United Airlines 10-K 23 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 13, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
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		314,622,651
Entity Public Float			$ 12,558,237,332
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, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating revenue:
Passenger-Mainline	$ 25,414	$ 26,333	$ 26,785
Passenger-Regional	6,043	6,452	6,977
Total passenger revenue	31,457	32,785	33,762
Cargo	876	937	938
Other operating revenue	4,223	4,142	4,201
Total revenue	36,556	37,864	38,901
Operating expense:
Salaries and related costs	10,275	9,713	8,935
Aircraft fuel	5,813	7,522	11,675
Regional capacity purchase	2,197	2,290	2,344
Landing fees and other rent	2,165	2,203	2,274
Depreciation and amortization	1,977	1,819	1,679
Aircraft maintenance materials and outside repairs	1,749	1,651	1,779
Distribution expenses	1,303	1,342	1,373
Aircraft rent	680	754	883
Special charges (Note 16)	638	326	443
Other operating expenses	5,421	5,078	5,143
Total operating expenses	32,218	32,698	36,528
Operating income	4,338	5,166	2,373
Nonoperating income (expense):
Interest expense	(614)	(669)	(735)
Interest capitalized	72	49	52
Interest income	42	25	22
Miscellaneous, net (Note 16)	(19)	(352)	(584)
Total other expense	(519)	(947)	(1,245)
Income before income taxes	3,819	4,219	1,128
Income tax expense (benefit)	1,556	(3,121)	(4)
Net income	$ 2,263	$ 7,340	$ 1,132
Earnings per share, basic	$ 6.86	$ 19.52	$ 3.05
Earnings per share, diluted	$ 6.85	$ 19.47	$ 2.93
United Airlines, Inc.
Operating revenue:
Passenger-Mainline	$ 25,414	$ 26,333	$ 26,785
Passenger-Regional	6,043	6,452	6,977
Total passenger revenue	31,457	32,785	33,762
Cargo	876	937	938
Other operating revenue	4,223	4,142	4,201
Total revenue	36,556	37,864	38,901
Operating expense:
Salaries and related costs	10,275	9,713	8,935
Aircraft fuel	5,813	7,522	11,675
Regional capacity purchase	2,197	2,290	2,344
Landing fees and other rent	2,165	2,203	2,274
Depreciation and amortization	1,977	1,819	1,679
Aircraft maintenance materials and outside repairs	1,749	1,651	1,779
Distribution expenses	1,303	1,342	1,373
Aircraft rent	680	754	883
Special charges (Note 16)	638	326	443
Other operating expenses	5,418	5,076	5,139
Total operating expenses	32,215	32,696	36,524
Operating income	4,341	5,168	2,377
Nonoperating income (expense):
Interest expense	(614)	(670)	(742)
Interest capitalized	72	49	52
Interest income	42	25	22
Miscellaneous, net (Note 16)	(19)	(351)	(599)
Total other expense	(519)	(947)	(1,267)
Income before income taxes	3,822	4,221	1,110
Income tax expense (benefit)	1,558	(3,080)	(4)
Net income	$ 2,264	$ 7,301	$ 1,114

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 2,263	$ 7,340	$ 1,132
Other comprehensive income (loss), net change related to:
Employee benefit plans, net of taxes	(313)	70	(1,171)
Fuel derivative financial instruments, net of taxes	316	182	(510)
Investments and other, net of taxes	(1)	(4)	(6)
Comprehensive income (loss) adjustments	2	248	(1,687)
Total comprehensive income (loss), net	2,265	7,588	(555)
United Airlines, Inc.
Net income	2,264	7,301	1,114
Other comprehensive income (loss), net change related to:
Employee benefit plans, net of taxes	(313)	70	(1,171)
Fuel derivative financial instruments, net of taxes	316	182	(510)
Investments and other, net of taxes	(1)	(4)	(6)
Comprehensive income (loss) adjustments	2	248	(1,687)
Total comprehensive income (loss), net	$ 2,266	$ 7,549	$ (573)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 2,179	$ 3,006
Short-term investments	2,249	2,190
Receivables, less allowance for doubtful accounts (2016-$10; 2015-$18)	1,176	1,128
Fuel hedge collateral deposits		26
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2016-$295; 2015-$235)	873	738
Prepaid expenses and other	832	740
Total current assets	7,309	7,828
Operating property and equipment: Owned-
Flight equipment	25,873	23,728
Other property and equipment	5,652	4,542
Operating property and equipment - owned, gross	31,525	28,270
Less-Accumulated depreciation and amortization	(9,975)	(8,339)
Operating property and equipment - owned, net	21,550	19,931
Purchase deposits for flight equipment	1,059	788
Capital leases-
Flight equipment	1,319	1,527
Other property and equipment	331	332
Operating property and equipment - capital leases, gross	1,650	1,859
Less-Accumulated amortization	(941)	(998)
Operating property and equipment - capital leases, net	709	861
Total property, plant, and equipment, net	23,318	21,580
Other assets:
Goodwill	4,523	4,523
Intangibles, less accumulated amortization (2016-$1,234; 2015-$1,144)	3,632	4,136
Deferred income taxes	655	2,037
Restricted cash	124	204
Other, net	579	553
Other assets total	9,513	11,453
Total assets	40,140	40,861
Current liabilities:
Advance ticket sales	3,730	3,753
Frequent flyer deferred revenue	2,135	2,117
Accounts payable	2,139	1,869
Accrued salaries and benefits	2,307	2,350
Current maturities of long-term debt	849	1,224
Current maturities of capital leases	116	135
Fuel derivative instruments		124
Other	1,010	842
Total current liabilities	12,286	12,414
Long-term debt	9,918	9,673
Long-term obligations under capital leases	822	727
Other liabilities and deferred credits:
Frequent flyer deferred revenue	2,748	2,826
Postretirement benefit liability	1,581	1,882
Pension liability	1,892	1,488
Advanced purchase of miles	430	1,010
Lease fair value adjustment, net	277	359
Other	1,527	1,516
Total Other liabilities and deferred credits	8,455	9,081
Commitments and contingencies
Stockholder's equity:
Preferred stock
Common stock	3	4
Additional capital invested	6,569	7,946
Retained earnings	3,427	3,457
Stock held in treasury, at cost	(511)	(1,610)
Accumulated other comprehensive loss	(829)	(831)
Total stockholders' equity	8,659	8,966
Total liabilities and stockholders' equity (deficit)	40,140	40,861
United Airlines, Inc.
Current assets:
Cash and cash equivalents	2,173	3,000
Short-term investments	2,249	2,190
Receivables, less allowance for doubtful accounts (2016-$10; 2015-$18)	1,176	1,128
Fuel hedge collateral deposits		26
Aircraft fuel, spare parts and supplies, less obsolescence allowance (2016-$295; 2015-$235)	873	738
Prepaid expenses and other	832	787
Total current assets	7,303	7,869
Operating property and equipment: Owned-
Flight equipment	25,873	23,728
Other property and equipment	5,652	4,542
Operating property and equipment - owned, gross	31,525	28,270
Less-Accumulated depreciation and amortization	(9,975)	(8,339)
Operating property and equipment - owned, net	21,550	19,931
Purchase deposits for flight equipment	1,059	788
Capital leases-
Flight equipment	1,319	1,527
Other property and equipment	331	332
Operating property and equipment - capital leases, gross	1,650	1,859
Less-Accumulated amortization	(941)	(998)
Operating property and equipment - capital leases, net	709	861
Total property, plant, and equipment, net	23,318	21,580
Other assets:
Goodwill	4,523	4,523
Intangibles, less accumulated amortization (2016-$1,234; 2015-$1,144)	3,632	4,136
Deferred income taxes	612	1,995
Restricted cash	124	204
Other, net	579	554
Other assets total	9,470	11,412
Total assets	40,091	40,861
Current liabilities:
Advance ticket sales	3,730	3,753
Frequent flyer deferred revenue	2,135	2,117
Accounts payable	2,144	1,874
Accrued salaries and benefits	2,307	2,350
Current maturities of long-term debt	849	1,224
Current maturities of capital leases	116	135
Fuel derivative instruments		124
Other	1,009	840
Total current liabilities	12,290	12,417
Long-term debt	9,918	9,673
Long-term obligations under capital leases	822	727
Other liabilities and deferred credits:
Frequent flyer deferred revenue	2,748	2,826
Postretirement benefit liability	1,581	1,882
Pension liability	1,892	1,488
Advanced purchase of miles	430	1,010
Lease fair value adjustment, net	277	359
Other	1,527	1,516
Total Other liabilities and deferred credits	8,455	9,081
Commitments and contingencies
Stockholder's equity:
Additional capital invested	3,573	6,138
Retained earnings	5,937	3,673
Accumulated other comprehensive loss	(829)	(831)
Receivable from related parties	(75)	(17)
Total stockholders' equity	8,606	8,963
Total liabilities and stockholders' equity (deficit)	$ 40,091	$ 40,861

