933) Total liability $ (1,946) $ (1,995) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial gain $ 236 $ 233 Prior service credit 246 278 Total accumulated other comprehensive income $ 482 $ 511 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): 2015 2014 Projected benefit obligation $ 4,292 $ 4,625 Accumulated benefit obligation 3,655 3,930 Fair value of plan assets 2,794 2,387 Net periodic benefit cost for the years ended December 31 included the following components (in millions): 2015 2014 2013 Pension Other Pension Other Pension Other Service cost $ 124 $ 21 $ 98 $ 19 $ 121 $ 52 Interest cost 200 82 201 88 191 110 Expected return on plan assets (194) (2) (180) (2) (163) (2) Amortization of unrecognized actuarial (gain) loss 85 (22) 12 (47) 48 3 Amortization of prior service credits — (32) — (31) — (3) Other 4 — 1 — (8) 2 Net periodic benefit cost $ 219 $ 47 $ 132 $ 27 $ 189 $ 162 The estimated amounts that will be amortized in 2016 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions): Pension Other Actuarial (gain) loss $ 71 $ (22) Prior service credit — (32) The assumptions used for the benefit plans were as follows: Pension Benefits Assumptions used to determine benefit obligations 2015 2014 Discount rate 4.58% 4.20% Rate of compensation increase 3.66% 3.66% Assumptions used to determine net expense Discount rate 4.20% 5.10% Expected return on plan assets 7.40% 7.36% Rate of compensation increase 3.51% 3.50% Other Postretirement Benefits Assumptions used to determine benefit obligations 2015 2014 Discount rate 4.49% 4.07% Assumptions used to determine net expense Discount rate 4.07% 4.94% Expected return on plan assets 3.00% 4.00% Health care cost trend rate assumed for next year 6.75% 7.00% Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023) 5.00% 5.00% During 2015, 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 2015 discount rate for substantially all of its plans by using a hypothetical portfolio of high quality bonds at December 31, 2015, 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 Rate of Return Equity securities 30-40 % 9.5 % Fixed-income securities 34-44 5.0 Alternatives 14-27 7.3 Other 0-10 7.0 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, 2015 $ 13 $ (11) Effect on postretirement benefit obligation at December 31, 2015 219 (191) A one percentage point decrease in the weighted average discount rate would increase the postretirement benefit liability by approximately $227 million and increase the estimated 2015 benefits expense by approximately $12 million. Fair Value Information. 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. (b) Income approach. The following tables present information about United’s pension and other postretirement plan assets at December 31 (in millions): 2015 2014 Pension Plan Assets: Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Equity securities funds $ 1,135 $ 254 $ 881 $ — $ 1,181 $ 388 $ 793 $ — Fixed-income securities 1,109 — 1,100 9 813 — 813 — Alternatives 527 — 267 260 359 — 148 211 Insurance contract 18 — — 18 21 — — 21 Other investments 186 37 149 — 188 — 165 23 Total $ 2,975 $ 291 $ 2,397 $ 287 $ 2,562 $ 388 $ 1,919 $ 255 Other Postretirement Benefit Plan Assets: Deposit administration fund $ 56 $ — $ — $ 56 $ 57 $ — $ — $ 57 Equity and Fixed-Income. Insurance Contract and Deposit Administration Fund. Alternatives. Other investments. The reconciliation of United’s defined benefit plan assets measured at fair value using unobservable inputs (Level 3) for the years ended December 31, 2015 and 2014 is as follows (in millions): 2015 2014 Balance at beginning of year $ 312 $ 293 Actual return on plan assets: Sold during the year 11 7 Held at year end (1) 6 Purchases, sales, issuances and settlements (net) 21 6 Balance at end of year $ 343 $ 312 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 2015 calendar year. In 2016, 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, 2015 are as follows (in millions): Pension Other Postretirement Other Postretirement— subsidy receipts 2016 $ 282 $ 125 $ 5 2017 287 128 5 2018 286 131 6 2019 292 135 6 2020 293 140 7 Years 2021 – 2025 1,577 761 40 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 $522 million, $503 million and $433 million in the years ended December 31, 2015, 2014 and 2013, respectively. Multi-Employer Plans United’s participation in the IAM National Pension Plan (“IAM Plan”) for the annual period ended December 31, 2015 is outlined in the table below. There have been no significant changes that affect the comparability 2015 and 2014 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 $382 million in employers’ contributions for the year ended December 31, 2014. For 2014, 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 (2015 and 2014) Green Zone. Plans in the green zone are at least 80 percent funded. FIP/RP Status Pending/Implemented No United’s Contributions $40 million, $39 million and $38 million in the years ended December 31, 2015, 2014 and 2013, 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 2015. Profit Sharing Substantially all employees participate in profit sharing based on a percentage of pre-tax earnings, excluding special items, profit sharing expense and share-based compensation. Profit sharing percentages range from 5% to 20% depending on the work group, and in some cases profit sharing percentages vary above and below certain pre-tax margin thresholds. Eligible U.S. co-workers in each participating work group receive 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. Eligible non-U.S. co-workers receive profit sharing 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 $698 million, $235 million and $190 million in 2015, 2014 and 2013, respectively. Profit sharing expense is recorded as a component of Salaries and related costs in the Company’s statements of consolidated operations.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements	NOTE 9 - FAIR VALUE MEASUREMENTS Fair Value Information. 2015 2014 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 UAL Cash and cash equivalents $ 3,006 $ 3,006 $ — $ — $ 2,002 $ 2,002 $ — $ — Short-term investments: Corporate debt 891 — 891 — 876 — 876 — Asset-backed securities 710 — 710 — 901 — 901 — Certificates of deposit placed through an account registry service (“CDARS”) 281 — 281 — 256 — 256 — U.S. government and agency notes 72 — 72 — 68 — 68 — Auction rate securities 9 — — 9 26 — — 26 Other fixed-income securities 227 — 227 — 255 — 255 — Enhanced equipment trust certificates (“EETC”) 26 — — 26 28 — — 28 Fuel derivatives liability, net 124 — 124 — 717 — 717 — Foreign currency derivatives — — — — 2 — 2 — Restricted cash 206 206 — — 320 320 — — United Cash and cash equivalents $ 3,000 $ 3,000 $ — $ — $ 1,996 $ 1,996 $ — $ — Short-term investments: Corporate debt 891 — 891 — 876 — 876 — Asset-backed securities 710 — 710 — 901 — 901 — CDARS 281 — 281 — 256 — 256 — U.S. government and agency notes 72 — 72 — 68 — 68 — Auction rate securities 9 — — 9 26 — — 26 Other fixed-income securities 227 — 227 — 255 — 255 — EETC 26 — — 26 28 — — 28 Fuel derivatives liability, net 124 — 124 — 717 — 717 — Foreign currency derivatives — — — — 2 — 2 — Restricted cash 206 206 — — 320 320 — — Convertible debt derivative asset — — — — 712 — — 712 Convertible debt derivative option liability — — — — 511 — — 511 United’s debt-related derivatives presented in the tables above related to (a) supplemental indentures that provided that United’s convertible debt was 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 were required to be separated and accounted for as though they were 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 related to the 4.5% Convertible Notes due 2015 (the “4.5% Convertible Notes”). Gains (losses) on these derivatives were recorded in Nonoperating income (expense): Miscellaneous, net in United’s statements of consolidated operations. These derivatives along with their gains (losses) were reported in United’s separate financial statements and were eliminated in consolidation for UAL. 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. The derivative assets and liabilities associated with the 4.5% Convertible Notes were settled in connection with the retirement of the related convertible debt, and the final accounting did not materially impact UAL’s or United’s statements of consolidated operations. Available-for-sale investment maturities 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 2015 2014 Carrying Fair Value Carrying Fair Value Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Long-term debt $ 10,897 $ 11,371 $ — $ 8,646 $ 2,725 $ 11,266 $ 12,386 $ — $ 8,568 $ 3,818 (a) 2014 amount differs from the amount reported in the Company’s Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information. 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.

Hedging Activities

Hedging Activities	12 Months Ended
	Dec. 31, 2015
Hedging Activities	NOTE 10 - HEDGING ACTIVITIES Fuel Derivatives The Company may hedge a portion of its future fuel requirements to protect against increases in the price of fuel. The Company may restructure hedges in response to market conditions prior to their original settlement dates which may result in changes in hedge coverage levels and the potential recognition of gains or losses on such hedge contracts. As of December 31, 2015, the Company had hedged approximately 17% of its projected fuel requirements (652 million gallons) for 2016, with commonly used financial hedge instruments based on aircraft fuel or crude oil. As of December 31, 2015, the Company had fuel hedges expiring through December 2016. 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 hedge accounting treatment typically include swaps, call options, collars (which consist of a purchased call option and a sold put option), four-way collars (a collar with a higher strike sold call option and a lower strike purchased put option) and other combinations of options. Generally, utilizing hedge accounting, all periodic changes in the fair value of 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 uses certain combinations of derivative contracts that are economic hedges but do not qualify for hedge accounting under GAAP. Additionally, the Company may enter into contracts at different times and later combine those contracts into structures designated for hedge accounting. As with derivatives that qualify for hedge accounting, the economic hedges and individual contracts are part of the Company’s program to mitigate the adverse financial impact of potential increases in the price of fuel. The Company records changes in the fair value of these various contracts that are not designated for hedge accounting 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. In addition to cash flow hedges, the Company from time to time enters into fair value hedges related to its aircraft fuel inventory using derivatives such as swaps and futures contracts based on aircraft fuel. Under fair value hedge accounting, the Company records changes in the fair value of both the hedging derivative and the hedged aircraft fuel inventory as fuel expense. The Company records ineffectiveness on fair value hedges as Nonoperating income (expense): Miscellaneous, net in the statements of consolidated operations. As of December 31, 2015, fair value hedges related to aircraft fuel were not material to the Company’s financial statements. The Company records each derivative instrument as a derivative asset or liability (on a gross basis) in its consolidated balance sheets , At December 31, the Company’s derivatives were reported in its consolidated balance sheets as follows (in millions): Classification Balance Sheet Location 2015 2014 Derivatives designated as cash flow hedges Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 119 $ 450 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 27 $ 119 $ 477 Derivatives not designated for hedge accounting Assets: Fuel contracts due within one year Receivables $ — $ 6 Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 5 $ 244 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 2 Total liabilities $ 5 $ 246 Total derivatives Assets: Fuel contracts due within one year Receivables $ — $ 6 Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 124 $ 694 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 29 Total liabilities $ 124 $ 723 Derivative Credit Risk and Fair Value The Company is exposed to credit losses in the event of non-performance 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 had on deposit $26 million and $577 million of collateral with fuel derivative counterparties as of December 31, 2015 and December 31, 2014, respectively. The collateral is recorded as Fuel hedge collateral deposits on the Company’s consolidated balance sheets. 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, 2015 December 31, 2014 Fuel derivative instruments $ 98 $ 209 Other liabilities and deferred credits: Other — 30 Hedge derivatives liabilities, net $ 98 $ 239 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 Loss Recognized in AOCI on Derivatives (Effective Portion) Loss Reclassified from (Fuel Expense) (Effective Portion) Amount of Loss 2015 2014 2015 2014 2015 2014 Fuel contracts $ (320) $ (599) $ (604) $ (89) $ — $ (3) Derivatives not designated for hedge accounting Amount of Gain (Loss) Recognized 2015 2014 2013 Fuel contracts $ (80) $ (462 ) $ 79 Foreign Currency Derivatives The Company generates revenues and incurs expenses in numerous foreign currencies. Changes in foreign currency exchange rates impact the Company’s results of operations through changes in the dollar value of foreign currency-denominated operating revenues and expenses. Some of the Company’s more significant foreign currency exposures include the Canadian dollar, Chinese renminbi, European euro, British pound and Japanese yen. At times, the Company uses derivative financial instruments, such as options, collars and forward contracts, to hedge its exposure to foreign currency. At December 31, 2015, the Company had foreign currency derivative contracts in place to hedge European euro denominated sales. The notional amount of the hedges equates to 18% of the Company’s projected European euro denominated net cash inflows for 2016. Net cash relates primarily to passenger ticket sales inflows partially offset by expenses paid in local currencies. At December 31, 2015, the fair value of the Company’s foreign currency derivatives was not material to the Company’s financial statements.