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Receivables, allowance for doubtful accounts	$ 10	$ 18
Aircraft fuel, spare parts and supplies, obsolescence allowance	295	235
Intangibles, accumulated amortization	$ 1,234	$ 1,144
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	314,612,744	364,609,108
United Airlines, Inc.
Receivables, allowance for doubtful accounts	$ 10	$ 18
Aircraft fuel, spare parts and supplies, obsolescence allowance	295	235
Intangibles, accumulated amortization	$ 1,234	$ 1,144
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, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income	$ 2,263	$ 7,340	$ 1,132
Adjustments to reconcile net income to net cash provided by operating activities -
Deferred income taxes	1,648	(3,177)	13
Depreciation and amortization	1,977	1,819	1,679
Special charges, non-cash portion	391	247	78
Other operating activities	109	115	(21)
Changes in operating assets and liabilities -
(Increase) decrease in fuel hedge collateral	26	551	(577)
(Decrease) increase in fuel derivatives	(20)	(305)	436
Decrease in other liabilities	(114)	(198)	(238)
Decrease in frequent flyer deferred revenue and advanced purchase of miles	(641)	(200)	(88)
Increase in other assets	(298)	(160)	(34)
Increase (decrease) in accounts payable	239	(77)	(251)
Increase (decrease) in advance ticket sales	(22)	52	296
(Increase) decrease in receivables	(16)	(15)	209
Net cash provided by operating activities	5,542	5,992	2,634
Cash Flows from Investing Activities:
Capital expenditures	(3,223)	(2,747)	(2,005)
Purchases of short-term and other investments	(2,768)	(2,517)	(3,569)
Proceeds from sale of short-term and other investments	2,712	2,707	3,112
Proceeds from sale of property and equipment	28	86	94
Other, net	13	(136)	37
Net cash used in investing activities	(3,238)	(2,607)	(2,331)
Cash Flows from Financing Activities:
Repurchases of common stock	(2,614)	(1,233)	(312)
Payments of long-term debt	(1,215)	(2,178)	(2,503)
Proceeds from issuance of long-term debt	808	1,073	1,432
Principal payments under capital leases	(136)	(123)	(127)
Capitalized financing costs	(64)	(37)	(104)
Proceeds from the exercise of stock options	6	16	60
Other, net	2	(13)	(42)
Net cash used in financing activities	(3,213)	(2,495)	(1,596)
Net increase (decrease) in cash, cash equivalents and restricted cash	(909)	890	(1,293)
Cash, cash equivalents and restricted cash at beginning of year	3,212	2,322	3,615
Cash, cash equivalents and restricted cash at end of year	2,303	3,212	2,322
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	386	866	1,114
Airport construction financing	91	17	14
Operating lease conversions to capital lease	12	285
Exchange of convertible notes for common stock		202	260
Cash Paid (Refunded) During the Period for:
Interest	584	660	748
Income taxes	14	15	(16)
United Airlines, Inc.
Cash Flows from Operating Activities:
Net income	2,264	7,301	1,114
Adjustments to reconcile net income to net cash provided by operating activities -
Deferred income taxes	1,650	(3,136)	13
Depreciation and amortization	1,977	1,819	1,679
Special charges, non-cash portion	391	247	78
Other operating activities	108	115	4
Changes in operating assets and liabilities -
(Increase) decrease in fuel hedge collateral	26	551	(577)
(Decrease) increase in fuel derivatives	(20)	(305)	436
Decrease in other liabilities	(112)	(199)	(236)
Decrease in frequent flyer deferred revenue and advanced purchase of miles	(641)	(200)	(88)
Increase in other assets	(251)	(160)	(34)
Increase (decrease) in accounts payable	239	(77)	(251)
Increase (decrease) in advance ticket sales	(22)	52	296
(Increase) decrease in receivables	(16)	(15)	209
Increase in intercompany receivables	(58)	(12)
Decrease in intercompany payables			(118)
Net cash provided by operating activities	5,535	5,981	2,525
Cash Flows from Investing Activities:
Capital expenditures	(3,223)	(2,747)	(2,005)
Purchases of short-term and other investments	(2,768)	(2,517)	(3,569)
Proceeds from sale of short-term and other investments	2,712	2,707	3,112
Proceeds from sale of property and equipment	28	86	94
Other, net	13	(136)	37
Net cash used in investing activities	(3,238)	(2,607)	(2,331)
Cash Flows from Financing Activities:
Dividend to UAL	(2,614)	(1,233)	(212)
Payments of long-term debt	(1,215)	(2,178)	(2,503)
Proceeds from issuance of long-term debt	808	1,073	1,432
Principal payments under capital leases	(136)	(123)	(127)
Capitalized financing costs	(64)	(37)	(104)
Proceeds from the exercise of stock options	6	16	60
Other, net	9	(2)	(33)
Net cash used in financing activities	(3,206)	(2,484)	(1,487)
Net increase (decrease) in cash, cash equivalents and restricted cash	(909)	890	(1,293)
Cash, cash equivalents and restricted cash at beginning of year	3,206	2,316	3,609
Cash, cash equivalents and restricted cash at end of year	2,297	3,206	2,316
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	386	866	1,114
Airport construction financing	91	17	14
Operating lease conversions to capital lease	12	285
Transfer of UAL subsidiaries to United			186
Exchange of convertible notes for common stock			156
Cash Paid (Refunded) During the Period for:
Interest	584	660	748
Income taxes	$ 14	$ 15	$ (16)

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, 2013			362
Beginning 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)	(1,687)							(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	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)
Net income	2,263	2,264					2,263	2,264
Other comprehensive income (loss)	2	2							2	2
Dividend and other capital distributions to UAL		(2,603)			(2,603)
Share-based compensation	32	32		32	32
Proceeds from exercise of stock options	6			6
UAL contribution related to stock plans		6			6
Repurchases of common stock	$ (2,607)					(2,607)
Repurchases of common stock (in shares)	(50)		(50)
Treasury stock retired			$ (1)	(1,415)		3,709	(2,293)
Other	$ (3)	(58)				(3)					(58)
Ending Balance (in shares) at Dec. 31, 2016			315
Ending Balance at Dec. 31, 2016	$ 8,659	$ 8,606	$ 3	$ 6,569	$ 3,573	$ (511)	$ 3,427	$ 5,937	$ (829)	$ (829)	$ (75)

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Significant Accounting Policies	NOTE 1 - SIGNIFICANT ACCOUNTING POLICIES (a) Use of Estimates— (b) Revenue Recognition— Non-refundable Fees charged in association with changes or extensions to non-refundable non-refundable 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, 2016, 2015 and 2014. (c) Frequent Flyer Accounting— ® non-airline non-travel Miles Earned in Conjunction with Flights When frequent flyers earn miles for flights, 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 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 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’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 United has a significant contract, the Second Amended and Restated Co-Branded “Co-Brand co-branded Co-Brand 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 The Company records passenger revenue related to the air transportation element when the transportation is delivered. The other elements are generally recognized as Other operating revenue when earned. Expiration of Miles The Company accounts for miles sold and awarded that will never be redeemed by program members, which we refer to as breakage. The Company reviews its breakage estimates annually based upon the latest available information regarding redemption and expiration patterns. Miles expire after 18 months of member account inactivity. The Company’s estimate of the expected expiration of miles requires significant management judgment. Current and future changes to expiration assumptions or to the expiration policy, or to program rules and program redemption opportunities, may result in material changes to the deferred revenue balance as well as recognized revenues from the programs. Other Information The following table provides additional information related to the frequent flyer program (in millions): Year Ended Cash Proceeds Other Revenue Increase in Frequent Decrease in 2016 $ 3,022 $ 1,221 $ 2,050 $ (249) 2015 2,999 1,050 2,173 (224) 2014 2,861 882 2,178 (199) (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 decrease in the advance purchase of miles obligation due to cash payments for the sale of miles 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 and reserves for institutions that process credit card ticket sales. 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. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the statements of consolidated cash flows: UAL United At December 31, At December 31, 2016 2015 2014 2016 2015 2014 Current assets: Cash and cash equivalents $ 2,179 $ 3,006 $ 2,002 $ 2,173 $ 3,000 $ 1,996 Restricted cash included in Prepaid expenses and other — 2 44 — 2 44 Other assets: Restricted cash 124 204 276 124 204 276 Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows $ 2,303 $ 3,212 $ 2,322 $ 2,297 $ 3,206 $ 2,316 (e) Short-term Investments— available-for-sale available-for-sale (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, 2016 and 2015, the Company had a carrying value of computer software of $356 million and $279 million, respectively. For the years ended December 31, 2016, 2015 and 2014, the Company’s depreciation expense related to computer software was $108 million, $93 million and $81 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— power-by-the-hour (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— non-air non-air (t) Recently Issued Accounting Standards— Revenue from Contracts with Customers. Revenue Recognition In 2016, the FASB amended the FASB Accounting Standards Codification and created a new Topic 842, Leases right-of-use Leases In 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting 2016-09”) . paid-in 2016-09 In 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments 2016-15”). Statement of Cash Flows 2016-15 In 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash 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)

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2016
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): 2016 2015 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 $ 771 $ 1,177 $ 702 Hubs 20 145 82 145 74 Contracts 13 135 95 135 86 Patents and tradenames 3 108 108 108 108 Airport slots and gates 8 97 97 97 97 Other 25 109 81 109 77 Total $ 1,771 $ 1,234 $ 1,771 $ 1,144 Indefinite-lived intangible assets Route authorities $ 1,562 $ 1,570 Airport slots and gates 536 942 Tradenames and logos 593 593 Alliances 404 404 Total $ 3,095 $ 3,509 (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 2016, 2015 and 2014 was $90 million, $105 million and $128 million, respectively. Projected amortization expense in 2017, 2018, 2019, 2020 and 2021 is $79 million, $70 million, $64 million, $58 million and $53 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, 2016
Common Stockholders' Equity and Preferred Securities	NOTE 3 - COMMON STOCKHOLDERS’ EQUITY AND PREFERRED SECURITIES In 2016, UAL repurchased approximately 50 million shares of UAL common stock for $2.6 billion. As of December 31, 2016, the Company had approximately $1.8 billion remaining to purchase shares under its share program. 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 may repurchase shares of UAL common stock subject to prevailing market conditions, and may discontinue such repurchases at any time. 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. In 2016, the Company retired 70 million treasury shares that were originally acquired at an average cost of approximately $53 per share. At December 31, 2016, approximately 5 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, 2016, 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, 2016
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): 2016 2015 2014 Basic earnings per share: Earnings available to common stockholders $ 2,263 $ 7,340 $ 1,132 Basic weighted-average shares outstanding 329.9 376.1 371.1 Earnings per share, basic $ 6.86 $ 19.52 $ 3.05 Diluted earnings per share: Earnings available to common stockholders $ 2,263 $ 7,340 $ 1,132 Effect of dilutive securities — — 11 Earnings available to common stockholders including the effect of dilutive securities $ 2,263 $ 7,340 $ 1,143 Diluted shares outstanding: Basic weighted-average shares outstanding 329.9 376.1 371.1 Effect of convertible notes — 0.3 17.7 Effect of employee stock awards 0.4 0.5 0.9 Diluted weighted-average shares outstanding 330.3 376.9 389.7 Earnings per share, diluted $ 6.85 $ 19.47 $ 2.93 The number of antidilutive securities excluded from the computation of diluted earnings per share amounts was not material.

Share-Based Compensation Plans

Share-Based Compensation Plans	12 Months Ended
	Dec. 31, 2016
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 All awards are recorded as either equity or a liability in the Company’s consolidated balance sheets. The share-based During 2016, UAL granted share-based compensation awards pursuant to the United Continental Holdings, Inc. 2008 Incentive Compensation Plan. These share-based compensation awards include approximately 1.9 million RSUs, 0.4 million shares of restricted stock and 0.4 million stock options. The time-vested RSUs and the restricted stock awards vest in one-third 20-day pre-tax 20-day one-third ten-year The following table provides information related to UAL’s share-based compensation plan cost for the years ended December 31 (in millions): 2016 2015 2014 Compensation cost (a): RSUs $ 58 $ 52 $ 104 Restricted stock 11 6 10 Stock options 1 — — Total $ 70 $ 58 $ 114 (a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million in 2014 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 as of December 31, 2016 (in millions, except as noted): Unearned Weighted- Average Remaining (in years) RSUs $ 49 1.5 Restricted stock 11 1.5 Stock options 5 3.2 Total $ 65 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 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 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 2.6 0.3 48.68 Granted 1.9 0.4 50.63 Vested (1.4) (0.1) 41.47 Forfeited (0.2) (0.1) 53.42 Non-vested 2.9 0.5 52.00 The fair value of RSUs and restricted stock that vested in 2016, 2015 and 2014 was $80 million, $92 million and $97 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 either equity or liability awards based on their method of settlement. Restricted stock vesting and the recognition of the expense is similar to the stock option vesting described below. Stock Options The Company determined the fair value of stock options at the grant date using a Black Scholes option pricing model, which requires the use of several assumptions. The risk-free interest rate is based on the U.S. treasury yield curve in effect for the expected term of the option at the time of grant. The dividend yield on UAL’s common stock was assumed to be zero since UAL did not have any plans to pay dividends at the time of the option grants. The volatility assumptions were based upon historical volatilities of UAL using daily stock price returns equivalent to the expected term of the option. The expected lives of the options were determined based upon a simplified assumption that the option will be exercised evenly from vesting to expiration due to the Company’s lack of relevant historical data. As of December 31, 2016, there were approximately 0.5 million outstanding stock option awards, 0.1 million of which were exercisable, with weighted-average exercise prices of $46.83 and $18.58, respectively, intrinsic values of $14 million and $7 million, respectively, and weighted-average remaining contractual lives (in years) of 6.3 and 1.6, respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2016
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 Pension and Fuel Investments Pension and Fuel Total Balance at December 31, 2013 $ 699 $ 11 $ 13 $ (115) $ — (c) $ 608 Other comprehensive loss before reclassifications (a) (1,106) (b) (599) — — — (1,705) Amounts reclassified from accumulated other comprehensive income (a) (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) $ — (c) $ (1,079) Other comprehensive income (loss) before reclassifications 78 (b) (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) Other comprehensive income (loss) before reclassifications (517) (b) (4) — 186 1 (334) Amounts reclassified from accumulated other comprehensive income 26 217 (1) (8) 102 336 Net current-period other comprehensive income (loss) (491) 213 (1) 178 103 2 Balance at December 31, 2016 $ (854) $ (2) $ 2 $ 24 $ 1 $ (829) Details about AOCI Components Amount Reclassified from AOCI to Affected Line Item in Year Ended December 31, 2016 2015 2014 Fuel derivative contracts Fuel contracts-reclassifications of losses into earnings $ 217 $ 604 $ 89 Aircraft fuel Pension and Postretirement liabilities Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (d) 26 31 (65) Salaries and related costs Investments and other Available-for-sale (1) — (6) Miscellaneous, net (a) Income tax expense for these items was offset by the Company’s valuation allowance. (b) Prior service credits increased by $30 million, $0 million and $3 million and actuarial gains (losses) increased (decreased) by approximately $560 million, $78 million and $(1.1) billion for 2016, 2015 and 2014, respectively. (c) Deferred tax balance was offset by the Company’s valuation allowance. (d) This AOCI component is included in the computation of net periodic pension and other postretirement costs (see Note 8 of this report for additional information). Prior to the release of the deferred income tax valuation allowance in the third quarter of 2015, the Company recorded approximately $465 million of valuation allowance adjustments in AOCI. Subsequent to the release of the deferred income tax valuation allowance in 2015, the $465 million debit remained within AOCI, of which $180 million related to losses on fuel hedges designated for hedge accounting and $285 million related to pension and other postretirement liabilities. Accounting rules required the adjustments to remain in AOCI as long as the Company had fuel derivatives designated for cash flow hedge accounting and the Company continues to provide pension and postretirement benefits. In 2016, we settled all of our fuel hedges and have not entered into any new fuel derivative contracts for hedge accounting. Accordingly, the Company reclassified the $180 million to income tax expense in 2016.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Taxes	NOTE 7 - INCOME TAXES The significant components of the income tax expense (benefit) are as follows (in millions): 2016 UAL United Current $ (92) $ (92) Deferred 1,648 1,650 $ 1,556 $ 1,558 2015 Current $ 56 $ 56 Deferred (3,177) (3,136) $ (3,121) $ (3,080) 2014 Current $ (17) $ (17) Deferred 13 13 $ (4) $ (4) The income tax provision differed from amounts computed at the statutory federal income tax rate, as follows (in millions): UAL 2016 2015 2014 Income tax provision at statutory rate $ 1,337 $ 1,477 $ 395 State income taxes, net of federal income tax 38 38 10 Foreign income taxes 3 4 2 Nondeductible employee meals 16 15 15 Income tax adjustment 180 — — State rate change (12) — — Valuation allowance 20 (4,662) (435) Other, net (26) 7 9 $ 1,556 $ (3,121) $ (4) United 2016 2015 2014 Income tax provision at statutory rate $ 1,338 $ 1,477 $ 388 State income taxes, net of federal income tax 38 38 10 Foreign income taxes 3 4 2 Nondeductible employee meals 16 15 15 Derivative market adjustment — — (7) Income tax adjustment 180 — — State rate change (12) — — Valuation allowance 20 (4,621) (421) Other, net (25) 7 9 $ 1,558 $ (3,080) $ (4) The Company’s effective tax rate for the year ended December 31, 2016 differed from the federal statutory rate of 35% primarily because of the non-cash Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2016 and 2015 were as follows (in millions): UAL United December 31, December 31, 2016 2015 2016 2015 Deferred income tax asset (liability): Federal and state net operating loss (“NOL”) carryforwards $ 1,613 $ 2,897 $ 1,571 $ 2,855 Deferred revenue 2,096 2,160 2,096 2,160 Employee benefits, including pension, postretirement and medical 1,662 1,662 1,662 1,662 Alternative minimum tax (“AMT”) credit carryforwards 116 232 116 232 Other 523 566 522 566 Less: Valuation allowance (68) (48) (68) (48) Total deferred tax assets $ 5,942 $ 7,469 $ 5,899 $ 7,427 Depreciation $ (3,961) $ (3,921) $ (3,961) $ (3,921) Intangibles (1,326) (1,511) (1,326) (1,511) Total deferred tax liabilities $ (5,287) $ (5,432) $ (5,287) $ (5,432) Net deferred tax asset $ 655 $ 2,037 $ 612 $ 1,995 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 Company’s 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 pre-tax 20-year The Company periodically assesses whether it is more likely than not that it will generate sufficient taxable income to realize its deferred income tax assets. The Company establishes valuation allowances if it is not likely it will realize its deferred income tax assets. In making this determination, the Company considers all available positive and negative evidence and makes certain assumptions. The Company considers, among other things, projected future taxable income, scheduled reversals of deferred tax liabilities, the overall business environment, the Company’s historical financial results and tax planning strategies. In evaluating the likelihood of utilizing the Company’s net deferred income tax assets, the significant factors that the Company considers include (1) the Company’s recent history and forecasted profitability; (2) growth in the U.S. and global economies; and (3) future impact of taxable temporary differences. In 2015, the Company concluded that its deferred income tax assets were more likely than not to be realized and 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. The Company has a valuation allowance of $68 million for certain state and local NOLs and credit carryforwards. 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 unrecognized tax benefits related to uncertain tax positions were $74 million, $24 million and $9 million at 2016, 2015 and 2014, respectively. Included in the ending balance at 2016 is $20 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 2016, 2015 and 2014. The Company does not expect significant increases or decreases in their unrecognized tax benefits within the next 12 months. There are no material amounts included in the balance at December 31, 2016 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, 2016
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 non-pilot Other Postretirement Plans United maintains 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, Actuarial assumption changes are reflected as a component of the net actuarial gains/(losses) during 2016 and 2015. 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 2016 and 2015 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: $ 4,158 $ 3,795 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 4,473 $ 4,803 Service cost 112 124 Interest cost 200 200 Actuarial (gain) loss 738 (298) Gross benefits paid and settlements (243) (343) Other (27) (13) Projected benefit obligation at end of year $ 5,253 $ 4,473 Change in plan assets: Fair value of plan assets at beginning of year $ 2,975 $ 2,562 Actual gain (loss) on plan assets 230 (59) Employer contributions 421 824 Gross benefits paid and settlements (243) (343) Other (28) (9) Fair value of plan assets at end of year $ 3,355 $ 2,975 Funded status—Net amount recognized $ (1,898) $ (1,498) Pension Benefits December 31, 2016 December 31, 2015 Amounts recognized in the consolidated balance sheets consist of: Noncurrent asset $ 2 $ 2 Current liability (8) (12) Noncurrent liability (1,892) (1,488) Total liability $ (1,898) $ (1,498) Amounts recognized in accumulated other comprehensive loss consist of: Net actuarial loss $ (1,482) $ (844) Prior service loss (1) (1) Total accumulated other comprehensive loss $ (1,483) $ (845) Other Postretirement Benefits Year Ended Year Ended Change in benefit obligation: Benefit obligation at beginning of year $ 2,002 $ 2,052 Service cost 19 21 Interest cost 86 82 Plan participants’ contributions 69 68 Benefits paid (191) (205) Actuarial gain (165) (22) Plan amendments (138) — Other 5 6 Benefit obligation at end of year $ 1,687 $ 2,002 Change in plan assets: Fair value of plan assets at beginning of year $ 56 $ 57 Actual return on plan assets 2 1 Employer contributions 119 135 Plan participants’ contributions 69 68 Benefits paid (191) (205) Fair value of plan assets at end of year 55 56 Funded status—Net amount recognized $ (1,632) $ (1,946) Other Postretirement Benefits December 31, 2016 December 31, 2015 Amounts recognized in the consolidated balance sheets consist of: Current liability $ (51) $ (64) Noncurrent liability (1,581) (1,882) Total liability $ (1,632) $ (1,946) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial gain $ 384 $ 236 Prior service credit 245 246 Total accumulated other comprehensive income $ 629 $ 482 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): 2016 2015 Projected benefit obligation $ 5,025 $ 4,292 Accumulated benefit obligation 3,985 3,655 Fair value of plan assets 3,164 2,794 Net periodic benefit cost for the years ended December 31 included the following components (in millions): 2016 2015 2014 Pension Other Pension Other Pension Other Service cost $ 112 $ 19 $ 124 $ 21 $ 98 $ 19 Interest cost 200 86 200 82 201 88 Expected return on plan assets (216) (2) (194) (2) (180) (2) Curtailment gain — (107) — — — — Amortization of unrecognized actuarial (gain) loss 76 (19) 85 (22) 12 (47) Amortization of prior service credits — (31) — (32) — (31) Other 5 — 4 — 1 — Net periodic benefit cost $ 177 $ (54) $ 219 $ 47 $ 132 $ 27 As part of the ratified contract with the Association of Flight Attendants (“AFA”) in 2016, the Company amended two of its flight attendant postretirement medical plans. The amendments triggered curtailment accounting, resulting in the recognition of a one-time one-time The estimated amounts that will be amortized in 2017 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions): Pension Other Actuarial (gain) loss $ 127 $ (36) Prior service credit — (37) The assumptions used for the benefit plans were as follows: Pension Benefits Assumptions used to determine benefit obligations 2016 2015 Discount rate 4.18% 4.58% Rate of compensation increase 3.54% 3.66% Assumptions used to determine net expense Discount rate 4.58% 4.20% Expected return on plan assets 7.04% 7.40% Rate of compensation increase 3.53% 3.51% Other Postretirement Benefits Assumptions used to determine benefit obligations 2016 2015 Discount rate 4.07% 4.49% Assumptions used to determine net expense Discount rate 4.49% 4.07% Expected return on plan assets 3.00% 3.00% Health care cost trend rate assumed for next year 6.50% 6.75% Rate to which the cost trend rate is assumed to decline (ultimate trend rate in 2023) 5.00% 5.00% 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 2016 discount rate for substantially all of its plans by using a hypothetical portfolio of high quality bonds at December 31, 2016, that would provide the necessary cash flows to match projected benefit payments. We develop our expected long-term rate of return assumption for our defined benefit 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 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, 2016 $ 13 $ (11) Effect on postretirement benefit obligation at December 31, 2016 169 (149) A one percentage point decrease in the weighted average discount rate would increase the postretirement benefit liability by approximately $181 million and increase the estimated 2016 benefits expense by approximately $11 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): 2016 2015 Pension Plan Assets: Total Level 1 Level 2 Level 3 Assets Total Level 1 Level 2 Level 3 Assets Equity securities funds $ 1,173 $ 230 $ 111 $ — $ 832 $ 1,135 $ 254 $ 135 $ — $ 746 Fixed-income securities 1,298 — 824 11 463 1,109 — 877 9 223 Alternatives 586 — — 134 452 527 — 1 125 401 Other investments 298 47 68 87 96 204 37 56 18 93 Total $ 3,355 $ 277 $ 1,003 $ 232 $ 1,843 $ 2,975 $ 291 $ 1,069 $ 152 $ 1,463 Other Postretirement Benefit Plan Assets: Deposit administration fund $ 55 $ — $ — $ 55 $ — $ 56 $ — $ — $ 56 $ — (a) In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) have not been classified in the fair value hierarchy. These investments are commingled funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S. Equity and Fixed-Income. non-U.S. non-U.S 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, 2016 and 2015 is as follows (in millions): 2016 2015 Balance at beginning of year $ 208 $ 188 Actual return on plan assets: Sold during the year 4 8 Held at year end 3 (1) Purchases, sales, issuances and settlements (net) 72 13 Balance at end of year $ 287 $ 208 Funding requirements for tax-qualified The estimated future benefit payments, net of expected participant contributions, in United’s pension plans and other postretirement benefit plans as of December 31, 2016 are as follows (in millions): Pension Other Postretirement Other Postretirement— subsidy receipts 2017 $ 303 $ 112 $ 6 2018 300 117 6 2019 310 122 7 2020 319 126 7 2021 337 130 8 Years 2022 – 2026 1,782 682 44 Defined Contribution Plans Depending upon the employee group, employer contributions consist of matching contributions and/or non-elective Multi-Employer Plans United’s participation in the IAM National Pension Plan (“IAM Plan”) for the annual period ended December 31, 2016 is outlined in the table below. There have been no significant changes that affect the comparability 2016 and 2015 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 $395 million in employers’ contributions for the year ended December 31, 2015. For 2015, 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 Pension Protection Act Zone Status (2016 and 2015) Green Zone. Plans in the green zone are at least 80 percent funded. FIP/RP Status Pending/Implemented No United’s Contributions $41 million, $40 million and $39 million in the years ended December 31, 2016, 2015 and 2014, 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 2016. Profit Sharing Substantially all employees participate in profit sharing based on a percentage of pre-tax pre-tax co-workers co-worker’s co-workers non-U.S. co-workers