Debt

Debt	12 Months Ended
	Dec. 31, 2015
Debt	NOTE 11 - DEBT (In millions) At December 31, 2015 2014 Secured Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.37% as of December 31, 2015), payable through 2027 $ 7,971 $ 7,464 Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 2.85%, payable through 2027 1,302 1,151 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 875 884 Term loan, LIBOR subject to a 0.75% floor, plus 3.00%, or alternative rate based on certain market rates plus 2%, due 2021 194 499 Unsecured 6% Notes due 2026 to 2028 (a) — 632 6% Senior Notes due 2020 (a) 300 300 6.375% Senior Notes due 2018 (a) 300 300 4.5% Convertible Notes due 2015 — 202 Other 100 101 11,042 11,533 Less: unamortized debt discount, premiums and debt issuance costs (145) (267) (b) Less: current portion of long-term debt (1,224) (1,313) Long-term debt, net $ 9,673 $ 9,953 (a) UAL is the issuer of this debt. United is a guarantor. (b) 2014 amount differs from the amount reported in the Company’s Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information. The table below presents the Company’s contractual principal payments at December 31, 2015 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions): 2016 $ 1,224 2017 822 2018 1,359 2019 1,788 2020 942 After 2020 4,907 $ 11,042 As of December 31, 2015, a substantial portion of the Company’s assets, principally aircraft, route authorities and loyalty program intangible assets, was pledged under various loan and other agreements. As of December 31, 2015, 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. Secured debt 2013 Credit and Guaranty Agreement. The term loans under the Credit Agreement bear interest at a variable rate equal to LIBOR plus a margin of, in the case of the Term Loan due 2019, 2.75% per annum and, in the case of the Term Loan due 2021, 3.0% per annum, subject in each case to a 0.75% floor. Borrowings under the revolving credit facility of 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 loans must be repaid in consecutive quarterly installments of 0.25% of the original principal amount thereof, with any unpaid balance due, in the case of the Term Loan due 2019, on April 1, 2019 and, in the case of the Term Loan due 2021, on September 15, 2021. United may prepay all or a portion of the term loans 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 Term Loan due 2021 ranks pari passu with the Term Loan due 2019 that United originally borrowed under the Credit Agreement. The Credit Agreement requires United to repay the term loans and any other outstanding borrowings under the Credit Agreement at par plus accrued and unpaid interest if certain changes of control of UAL occur. As of December 31, 2015, 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, 2015, United had cash collateralized $70 million of letters of credit. United also had $437 million of performance bonds relating to various real estate, customs and aircraft financing obligations at December 31, 2015. 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. EETCs. In November 2015 and August 2014, 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 has received and recorded all of the proceeds from the November 2015 and August 2014 pass-through trusts as debt as of December 31, 2015. Certain details of the pass-through trusts with proceeds received from issuance of debt in 2015 are as follows (in millions, except stated interest rate): EETC Date Class Principal Final expected Stated Total debt Proceeds Remaining November 2015 AA $ 334 December 2027 3.45% $ 334 $ 334 $ — November 2015 A 100 December 2022 3.70% 100 100 — August 2014 A 823 September 2026 3.75% 823 711 — August 2014 B 238 September 2022 4.625% 238 206 — $ 1,495 $ 1,495 $ 1,351 $ — In 2015, United borrowed approximately $590 million aggregate principal amount from various financial institutions to finance the purchase of several aircraft delivered in 2015. The notes evidencing these borrowings, which are secured by the related aircraft, have maturity dates ranging from 2025 to 2027 and interest rates comprised of the LIBOR plus a specified margin. Unsecured debt 6% Notes due 2026. 6% Notes due 2028. In 2015, the Company recorded a nonoperating special charge of $134 million for the extinguishment of the 2026 Notes and the 2028 Notes. The nonoperating special charge is related to the write-off of unamortized debt discounts. 4.5% Convertible Notes due 2015. 4.5% Senior Limited-Subordination Convertible Notes due 2021. Convertible Debt Securities and Derivatives. In addition, UAL’s contractual commitment to provide common stock to satisfy United’s obligation upon conversion of the debt was 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 derivative on a separate-entity reporting basis as of December 31, 2014 was an asset of $712 million. The fair value of the embedded conversion options as of December 31, 2014 was a liability of $511 million. The 4.5% Convertible Notes and their related indenture derivative and conversion options were retired in 2015. The initial contribution of the indenture derivatives to United by UAL was accounted for as additional paid-in capital in United’s separate-entity financial statements. Changes in fair value of both the indenture derivative and the embedded conversion options subsequent to October 1, 2010 were recognized in Nonoperating income (expense). 6% Convertible Senior Notes due 2029 . 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 Various equipment notes and other notes payable Secured by certain aircraft. The indentures contain events of default that are customary for aircraft financing, including in certain cases cross default to other related aircraft. 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. 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. 6.375% Senior Notes due 2018 6% Senior Notes due 2020 The indentures for these notes 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. The indentures contain events of default that are customary for similar financings.

Advanced Purchase of Miles

Advanced Purchase of Miles	12 Months Ended
	Dec. 31, 2015
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. The balance of pre-purchased miles is eligible to be allocated by Chase to MileagePlus members’ accounts by a maximum of $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 credit card processing agreement among United, Paymentech, LLC and JPMorgan Chase Bank, N.A.

Leases and Capacity Purchase Ag

Leases and Capacity Purchase Agreements	12 Months Ended
	Dec. 31, 2015
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, 2015, 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 Facility and Other Aircraft Operating 2016 $ 206 $ 1,252 $ 1,317 2017 162 1,161 1,317 2018 151 899 1,100 2019 86 809 918 2020 66 920 708 After 2020 747 6,799 2,660 Minimum lease payments $ 1,418 $ 11,840 $ 8,020 Imputed interest (556) Present value of minimum lease payments 862 Current portion (135) Long-term obligations under capital leases $ 727 As of December 31, 2015, United’s aircraft capital lease minimum payments relate to leases of 47 mainline and 29 regional aircraft as well as to leases of nonaircraft assets. Imputed interest rate ranges are 3.5% to 20.8%. Aircraft operating leases have initial terms of five to twenty-six years, with expiration dates ranging from 2016 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. During 2015, the Company reached an agreement with AerCap Holdings N.V., a major aircraft leasing company, to lease used Airbus A319s. Eleven aircraft will be delivered over the next two years beginning in early 2016. In addition, up to 14 more aircraft may be delivered over the next five years subject to certain conditions. 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, 2015. 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. United’s nonaircraft rent expense was approximately $1.3 billion, $1.4 billion and $1.3 billion for the years ended December 31, 2015, 2014 and 2013, 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 $461 million, $442 million and $428 million for the years ended December 31, 2015, 2014 and 2013, 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 nine years for United. The lease valuation adjustments are classified within other noncurrent liabilities and the net accretion amounts are $107 million, $160 million and $173 million for the years ended December 31, 2015, 2014 and 2013, 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 predetermined 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 521 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. See Part I, Item 2, “Properties” of this report for additional information. In 2015, United entered into amendments to the CPA with SkyWest Airlines, Inc. (“SkyWest”), a wholly-owned subsidiary of SkyWest, Inc., to operate an additional 25 new 76-seat Embraer S.A. (“Embraer”) E175 aircraft under the United Express brand. SkyWest will purchase all of these 76-seat aircraft directly from the manufacturer with deliveries in 2016 and 2017. In 2015, United also entered into amendments to the CPA with Mesa Air Group, Inc. and Mesa Airlines, Inc. (“Mesa”), a wholly-owned subsidiary of Mesa Air Group, Inc., pursuant to which Mesa will operate under the United Express brand new Embraer E175 aircraft, 15 of which have delivered or are scheduled to deliver in 2016. United will assign its purchase obligations to Mesa with respect to 10 Embraer E175 aircraft at the time of each aircraft’s delivery, subject to certain conditions. Mesa will purchase the remaining five aircraft directly from Embraer; however, United has agreed that United will, under certain conditions, purchase these five aircraft directly from Embraer. In 2015, United entered into a new Embraer ERJ 145 CPA with Champlain Enterprises, Inc. operating as CommutAir, pursuant to which CommutAir will operate under the United Express brand 40 used Embraer ERJ145 aircraft that are currently being operated by a different carrier operating under the United Express brand, with transfers that started in December 2015 and will continue through 2017. In 2014 and 2015, United entered into amendments to a contract with Shuttle America Corporation (“Shuttle America”), a wholly-owned subsidiary of Republic Airways Holdings, for Shuttle America to operate 40 new Embraer E175 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 forty 76-seat Embraer E175 aircraft with remaining deliveries from 2016 through 2017, although United has the right to acquire the aircraft under certain circumstances and lease the aircraft to Shuttle America. These 40 aircraft are in addition to United’s other 113 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 the remaining 13 Q400 aircraft from United Express service by the second quarter of 2016. 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, 2015, our future payments through the end of the terms of our CPAs are presented in the table below (in millions): 2016 $ 1,834 2017 1,884 2018 1,550 2019 1,290 2020 1,155 After 2020 4,932 $ 12,645 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 2016 would result in a corresponding change in annual cash obligations under the CPAs of approximately $144 million (7.9%).

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2015
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 EETCs. 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
	Dec. 31, 2015
Commitments and Contingencies	NOTE 15 - COMMITMENTS AND CONTINGENCIES Commitments. Aircraft Type Number of Firm Airbus A350-1000 35 Boeing 737NG/737 MAX 9 155 Boeing 777-300ER 10 Boeing 787-8/-9/-10 30 Embraer E175 10 (a) United also has options and purchase rights for additional aircraft. The aircraft listed in the table above are scheduled for delivery from 2016 through 2024. The table below summarizes United’s commitments as of December 31, 2015, 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). The table below is adjusted to include the impact of the January 2016 Boeing 737NG aircraft order discussed above. Any new firm aircraft orders, including through the exercise of purchase options and purchase rights, will increase the total future capital commitments of the Company. 2016 $ 3.4 2017 3.1 2018 3.3 2019 2.9 2020 2.8 After 2020 7.7 $ 23.2 As of December 31, 2015 (as adjusted to include the order discussed above), 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 may be necessary to satisfy the Company’s capital commitments for its firm order aircraft and other related capital expenditures. Legal and Environmental. Guarantees and Indemnifications. As of December 31, 2015, United is the guarantor of approximately $1.9 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 $302 million of these obligations are accounted for as capital leases. All of these bonds are due between 2017 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, 2015, the Company had $2.4 billion of floating rate debt and $118 million of fixed rate debt, with remaining terms of up to 12 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 12 years and an aggregate balance of $2.4 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. Regional Capacity Purchase. Credit Card Processing Agreements. Labor Negotiations. The Company has reached joint collective bargaining agreements with the majority of its employee groups since the merger transaction in 2010. The Company continues to negotiate in mediation for a joint flight attendant collective bargaining agreement, extensions to the IAM represented employees’ agreements and a joint technician and related employees’ collective bargaining agreement following the rejected proposal for ratification of a joint technician and related employees’ agreement. The Company can provide no assurance that a successful or timely resolution of these labor negotiations will be achieved.

Special Items

Special Items	12 Months Ended
	Dec. 31, 2015
Special Items	NOTE 16 - SPECIAL ITEMS 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: 2015 2014 2013 Severance and benefit costs $ 107 $ 199 $ 105 Impairment of assets 79 49 33 Integration-related costs 60 96 205 Labor agreement costs 18 — 127 (Gains) losses on sale of assets and other miscellaneous (gains) losses, net 62 99 50 Special charges 326 443 520 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 202 74 — Income tax benefit related to special charges (11) (10) (7) Income tax benefit associated with valuation allowance release (Note 7) (3,130) — — Total operating and nonoperating special charges, net of income taxes $ (2,613) $ 507 $ 513 2015 The Company recorded $107 million of severance and benefit costs primarily related to a voluntary early-out program for its flight attendants. In 2014, more than 2,500 flight attendants elected 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 through the end of 2016. The Company recorded $33 million ($22 million net of related income tax benefit) related to its annual assessment of impairment of its indefinite-lived intangible assets (certain domestic slots and international Pacific routes), $8 million for the write-off of unexercised aircraft purchase options and $7 million for inventory held for sale. The Company also recorded other impairments, including $10 million for discontinued internal software projects and $10 million for the impairment of several engines held for sale. Integration-related costs include compensation costs related primarily to systems integration and training for employees. During 2015, the Company also recorded $32 million related to charges for legal matters, $18 million related to collective bargaining agreements, $16 million for the cease use of an aircraft under lease and $14 million for losses on the sale of aircraft and other miscellaneous gains and losses. The Company recorded $202 million of losses as part of Nonoperating income (expense): Miscellaneous, net due primarily to the write-off of $134 million related to the unamortized non-cash debt discount from the extinguishment of the 2026 Notes and the 2028 Notes. During 2015, the Company also recorded a $61 million foreign exchange loss related to its cash holdings in Venezuela. The Venezuelan government has maintained currency controls and fixed official exchange rates (i.e. Sistema Complementario de Administracion de Divisas (“SICAD”), and Sistema Marginal de Divisas (“SIMADI”)) for many years. Previously, airlines were permitted to use the more favorable SICAD rate (currently 13.5 Venezuelan bolivars to one U.S. dollar) if repatriating profits and for payments of local goods and services in Venezuela. During 2015, many of the payments for local goods and services have transitioned to utilizing the SIMADI rate (currently 200 Venezuelan bolivars to one U.S. dollar) or have been required to be paid in U.S. dollars. Furthermore, the Venezuelan government has not permitted the exchange and repatriations of local currency since mid-2014. As a result, the Company changed the exchange rate from historical SICAD rates to a combination of SIMADI and SICAD rates based on projections of future cash payments. Including this adjustment, the Company’s resulting cash balance held in Venezuelan bolivars at December 31, 2015 is approximately $13 million. 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 through the end of 2016. In addition, the Company recorded $58 million of severance and benefits primarily related to reductions of management and front-line employees, including from Hopkins International Airport (“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. 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 also 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. Integration-related costs included 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 included an accrual for remaining lease payments and an amount for maintenance return conditions. The Company decided to permanently ground these 21 Embraer ERJ 135 aircraft as a result of new Embraer E175 regional jet deliveries, the impact of pilot shortages at regional carriers and fuel prices. In addition, the Company also recorded $33 million for losses on the sale of assets and other special charges. 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 $64 million of expense primarily associated with the write-off of the related non-cash debt discounts. The Company also recorded $10 million of foreign exchange losses in Venezuela in 2014. 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. 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. 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 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. 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 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 Accrual 107 30 Payments (189) (54) Balance at December 31, 2015 $ 27 $ 78 The Company’s accrual and payment activity is primarily related to severance and other compensation expense associated with voluntary employee early retirement programs.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Information	NOTE 17 - 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): 2015 Domestic (U.S. and Canada) $ 21,931 Pacific 5,498 Atlantic 7,068 Latin America 3,367 Total $ 37,864 2014 Domestic (U.S. and Canada) $ 22,320 Pacific 5,767 Atlantic 7,321 Latin America 3,493 Total $ 38,901 2013 Domestic (U.S. and Canada) $ 22,092 Pacific 5,794 Atlantic 7,132 Latin America 3,261 Total $ 38,279 (a) (a) UAL and United amounts are substantially the same. 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 Da

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Data	NOTE 18 - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) UAL Quarter Ended (In millions, except per share amounts) March 31 June 30 September 30 December 31 2015 Operating revenue $ 8,608 $ 9,914 $ 10,306 $ 9,036 Income from operations 741 1,445 1,899 1,081 Net income 508 1,193 4,816 823 Basic earnings per share 1.33 3.14 12.83 2.24 Diluted earnings per share 1.32 3.14 12.82 2.24 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 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 2015 Operating: Severance and benefit costs $ 50 $ 25 $ 28 $ 4 Impairment of assets 2 11 18 48 Integration-related costs 18 14 15 13 (Gains) losses on sale of assets and other miscellaneous (gains) losses, net (6) 5 15 66 Special charges 64 55 76 131 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 6 128 61 7 Income tax benefit related to special charges — — — (11) Income tax expense (benefit) associated with valuation allowance release — — (3,218) 88 Total operating and nonoperating special items, net of income taxes $ 70 $ 183 $ (3,081) $ 215 2014 Operating: Severance and benefit costs $ 14 $ 38 $ 6 $ 141 Impairment of assets 1 32 — 16 Integration-related costs 34 17 28 17 Costs associated with permanently grounding Embraer ERJ 135 aircraft — 66 — — Losses on sale of assets and other special (gains) losses, net 3 16 9 5 Special charges 52 169 43 179 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 21 — — 53 Income tax benefit related to special charges (1) — (3) (6) Total operating and nonoperating special charges, net of income taxes $ 72 $ 169 $ 40 $ 226 See Note 16 of this report for additional information of these items.

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Schedule II Valuation and Qualifying Accounts	Schedule II Valuation and Qualifying Accounts For the Years Ended December 31, 2015, 2014 and 2013 (In millions) Description Balance at Beginning of Period Additions Charged to Costs and Expenses Deductions Other Balance at End of Period Allowance for doubtful accounts—UAL and United: 2015 $ 22 $ 25 $ 29 $ — $ 18 2014 13 45 36 — 22 2013 13 35 35 — 13 Obsolescence allowance—spare parts—UAL and United: 2015 $ 169 $ 38 $ — $ 28 $ 235 2014 162 35 28 — 169 2013 125 38 1 — 162 Valuation allowance for deferred tax assets—UAL: 2015 $ 4,751 $ — $ 4,703 $ — $ 48 2014 4,591 156 — 4 (b) 4,751 2013 5,388 7 888 84 (b) 4,591 Valuation allowance for deferred tax assets—United: 2015 $ 4,721 $ — $ 4,673 $ — $ 48 2014 4,561 167 — (7) (b) 4,721 2013 5,288 8 898 163 (b) 4,561 (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 Polici27

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Use of Estimates	(a) Use of Estimates—
Revenue Recognition	(b) Revenue Recognition— 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, 2015, 2014 and 2013.
Frequent Flyer Accounting	(c) Frequent Flyer Accounting— 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 consolidated 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 is based on an equivalent ticket value less fulfillment discount, which incorporates the expected redemption of miles, as the best estimate of selling price for these miles. The equivalent ticket value 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. 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 the following significant 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; and other travel related benefits. 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. 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 December 31, Cash Proceeds Other Revenue Increase in Frequent Increase 2015 $ 2,999 $ 1,050 $ 2,173 $ (224) 2014 2,861 882 2,178 (199) 2013 2,903 903 2,174 (174) (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— 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. The Company’s net cash inflows associated with its restricted cash balances for the years ended December 31, 2015, 2014 and 2013 were $114 million, $75 million and $52 million, respectively.
Short-term Investments	(e) Short-term Investments—
Aircraft Fuel, Spare Parts and Supplies	(f) Aircraft Fuel, Spare Parts and Supplies—
Property and Equipment	(g) Property and Equipment— 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 5 Building improvements 1 to 40 As of December 31, 2015 and 2014, the Company had a carrying value of computer software of $279 million and $281 million, respectively. For the years ended December 31, 2015, 2014 and 2013, the Company’s depreciation expense related to computer software was $93 million, $81 million and $72 million, respectively. Aircraft and aircraft spare parts were assumed to have residual values of approximately 10% of original cost, and other categories of property and equipment were assumed to have no residual value.
Maintenance and Repairs	(h) Maintenance and Repairs—
Lease Fair Value Adjustments	(i) Lease Fair Value Adjustments—
Regional Capacity Purchase	(j) Regional Capacity Purchase—
Advertising	(k) Advertising—
Intangibles	(l) Intangibles—
Long-Lived Asset Impairments	(m) Long-Lived Asset Impairments—
Share-Based Compensation	(n) Share-Based Compensation—
Ticket Taxes	(o) Ticket Taxes—
Retirement of Leased Aircraft	(p) Retirement of Leased Aircraft—
Uncertain Income Tax Positions	(q) Uncertain Income Tax Positions—
Labor Costs	(r) Labor Costs—
Third-Party Business	(s) Third-Party Business—
Recently Issued Accounting Standards	(t) Recently Issued Accounting Standards— Revenue from Contracts with Customers. Revenue Recognition The FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The FASB issued Accounting Standards Update No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). The FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes

Significant Accounting Polici28

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
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 December 31, Cash Proceeds Other Revenue Increase in Frequent Increase 2015 $ 2,999 $ 1,050 $ 2,173 $ (224) 2014 2,861 882 2,178 (199) 2013 2,903 903 2,174 (174) (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 5 Building improvements 1 to 40

Goodwill and Other Intangible29

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Other Intangible Assets	The following table presents information about the Company’s goodwill and other intangible assets at December 31 (in millions): 2015 2014 Item Asset life (a) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Goodwill $ 4,523 $ 4,523 Finite-lived intangible assets Frequent flyer database (b) 22 $ 1,177 $ 702 $ 1,177 $ 624 Hubs 20 145 74 145 67 Contracts 12 135 86 155 86 Patents and tradenames 3 108 108 108 108 Airport slots and gates 8 97 97 97 97 Other 25 109 77 109 67 Total $ 1,771 $ 1,144 $ 1,791 $ 1,049 Indefinite-lived intangible assets Route authorities $ 1,570 $ 1,589 Airport slots and gates 942 956 Tradenames and logos 593 593 Alliances 404 404 Total $ 3,509 $ 3,542 (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 Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Computation of Earnings Per Share	The computations of UAL’s basic and diluted earnings per share are set forth below for the years ended December 31 (in millions, except per share amounts): 2015 2014 2013 Basic earnings per share: Earnings available to common stockholders $ 7,340 $ 1,132 $ 571 Basic weighted-average shares outstanding 376 371 348 Earnings per share, basic $ 19.52 $ 3.05 $ 1.64 Diluted earnings per share: Earnings available to common stockholders $ 7,340 $ 1,132 $ 571 Effect of dilutive securities — 11 26 Earnings available to common stockholders including the effect of dilutive securities $ 7,340 $ 1,143 $ 597 Diluted shares outstanding: Basic weighted-average shares outstanding 376 371 348 Effect of convertible notes — 18 42 Effect of employee stock awards 1 1 1 Diluted weighted-average shares outstanding 377 390 391 Earnings per share, diluted $ 19.47 $ 2.93 $ 1.53

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 2013 Compensation cost (a): RSUs $ 52 $ 104 $ 88 Restricted stock 6 10 11 Other — — 1 Total $ 58 $ 114 $ 100 (a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million and $9 million in 2014 and 2013, respectively, that was recorded in integration-related costs as a component of special items.
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, 2015 (in millions, except as noted): Unearned Weighted- Average Remaining (in years) RSUs $ 37 1.5 Restricted stock 4 1.4 Total $ 41
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- 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 Forfeited (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 Forfeited (0.3) (0.1) 28.88 Non-vested at December 31, 2014 3.8 0.7 32.55 Granted 1.0 0.2 66.53 Vested (1.6) (0.4) 31.14 Forfeited (0.6) (0.2) 46.23 Non-vested at December 31, 2015 2.6 0.3 48.68

Accumulated Other Comprehensi32

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2015
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): Deferred Taxes UAL (a) Pension and Unrealized Gains (Losses) on Derivatives Investments Pension and Derivative Total Balance at December 31, 2012 $ (927) $ (10) $ 6 $ (115) $ — (d) $ (1,046) Other comprehensive income before reclassifications (b) 1,584 (c) 39 7 — — 1,630 Amounts reclassified from accumulated other comprehensive income (b) 42 (18) — — — 24 Net current-period other comprehensive income (loss) 1,626 21 7 — — 1,654 Balance at December 31, 2013 $ 699 $ 11 $ 13 $ (115) $ — (d) $ 608 Other comprehensive loss before reclassifications (b) (1,106) (c) (599) — — — (1,705) Amounts reclassified from accumulated other comprehensive income (b) (65) 89 (6) — — 18 Net current-period other comprehensive income (loss) (1,171) (510) (6) — — (1,687) Balance at December 31, 2014 $ (472) $ (499) $ 7 $ (115) $ — (d) $ (1,079) Other comprehensive income (loss) before reclassifications 78 (c) (320) (4) (28) 115 (159) Amounts reclassified from accumulated other comprehensive income 31 604 — (11) (217) 407 Net current-period other comprehensive income (loss) 109 284 (4) (39) (102) 248 Balance at December 31, 2015 $ (363) $ (215) $ 3 $ (154) $ (102) $ (831) Details about AOCI Components Amount Reclassified from AOCI to Affected Line Item in Year Ended December 31, 2015 2014 2013 Derivatives designated as cash flow hedges Fuel contracts-reclassifications of (gains) losses into earnings $ 604 $ 89 $ (18) Aircraft fuel Amortization of pension and postretirement items Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (e) 31 (65) 42 Salaries and related costs Investments and other Available-for-sale securities—reclassifications of gains into earnings — (6) — Miscellaneous, net (a) UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013. (b) Income tax expense for these items was offset by the Company’s valuation allowance. (c) Prior service credits increased by $0 million, $3 million and $331 million and actuarial gains (losses) increased by approximately $78 million, $(1.1) billion and $1.3 billion for 2015, 2014 and 2013, respectively. (d) Deferred tax balance was offset by the Company’s valuation allowance. (e) 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
	Dec. 31, 2015
Components of Income Tax Expense (Benefit)	The significant components of the income tax expense (benefit) are as follows (in millions): 2015 UAL United Current $ 56 $ 56 Deferred (3,177) (3,136) $ (3,121) $ (3,080) 2014 Current $ (17) $ (17) Deferred 13 13 $ (4) $ (4) 2013 Current $ (18) $ (18) Deferred (14) 1 $ (32) $ (17)
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 2015 2014 2013 Income tax provision at statutory rate $ 1,477 $ 395 $ 189 State income taxes, net of federal income tax 60 16 5 Foreign income taxes 4 2 3 Nondeductible employee meals 15 15 15 State rate change — — (33) Valuation allowance (4,684) (441) (219) Other, net 7 9 8 $ (3,121) $ (4) $ (32) United 2015 2014 2013 Income tax provision at statutory rate $ 1,477 $ 388 $ 223 State income taxes, net of federal income tax 60 15 5 Foreign income taxes 4 2 3 Nondeductible employee meals 15 15 15 Derivative market adjustment — (7) (24) State rate change — — (33) Valuation allowance (4,643) (426) (229) Other, net 7 9 23 $ (3,080) $ (4) $ (17)
Components of Deferred Tax Assets and Liabilities	Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2015 and 2014 were as follows (in millions): UAL United December 31, December 31, 2015 2014 2015 2014 Deferred income tax asset (liability): Federal and state net operating loss (“NOL”) carryforwards $ 2,897 $ 3,491 $ 2,855 $ 3,423 Deferred revenue 2,160 2,287 2,160 2,287 Employee benefits, including pension, postretirement and medical 1,662 1,943 1,662 1,943 Alternative minimum tax (“AMT”) credit carryforwards 232 214 232 214 Other 566 657 566 659 Less: Valuation allowance (48) (4,751) (48) (4,721) Total deferred tax assets $ 7,469 $ 3,841 $ 7,427 $ 3,805 Depreciation, capitalized interest and other $ (3,921) $ (3,212) $ (3,921) $ (3,212) Intangibles (1,511) (1,545) (1,511) (1,545) Other — (84) — (48) Total deferred tax liabilities $ (5,432) $ (4,841) $ (5,432) $ (4,805) Net deferred tax asset (liability) $ 2,037 $ (1,000) $ 1,995 $ (1,000)

Pension and Other Postretirem34

Pension and Other Postretirement Plans (Tables)	12 Months Ended
	Dec. 31, 2015
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 Accumulated benefit obligation: $ 3,795 $ 4,068 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 4,803 $ 4,000 Service cost 124 98 Interest cost 200 201 Actuarial (gain) loss (298) 807 Gross benefits paid and settlements (343) (281) Other (13) (22) Projected benefit obligation at end of year $ 4,473 $ 4,803 Change in plan assets: Fair value of plan assets at beginning of year $ 2,562 $ 2,397 Actual gain (loss) on plan assets (59) 151 Employer contributions 824 307 Gross benefits paid and settlements (343) (281) Other (9) (12) Fair value of plan assets at end of year $ 2,975 $ 2,562 Funded status—Net amount recognized $ (1,498) $ (2,241) Other Postretirement Benefits Year Ended Year Ended Change in benefit obligation: Benefit obligation at beginning of year $ 2,052 $ 1,819 Service cost 21 19 Interest cost 82 88 Plan participants’ contributions 68 67 Benefits paid (205) (212) Actuarial (gain) loss (22) 262 Other 6 9 Benefit obligation at end of year $ 2,002 $ 2,052 Change in plan assets: Fair value of plan assets at beginning of year $ 57 $ 57 Actual return on plan assets 1 1 Employer contributions 135 144 Plan participants’ contributions 68 67 Benefits paid (205) (212) Fair value of plan assets at end of year 56 57 Funded status—Net amount recognized $ (1,946) $ (1,995
Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss)	Pension Benefits December 31, 2015 December 31, 2014 Amounts recognized in the consolidated balance sheets consist of: Noncurrent asset $ 2 $ 2 Current liability (12) (17) Noncurrent liability (1,488) (2,226) Total liability $ (1,498) $ (2,241) Amounts recognized in accumulated other comprehensive loss consist of: Net actuarial loss $ (844) $ (982) Prior service loss (1) (1) Total accumulated other comprehensive loss $ (845) $ (983) Other Postretirement Benefits December 31, 2015 December 31, 2014 Amounts recognized in the consolidated balance sheets consist of: Current liability $ (64) $ (62) Noncurrent liability (1,882) (1,933) Total liability $ (1,946) $ (1,995) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial gain $ 236 $ 233 Prior service credit 246 278 Total accumulated other comprehensive income $ 482 $ 511
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): 2015 2014 Projected benefit obligation $ 4,292 $ 4,625 Accumulated benefit obligation 3,655 3,930 Fair value of plan assets 2,794 2,387
Components Of Net Periodic Benefit Cost	Net periodic benefit cost for the years ended December 31 included the following components (in millions): 2015 2014 2013 Pension Other Pension Other Pension Other Service cost $ 124 $ 21 $ 98 $ 19 $ 121 $ 52 Interest cost 200 82 201 88 191 110 Expected return on plan assets (194) (2) (180) (2) (163) (2) Amortization of unrecognized actuarial (gain) loss 85 (22) 12 (47) 48 3 Amortization of prior service credits — (32) — (31) — (3) Other 4 — 1 — (8) 2 Net periodic benefit cost $ 219 $ 47 $ 132 $ 27 $ 189 $ 162
Amortized Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost	The estimated amounts that will be amortized in 2016 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions): Pension Other Actuarial (gain) loss $ 71 $ (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 2015 2014 Discount rate 4.58% 4.20% Rate of compensation increase 3.66% 3.66% Assumptions used to determine net expense Discount rate 4.20% 5.10% Expected return on plan assets 7.40% 7.36% Rate of compensation increase 3.51% 3.50% Other Postretirement Benefits Assumptions used to determine benefit obligations 2015 2014 Discount rate 4.49% 4.07% Assumptions used to determine net expense Discount rate 4.07% 4.94% Expected return on plan assets 3.00% 4.00% Health care cost trend rate assumed for next year 6.75% 7.00% Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023) 5.00% 5.00%
Allocation of Plan Assets	United’s plan assets are allocated within the following guidelines: Percent of Total Expected Long-Term Rate of Return Equity securities 30-40 % 9.5 % Fixed-income securities 34-44 5.0 Alternatives 14-27 7.3 Other 0-10 7.0
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, 2015 $ 13 $ (11) Effect on postretirement benefit obligation at December 31, 2015 219 (191)
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): 2015 2014 Pension Plan Assets: Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Equity securities funds $ 1,135 $ 254 $ 881 $ — $ 1,181 $ 388 $ 793 $ — Fixed-income securities 1,109 — 1,100 9 813 — 813 — Alternatives 527 — 267 260 359 — 148 211 Insurance contract 18 — — 18 21 — — 21 Other investments 186 37 149 — 188 — 165 23 Total $ 2,975 $ 291 $ 2,397 $ 287 $ 2,562 $ 388 $ 1,919 $ 255 Other Postretirement Benefit Plan Assets: Deposit administration fund $ 56 $ — $ — $ 56 $ 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, 2015 and 2014 is as follows (in millions): 2015 2014 Balance at beginning of year $ 312 $ 293 Actual return on plan assets: Sold during the year 11 7 Held at year end (1) 6 Purchases, sales, issuances and settlements (net) 21 6 Balance at end of year $ 343 $ 312
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, 2015 are as follows (in millions): Pension Other Postretirement Other Postretirement— subsidy receipts 2016 $ 282 $ 125 $ 5 2017 287 128 5 2018 286 131 6 2019 292 135 6 2020 293 140 7 Years 2021 – 2025 1,577 761 40
Multi-Employer Plans	Pension Fund IAM National Pension Fund EIN/ Pension Plan Number 51-6031295 - 002 Pension Protection Act Zone Status (2015 and 2014) Green Zone. Plans in the green zone are at least 80 percent funded. FIP/RP Status Pending/Implemented No United’s Contributions $40 million, $39 million and $38 million in the years ended December 31, 2015, 2014 and 2013, respectively Surcharge Imposed No Expiration Date of Collective Bargaining Agreement N/A