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Measurements	NOTE 9 - FAIR VALUE MEASUREMENTS Fair Value Information. 2016 2015 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 UAL Cash and cash equivalents $ 2,179 $ 2,179 $ — $ — $ 3,006 $ 3,006 $ — $ — Short-term investments: Corporate debt 835 — 835 — 891 — 891 — Asset-backed securities 792 — 792 — 710 — 710 — Certificates of deposit placed through an account registry service (“CDARS”) 246 — 246 — 281 — 281 — U.S. government and agency notes 140 — 140 — 72 — 72 — Auction rate securities — — — — 9 — — 9 Other fixed-income securities 54 — 54 — 26 — 26 — Other investments measured at NAV (a) 182 — — — 201 — — — Restricted cash 124 124 — — 206 206 — — Enhanced equipment trust certificates (“EETC”) 23 — — 23 26 — — 26 Fuel derivatives liability, net — — — — 124 — 124 — (a) In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statement of financial position. The investments measured using NAV are shares of mutual funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S. three-day Available-for-sale available-for-sale. Derivative instruments and investments presented in the table 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 2016 2015 Carrying Fair Value Carrying Fair Value Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Long-term debt $ 10,767 $ 11,055 $ — $ 8,184 $ 2,871 $ 10,897 $ 11,371 $ — $ 8,646 $ 2,725 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 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. 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.

Hedging Activities

Hedging Activities	12 Months Ended
	Dec. 31, 2016
Hedging Activities	NOTE 10—HEDGING ACTIVITIES Fuel Derivatives As of December 31, 2016, the Company did not have any fuel hedging contracts outstanding to hedge its fuel consumption. The last of the Company’s fuel hedge derivatives designated for cash flow hedge accounting expired in December 2016. The Company’s current strategy is to not enter into transactions to hedge its fuel consumption, although the Company regularly reviews its strategy based on market conditions and other factors. 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 2016 2015 Derivatives designated as cash flow hedges Liabilities: Fuel contracts due within one year Fuel derivative instruments $ — $ 119 Derivatives not designated for hedge accounting Liabilities: Fuel contracts due within one year Fuel derivative instruments $ — $ 5 Total derivatives Total liabilities $ — $ 124 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 in AOCI on Derivatives (Effective Portion) Loss Reclassified from (Fuel Expense) (Effective Portion) Amount of Loss 2016 2015 2016 2015 2016 2015 Fuel contracts $ (4) $ (320) $ (217) $ (604) $ — $ — Derivatives not designated for hedge accounting Amount of Loss Recognized 2016 2015 2014 Fuel contracts $ — $ (80 ) $ (462) Foreign Currency Derivatives As of December 31, 2016, the Company did not have any foreign currency contracts outstanding to hedge its foreign currency sales. The last of the Company’s foreign currency derivatives designated for cash flow hedge accounting expired in December 2016. The Company’s current strategy is to not enter into transactions to hedge its foreign currency sales, although the Company regularly reviews its strategy based on market conditions and other factors.

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt	NOTE 11 - DEBT (In millions) At December 31, 2016 2015 Secured Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 $ 7,586 $ 7,971 Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 2.85%, payable through 2028 1,546 1,302 Term loan, LIBOR subject to a 0.75% floor, plus 2.50%, or alternative rate based on certain market rates plus 1.50%, due 2019 866 875 Term loan, LIBOR subject to a 0.75% floor, plus 2.75%, or alternative rate based on certain market rates plus 1.75%, due 2021 192 194 Unsecured 6% Senior Notes due 2020 (a) 300 300 6.375% Senior Notes due 2018 (a) 300 300 Other 101 100 10,891 11,042 Less: unamortized debt discount, premiums and debt issuance costs (124) (145) Less: current portion of long-term debt (849) (1,224) Long-term debt, net $ 9,918 $ 9,673 (a) UAL is the issuer of this debt. United is a guarantor. The table below presents the Company’s contractual principal payments at December 31, 2016 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions): 2017 $ 849 2018 1,427 2019 1,852 2020 1,007 2021 1,174 After 2021 4,582 $ 10,891 As of December 31, 2016, a substantial portion of the Company’s assets, principally aircraft, route authorities, airport slots and loyalty program intangible assets, was pledged under various loan and other agreements. As of December 31, 2016, 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. 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 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, 2016, 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, 2016, United had cash collateralized $72 million of letters of credit. United also had $383 million of surety bonds securing various obligations at December 31, 2016. Most of the letters of credit have evergreen clauses and are expected to be renewed on an annual basis and the surety bonds have expiration dates through 2021. EETCs. In September 2016 and June 2016, United created separate EETC pass-through trusts, each of which issued pass-through certificates. The proceeds of the issuance of the pass-through certificates are used to purchase equipment notes issued by United and secured by its aircraft. The Company records the debt obligation upon issuance of the equipment notes rather than upon the initial issuance of the pass-through certificates. United expects to receive all proceeds from the September 2016 and June 2016 pass-through trusts by the end of the second quarter of 2017. Certain details of the pass-through trusts with proceeds received from issuance of debt in 2016 are as follows (in millions, except stated interest rate): EETC Date Class Principal Final expected Stated Total debt as of December 31, 2016 Proceeds Remaining September 2016 AA $ 637 October 2028 2.875% $ 80 $ 80 $ 557 September 2016 A 283 October 2028 3.10% 36 36 247 June 2016 AA 729 July 2028 3.10% 410 410 319 June 2016 A 324 July 2028 3.45% 182 182 142 $ 1,973 $ 708 $ 708 $ 1,265 In 2016, United borrowed approximately $369 million aggregate principal amount from various financial institutions to finance the purchase of several aircraft delivered in 2016. The notes evidencing these borrowings, which are secured by the related aircraft, have maturity dates ranging from 2026 to 2028 and have interest rates comprised of the LIBOR plus a specified margin. Unsecured debt 5% Senior Notes due 2024. 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 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 5% Senior Notes due 2024 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.