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 UAL Cash and cash equivalents $ 3,006 $ 3,006 $ — $ — $ 2,002 $ 2,002 $ — $ — Short-term investments: Corporate debt 891 — 891 — 876 — 876 — Asset-backed securities 710 — 710 — 901 — 901 — Certificates of deposit placed through an account registry service (“CDARS”) 281 — 281 — 256 — 256 — U.S. government and agency notes 72 — 72 — 68 — 68 — Auction rate securities 9 — — 9 26 — — 26 Other fixed-income securities 227 — 227 — 255 — 255 — Enhanced equipment trust certificates (“EETC”) 26 — — 26 28 — — 28 Fuel derivatives liability, net 124 — 124 — 717 — 717 — Foreign currency derivatives — — — — 2 — 2 — Restricted cash 206 206 — — 320 320 — — United Cash and cash equivalents $ 3,000 $ 3,000 $ — $ — $ 1,996 $ 1,996 $ — $ — Short-term investments: Corporate debt 891 — 891 — 876 — 876 — Asset-backed securities 710 — 710 — 901 — 901 — CDARS 281 — 281 — 256 — 256 — U.S. government and agency notes 72 — 72 — 68 — 68 — Auction rate securities 9 — — 9 26 — — 26 Other fixed-income securities 227 — 227 — 255 — 255 — EETC 26 — — 26 28 — — 28 Fuel derivatives liability, net 124 — 124 — 717 — 717 — Foreign currency derivatives — — — — 2 — 2 — Restricted cash 206 206 — — 320 320 — — Convertible debt derivative asset — — — — 712 — — 712 Convertible debt derivative option liability — — — — 511 — — 511
Carrying Values and Estimated Fair Values of Financial Instruments	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 2015 2014 Carrying Fair Value Carrying Fair Value Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Long-term debt $ 10,897 $ 11,371 $ — $ 8,646 $ 2,725 $ 11,266 $ 12,386 $ — $ 8,568 $ 3,818 (a) 2014 amount differs from the amount reported in the Company’s Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information.

Hedging Activities (Tables)

Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2015
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 2015 2014 Derivatives designated as cash flow hedges Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 119 $ 450 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 27 $ 119 $ 477 Derivatives not designated for hedge accounting Assets: Fuel contracts due within one year Receivables $ — $ 6 Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 5 $ 244 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 2 Total liabilities $ 5 $ 246 Total derivatives Assets: Fuel contracts due within one year Receivables $ — $ 6 Liabilities: Fuel contracts due within one year Fuel derivative instruments $ 124 $ 694 Fuel contracts with maturities greater than one year Other liabilities and deferred credits: Other — 29 Total liabilities $ 124 $ 723
Offsetting 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, 2015 December 31, 2014 Fuel derivative instruments $ 98 $ 209 Other liabilities and deferred credits: Other — 30 Hedge derivatives liabilities, net $ 98 $ 239
Schedule of 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 Loss Recognized in AOCI on Derivatives (Effective Portion) Loss Reclassified from (Fuel Expense) (Effective Portion) Amount of Loss 2015 2014 2015 2014 2015 2014 Fuel contracts $ (320) $ (599) $ (604) $ (89) $ — $ (3)
Schedule of Derivative Instruments not Designated as Hedges Losses	Derivatives not designated for hedge accounting Amount of Gain (Loss) Recognized 2015 2014 2013 Fuel contracts $ (80) $ (462 ) $ 79

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Debt	(In millions) At December 31, 2015 2014 Secured Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.37% as of December 31, 2015), payable through 2027 $ 7,971 $ 7,464 Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 2.85%, payable through 2027 1,302 1,151 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 875 884 Term loan, LIBOR subject to a 0.75% floor, plus 3.00%, or alternative rate based on certain market rates plus 2%, due 2021 194 499 Unsecured 6% Notes due 2026 to 2028 (a) — 632 6% Senior Notes due 2020 (a) 300 300 6.375% Senior Notes due 2018 (a) 300 300 4.5% Convertible Notes due 2015 — 202 Other 100 101 11,042 11,533 Less: unamortized debt discount, premiums and debt issuance costs (145) (267) (b) Less: current portion of long-term debt (1,224) (1,313) Long-term debt, net $ 9,673 $ 9,953 (a) UAL is the issuer of this debt. United is a guarantor. (b) 2014 amount differs from the amount reported in the Company’s Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information.
Contractual Principal Payments	The table below presents the Company’s contractual principal payments at December 31, 2015 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions): 2016 $ 1,224 2017 822 2018 1,359 2019 1,788 2020 942 After 2020 4,907 $ 11,042
Details of Pass Through Trusts	Certain details of the pass-through trusts with proceeds received from issuance of debt in 2015 are as follows (in millions, except stated interest rate): EETC Date Class Principal Final expected Stated Total debt Proceeds Remaining November 2015 AA $ 334 December 2027 3.45% $ 334 $ 334 $ — November 2015 A 100 December 2022 3.70% 100 100 — August 2014 A 823 September 2026 3.75% 823 711 — August 2014 B 238 September 2022 4.625% 238 206 — $ 1,495 $ 1,495 $ 1,351 $ —
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 Various equipment notes and other notes payable Secured by certain aircraft. The indentures contain events of default that are customary for aircraft financing, including in certain cases cross default to other related aircraft. 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. 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. 6.375% Senior Notes due 2018 6% Senior Notes due 2020 The indentures for these notes 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. The indentures contain events of default that are customary for similar financings.

Leases and Capacity Purchase 38

Leases and Capacity Purchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2015
Future Minimum Lease Payments for Capital and Operating Leases	At December 31, 2015, 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 Facility and Other Aircraft Operating 2016 $ 206 $ 1,252 $ 1,317 2017 162 1,161 1,317 2018 151 899 1,100 2019 86 809 918 2020 66 920 708 After 2020 747 6,799 2,660 Minimum lease payments $ 1,418 $ 11,840 $ 8,020 Imputed interest (556) Present value of minimum lease payments 862 Current portion (135) Long-term obligations under capital leases $ 727
Future Lease Payment Under Terms of Capacity Purchase Agreement	Based on these assumptions as of December 31, 2015, our future payments through the end of the terms of our CPAs are presented in the table below (in millions): 2016 $ 1,834 2017 1,884 2018 1,550 2019 1,290 2020 1,155 After 2020 4,932 $ 12,645

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Commitments to Purchase Aircrafts	The table below is adjusted to include the impact of the January 2016 Boeing 737NG aircraft order discussed above. Any new firm aircraft orders, including through the exercise of purchase options and purchase rights, will increase the total future capital commitments of the Company. 2016 $ 3.4 2017 3.1 2018 3.3 2019 2.9 2020 2.8 After 2020 7.7 $ 23.2
Aircraft Type
Schedule of Commitments to Purchase Aircrafts	As of December 31, 2015 (as adjusted to include the order discussed above), United had firm commitments and options to purchase aircraft from Boeing, Embraer and Airbus S.A.S. (“Airbus”) presented in the table below: Aircraft Type Number of Firm Airbus A350-1000 35 Boeing 737NG/737 MAX 9 155 Boeing 777-300ER 10 Boeing 787-8/-9/-10 30 Embraer E175 10 (a) United also has options and purchase rights for additional aircraft.

Special Items (Tables)

Special Items (Tables)	12 Months Ended
	Dec. 31, 2015
Components of Special Items	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: 2015 2014 2013 Severance and benefit costs $ 107 $ 199 $ 105 Impairment of assets 79 49 33 Integration-related costs 60 96 205 Labor agreement costs 18 — 127 (Gains) losses on sale of assets and other miscellaneous (gains) losses, net 62 99 50 Special charges 326 443 520 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 202 74 — Income tax benefit related to special charges (11) (10) (7) Income tax benefit associated with valuation allowance release (Note 7) (3,130) — — Total operating and nonoperating special charges, net of income taxes $ (2,613) $ 507 $ 513
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 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 Accrual 107 30 Payments (189) (54) Balance at December 31, 2015 $ 27 $ 78

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2015
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): 2015 Domestic (U.S. and Canada) $ 21,931 Pacific 5,498 Atlantic 7,068 Latin America 3,367 Total $ 37,864 2014 Domestic (U.S. and Canada) $ 22,320 Pacific 5,767 Atlantic 7,321 Latin America 3,493 Total $ 38,901 2013 Domestic (U.S. and Canada) $ 22,092 Pacific 5,794 Atlantic 7,132 Latin America 3,261 Total $ 38,279 (a) (a) UAL and United amounts are substantially the same.

Selected Quarterly Financial 42

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Selected Quarterly Financial Data	UAL Quarter Ended (In millions, except per share amounts) March 31 June 30 September 30 December 31 2015 Operating revenue $ 8,608 $ 9,914 $ 10,306 $ 9,036 Income from operations 741 1,445 1,899 1,081 Net income 508 1,193 4,816 823 Basic earnings per share 1.33 3.14 12.83 2.24 Diluted earnings per share 1.32 3.14 12.82 2.24 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
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 2015 Operating: Severance and benefit costs $ 50 $ 25 $ 28 $ 4 Impairment of assets 2 11 18 48 Integration-related costs 18 14 15 13 (Gains) losses on sale of assets and other miscellaneous (gains) losses, net (6) 5 15 66 Special charges 64 55 76 131 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 6 128 61 7 Income tax benefit related to special charges — — — (11) Income tax expense (benefit) associated with valuation allowance release — — (3,218) 88 Total operating and nonoperating special items, net of income taxes $ 70 $ 183 $ (3,081) $ 215 2014 Operating: Severance and benefit costs $ 14 $ 38 $ 6 $ 141 Impairment of assets 1 32 — 16 Integration-related costs 34 17 28 17 Costs associated with permanently grounding Embraer ERJ 135 aircraft — 66 — — Losses on sale of assets and other special (gains) losses, net 3 16 9 5 Special charges 52 169 43 179 Nonoperating and income taxes: Loss on extinguishment of debt and other, net 21 — — 53 Income tax benefit related to special charges (1) — (3) (6) Total operating and nonoperating special charges, net of income taxes $ 72 $ 169 $ 40 $ 226

Significant Accounting Polici43

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Cash inflows (outflows) associated with its restricted cash balances	$ 114	$ 75	$ 52
Residual value	10.00%
Carrying value of computer software	$ 279	281
Advertising expense	$ 201	179	178
Minimum
Summary Of Significant Accounting Policies [Line Items]
Refundable tickets expiration period	1 year
Recently Issued Accounting Standards
Summary Of Significant Accounting Policies [Line Items]
Reclassification of debt issuance costs adjustments of carrying amount	$ 170	167
Reclassification of deferred income taxes to other assets	1,500
Reclassification of deferred income taxes to other liabilities and deferred income taxes		591
Recently Issued Accounting Standards | Pension Benefits
Summary Of Significant Accounting Policies [Line Items]
Pension plan investments measured at net asset value per share	1,400
Recently Issued Accounting Standards | Short-term Investments
Summary Of Significant Accounting Policies [Line Items]
Investments in certain entities that calculate net asset value per share included in short-term investments	200
Computer software
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense related to computer software	$ 93	$ 81	$ 72
Aircraft and aircraft spare parts
Summary Of Significant Accounting Policies [Line Items]
Residual value	10.00%

Schedule of Information Related

Schedule of Information Related to Amounts Recorded Related to Frequent Flyer Program (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Cash Proceeds from Miles Sold and Earned		$ 2,999	$ 2,861	$ 2,903
Other Revenue Recognized Upon Award of Miles to Third-Party Customers	[1]	1,050	882	903
Increase in Frequent Flyer Deferred Revenue for Miles Awarded	[2]	2,173	2,178	2,174
Increase (Decrease) in Advanced Purchase of Miles	[3]	$ (224)	$ (199)	$ (174)
[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 Prope

Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2015
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 Intangible46

Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets [Line Items]
Goodwill		$ 4,523	$ 4,523
Finite-lived intangible assets, Gross Carrying Amount		1,771	1,791
Finite-lived intangible assets, Accumulated Amortization		1,144	1,049
Indefinite-lived intangible assets, Gross Carrying Amount		$ 3,509	3,542
Frequent Flyer Database
Goodwill And Intangible Assets [Line Items]
Asset life	[1],[2]	22 years
Finite-lived intangible assets, Gross Carrying Amount	[1]	$ 1,177	1,177
Finite-lived intangible assets, Accumulated Amortization	[1]	$ 702	624
Hubs
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	20 years
Finite-lived intangible assets, Gross Carrying Amount		$ 145	145
Finite-lived intangible assets, Accumulated Amortization		$ 74	67
Contracts
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	12 years
Finite-lived intangible assets, Gross Carrying Amount		$ 135	155
Finite-lived intangible assets, Accumulated Amortization		$ 86	86
Patents And Trade Names
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	3 years
Finite-lived intangible assets, Gross Carrying Amount		$ 108	108
Finite-lived intangible assets, Accumulated Amortization		$ 108	108
Airport Slots and Gates
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	8 years
Finite-lived intangible assets, Gross Carrying Amount		$ 97	97
Finite-lived intangible assets, Accumulated Amortization		$ 97	97
Other Intangible Assets
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	25 years
Finite-lived intangible assets, Gross Carrying Amount		$ 109	109
Finite-lived intangible assets, Accumulated Amortization		77	67
Route Authorities
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount		1,570	1,589
Airport Slots And Gates
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount		942	956
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
[1]	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.
[2]	Weighted average life expressed in years.

Goodwill and Other Intangible47

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Actual and Estimated Amortization Expense [Line Items]
Actual amortization	$ 105	$ 128	$ 142
Projected amortization in 2016	90
Projected amortization in 2017	79
Projected amortization in 2018	70
Projected amortization in 2019	64
Projected amortization in 2020	$ 58

Common Stockholders' Equity a48

Common Stockholders' Equity and Preferred Securities - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2015	Dec. 31, 2015	Oct. 31, 2015	Jul. 21, 2015	Dec. 31, 2014
Schedule Of Stockholders Equity [Line Items]
Share repurchase program authorized amount				$ 3,000,000,000	$ 1,000,000,000
Agreement to repurchase through an accelerated share repurchase program			$ 300,000,000
Amount remaining under repurchase program		$ 2,400,000,000
Common stock reserved for future issuance		8,000,000
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]
Number of shares repurchased	5,000,000
Average price per share under repurchase program		$ 58.14
Open Market Repurchase Program
Schedule Of Stockholders Equity [Line Items]
Number of shares repurchased		16,000,000
Number of shares repurchased, value		$ 932,000,000

Computation of Earnings Per Sha

Computation of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Basic earnings per share:
Earnings available to common stockholders									$ 7,340	$ 1,132	$ 571
Basic weighted-average shares outstanding									376	371	348
Earnings per share, basic	$ 2.24	$ 12.83	$ 3.14	$ 1.33	$ 0.08	$ 2.49	$ 2.11	$ (1.66)	$ 19.52	$ 3.05	$ 1.64
Diluted earnings per share:
Earnings available to common stockholders									$ 7,340	$ 1,132	$ 571
Effect of dilutive securities										11	26
Earnings available to common stockholders including the effect of dilutive securities									$ 7,340	$ 1,143	$ 597
Diluted shares outstanding:
Basic weighted-average shares outstanding									376	371	348
Effect of convertible notes										18	42
Effect of employee stock awards									1	1	1
Diluted weighted-average shares outstanding									377	390	391
Earnings per share, diluted	$ 2.24	$ 12.82	$ 3.14	$ 1.32	$ 0.07	$ 2.37	$ 2.01	$ (1.66)	$ 19.47	$ 2.93	$ 1.53

Share-Based Compensation Plan50

Share-Based Compensation Plans - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock option awards		0.5
Outstanding weighted average exercise price		$ 26.80
RSUs
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
Share-Based Compensation, award granted	0.3	1	0.9	1.8
Share-Based Compensation, vesting period	3 years
Liabilities related to share based payments		$ 102
Payment related to share-based liabilities		85	$ 86	$ 29
Equity awards fair value		$ 92	$ 97	$ 22
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	0.2	0.2	0.3	0.5
Share-Based Compensation, vesting period	3 years
Performance Shares
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
Share-Based Compensation, award granted	0.6
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, vesting date	Dec. 31, 2017

Schedule of Share-Based Compens

Schedule of Share-Based Compensation Plan Cost (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	$ 58	$ 114	$ 100
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	52	104	88
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	$ 6	$ 10	11
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]			$ 1
[1]	All compensation cost is recorded to Salaries and related costs, with the exception of $3 million and $9 million in 2014 and 2013, respectively, that was recorded in integration-related costs as a component of special items.

Schedule of Share-Based Compe52

Schedule of Share-Based Compensation Plan Cost (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs	$ 13	$ 15	$ 14	$ 18	$ 17	$ 28	$ 17	$ 34	$ 60	$ 96	$ 205
Special Charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs										$ 3	$ 9

Schedule of Unearned Compensati

Schedule of Unearned Compensation and Weighted Average Remaining Period for Outstanding Share-Based Awards (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 41
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 37
Weighted- Average Remaining Period (in years)	1 year 6 months
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 4
Weighted- Average Remaining Period (in years)	1 year 4 months 24 days

Schedule of Restricted Stock Un

Schedule of Restricted Stock Unit and Restricted Stock Activity (Detail) - $ / shares shares in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	0.7	0.7	0.9	0.8
Granted, Stock	0.2	0.2	0.3	0.5
Vested, Stock		(0.4)	(0.4)	(0.3)
Forfeited, Stock		(0.2)	(0.1)	(0.1)
Non-vested at end of year, Stock		0.3	0.7	0.9
Weighted-Average Grant Price at beginning of year	$ 32.55	$ 32.55	$ 25.02	$ 23.94
Granted, Weighted-Average Grant Price		66.53	43.33	25.98
Vested, Weighted-Average Grant Price		31.14	24.66	23.93
Forfeited, Weighted-Average Grant Price		46.23	28.88	24.76
Non-vested at end of year, Weighted-Average Grant Price		$ 48.68	$ 32.55	$ 25.02
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	3.8	3.8	5.4	4.3
Granted, Stock	0.3	1	0.9	1.8
Vested, Stock		(1.6)	(2.2)	(0.5)
Forfeited, Stock		(0.6)	(0.3)	(0.2)
Non-vested at end of year, Stock		2.6	3.8	5.4

Components of Accumulated Other

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (1,079)	$ 608		$ (1,046)
Other comprehensive income (loss) before reclassifications	[1]	(159)	(1,705)	[2]	1,630	[2]
Amounts reclassified from accumulated other comprehensive income	[1]	407	18	[2]	24	[2]
Comprehensive income (loss) adjustments	[1]	248	(1,687)		1,654
Ending Balance	[1]	(831)	(1,079)		608
Pension and Other Postretirement Liabilities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(472)	699		(927)
Other comprehensive income (loss) before reclassifications	[1],[3]	78	(1,106)	[2]	1,584	[2]
Amounts reclassified from accumulated other comprehensive income	[1]	31	(65)	[2]	42	[2]
Comprehensive income (loss) adjustments	[1]	109	(1,171)		1,626
Ending Balance	[1]	(363)	(472)		699
Derivative Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(499)	11		(10)
Other comprehensive income (loss) before reclassifications	[1]	(320)	(599)	[2]	39	[2]
Amounts reclassified from accumulated other comprehensive income	[1]	604	89	[2]	(18)	[2]
Comprehensive income (loss) adjustments	[1]	284	(510)		21
Ending Balance	[1]	(215)	(499)		11
Investments and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	7	13		6
Other comprehensive income (loss) before reclassifications	[1]	(4)			7	[2]
Amounts reclassified from accumulated other comprehensive income	[1],[2]		(6)
Comprehensive income (loss) adjustments	[1]	(4)	(6)		7
Ending Balance	[1]	3	7		13
Pension and Other Postretirement Deferred Taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(115)	$ (115)		$ (115)
Other comprehensive income (loss) before reclassifications	[1]	(28)		[2]		[2]
Amounts reclassified from accumulated other comprehensive income	[1]	(11)
Comprehensive income (loss) adjustments	[1]	(39)
Ending Balance	[1]	(154)	$ (115)		$ (115)
Derivative Contracts Deferred Taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1],[4]
Other comprehensive income (loss) before reclassifications	[1]	115		[2]		[2]
Amounts reclassified from accumulated other comprehensive income	[1]	(217)
Comprehensive income (loss) adjustments	[1]	(102)
Ending Balance	[1]	$ (102)				[4]
[1]	UAL and United amounts are substantially the same except for an additional $1 million and $6 million of additional gains related to investments and other and an income tax benefit, respectively, at United in 2013.
[2]	Income tax expense for these items was offset by the Company's valuation allowance.
[3]	Prior service credits increased by $0 million, $3 million and $331 million and actuarial gains (losses) increased by approximately $78 million, $(1.1) billion and $1.3 billion for 2015, 2014 and 2013, respectively.
[4]	Deferred tax balance was offset by the Company's valuation allowance.

Details about Accumulated Other

Details about Accumulated Other Comprehensive Income Components (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	[1]	$ 31	$ (65)	$ 42
Miscellaneous, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Available-for-sale securities-reclassifications of gains into earnings			(6)
Fuel Oil Contract | Cash Flow Hedging | Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of (gains) losses into earnings		$ 604	$ 89	$ (18)
[1]	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 Oth57

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Increase in prior service credits	$ 0	$ 3	$ 331
Increase in actuarial gains (losses)	$ 78	$ (1,100)	1,300
United Airlines, Inc.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Additional gains related to investments and other			1
Income tax (expense) benefit			$ 6

Components of Income Tax Expens

Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components Of Income Tax Expense Benefit [Line Items]
Current	$ 56	$ (17)	$ (18)
Deferred	(3,177)	13	(14)
Income tax expense (benefit)	(3,121)	(4)	(32)
United Airlines, Inc.
Components Of Income Tax Expense Benefit [Line Items]
Current	56	(17)	(18)
Deferred	(3,136)	13	1
Income tax expense (benefit)	$ (3,080)	$ (4)	$ (17)

Income Tax Provision Differed f

Income Tax Provision Differed from Amounts Computed at Statutory Federal Income Tax Rate (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Line Items]
Income tax provision at statutory rate	$ 1,477	$ 395	$ 189
State income taxes, net of federal income tax	60	16	5
Foreign income taxes	4	2	3
Nondeductible employee meals	15	15	15
State rate change			(33)
Valuation allowance	(4,684)	(441)	(219)
Other, net	7	9	8
Income tax expense (benefit)	(3,121)	(4)	(32)
United Airlines, Inc.
Income Taxes [Line Items]
Income tax provision at statutory rate	1,477	388	223
State income taxes, net of federal income tax	60	15	5
Foreign income taxes	4	2	3
Nondeductible employee meals	15	15	15
Derivative market adjustment		(7)	(24)
State rate change			(33)
Valuation allowance	(4,643)	(426)	(229)
Other, net	7	9	23
Income tax expense (benefit)	$ (3,080)	$ (4)	$ (17)

Components of Deferred Tax Asse

Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	$ 2,897	$ 3,491
Deferred revenue	2,160	2,287
Employee benefits, including pension, postretirement and medical	1,662	1,943
Alternative minimum tax ("AMT") credit carryforwards	232	214
Other	566	657
Less: Valuation allowance	(48)	(4,751)
Total deferred tax assets	7,469	3,841
Depreciation, capitalized interest and other	(3,921)	(3,212)
Intangibles	(1,511)	(1,545)
Other		(84)
Total deferred tax liabilities	(5,432)	(4,841)
Net deferred tax asset	2,037
Net deferred tax (liability)		(1,000)
United Airlines, Inc.
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	2,855	3,423
Deferred revenue	2,160	2,287
Employee benefits, including pension, postretirement and medical	1,662	1,943
Alternative minimum tax ("AMT") credit carryforwards	232	214
Other	566	659
Less: Valuation allowance	(48)	(4,721)
Total deferred tax assets	7,427	3,805
Depreciation, capitalized interest and other	(3,921)	(3,212)
Intangibles	(1,511)	(1,545)
Other		(48)
Total deferred tax liabilities	(5,432)	(4,805)
Net deferred tax asset	$ 1,995
Net deferred tax (liability)		$ (1,000)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Line Items]
Alternative minimum tax ("AMT") credit carryforwards	$ 232		$ 232	$ 214
Income tax expense (benefit)			(3,121)	(4)	$ (32)
Income tax benefit associated with valuation allowance release	88	$ (3,218)	(3,130)
Pre-tax profit benefited from lower oil prices and improved efficiency			4,219	1,128	539
Valuation allowance	48		$ 48	4,751
Federal statutory income tax rate			35.00%
Unrecognized tax benefits	24		$ 24	$ 9	$ 14
Unrecognized tax benefits that would impact effective tax rate if recognized	21		21
Derivative
Income Taxes [Line Items]
Valuation allowance	180		$ 180
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
Pension Benefits
Income Taxes [Line Items]
Valuation allowance	285		$ 285
2,025
Income Taxes [Line Items]
Net operating loss expiration amount	2,100		2,100
2,026
Income Taxes [Line Items]
Net operating loss expiration amount	2,000		2,000
2,027
Income Taxes [Line Items]
Net operating loss expiration amount	1,400		1,400
Thereafter
Income Taxes [Line Items]
Net operating loss expiration amount	2,500		2,500
Valuation Allowance Reversal | Current year income
Income Taxes [Line Items]
Valuation allowance release			1,500
Valuation Allowance Reversal | Gross Amount
Income Taxes [Line Items]
Valuation allowance release			4,700
Federal
Income Taxes [Line Items]
NOL carry forwards	8,000		8,000
State
Income Taxes [Line Items]
NOL carry forwards	103		103
Valuation allowance	$ 48		$ 48