Advanced Purchase of Miles

Advanced Purchase of Miles	12 Months Ended
	Dec. 31, 2016
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 remaining balance of pre-purchased Co-Brand pre-purchased

Leases and Capacity Purchase Ag

Leases and Capacity Purchase Agreements	12 Months Ended
	Dec. 31, 2016
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, 2016, 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 2017 $ 183 $ 1,256 $ 1,271 2018 170 1,106 1,074 2019 105 991 894 2020 85 1,104 669 2021 84 888 551 After 2021 915 6,702 2,049 Minimum lease payments $ 1,542 $ 12,047 $ 6,508 Imputed interest (604) Present value of minimum lease payments 938 Current portion (116) Long-term obligations under capital leases $ 822 As of December 31, 2016, United’s aircraft capital lease minimum payments relate to leases of 38 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 26 years, with expiration dates ranging from 2017 through 2028. 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 S.A.S (“Airbus”) A319s. Five such aircraft are expected to be delivered in 2017. In addition, up to 14 more aircraft may be delivered over the next four 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 $1.4 billion of underlying debt and interest thereon as of December 31, 2016. These leases are typically with municipalities or other governmental entities, which are excluded from the consolidation requirements concerning a variable interest entity (“VIE”). To the extent United’s leases and related guarantees are with a separate legal entity other than a governmental entity, United is not the primary beneficiary because the lease terms are consistent with market terms at the inception of the lease and the lease does not include a residual value guarantee, fixed-price purchase option, or similar feature. In 2016, United signed a seven year lease extension through 2024 with the Metropolitan Washington Airports Authority to continue its use of terminals at Washington Dulles International Airport. United’s nonaircraft rent expense was approximately $1.2 billion, $1.3 billion and $1.4 billion for the years ended December 31, 2016, 2015 and 2014, 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 $439 million, $461 million and $442 million for the years ended December 31, 2016, 2015 and 2014, 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, primarily related to aircraft which make up the majority of the fair value lease adjustment balance, are one to eight years for United. The lease valuation adjustments are classified within other noncurrent liabilities and the net accretion amounts are $82 million, $107 million and $160 million for the years ended December 31, 2016, 2015 and 2014, 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 494 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 2016 and 2015, Republic Airline Inc. (“Republic”), a wholly-owned subsidiary of Republic Airways Holdings (“Republic Airways”), purchased and took delivery of 16 new 76-seat In 2016, United agreed to purchase 12 new Embraer E175 aircraft that were previously expected to be purchased by one of its United Express operators, and in the first quarter of 2017, United entered into a CPA amendment with Mesa Air Group, Inc. (“Mesa Air Group”) and Mesa Airlines, Inc. (“Mesa”), a wholly-owned subsidiary of Mesa Air Group, for Mesa to operate these 12 additional Embraer E175 aircraft under the United Express brand. As of December 31, 2016, all 12 of these aircraft are expected to be delivered in 2017. 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 76-seat In 2015, United entered into a new CPA with Champlain Enterprises, LLC d/b/a CommutAir (“CommutAir”), pursuant to which CommutAir will operate 40 used Embraer ERJ145 aircraft under the United Express brand that are currently being operated by a different United Express regional carrier, with transfers that are continuing through 2018. As of December 31, 2016, 28 aircraft are still pending transfer. 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 a regional carrier 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, 2016, our future payments through the end of the terms of our CPAs are presented in the table below (in billions): 2017 $ 1.9 2018 1.9 2019 1.3 2020 1.0 2021 1.0 After 2021 4.3 $ 11.4 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 2017 would result in a corresponding change in annual cash obligations under the CPAs of approximately $147 million.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2016
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 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

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies	NOTE 15 - COMMITMENTS AND CONTINGENCIES Commitments. Aircraft Type Number of Firm Commitments (a) Airbus A350-1000 35 Boeing 737NG/737MAX 165 Boeing 777-300ER 12 Boeing 787-8/-9/-10 21 Embraer E175 24 (a) United also has options and purchase rights for additional aircraft. The aircraft listed in the table above are scheduled for delivery from 2017 through 2027. To the extent the Company and the aircraft manufacturers with whom the Company has existing orders for new aircraft agree to modify the contracts governing those orders, the amount and timing of the Company’s future capital commitments could change. The table below summarizes United’s commitments as of December 31, 2016, which primarily relate to the acquisition of aircraft and related spare engines, aircraft improvements and include other capital purchase commitments for the years ended December 31 (in billions). 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. 2017 $ 4.5 2018 3.2 2019 3.1 2020 2.5 2021 2.2 After 2021 7.8 $ 23.3 In the first quarter of 2017, the Company announced that it will retire its fleet of Boeing 747 aircraft from scheduled service by the end of 2017. The Company does not expect there to be a material impact to depreciation and amortization expense. As of December 31, 2016, United had $1.3 billion in financing available through EETC transactions for the financing of all of its aircraft deliveries scheduled in the first half of 2017. See Note 11 of this report for additional information on aircraft financing. The Company has also 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, 2016, United is the guarantor of approximately $1.9 billion in aggregate principal amount of tax-exempt tax-exempt 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, 2016, the Company had $2.6 billion of floating rate debt and $90 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. non-U.S. As of December 31, 2016, United is the guarantor of $168 million of aircraft mortgage debt issued by one of United’s regional carriers. The aircraft mortgage debt is subject to similar increased cost provisions as described above for the Company’s debt and the Company would potentially be responsible for those costs under the guarantees. Fuel Consortia. tax-exempt tax-exempt Regional Capacity Purchase. Credit Card Processing Agreements. Labor Negotiations. . six-year

Special Items

Special Items	12 Months Ended
	Dec. 31, 2016
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: 2016 2015 2014 Impairment of assets $ 412 $ 79 $ 49 Cleveland airport lease restructuring 74 — — Labor agreement costs 64 18 — Severance and benefit costs 37 107 199 (Gains) losses on sale of assets and other special charges 51 122 195 Special charges 638 326 443 Nonoperating and income taxes: Losses (gain) on extinguishment of debt and other (1) 202 74 Income tax benefit related to special charges (229) (11) (10) Income tax adjustments (Notes 6 and 7) 180 (3,130 ) — Total operating and nonoperating special items, net of income taxes $ 588 $ (2,613 ) $ 507 2016 In April 2016, the Federal Aviation Administration (“FAA”) announced that it will designate Newark Liberty International Airport (“Newark”) as a Level 2 schedule-facilitated airport under the International Air Transport Association Worldwide Slot Guidelines effective October 30, 2016. The designation was associated with an updated demand and capacity analysis of Newark by the FAA. In 2016, the Company determined that the FAA’s action impaired the entire value of its Newark slots because the slots are no longer the mechanism that governs take-off In 2016, the City of Cleveland agreed to amend the Company’s lease, which runs through 2029, associated with certain excess airport terminal space (principally Terminal D) and related facilities at Hopkins International Airport (“Cleveland”). The Company recorded an accrual for remaining payments under the lease for facilities that the Company no longer uses and will continue to incur costs under the lease without economic benefit to the Company. This liability was measured and recorded at its fair value when the Company ceased its right to use such facilities leased to it pursuant to the lease. The Company recorded a net charge of $74 million ($47 million net of taxes) related to the amended lease. The fleet service, passenger service, storekeeper and other employees represented by the IAM ratified seven new contracts with the Company which extended the contracts through 2021. The technicians and related employees represented by the IBT ratified a six-year one-time one-time During 2016, the Company recorded $37 million ($24 million net of taxes) of severance and benefit costs related to a voluntary early-out During 2016, the Company recorded gains and losses on sale of assets and other special charges of $51 million ($33 million net of taxes). In addition, the Company recorded $8 million ($5 million net of taxes) of losses due to exchange rate changes in Venezuela applicable to funds held in local currency and recorded a $9 million ($6 million net of taxes) gain on the sale of an affiliate. 2015 During its annual assessment in the fourth quarter, the Company recorded $33 million ($22 million net of related income tax benefit) related to the impairment of its indefinite-lived intangible assets (certain domestic slots and international Pacific routes), $8 million for the write-off The Company recorded $107 million of severance and benefit costs primarily related to a voluntary early-out During 2015, the Company also recorded $18 million related to collective bargaining agreements, $60 million of integration-related costs primarily related to systems integration and training for employees, $32 million related to charges for settlements in connection with legal matters, $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 non-cash mid-2014. As 2014 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). The Company also recorded $33 million for charges related primarily to impairment of its flight equipment held for disposal associated with its Boeing 737-300 737-500 The Company recorded $141 million of severance and benefit costs related primarily to a voluntary early-out one-time 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. The Company also recorded $33 million for losses on the sale of assets and other special charges. In addition, $96 million of integration-related costs included compensation costs related to systems integration, training, severance and relocation for employees. 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 non-cash 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, 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 Accrual and related adjustments 37 (17) Payments (50) (20) Balance at December 31, 2016 $ 14 $ 41 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, 2016
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): 2016 Domestic (U.S. and Canada) $ 22,202 Pacific 4,959 Atlantic 6,157 Latin America 3,238 Total $ 36,556 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 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, 2016
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 2016 Operating revenue $ 8,195 $ 9,396 $ 9,913 $ 9,052 Income from operations 649 1,060 1,624 1,005 Net income 313 588 965 397 Basic earnings per share 0.88 1.78 3.02 1.26 Diluted earnings per share 0.88 1.78 3.01 1.26 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 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 2016 Operating: Impairment of assets $ — $ 412 $ — $ — Cleveland airport lease restructuring 74 — — — Labor agreement costs and related items 100 10 14 (60) Severance and benefit costs 8 6 13 10 (Gains) losses on sale of assets and other special charges 8 6 18 19 Special charges 190 434 45 (31) Nonoperating and income taxes: Losses (gain) on extinguishment of debt and other 8 (9) — — Income tax expense (benefit) related to special charges (72) (153) (16) 12 Income tax adjustments (Note 6) — — — 180 Total operating and nonoperating special items, net of income taxes $ 126 $ 272 $ 29 $ 161 2015 Operating: Impairment of assets $ 2 $ 11 $ 18 $ 48 Labor agreement costs and related items — — — 18 Severance and benefit costs 50 25 28 4 (Gains) losses on sale of assets and other special charges 12 19 30 61 Special charges 64 55 76 131 Nonoperating and income taxes: Losses on extinguishment of debt and other 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 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, 2016
Schedule II Valuation and Qualifying Accounts	Schedule II Valuation and Qualifying Accounts For the Years Ended December 31, 2016, 2015 and 2014 (In millions) Description Balance at Beginning of Period Additions Charged to Costs and Expenses Deductions (a) Other Balance at End of Period Allowance for doubtful accounts—UAL and United: 2016 $ 18 $ 18 $ 26 $ — $ 10 2015 22 25 29 — 18 2014 13 45 36 — 22 Obsolescence allowance—spare parts—UAL and United: 2016 $ 235 $ 61 $ 16 $ 15 $ 295 2015 169 38 — 28 235 2014 162 35 28 — 169 Valuation allowance for deferred tax assets—UAL: 2016 $ 48 $ 47 $ 27 $ — $ 68 2015 4,751 — 4,703 — 48 2014 4,591 156 — 4 4,751 Valuation allowance for deferred tax assets—United: 2016 $ 48 $ 47 $ 27 $ — $ 68 2015 4,721 — 4,673 — 48 2014 4,561 167 — (7) 4,721 (a) Deduction from reserve for purpose for which reserve was created.

Significant Accounting Polici27

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Use of Estimates	(a) Use of Estimates—
Revenue Recognition	(b) Revenue Recognition— Non-refundable Fees charged in association with changes or extensions to non-refundable non-refundable 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, 2016, 2015 and 2014.
Frequent Flyer Accounting	(c) Frequent Flyer Accounting— ® non-airline non-travel Miles Earned in Conjunction with Flights When frequent flyers earn miles for flights, 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 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 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’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 United has a significant contract, the Second Amended and Restated Co-Branded “Co-Brand co-branded Co-Brand 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 The Company records passenger revenue related to the air transportation element when the transportation is delivered. The other elements are generally recognized as Other operating revenue when earned. Expiration of Miles The Company accounts for miles sold and awarded that will never be redeemed by program members, which we refer to as breakage. The Company reviews its breakage estimates annually based upon the latest available information regarding redemption and expiration patterns. Miles expire after 18 months of member account inactivity. The Company’s estimate of the expected expiration of miles requires significant management judgment. Current and future changes to expiration assumptions or to the expiration policy, or to program rules and program redemption opportunities, may result in material changes to the deferred revenue balance as well as recognized revenues from the programs. Other Information The following table provides additional information related to the frequent flyer program (in millions): Year Ended Cash Proceeds Other Revenue Increase in Frequent Decrease in 2016 $ 3,022 $ 1,221 $ 2,050 $ (249) 2015 2,999 1,050 2,173 (224) 2014 2,861 882 2,178 (199) (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 decrease in the advance purchase of miles obligation due to cash payments for the sale of miles 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 and reserves for institutions that process credit card ticket sales. 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. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the statements of consolidated cash flows: UAL United At December 31, At December 31, 2016 2015 2014 2016 2015 2014 Current assets: Cash and cash equivalents $ 2,179 $ 3,006 $ 2,002 $ 2,173 $ 3,000 $ 1,996 Restricted cash included in Prepaid expenses and other — 2 44 — 2 44 Other assets: Restricted cash 124 204 276 124 204 276 Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows $ 2,303 $ 3,212 $ 2,322 $ 2,297 $ 3,206 $ 2,316
Short-term Investments	(e) Short-term Investments— available-for-sale available-for-sale
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, 2016 and 2015, the Company had a carrying value of computer software of $356 million and $279 million, respectively. For the years ended December 31, 2016, 2015 and 2014, the Company’s depreciation expense related to computer software was $108 million, $93 million and $81 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— power-by-the-hour
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— non-air non-air
Recently Issued Accounting Standards	(t) Recently Issued Accounting Standards— Revenue from Contracts with Customers. Revenue Recognition In 2016, the FASB amended the FASB Accounting Standards Codification and created a new Topic 842, Leases right-of-use Leases In 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting 2016-09”) . paid-in 2016-09 In 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments 2016-15”). Statement of Cash Flows 2016-15 In 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash 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)

Significant Accounting Polici28

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Information Related to Amounts Recorded Related to Frequent Flyer Programs	The following table provides additional information related to the frequent flyer program (in millions): Year Ended Cash Proceeds Other Revenue Increase in Frequent Decrease in 2016 $ 3,022 $ 1,221 $ 2,050 $ (249) 2015 2,999 1,050 2,173 (224) 2014 2,861 882 2,178 (199) (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 decrease in the advance purchase of miles obligation due to cash payments for the sale of miles less than miles awarded to customers.
Schedule of Cash and Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the statements of consolidated cash flows: UAL United At December 31, At December 31, 2016 2015 2014 2016 2015 2014 Current assets: Cash and cash equivalents $ 2,179 $ 3,006 $ 2,002 $ 2,173 $ 3,000 $ 1,996 Restricted cash included in Prepaid expenses and other — 2 44 — 2 44 Other assets: Restricted cash 124 204 276 124 204 276 Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows $ 2,303 $ 3,212 $ 2,322 $ 2,297 $ 3,206 $ 2,316
Schedule of Cash and Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the statements of consolidated cash flows: UAL United At December 31, At December 31, 2016 2015 2014 2016 2015 2014 Current assets: Cash and cash equivalents $ 2,179 $ 3,006 $ 2,002 $ 2,173 $ 3,000 $ 1,996 Restricted cash included in Prepaid expenses and other — 2 44 — 2 44 Other assets: Restricted cash 124 204 276 124 204 276 Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows $ 2,303 $ 3,212 $ 2,322 $ 2,297 $ 3,206 $ 2,316
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, 2016
Goodwill and Other Intangible Assets	The following table presents information about the Company’s goodwill and other intangible assets at December 31 (in millions): 2016 2015 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 $ 771 $ 1,177 $ 702 Hubs 20 145 82 145 74 Contracts 13 135 95 135 86 Patents and tradenames 3 108 108 108 108 Airport slots and gates 8 97 97 97 97 Other 25 109 81 109 77 Total $ 1,771 $ 1,234 $ 1,771 $ 1,144 Indefinite-lived intangible assets Route authorities $ 1,562 $ 1,570 Airport slots and gates 536 942 Tradenames and logos 593 593 Alliances 404 404 Total $ 3,095 $ 3,509 (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, 2016
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): 2016 2015 2014 Basic earnings per share: Earnings available to common stockholders $ 2,263 $ 7,340 $ 1,132 Basic weighted-average shares outstanding 329.9 376.1 371.1 Earnings per share, basic $ 6.86 $ 19.52 $ 3.05 Diluted earnings per share: Earnings available to common stockholders $ 2,263 $ 7,340 $ 1,132 Effect of dilutive securities — — 11 Earnings available to common stockholders including the effect of dilutive securities $ 2,263 $ 7,340 $ 1,143 Diluted shares outstanding: Basic weighted-average shares outstanding 329.9 376.1 371.1 Effect of convertible notes — 0.3 17.7 Effect of employee stock awards 0.4 0.5 0.9 Diluted weighted-average shares outstanding 330.3 376.9 389.7 Earnings per share, diluted $ 6.85 $ 19.47 $ 2.93

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2016
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): 2016 2015 2014 Compensation cost (a): RSUs $ 58 $ 52 $ 104 Restricted stock 11 6 10 Stock options 1 — — Total $ 70 $ 58 $ 114 (a) All compensation cost is recorded to Salaries and related costs, with the exception of $3 million in 2014 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 as of December 31, 2016 (in millions, except as noted): Unearned Weighted- Average Remaining (in years) RSUs $ 49 1.5 Restricted stock 11 1.5 Stock options 5 3.2 Total $ 65
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 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 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 2.6 0.3 48.68 Granted 1.9 0.4 50.63 Vested (1.4) (0.1) 41.47 Forfeited (0.2) (0.1) 53.42 Non-vested 2.9 0.5 52.00

Accumulated Other Comprehensi32

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
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 Pension and Fuel Investments Pension and Fuel Total Balance at December 31, 2013 $ 699 $ 11 $ 13 $ (115) $ — (c) $ 608 Other comprehensive loss before reclassifications (a) (1,106) (b) (599) — — — (1,705) Amounts reclassified from accumulated other comprehensive income (a) (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) $ — (c) $ (1,079) Other comprehensive income (loss) before reclassifications 78 (b) (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) Other comprehensive income (loss) before reclassifications (517) (b) (4) — 186 1 (334) Amounts reclassified from accumulated other comprehensive income 26 217 (1) (8) 102 336 Net current-period other comprehensive income (loss) (491) 213 (1) 178 103 2 Balance at December 31, 2016 $ (854) $ (2) $ 2 $ 24 $ 1 $ (829) Details about AOCI Components Amount Reclassified from AOCI to Affected Line Item in Year Ended December 31, 2016 2015 2014 Fuel derivative contracts Fuel contracts-reclassifications of losses into earnings $ 217 $ 604 $ 89 Aircraft fuel Pension and Postretirement liabilities Amortization of unrecognized (gains) losses and prior service cost and the effect of curtailments and settlements (d) 26 31 (65) Salaries and related costs Investments and other Available-for-sale (1) — (6) Miscellaneous, net (a) Income tax expense for these items was offset by the Company’s valuation allowance. (b) Prior service credits increased by $30 million, $0 million and $3 million and actuarial gains (losses) increased (decreased) by approximately $560 million, $78 million and $(1.1) billion for 2016, 2015 and 2014, respectively. (c) Deferred tax balance was offset by the Company’s valuation allowance. (d) This AOCI 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, 2016
Components of Income Tax Expense (Benefit)	The significant components of the income tax expense (benefit) are as follows (in millions): 2016 UAL United Current $ (92) $ (92) Deferred 1,648 1,650 $ 1,556 $ 1,558 2015 Current $ 56 $ 56 Deferred (3,177) (3,136) $ (3,121) $ (3,080) 2014 Current $ (17) $ (17) Deferred 13 13 $ (4) $ (4)
Income Tax Provision Differed from Amounts Computed at Statutory Federal Income Tax Rate	The income tax provision differed from amounts computed at the statutory federal income tax rate, as follows (in millions): UAL 2016 2015 2014 Income tax provision at statutory rate $ 1,337 $ 1,477 $ 395 State income taxes, net of federal income tax 38 38 10 Foreign income taxes 3 4 2 Nondeductible employee meals 16 15 15 Income tax adjustment 180 — — State rate change (12) — — Valuation allowance 20 (4,662) (435) Other, net (26) 7 9 $ 1,556 $ (3,121) $ (4) United 2016 2015 2014 Income tax provision at statutory rate $ 1,338 $ 1,477 $ 388 State income taxes, net of federal income tax 38 38 10 Foreign income taxes 3 4 2 Nondeductible employee meals 16 15 15 Derivative market adjustment — — (7) Income tax adjustment 180 — — State rate change (12) — — Valuation allowance 20 (4,621) (421) Other, net (25) 7 9 $ 1,558 $ (3,080) $ (4)
Components of Deferred Tax Assets and Liabilities	Temporary differences and carryforwards that give rise to deferred tax assets and liabilities at December 31, 2016 and 2015 were as follows (in millions): UAL United December 31, December 31, 2016 2015 2016 2015 Deferred income tax asset (liability): Federal and state net operating loss (“NOL”) carryforwards $ 1,613 $ 2,897 $ 1,571 $ 2,855 Deferred revenue 2,096 2,160 2,096 2,160 Employee benefits, including pension, postretirement and medical 1,662 1,662 1,662 1,662 Alternative minimum tax (“AMT”) credit carryforwards 116 232 116 232 Other 523 566 522 566 Less: Valuation allowance (68) (48) (68) (48) Total deferred tax assets $ 5,942 $ 7,469 $ 5,899 $ 7,427 Depreciation $ (3,961) $ (3,921) $ (3,961) $ (3,921) Intangibles (1,326) (1,511) (1,326) (1,511) Total deferred tax liabilities $ (5,287) $ (5,432) $ (5,287) $ (5,432) Net deferred tax asset $ 655 $ 2,037 $ 612 $ 1,995