Reconciliation of Change in Pro

Reconciliation of Change in Projected Benefit Obligation and Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation:	$ 3,795	$ 4,068
Benefit obligation at beginning of year	4,803	4,000
Service cost	124	98	$ 121
Interest cost	200	201	191
Actuarial (gain) loss	(298)	807
Gross benefits paid and settlements	(343)	(281)
Other	(13)	(22)
Benefit obligation at end of year	4,473	4,803	4,000
Balance at beginning of year	2,562	2,397
Actual gain (loss) on plan assets	(59)	151
Employer contributions	824	307
Gross benefits paid and settlements	(343)	(281)
Other	(9)	(12)
Balance at end of year	2,975	2,562	2,397
Funded status-Net amount recognized	(1,498)	(2,241)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	2,052	1,819
Service cost	21	19	52
Interest cost	82	88	110
Plan participants' contributions	68	67
Benefits paid	(205)	(212)
Actuarial (gain) loss	(22)	262
Other	6	9
Benefit obligation at end of year	2,002	2,052	1,819
Balance at beginning of year	57	57
Actual gain (loss) on plan assets	1	1
Employer contributions	135	144
Plan participants' contributions	68	67
Benefits paid	(205)	(212)
Balance at end of year	56	57	$ 57
Funded status-Net amount recognized	$ (1,946)	$ (1,995)

Amounts Recognized in Consolida

Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other Postretirement Benefits
Amounts recognized in the consolidated balance sheets consist of:
Current liability	$ (64)	$ (62)
Noncurrent liability	(1,882)	(1,933)
Total liability	(1,946)	(1,995)
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	236	233
Prior service credit (loss)	246	278
Total accumulated other comprehensive income (loss)	482	511
Pension Benefits
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent asset	2	2
Current liability	(12)	(17)
Noncurrent liability	(1,488)	(2,226)
Total liability	(1,498)	(2,241)
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	(844)	(982)
Prior service credit (loss)	(1)	(1)
Total accumulated other comprehensive income (loss)	$ (845)	$ (983)

Accumulated Benefit Obligation

Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 4,292	$ 4,625
Accumulated benefit obligation	3,655	3,930
Fair value of plan assets	$ 2,794	$ 2,387

Components of Net Periodic Bene

Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 124	$ 98	$ 121
Interest cost	200	201	191
Expected return on plan assets	(194)	(180)	(163)
Amortization of unrecognized actuarial (gain) loss	85	12	48
Other	4	1	(8)
Net periodic benefit cost	219	132	189
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	21	19	52
Interest cost	82	88	110
Expected return on plan assets	(2)	(2)	(2)
Amortization of unrecognized actuarial (gain) loss	(22)	(47)	3
Amortization of prior service credits	(32)	(31)	(3)
Other			2
Net periodic benefit cost	$ 47	$ 27	$ 162

Amortized Accumulated Other Com

Amortized Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$ 71
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	(22)
Prior service credit	$ (32)

Assumptions Used for Benefit Pl

Assumptions Used for Benefit Plans (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Assumptions used to determine benefit obligations
Discount rate	4.58%	4.20%
Rate of compensation increase	3.66%	3.66%
Assumptions used to determine net expense
Discount rate	4.20%	5.10%
Expected return on plan assets	7.40%	7.36%
Rate of compensation increase	3.51%	3.50%
Other Postretirement Benefits
Assumptions used to determine benefit obligations
Discount rate	4.49%	4.07%
Assumptions used to determine net expense
Discount rate	4.07%	4.94%
Expected return on plan assets	3.00%	4.00%
Health care cost trend rate assumed for next year	6.75%	7.00%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023)	5.00%	5.00%

Allocation of Plan Assets (Deta

Allocation of Plan Assets (Detail) - United Airlines, Inc.	12 Months Ended
	Dec. 31, 2015
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	30.00%
Percent of Total, Maximum	40.00%
Expected Long-Term Rate of Return	9.50%
Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	34.00%
Percent of Total, Maximum	44.00%
Expected Long-Term Rate of Return	5.00%
Alternatives
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	14.00%
Percent of Total, Maximum	27.00%
Expected Long-Term Rate of Return	7.30%
Other Investments
Defined Benefit Plan Disclosure [Line Items]
Percent of Total, Minimum	0.00%
Percent of Total, Maximum	10.00%
Expected Long-Term Rate of Return	7.00%

Pension and Other Postretirem69

Pension and Other Postretirement Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Effect on post retirement benefit obligation, 1% Decrease		$ 227
Effect on total service and interest cost, 1% Decrease		12
Profit sharing and payroll tax expense		$ 698	$ 235	$ 190
Multiemployer Plans, Pension | IAM National Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan contributions			$ 382
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		$ 191
Effect on total service and interest cost, 1% Decrease		11
Employer contributions		$ 135	$ 144
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		$ 824	307
United Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		522	503	433
United Airlines, Inc. | Multiemployer Plans, Pension | IAM National Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan contributions		$ 40	$ 39	$ 38
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 One-Percentage-Point

Effect of One-Percentage-Point Change in Assumed Health Care Trend Rate (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest cost,1% Decrease	$ (12)
Effect on post retirement benefit obligation, 1% Decrease	(227)
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	219
Effect on total service and interest cost,1% Decrease	(11)
Effect on post retirement benefit obligation, 1% Decrease	$ (191)

Pension and Other Postretirem71

Pension and Other Postretirement Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	$ 2,975	$ 2,562	$ 2,397
Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,135	1,181
Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,109	813
Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	527	359
Pension Benefits | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	18	21
Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	186	188
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	56	57	57
Other Postretirement Benefits | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	56	57
Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	291	388
Level 1 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	254	388
Level 1 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	37
Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	2,397	1,919
Level 2 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	881	793
Level 2 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,100	813
Level 2 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	267	148
Level 2 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	149	165
Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	343	312	$ 293
Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	287	255
Level 3 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	9
Level 3 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	260	211
Level 3 | Pension Benefits | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	18	21
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	$ 56	$ 57

Defined Benefit Plan Assets Mea

Defined Benefit Plan Assets Measured at Fair Value Using Unobservable Inputs (Level Three) (Detail) - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	$ 312	$ 293
Actual return on plan assets, Sold during the year	11	7
Actual return on plan assets, Held at year end	(1)	6
Purchases, sales, issuances and settlements (net)	21	6
Balance at end of year	$ 343	$ 312

Estimated Future Benefit Paymen

Estimated Future Benefit Payments (Detail) $ in Millions	Dec. 31, 2015USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2,016	$ 282
2,017	287
2,018	286
2,019	292
2,020	293
Years 2021 - 2025	1,577
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2,016	125
2,017	128
2,018	131
2,019	135
2,020	140
Years 2021 - 2025	761
Other Postretirement-Subsidy Receipts
Defined Benefit Plan Disclosure [Line Items]
2,016	5
2,017	5
2,018	6
2,019	6
2,020	7
Years 2021 - 2025	$ 40

Multi-Employer Plans (Detail)

Multi-Employer Plans (Detail) - Multiemployer Plans, Pension - IAM National Pension Plan - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Multiemployer Plans [Line Items]
EIN		516,031,295
Pension Plan Number		2
Pension Protection Act Zone Status (2015 and 2014)	[1]	Green
FIP/RP Status Pending/Implemented		No
United's Contributions			$ 382
Surcharge Imposed		No
United Airlines, Inc.
Multiemployer Plans [Line Items]
United's Contributions		$ 40	$ 39	$ 38
[1]	Plans in the green zone are at least 80 percent funded

Multi-Employer Plans (Parenthet

Multi-Employer Plans (Parenthetical) (Detail)	Dec. 31, 2015
Multiemployer Plans, Pension | IAM National Pension Plan | Minimum
Multiemployer Plans [Line Items]
Green zone funded percentage	80.00%

Financial Assets and Liabilitie

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative asset		$ 712
Convertible debt derivative option liability		511
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 3,006	2,002
Restricted cash	206	320
Fair Value, Measurements, Recurring | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,000	1,996
Restricted cash	206	320
Fair Value, Measurements, Recurring | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	710	901
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	710	901
Fair Value, Measurements, Recurring | Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	891	876
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	891	876
Fair Value, Measurements, Recurring | CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	281	256
Fair Value, Measurements, Recurring | CDARS | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	281	256
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	72	68
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	72	68
Fair Value, Measurements, Recurring | Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	9	26
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	9	26
Fair Value, Measurements, Recurring | Other Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	227	255
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	227	255
Fair Value, Measurements, Recurring | EETC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	26	28
Fair Value, Measurements, Recurring | EETC | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	26	28
Fair Value, Measurements, Recurring | Fuel Derivatives Liability, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	124	717
Fair Value, Measurements, Recurring | Fuel Derivatives Liability, Net | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	124	717
Fair Value, Measurements, Recurring | Foreign Currency Derivatives Asset, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net		2
Fair Value, Measurements, Recurring | Foreign Currency Derivatives Asset, Net | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net		2
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
Fair Value, Measurements, Recurring | Convertible Debt Derivative Option Liability | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative option liability		511
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,006	2,002
Restricted cash	206	320
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	3,000	1,996
Restricted cash	206	320
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	710	901
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	710	901
Fair Value, Measurements, Recurring | Level 2 | Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	891	876
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	891	876
Fair Value, Measurements, Recurring | Level 2 | CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	281	256
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	281	256
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	72	68
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	72	68
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	227	255
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	227	255
Fair Value, Measurements, Recurring | Level 2 | Fuel Derivatives Liability, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	124	717
Fair Value, Measurements, Recurring | Level 2 | Fuel Derivatives Liability, Net | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net	124	717
Fair Value, Measurements, Recurring | Level 2 | Foreign Currency Derivatives Asset, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net		2
Fair Value, Measurements, Recurring | Level 2 | Foreign Currency Derivatives Asset, Net | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net		2
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	9	26
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	9	26
Fair Value, Measurements, Recurring | Level 3 | EETC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	26	28
Fair Value, Measurements, Recurring | Level 3 | EETC | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
EETC	$ 26	28
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
Fair Value, Measurements, Recurring | Level 3 | Convertible Debt Derivative Option Liability | United Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt derivative option liability		$ 511

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Fair Value [Line Items]
Debt instrument principal amount			$ 248
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		34 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		3 years
EETC
Fair Value [Line Items]
Available-for-sale securities remaining maturities		2,019
Unsecured Debt | 4.5% Convertible Notes Due 2015
Fair Value [Line Items]
Debt instrument principal amount	$ 202
Debt instrument stated interest rate	4.50%
Common stock issued in exchange for convertible notes	11
Debt instrument maturity year	2,015

Carrying Values and Estimated F

Carrying Values and Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Carrying (Reported) Amount, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 10,897	$ 11,266	[1]
Estimate of Fair Value, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	11,371	12,386
Estimate of Fair Value, Fair Value Disclosure | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	8,646	8,568
Estimate of Fair Value, Fair Value Disclosure | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	$ 2,725	$ 3,818
[1]	2014 amount differs from the amount reported in the Company's Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information.

Hedging Activities - Additional

Hedging Activities - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)gal	Dec. 31, 2014USD ($)
Derivatives And Hedging Activities [Line Items]
Fuel hedges expiration date	2016-12
Fuel hedge collateral deposits	$ 26	$ 577
Fuel Derivative Instruments
Derivatives And Hedging Activities [Line Items]
Fuel hedge collateral deposits	$ 26	$ 577
2016 Projected
Derivatives And Hedging Activities [Line Items]
Percentage of projection for hedging financial instruments	17.00%
Volume of fuel hedging | gal	652,000,000
Cash Flow Hedging
Derivatives And Hedging Activities [Line Items]
Percentage of projection of European euro for hedging financial instruments for 2016	18.00%

Description of Derivative Instr

Description of Derivative Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	$ 124	$ 723
Receivables
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		6
Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	124	694
Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities		29
Designated as Hedging Instrument | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	119	477
Designated as Hedging Instrument | Cash Flow Hedging | Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	119	450
Designated as Hedging Instrument | Cash Flow Hedging | Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities		27
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	5	246
Not Designated as Hedging Instrument | Receivables
Derivatives, Fair Value [Line Items]
Fuel contracts, assets		6
Not Designated as Hedging Instrument | Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	$ 5	244
Not Designated as Hedging Instrument | Other
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities		$ 2

Offsetting Liabilities (Detail)

Offsetting Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset	$ 98	$ 239
Other
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset		30
Fuel Derivative Instruments
Offsetting Asset and Liabilities [Line Items]
Potential net fair value positions elected to offset	$ 98	$ 209

Schedule of Losses on Derivativ

Schedule of Losses on Derivative Instruments (Detail) - Designated as Hedging Instrument - Cash Flow Hedging - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Recognized in AOCI on Derivatives (Effective Portion)	$ (320)	$ (599)
Loss Reclassified from AOCI into Income (Fuel Expense) (Effective Portion)	$ (604)	(89)
Amount of Loss Recognized in Nonoperating income (expense): Miscellaneous, net (Ineffective Portion)		$ (3)

Schedule of Derivative Instrume

Schedule of Derivative Instruments not Designated as Hedges Losses (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss recognized in Nonoperating income (expense): Miscellaneous, net	$ (80)	$ (462)	$ 79

Debt (Detail)

Debt (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Jan. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt, Gross				$ 248
Less: current portion of long-term debt		$ (1,224)		(1,313)
Long-term debt, net		9,673		9,953
United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		11,042		11,533
Less: unamortized debt discount, premiums and debt issuance costs		(145)		(267)	[1]
Less: current portion of long-term debt		(1,224)		(1,313)
Long-term debt, net		9,673		9,953
Secured Debt | Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.37% as of December 31, 2015), payable through 2027 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		7,971		7,464
Secured Debt | Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2027 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		1,302		1,151
Secured Debt | Term Loan | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		875		884
Secured Debt | Term Loan, due 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		194		499
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	[2]			632
Unsecured Debt | Senior Notes 6% Due 2020 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	[2]	300		300
Unsecured Debt | 6.375% Senior Notes due 2018 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross	[2]	300		300
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
Unsecured Debt | Other Debt | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		100		101
Adjusted For Embedded Conversion Options | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term debt, net		$ 9,673		$ 9,953
[1]	2014 amount differs from the amount reported in the Company's Form 10-K for the fiscal year ended December 31, 2014 due to the adoption of an accounting standard update in 2015. See Note 1(t) Recently Issued Accounting Standards of this report for additional information.
[2]	UAL is the issuer of this debt. United is a guarantor.