Pension and Other Postretirem34

Pension and Other Postretirement Plans (Tables)	12 Months Ended
	Dec. 31, 2016
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: $ 4,158 $ 3,795 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 4,473 $ 4,803 Service cost 112 124 Interest cost 200 200 Actuarial (gain) loss 738 (298) Gross benefits paid and settlements (243) (343) Other (27) (13) Projected benefit obligation at end of year $ 5,253 $ 4,473 Change in plan assets: Fair value of plan assets at beginning of year $ 2,975 $ 2,562 Actual gain (loss) on plan assets 230 (59) Employer contributions 421 824 Gross benefits paid and settlements (243) (343) Other (28) (9) Fair value of plan assets at end of year $ 3,355 $ 2,975 Funded status—Net amount recognized $ (1,898) $ (1,498) Other Postretirement Benefits Year Ended Year Ended Change in benefit obligation: Benefit obligation at beginning of year $ 2,002 $ 2,052 Service cost 19 21 Interest cost 86 82 Plan participants’ contributions 69 68 Benefits paid (191) (205) Actuarial gain (165) (22) Plan amendments (138) — Other 5 6 Benefit obligation at end of year $ 1,687 $ 2,002 Change in plan assets: Fair value of plan assets at beginning of year $ 56 $ 57 Actual return on plan assets 2 1 Employer contributions 119 135 Plan participants’ contributions 69 68 Benefits paid (191) (205) Fair value of plan assets at end of year 55 56 Funded status—Net amount recognized $ (1,632) $ (1,946)
Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss)	Pension Benefits December 31, 2016 December 31, 2015 Amounts recognized in the consolidated balance sheets consist of: Noncurrent asset $ 2 $ 2 Current liability (8) (12) Noncurrent liability (1,892) (1,488) Total liability $ (1,898) $ (1,498) Amounts recognized in accumulated other comprehensive loss consist of: Net actuarial loss $ (1,482) $ (844) Prior service loss (1) (1) Total accumulated other comprehensive loss $ (1,483) $ (845) Other Postretirement Benefits December 31, 2016 December 31, 2015 Amounts recognized in the consolidated balance sheets consist of: Current liability $ (51) $ (64) Noncurrent liability (1,581) (1,882) Total liability $ (1,632) $ (1,946) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial gain $ 384 $ 236 Prior service credit 245 246 Total accumulated other comprehensive income $ 629 $ 482
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): 2016 2015 Projected benefit obligation $ 5,025 $ 4,292 Accumulated benefit obligation 3,985 3,655 Fair value of plan assets 3,164 2,794
Components Of Net Periodic Benefit Cost	Net periodic benefit cost for the years ended December 31 included the following components (in millions): 2016 2015 2014 Pension Other Pension Other Pension Other Service cost $ 112 $ 19 $ 124 $ 21 $ 98 $ 19 Interest cost 200 86 200 82 201 88 Expected return on plan assets (216) (2) (194) (2) (180) (2) Curtailment gain — (107) — — — — Amortization of unrecognized actuarial (gain) loss 76 (19) 85 (22) 12 (47) Amortization of prior service credits — (31) — (32) — (31) Other 5 — 4 — 1 — Net periodic benefit cost $ 177 $ (54) $ 219 $ 47 $ 132 $ 27
Amortized Accumulated Other Comprehensive Income (Loss) Into Net Periodic Benefit Cost	The estimated amounts that will be amortized in 2017 out of accumulated other comprehensive income (loss) into net periodic benefit cost are as follows (in millions): Pension Other Actuarial (gain) loss $ 127 $ (36) Prior service credit — (37)
Assumptions Used for Benefit Plans	The assumptions used for the benefit plans were as follows: Pension Benefits Assumptions used to determine benefit obligations 2016 2015 Discount rate 4.18% 4.58% Rate of compensation increase 3.54% 3.66% Assumptions used to determine net expense Discount rate 4.58% 4.20% Expected return on plan assets 7.04% 7.40% Rate of compensation increase 3.53% 3.51% Other Postretirement Benefits Assumptions used to determine benefit obligations 2016 2015 Discount rate 4.07% 4.49% Assumptions used to determine net expense Discount rate 4.49% 4.07% Expected return on plan assets 3.00% 3.00% Health care cost trend rate assumed for next year 6.50% 6.75% 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, 2016 $ 13 $ (11) Effect on postretirement benefit obligation at December 31, 2016 169 (149)
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): 2016 2015 Pension Plan Assets: Total Level 1 Level 2 Level 3 Assets Total Level 1 Level 2 Level 3 Assets Equity securities funds $ 1,173 $ 230 $ 111 $ — $ 832 $ 1,135 $ 254 $ 135 $ — $ 746 Fixed-income securities 1,298 — 824 11 463 1,109 — 877 9 223 Alternatives 586 — — 134 452 527 — 1 125 401 Other investments 298 47 68 87 96 204 37 56 18 93 Total $ 3,355 $ 277 $ 1,003 $ 232 $ 1,843 $ 2,975 $ 291 $ 1,069 $ 152 $ 1,463 Other Postretirement Benefit Plan Assets: Deposit administration fund $ 55 $ — $ — $ 55 $ — $ 56 $ — $ — $ 56 $ — (a) In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) have not been classified in the fair value hierarchy. These investments are commingled funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S.
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, 2016 and 2015 is as follows (in millions): 2016 2015 Balance at beginning of year $ 208 $ 188 Actual return on plan assets: Sold during the year 4 8 Held at year end 3 (1) Purchases, sales, issuances and settlements (net) 72 13 Balance at end of year $ 287 $ 208
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, 2016 are as follows (in millions): Pension Other Postretirement Other Postretirement— subsidy receipts 2017 $ 303 $ 112 $ 6 2018 300 117 6 2019 310 122 7 2020 319 126 7 2021 337 130 8 Years 2022 – 2026 1,782 682 44
Multi-Employer Plans	Pension Fund IAM National Pension Fund EIN/ Pension Plan Number 51-6031295 Pension Protection Act Zone Status (2016 and 2015) Green Zone. Plans in the green zone are at least 80 percent funded. FIP/RP Status Pending/Implemented No United’s Contributions $41 million, $40 million and $39 million in the years ended December 31, 2016, 2015 and 2014, 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, 2016
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The table below presents disclosures about the fair value of financial assets and liabilities measured at fair value on a recurring basis in the Company’s financial statements as of December 31 (in millions): 2016 2015 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 UAL Cash and cash equivalents $ 2,179 $ 2,179 $ — $ — $ 3,006 $ 3,006 $ — $ — Short-term investments: Corporate debt 835 — 835 — 891 — 891 — Asset-backed securities 792 — 792 — 710 — 710 — Certificates of deposit placed through an account registry service (“CDARS”) 246 — 246 — 281 — 281 — U.S. government and agency notes 140 — 140 — 72 — 72 — Auction rate securities — — — — 9 — — 9 Other fixed-income securities 54 — 54 — 26 — 26 — Other investments measured at NAV (a) 182 — — — 201 — — — Restricted cash 124 124 — — 206 206 — — Enhanced equipment trust certificates (“EETC”) 23 — — 23 26 — — 26 Fuel derivatives liability, net — — — — 124 — 124 — (a) In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statement of financial position. The investments measured using NAV are shares of mutual funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S. three-day
Carrying Values and Estimated Fair Values of Financial Instruments	The table below presents the carrying values and estimated fair values of financial instruments not presented in the tables above as of December 31 (in millions): Fair Value of Debt by Fair Value Hierarchy Level 2016 2015 Carrying Fair Value Carrying Fair Value Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Long-term debt $ 10,767 $ 11,055 $ — $ 8,184 $ 2,871 $ 10,897 $ 11,371 $ — $ 8,646 $ 2,725

Hedging Activities (Tables)

Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Description of Derivative Instruments	The table below presents the fair value amounts of fuel derivative assets and liabilities and the location of amounts recognized in the Company’s financial statements. At December 31, the Company’s derivatives were reported in its consolidated balance sheets as follows (in millions): Classification Balance Sheet Location 2016 2015 Derivatives designated as cash flow hedges Liabilities: Fuel contracts due within one year Fuel derivative instruments $ — $ 119 Derivatives not designated for hedge accounting Liabilities: Fuel contracts due within one year Fuel derivative instruments $ — $ 5 Total derivatives Total liabilities $ — $ 124
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 in AOCI on Derivatives (Effective Portion) Loss Reclassified from (Fuel Expense) (Effective Portion) Amount of Loss 2016 2015 2016 2015 2016 2015 Fuel contracts $ (4) $ (320) $ (217) $ (604) $ — $ —
Schedule of Derivative Instruments not Designated as Hedges Losses	Derivatives not designated for hedge accounting Amount of Loss Recognized 2016 2015 2014 Fuel contracts $ — $ (80 ) $ (462)