Debt (Parenthetical) (Detail)

Debt (Parenthetical) (Detail)		1 Months Ended	12 Months Ended
		Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 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			6.375%
Minimum | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date			2,025
Maximum | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date			2,027
Secured Debt | Notes payable, fixed interest rates of 1.42% to 12.00% (weighted average rate of 5.37% as of December 31, 2015), payable through 2027 | 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			5.37%	5.37%
Debt instrument, maturity date			2,027	2,027
Secured Debt | Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2027 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date			2,027	2,027
Secured Debt | Term Loan | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date			2,019	2,019
Secured Debt | Term Loan, due 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date			2,021	2,021
Secured Debt | LIBOR | Term Loan | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.75%	2.75%
Secured Debt | LIBOR | Term Loan, due 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			3.00%	3.00%
Secured Debt | LIBOR | Minimum | Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2027 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.20%	0.20%
Secured Debt | LIBOR | Maximum | Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2027 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.85%	2.85%
Secured Debt | Interest Rate Floor | Term Loan | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.75%	0.75%
Secured Debt | Interest Rate Floor | Term Loan, due 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.75%	0.75%
Secured Debt | Certain Market Interest Rates | Term Loan | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1.75%	1.75%
Secured Debt | Certain Market Interest Rates | Term Loan, due 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.00%	2.00%
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	[1]		6.00%	6.00%
Unsecured Debt | Senior Notes 6% Due 2020 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	[1]		6.00%	6.00%
Debt instrument, maturity date	[1]		2,020	2,020
Unsecured Debt | 6.375% Senior Notes due 2018 | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument stated interest rate	[1]		6.375%	6.375%
Debt instrument, maturity date	[1]		2,018	2,018
Unsecured Debt | 4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Debt instrument stated interest rate		4.50%
Debt instrument, maturity date		2,015
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			2,015	2,015
Unsecured Debt | Minimum | Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	[1]		2,026	2,026
Unsecured Debt | Maximum | Six Percent Senior Notes Due Twenty Twenty Six To Twenty Twenty Eight | United Airlines, Inc.
Debt Instrument [Line Items]
Debt instrument, maturity date	[1]		2,028	2,028
[1]	UAL is the issuer of this debt. United is a guarantor.

Contractual Principal Payments

Contractual Principal Payments (Detail) - UAL and United $ in Millions	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
2,016	$ 1,224
2,017	822
2,018	1,359
2,019	1,788
2,020	942
After 2,020	4,907
Long-term debt	$ 11,042

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($) shares in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Gross				$ 248,000,000
Aggregate principal amount of convertible senior notes exchanged			$ 202,000,000	$ 260,000,000	$ 240,000,000
6% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument stated interest rate				6.00%
Debt instrument maturity year				2,029
Common stock issued in exchange for convertible notes				12
Aggregate principal amount of convertible senior notes exchanged				$ 104,000,000
Secured Debt | Performance Bonds
Debt Instrument [Line Items]
Credit facility expiration year			2,019
Unsecured Debt | 4.5% Senior Limited-Subordination Convertible Notes Due 2021
Debt Instrument [Line Items]
Debt instrument maturity year		2,021
Debt instrument converted amount		$ 156,000,000
Debt instrument converted shares issued		5
Unsecured Debt | 4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.50%
Debt instrument maturity year	2,015
Debt purchased and retired				28,000,000
Debt instrument conversion rate			18.93
Long-term Debt, Gross	$ 202,000,000
Common stock issued in exchange for convertible notes	11
Adjustment to additional paid in capital upon debt redemption				34,000,000
United Airlines, Inc.
Debt Instrument [Line Items]
Borrowed principal amount			$ 590,000,000
Long-term Debt, Gross			$ 11,042,000,000	11,533,000,000
Convertible debt derivative asset				712,000,000
Convertible debt option liability				511,000,000
Aggregate principal amount of convertible senior notes exchanged				$ 156,000,000
United Airlines, Inc. | Minimum
Debt Instrument [Line Items]
Debt instrument maturity year			2,025
United Airlines, Inc. | Maximum
Debt Instrument [Line Items]
Debt instrument maturity year			2,027
United Airlines, Inc. | Revolving Credit Facility
Debt Instrument [Line Items]
Commitment fee percentage			0.75%
United Airlines, Inc. | Letters of credit | Cash Collateralized Letters of Credit
Debt Instrument [Line Items]
Credit facility outstanding amount			$ 70,000,000
United Airlines, Inc. | Letter of Credit and Performance Bonds
Debt Instrument [Line Items]
Credit facility outstanding amount			437,000,000
United Airlines, Inc. | Pass-through certificates
Debt Instrument [Line Items]
Long term debt			7,800,000,000
United Airlines, Inc. | 6% Notes due 2026 and 2028
Debt Instrument [Line Items]
Write off of unamortized discount			$ 134,000,000
United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Quarterly principal repayment amount			0.25%
United Airlines, Inc. | Secured Debt | Revolving Credit Facility
Debt Instrument [Line Items]
Credit agreement			$ 1,350,000,000
Available under revolving credit facility			1,350,000,000
United Airlines, Inc. | Secured Debt | Term Loan Facility Due April 2019
Debt Instrument [Line Items]
Credit agreement			900,000,000
Long term debt			$ 875,000,000
Debt instrument maturity date			Apr. 1, 2019
United Airlines, Inc. | Secured Debt | Term Loan Facility Due April 2019 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.75%
United Airlines, Inc. | Secured Debt | Term Loan Facility Due September 2021
Debt Instrument [Line Items]
Credit agreement			$ 500,000,000
Long term debt			$ 194,000,000
Debt instrument maturity date			Sep. 15, 2021
Debt instrument stated interest rate			3.00%
United Airlines, Inc. | Secured Debt | Revolving Credit Facility Available For Drawing until April 2018
Debt Instrument [Line Items]
Credit agreement			$ 1,350,000,000
Revolving credit facility available for drawing date			2018-04
United Airlines, Inc. | Secured Debt | Revolving Credit Facility Available For Drawing until January 2019
Debt Instrument [Line Items]
Credit agreement			$ 1,315,000,000
Revolving credit facility available for drawing date			2019-01
United Airlines, Inc. | Secured Debt | Term Loan | Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.75%
United Airlines, Inc. | Secured Debt | Term Loan, due 2021
Debt Instrument [Line Items]
Debt instrument maturity year			2,021	2,021
Long-term Debt, Gross			$ 194,000,000	$ 499,000,000
United Airlines, Inc. | Secured Debt | Term Loan, due 2021 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			3.00%	3.00%
United Airlines, Inc. | Secured Debt | Term Loan, due 2021 | Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.75%	0.75%
United Airlines, Inc. | Secured Debt | Term Loan, due 2021 | Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.00%	2.00%
United Airlines, Inc. | Unsecured Debt | 6% Notes due 2026
Debt Instrument [Line Items]
Debt instrument stated interest rate			6.00%
Debt instrument maturity year			2,026
Debt purchased and retired			$ 321,000,000
United Airlines, Inc. | Unsecured Debt | 6% Notes Due 2028
Debt Instrument [Line Items]
Debt instrument stated interest rate			6.00%
Debt instrument maturity year			2,028
Debt purchased and retired			$ 311,000,000
United Airlines, Inc. | Unsecured Debt | 4.5% Convertible Notes Due 2015
Debt Instrument [Line Items]
Debt instrument stated interest rate			4.50%	4.50%
Debt instrument maturity year			2,015	2,015
Long-term Debt, Gross				$ 202,000,000
Adjustment to additional paid in capital upon debt redemption				$ 62,000,000
Debt instrument convertible effective interest rate			4.50%

Details of Pass Through Trusts

Details of Pass Through Trusts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total debt recorded		$ 248
Proceeds received from issuance of debt	$ 1,073	1,432	$ 1,423
United Airlines, Inc.
Debt Instrument [Line Items]
Principal	590
Total debt recorded	11,042	11,533
Proceeds received from issuance of debt	1,073	$ 1,432	$ 1,423
United Airlines, Inc. | Class AA Pass Through Certificates | November 2015
Debt Instrument [Line Items]
Principal	$ 334
Final expected distribution date	2027-12
Stated interest rate	3.45%
Total debt recorded	$ 334
Proceeds received from issuance of debt	334
Remaining proceeds from issuance of debt to be received in future periods	0
United Airlines, Inc. | Class A Pass Through Certificates | November 2015
Debt Instrument [Line Items]
Principal	$ 100
Final expected distribution date	2022-12
Stated interest rate	3.70%
Total debt recorded	$ 100
Proceeds received from issuance of debt	100
Remaining proceeds from issuance of debt to be received in future periods	0
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	$ 823
Proceeds received from issuance of debt	711
Remaining proceeds from issuance of debt to be received in future periods	0
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	4.625%
Total debt recorded	$ 238
Proceeds received from issuance of debt	206
Remaining proceeds from issuance of debt to be received in future periods	0
United Airlines, Inc. | EETC
Debt Instrument [Line Items]
Principal	1,495
Total debt recorded	1,495
Proceeds received from issuance of debt	1,351
Remaining proceeds from issuance of debt to be received in future periods	$ 0

Summary of Collateral Covenants

Summary of Collateral Covenants and Cross Default Provisions (Detail)	12 Months Ended
	Dec. 31, 2015
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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program.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.
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Collateral, Covenants and Cross Default Provisions	The indentures for these notes 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. 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 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, although the Company currently has ample ability under these restrictions to repurchase stock under the Company’s share repurchase program. The indentures contain events of default that are customary for similar financings.

Summary of Collateral Covenan90

Summary of Collateral Covenants and Cross Default Provisions (Parenthetical) (Detail) $ in Billions	12 Months Ended
	Dec. 31, 2015USD ($)
Credit Agreement
Debt Instrument [Line Items]
Unrestricted liquidity required for credit agreement	$ 3
Minimum ratio of appraised value of collateral for Credit Agreement	167.00%
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.375%
Debt instrument maturity year	2,018
Senior Notes 6% Due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2,020

Advanced Purchase of Miles - Ad

Advanced Purchase of Miles - Additional Information (Detail)	Dec. 31, 2015USD ($)
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 2016	$ 249,000,000

Future Minimum Lease Payments f

Future Minimum Lease Payments for Capital and Operating Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Capital Leases
2,016	$ 206
2,017	162
2,018	151
2,019	86
2,020	66
After 2,020	747
Minimum lease payments	1,418
Imputed interest	(556)
Present value of minimum lease payments	862
Current portion	(135)	$ (110)
Long-term obligations under capital leases	727	$ 571
Present value of minimum lease payments	862
Facility and Other Operating Leases
Operating Leases
2,016	1,252
2,017	1,161
2,018	899
2,019	809
2,020	920
After 2,020	6,799
Minimum lease payments	11,840
Aircraft Operating Leases
Operating Leases
2,016	1,317
2,017	1,317
2,018	1,100
2,019	918
2,020	708
After 2,020	2,660
Minimum lease payments	$ 8,020

Leases and Capacity Purchase 93

Leases and Capacity Purchase Agreements - (Capital Leases) - Additional Information (Detail) - United Airlines, Inc.	12 Months Ended
	Dec. 31, 2015Aircraft
Minimum
Capital Leased Assets [Line Items]
Imputed interest rate	3.50%
Maximum
Capital Leased Assets [Line Items]
Imputed interest rate	20.80%
Mainline
Capital Leased Assets [Line Items]
Number of assets subject to lease	47
Regional Carrier
Capital Leased Assets [Line Items]
Number of assets subject to lease	29

Leases and Capacity Purchase 94

Leases and Capacity Purchase Agreements - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)Aircraft	Dec. 31, 2014USD ($)Aircraft	Dec. 31, 2013USD ($)
Operating Leased Assets [Line Items]
Regional capacity purchase expense | $		$ 2,290	$ 2,344	$ 2,419
Scenario Forecast | Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Scheduled block hours increase (decrease) percentage	10.00%
Change in cash obligation | $	$ 144
Cash obligation increase (decrease) percentage	7.90%
Aircraft Operating Leases
Operating Leased Assets [Line Items]
Operating leases obligations | $		$ 8,020
Facility and Other Operating Leases
Operating Leased Assets [Line Items]
Operating lease extended expiration year		2,041
Operating leases obligations | $		$ 11,840
Minimum | Aircraft Operating Leases
Operating Leased Assets [Line Items]
Operating lease term		5 years
Operating lease expiration date, in years		2,016
Maximum | Aircraft Operating Leases
Operating Leased Assets [Line Items]
Operating lease term		26 years
Operating lease expiration date, in years		2,024
CommutAir | Embraer ERJ145 Aircraft | Capacity Purchase Arrangement
Operating Leased Assets [Line Items]
Number of aircraft operated		40
CommutAir | Minimum | Embraer ERJ145 Aircraft | Capacity Purchase Arrangement
Operating Leased Assets [Line Items]
Used aircraft, scheduled transfer start date		2015-12
CommutAir | Maximum | Embraer ERJ145 Aircraft | Capacity Purchase Arrangement
Operating Leased Assets [Line Items]
Used aircraft, scheduled transfer end date		2,017
AerCap Holdings N.V. | A319 aircraft | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
Number of used aircraft expected to be delivered over the next two years beginning in early 2016		11
AerCap Holdings N.V. | Maximum | A319 aircraft | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
Number of used aircraft expected to be delivered over the next five years		14
United Airlines, Inc.
Operating Leased Assets [Line Items]
Nonaircraft rent expense | $		$ 1,300	1,400	1,300
Regional capacity purchase expense | $		2,290	2,344	2,419
United Airlines, Inc. | Regional Aircraft
Operating Leased Assets [Line Items]
Regional capacity purchase expense | $		461	442	428
United Airlines, Inc. | Revaluation of Liabilities
Operating Leased Assets [Line Items]
Net accretion amounts | $		$ 107	$ 160	$ 173
United Airlines, Inc. | Capacity Purchase Agreements
Operating Leased Assets [Line Items]
Number of aircraft operated		521
Airline capacity purchase arrangements, expiration year		2,029
United Airlines, Inc. | Variable Interest Entity, Not Primary Beneficiary
Operating Leased Assets [Line Items]
Operating leases obligations | $		$ 1,500
United Airlines, Inc. | Aircraft Operating Leases
Operating Leased Assets [Line Items]
Number of aircraft operated		113
United Airlines, Inc. | Aircraft Operating Leases | Embraer E170 Aircraft | Extension of Term
Operating Leased Assets [Line Items]
Number of aircraft operated		38	38
United Airlines, Inc. | Aircraft Operating Leases | Embraer E175 Aircraft | New Lease Arrangement
Operating Leased Assets [Line Items]
Number of aircraft operated		40	40
United Airlines, Inc. | Aircraft Operating Leases | Q400 aircraft
Operating Leased Assets [Line Items]
Number of aircraft operated		13	13
United Airlines, Inc. | Aircraft Leases | Embraer E175 Aircraft
Operating Leased Assets [Line Items]
Number of aircraft right to acquire		40
United Airlines, Inc. | Minimum
Operating Leased Assets [Line Items]
Lease Fair Value Adjustment, Remaining Lease Term		1 year
United Airlines, Inc. | Minimum | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,016
United Airlines, Inc. | Minimum | Aircraft Leases | Embraer E175 Aircraft
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,016
United Airlines, Inc. | Maximum
Operating Leased Assets [Line Items]
Lease Fair Value Adjustment, Remaining Lease Term		9 years
United Airlines, Inc. | Maximum | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,024
United Airlines, Inc. | Maximum | Aircraft Leases | Embraer E175 Aircraft
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,017
SkyWest | Embraer E175 Aircraft | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
Number of aircraft operated		25
SkyWest | Minimum | Embraer E175 Aircraft | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,016
SkyWest | Maximum | Embraer E175 Aircraft | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,017
Mesa | Embraer E175 Aircraft | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
New aircraft, scheduled delivery date		2,016
Number of aircraft to be acquired		15
Mesa | Embraer E175 Aircraft | At the time of each aircraft's delivery, subject to certain conditions | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
Number of aircraft to be acquired		10
Mesa | Embraer E175 Aircraft | Aircrafts directly purchased from Embraer | Capacity Purchase Arrangement | Capital Addition Purchase Commitments
Operating Leased Assets [Line Items]
Number of aircraft to be acquired		5

Future Lease Payment Under Term

Future Lease Payment Under Terms of Capacity Purchase Agreement (Detail) $ in Millions	Dec. 31, 2015USD ($)
Long-term Purchase Commitment [Line Items]
2,016	$ 1,834
2,017	1,884
2,018	1,550
2,019	1,290
2,020	1,155
After 2,020	4,932
Contractual Obligation, Total	$ 12,645

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Detail) - Variable Interest Entity, Not Primary Beneficiary	Dec. 31, 2015Aircraft
Mainline
Variable Interest Entity [Line Items]
Aircraft under operating lease, fixed purchase options	47
Regional Carrier
Variable Interest Entity [Line Items]
Aircraft under operating lease	207

Schedule of Commitments to Purc

Schedule of Commitments to Purchase Aircrafts (Detail) - United Airlines, Inc. - Capital Addition Purchase Commitments	Dec. 31, 2015Aircraft	[1]
Airbus A350-1000 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	35
Boeing 737NG/737 MAX 9 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	155
Boeing 777-300ER Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	10
Boeing 787-8/-9/-10 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	30
Embraer E175 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	10
[1]	United also has options and purchase rights for additional aircraft.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) Employee in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)EmployeeOption	Dec. 31, 2014USD ($)
Commitments and Contingencies [Line Items]
Debt instrument principal amount		$ 248,000,000
Number of call options to purchase regional jet aircraft | Option	279
Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	$ 1,900,000,000
Operating leases obligations	1,500,000,000
Capital leases obligations	302,000,000
Tax-exempt special facilities revenue bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	224,000,000
Contingent liabilities based on participation	1,300,000,000
Floating Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	2,400,000,000
Fixed Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	118,000,000
Loans And Leases From Non U S Entities
Commitments and Contingencies [Line Items]
Debt instrument principal amount	$ 2,400,000,000
Minimum | Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2,017
Minimum | Tax-exempt special facilities revenue bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2,017
Maximum
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	2,038
Maximum | Tax-exempt special facilities revenue bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2,041
Maximum | Loans And Leases From Non U S Entities
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms (years)	12 years
United Airlines, Inc.
Commitments and Contingencies [Line Items]
Debt instrument principal amount	$ 11,042,000,000	$ 11,533,000,000
Number of employees | Employee	84
Percentage of employees represented by various U.S. labor organizations	80.00%
United Airlines, Inc. | Minimum
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2,025
United Airlines, Inc. | Maximum
Commitments and Contingencies [Line Items]
Debt instrument maturity year	2,027
Capital Addition Purchase Commitments | United Airlines, Inc. | Minimum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date	2,016
Capital Addition Purchase Commitments | United Airlines, Inc. | Maximum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date	2,024

Schedule of Acquisition of Airc

Schedule of Acquisition of Aircrafts and Related Spare Engines (Detail) $ in Billions	Dec. 31, 2015USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
2,016	$ 3.4
2,017	3.1
2,018	3.3
2,019	2.9
2,020	2.8
After 2,020	7.7
Total commitments	$ 23.2

Components of Special Items (De

Components of Special Items (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating:
Severance and benefit costs	$ 4	$ 28	$ 25	$ 50	$ 141	$ 6	$ 38	$ 14	$ 107	$ 199	$ 105
Impairment of assets	48	18	11	2	16		32	1	79	49	33
Integration-related costs	13	15	14	18	17	28	17	34	60	96	205
Labor agreement costs									18		127
(Gains) losses on sale of assets and other miscellaneous (gains) losses, net	66	15	5	(6)	5	9	16	3	62	99	50
Special charges	131	76	55	64	179	43	169	52	326	443	520
Nonoperating and income taxes:
Loss on extinguishment of debt and other, net	7	61	128	6	53			21	202	74
Income tax benefit related to special charges	(11)				(6)	(3)		(1)	(11)	(10)	(7)
Income tax benefit associated with valuation allowance release (Note 7)	88	(3,218)							(3,130)
Total operating and nonoperating special charges, net of income taxes	$ 215	$ (3,081)	$ 183	$ 70	$ 226	$ 40	$ 169	$ 72	$ (2,613)	$ 507	$ 513

Special Items - Additional Info

Special Items - Additional Information (Detail)	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)VEF / $	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)VEF / $	Dec. 31, 2014USD ($)AircraftAttendant	Dec. 31, 2013USD ($)AircraftEmployee
Special Charges [Line Items]
Severance and benefits	$ 4,000,000	$ 28,000,000	$ 25,000,000	$ 50,000,000	$ 141,000,000	$ 6,000,000	$ 38,000,000	$ 14,000,000	$ 107,000,000	$ 199,000,000	$ 105,000,000
Impairment of indefinite-lived intangible assets									33,000,000	16,000,000	1,000,000
Impairment of indefinite-lived intangible assets, net of tax benefits									22,000,000	10,000,000
Costs associated with aircraft							66,000,000		8,000,000	66,000,000
Inventory held for sale	7,000,000								7,000,000
Impairment for discontinued internal software projects									10,000,000
Impairment charges of equipment held for disposal									10,000,000
Charges for legal matters									32,000,000
Collective bargaining agreements									18,000,000		127,000,000
Cease use of an aircraft under lease									16,000,000		5,000,000
(Gains) losses on sale of assets and other miscellaneous (gains) losses, net	$ 66,000,000	15,000,000	5,000,000	(6,000,000)	5,000,000	$ 9,000,000	$ 16,000,000	3,000,000	62,000,000	99,000,000	$ 50,000,000
Venezuela local currency loss									$ 61,000,000
Foreign currency exchange rate per US dollar, description									200 Venezuelan bolivars to one U.S. dollar
Foreign currency exchange rate | VEF / $	200								200
Loss on extinguishment of debt and other, net	$ 7,000,000	$ 61,000,000	$ 128,000,000	$ 6,000,000	53,000,000			$ 21,000,000	$ 202,000,000	$ 74,000,000
Number of positions eliminated | Employee											1,200
Number of leased aircraft | Aircraft										21
Lease expiry year										2,018
Debt instrument principal amount					$ 248,000,000					$ 248,000,000
Adjustment of reserves for certain legal matters											$ 29,000,000
Loss on sale of asset											3,000,000
Unsecured Debt
Special Charges [Line Items]
Venezuela local currency loss										10,000,000
Loss on extinguishment of debt and other, net										64,000,000
International Association of Machinists
Special Charges [Line Items]
Collective bargaining agreements											127,000,000
Cleveland
Special Charges [Line Items]
Severance and benefits										$ 58,000,000
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%
United Airlines, Inc.
Special Charges [Line Items]
Debt instrument principal amount	11,042,000,000				$ 11,533,000,000				11,042,000,000	$ 11,533,000,000
United Airlines, Inc. | 6% Notes due 2026 and 2028
Special Charges [Line Items]
Write off of unamortized discount									134,000,000
Boeing 737-300 and 737-500 fleets
Special Charges [Line Items]
Impairment charges of equipment held for disposal										33,000,000	32,000,000
Temporarily grounded Boeing 787 aircraft
Special Charges [Line Items]
Costs associated with aircraft											18,000,000
Venezuelan bolivars
Special Charges [Line Items]
Unrestricted cash balance held as Venezuelan bolivars	$ 13,000,000								$ 13,000,000
Scenario, Previously Reported
Special Charges [Line Items]
Foreign currency exchange rate per US dollar, description									13.5 Venezuelan bolivars to one U.S. dollar
Foreign currency exchange rate | VEF / $	13.5								13.5
Voluntary early out program
Special Charges [Line Items]
Severance and benefits										$ 141,000,000
Number of positions eliminated | Attendant										2,500
Number of positions eliminated | Attendant										2,500
Voluntary early out program | Maximum
Special Charges [Line Items]
Severance payment per participant	$ 100,000				$ 100,000				$ 100,000	$ 100,000
Integration Related
Special Charges [Line Items]
(Gains) losses on sale of assets and other miscellaneous (gains) losses, net									$ 14,000,000	$ 33,000,000
Voluntary retirement program
Special Charges [Line Items]
Severance and benefits											$ 64,000,000
Number of leased aircraft | Aircraft											4
Accruals for future rent											$ 11,000,000
Voluntary Leave of Absence Program
Special Charges [Line Items]
Severance and benefits											26,000,000
Involuntary severance programs
Special Charges [Line Items]
Severance and benefits											$ 15,000,000

Accrual Activity (Detail)

Accrual Activity (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Severance and Benefits
Schedule Of Accrual Activity [Line Items]
Beginning Balance	$ 109	$ 91	$ 65
Accrual	107	199	120
Payments	(189)	(181)	(94)
Ending Balance	27	109	91
Permanently Grounded Aircraft
Schedule Of Accrual Activity [Line Items]
Beginning Balance	102	11	5
Accrual	30	102	10
Payments	(54)	(11)	(4)
Ending Balance	$ 78	$ 102	$ 11

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015Segment
Segment Reporting Information [Line Items]
Number of Operating Segments	1

Operating Revenue by Principle

Operating Revenue by Principle Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total revenues	$ 9,036	$ 10,306	$ 9,914	$ 8,608	$ 9,313	$ 10,563	$ 10,329	$ 8,696	$ 37,864	$ 38,901	$ 38,279	[1]
Domestic (U.S. and Canada)
Segment Reporting Information [Line Items]
Total revenues									21,931	22,320	22,092
Pacific
Segment Reporting Information [Line Items]
Total revenues									5,498	5,767	5,794
Atlantic
Segment Reporting Information [Line Items]
Total revenues									7,068	7,321	7,132
Latin America
Segment Reporting Information [Line Items]
Total revenues									$ 3,367	$ 3,493	$ 3,261
[1]	UAL and United amounts are substantially the same.

Schedule of Selected Quarterly

Schedule of Selected Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Data [Line Items]
Operating revenue	$ 9,036	$ 10,306	$ 9,914	$ 8,608	$ 9,313	$ 10,563	$ 10,329	$ 8,696	$ 37,864	$ 38,901	$ 38,279	[1]
Income (loss) from operations	1,081	1,899	1,445	741	625	1,191	906	(349)	5,166	2,373	1,249
Net income (loss)	$ 823	$ 4,816	$ 1,193	$ 508	$ 28	$ 924	$ 789	$ (609)	$ 7,340	$ 1,132	$ 571
Basic earnings (loss) per share	$ 2.24	$ 12.83	$ 3.14	$ 1.33	$ 0.08	$ 2.49	$ 2.11	$ (1.66)	$ 19.52	$ 3.05	$ 1.64
Diluted earnings (loss) per share	$ 2.24	$ 12.82	$ 3.14	$ 1.32	$ 0.07	$ 2.37	$ 2.01	$ (1.66)	$ 19.47	$ 2.93	$ 1.53
[1]	UAL and United amounts are substantially the same.

Schedule of Effect of Four Quar

Schedule of Effect of Four Quarters Events (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating:
Severance and benefit costs	$ 4	$ 28	$ 25	$ 50	$ 141	$ 6	$ 38	$ 14	$ 107	$ 199	$ 105
Impairment of assets	48	18	11	2	16		32	1	79	49	33
Integration-related costs	13	15	14	18	17	28	17	34	60	96	205
Costs associated with permanently grounding Embraer ERJ 135 aircraft							66		8	66
(Gains) losses on sale of assets and other miscellaneous (gains) losses, net	66	15	5	(6)	5	9	16	3	62	99	50
Special charges	131	76	55	64	179	43	169	52	326	443	520
Nonoperating and income taxes:
Loss on extinguishment of debt and other, net	7	61	128	6	53			21	202	74
Income tax benefit related to special charges	(11)				(6)	(3)		(1)	(11)	(10)	(7)
Income tax expense (benefit) associated with valuation allowance release	88	(3,218)							(3,130)
Total operating and nonoperating special charges, net of income taxes	$ 215	$ (3,081)	$ 183	$ 70	$ 226	$ 40	$ 169	$ 72	$ (2,613)	$ 507	$ 513

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 4,751	$ 4,591	$ 5,388
Additions Charged to Costs and Expenses			156	7
Deductions	[1]	4,703		888
Other	[2]		4	84
Balance at End of Period		48	4,751	4,591
UAL and United | Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		22	13	13
Additions Charged to Costs and Expenses		25	45	35
Deductions	[1]	29	36	35
Balance at End of Period		18	22	13
UAL and United | Obsolescence allowance-spare parts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		169	162	125
Additions Charged to Costs and Expenses		38	35	38
Deductions	[1]		28	1
Other		28
Balance at End of Period		235	169	162
United Airlines, Inc. | Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		4,721	4,561	5,288
Additions Charged to Costs and Expenses			167	8
Deductions	[1]	4,673		898
Other	[2]		(7)	163
Balance at End of Period		$ 48	$ 4,721	$ 4,561
[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.