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt	(In millions) At December 31, 2016 2015 Secured Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 $ 7,586 $ 7,971 Notes payable, floating interest rates of the London Interbank Offered Rate (“LIBOR”) plus 0.20% to 2.85%, payable through 2028 1,546 1,302 Term loan, LIBOR subject to a 0.75% floor, plus 2.50%, or alternative rate based on certain market rates plus 1.50%, due 2019 866 875 Term loan, LIBOR subject to a 0.75% floor, plus 2.75%, or alternative rate based on certain market rates plus 1.75%, due 2021 192 194 Unsecured 6% Senior Notes due 2020 (a) 300 300 6.375% Senior Notes due 2018 (a) 300 300 Other 101 100 10,891 11,042 Less: unamortized debt discount, premiums and debt issuance costs (124) (145) Less: current portion of long-term debt (849) (1,224) Long-term debt, net $ 9,918 $ 9,673 (a) UAL is the issuer of this debt. United is a guarantor.
Contractual Principal Payments	The table below presents the Company’s contractual principal payments at December 31, 2016 under then-outstanding long-term debt agreements in each of the next five calendar years (in millions): 2017 $ 849 2018 1,427 2019 1,852 2020 1,007 2021 1,174 After 2021 4,582 $ 10,891
Details of Pass Through Trusts	Certain details of the pass-through trusts with proceeds received from issuance of debt in 2016 are as follows (in millions, except stated interest rate): EETC Date Class Principal Final expected Stated Total debt as of December 31, 2016 Proceeds Remaining September 2016 AA $ 637 October 2028 2.875% $ 80 $ 80 $ 557 September 2016 A 283 October 2028 3.10% 36 36 247 June 2016 AA 729 July 2028 3.10% 410 410 319 June 2016 A 324 July 2028 3.45% 182 182 142 $ 1,973 $ 708 $ 708 $ 1,265
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 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 5% Senior Notes due 2024 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.

Leases and Capacity Purchase 38

Leases and Capacity Purchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2016
Future Minimum Lease Payments for Capital and Operating Leases	At December 31, 2016, 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 2017 $ 183 $ 1,256 $ 1,271 2018 170 1,106 1,074 2019 105 991 894 2020 85 1,104 669 2021 84 888 551 After 2021 915 6,702 2,049 Minimum lease payments $ 1,542 $ 12,047 $ 6,508 Imputed interest (604) Present value of minimum lease payments 938 Current portion (116) Long-term obligations under capital leases $ 822
Future Lease Payment Under Terms of Capacity Purchase Agreement	Based on these assumptions as of December 31, 2016, our future payments through the end of the terms of our CPAs are presented in the table below (in billions): 2017 $ 1.9 2018 1.9 2019 1.3 2020 1.0 2021 1.0 After 2021 4.3 $ 11.4

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Commitments to Purchase Aircrafts	The table below summarizes United’s commitments as of December 31, 2016, which primarily relate to the acquisition of aircraft and related spare engines, aircraft improvements and include other capital purchase commitments for the years ended December 31 (in billions). 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. 2017 $ 4.5 2018 3.2 2019 3.1 2020 2.5 2021 2.2 After 2021 7.8 $ 23.3
Aircraft Type
Schedule of Commitments to Purchase Aircrafts	Commitments. Aircraft Type Number of Firm Commitments (a) Airbus A350-1000 35 Boeing 737NG/737MAX 165 Boeing 777-300ER 12 Boeing 787-8/-9/-10 21 Embraer E175 24 (a) United also has options and purchase rights for additional aircraft.

Special Items (Tables)

Special Items (Tables)	12 Months Ended
	Dec. 31, 2016
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: 2016 2015 2014 Impairment of assets $ 412 $ 79 $ 49 Cleveland airport lease restructuring 74 — — Labor agreement costs 64 18 — Severance and benefit costs 37 107 199 (Gains) losses on sale of assets and other special charges 51 122 195 Special charges 638 326 443 Nonoperating and income taxes: Losses (gain) on extinguishment of debt and other (1) 202 74 Income tax benefit related to special charges (229) (11) (10) Income tax adjustments (Notes 6 and 7) 180 (3,130 ) — Total operating and nonoperating special items, net of income taxes $ 588 $ (2,613 ) $ 507
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, 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 Accrual and related adjustments 37 (17) Payments (50) (20) Balance at December 31, 2016 $ 14 $ 41

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
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): 2016 Domestic (U.S. and Canada) $ 22,202 Pacific 4,959 Atlantic 6,157 Latin America 3,238 Total $ 36,556 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

Selected Quarterly Financial 42

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Selected Quarterly Financial Data	UAL Quarter Ended (In millions, except per share amounts) March 31 June 30 September 30 December 31 2016 Operating revenue $ 8,195 $ 9,396 $ 9,913 $ 9,052 Income from operations 649 1,060 1,624 1,005 Net income 313 588 965 397 Basic earnings per share 0.88 1.78 3.02 1.26 Diluted earnings per share 0.88 1.78 3.01 1.26 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
Schedule of Effect of Four Quarters Events	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 2016 Operating: Impairment of assets $ — $ 412 $ — $ — Cleveland airport lease restructuring 74 — — — Labor agreement costs and related items 100 10 14 (60) Severance and benefit costs 8 6 13 10 (Gains) losses on sale of assets and other special charges 8 6 18 19 Special charges 190 434 45 (31) Nonoperating and income taxes: Losses (gain) on extinguishment of debt and other 8 (9) — — Income tax expense (benefit) related to special charges (72) (153) (16) 12 Income tax adjustments (Note 6) — — — 180 Total operating and nonoperating special items, net of income taxes $ 126 $ 272 $ 29 $ 161 2015 Operating: Impairment of assets $ 2 $ 11 $ 18 $ 48 Labor agreement costs and related items — — — 18 Severance and benefit costs 50 25 28 4 (Gains) losses on sale of assets and other special charges 12 19 30 61 Special charges 64 55 76 131 Nonoperating and income taxes: Losses on extinguishment of debt and other 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 See Note 16 of this report for additional information of these items.

Significant Accounting Polici43

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Residual value	10.00%
Carrying value of computer software	$ 356	$ 279
Advertising expense	$ 220	201	$ 179
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]
Restricted cash and cash equivalents	$ 124	206	320
Recently Issued Accounting Standards | Pension Benefits
Summary Of Significant Accounting Policies [Line Items]
Pension plan investments measured at net asset value per share	1,800
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	182
Computer software
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense related to computer software	$ 108	$ 93	$ 81
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, 2016	Dec. 31, 2015	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Cash Proceeds from Miles Sold and Earned		$ 3,022	$ 2,999	$ 2,861
Other Revenue Recognized Upon Award of Miles to Third-Party Customers	[1]	1,221	1,050	882
Increase in Frequent Flyer Deferred Revenue for Miles Awarded	[2]	2,050	2,173	2,178
Decrease in Advanced Purchase of Miles	[3]	$ (249)	$ (224)	$ (199)
[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 decrease in the advance purchase of miles obligation due to cash payments for the sale of miles less than miles awarded to customers.

Schedule of Cash and Cash Equiv

Schedule of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 2,179	$ 3,006	$ 2,002
Other assets:
Restricted cash	124	204	276
Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows	2,303	3,212	2,322	$ 3,615
Prepaid Expenses and Other
Current assets:
Restricted cash		2	44
United Airlines, Inc.
Current assets:
Cash and cash equivalents	2,173	3,000	1,996
Other assets:
Restricted cash	124	204	276
Total cash, cash equivalents and restricted cash shown in the statement of consolidated cash flows	$ 2,297	3,206	2,316	$ 3,609
United Airlines, Inc. | Prepaid Expenses and Other
Current assets:
Restricted cash		$ 2	$ 44

Estimated Useful Lives of Prope

Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
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 Intangible47

Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets [Line Items]
Goodwill		$ 4,523	$ 4,523
Finite-lived intangible assets, Gross Carrying Amount		1,771	1,771
Finite-lived intangible assets, Accumulated Amortization		1,234	1,144
Indefinite-lived intangible assets, Gross Carrying Amount		$ 3,095	3,509
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]	$ 771	702
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		$ 82	74
Contracts
Goodwill And Intangible Assets [Line Items]
Asset life	[2]	13 years
Finite-lived intangible assets, Gross Carrying Amount		$ 135	135
Finite-lived intangible assets, Accumulated Amortization		$ 95	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		81	77
Route Authorities
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount		1,562	1,570
Airport Slots And Gates
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Carrying Amount		536	942
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 Intangible48

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Actual and Estimated Amortization Expense [Line Items]
Actual amortization	$ 90	$ 105	$ 128
Projected amortization in 2017	79
Projected amortization in 2018	70
Projected amortization in 2019	64
Projected amortization in 2020	58
Projected amortization in 2021	$ 53

Common Stockholders' Equity a49

Common Stockholders' Equity and Preferred Securities - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Stockholders Equity [Line Items]
Number of shares repurchased	50,000,000
Repurchases of common stock	$ 2,607	$ 1,232	$ 320
Amount remaining under repurchase programs	$ 1,800
Treasury stock, shares, retired	70,000,000
Treasury stock retired, average cost per share	$ 53
Common stock reserved for future issuance	5,000,000
Junior preferred stock outstanding	2
Junior preferred stock par value per share	$ 0.01
Preferred stock authorized to issue	250,000,000

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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic earnings per share:
Earnings available to common stockholders									$ 2,263	$ 7,340	$ 1,132
Basic weighted-average shares outstanding									329.9	376.1	371.1
Earnings per share, basic	$ 1.26	$ 3.02	$ 1.78	$ 0.88	$ 2.24	$ 12.83	$ 3.14	$ 1.33	$ 6.86	$ 19.52	$ 3.05
Diluted earnings per share:
Earnings available to common stockholders									$ 2,263	$ 7,340	$ 1,132
Effect of dilutive securities											11
Earnings available to common stockholders including the effect of dilutive securities									$ 2,263	$ 7,340	$ 1,143
Diluted shares outstanding:
Basic weighted-average shares outstanding									329.9	376.1	371.1
Effect of convertible notes										0.3	17.7
Effect of employee stock awards									0.4	0.5	0.9
Diluted weighted-average shares outstanding									330.3	376.9	389.7
Earnings per share, diluted	$ 1.26	$ 3.01	$ 1.78	$ 0.88	$ 2.24	$ 12.82	$ 3.14	$ 1.32	$ 6.85	$ 19.47	$ 2.93

Share-Based Compensation Plan51

Share-Based Compensation Plans - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock option awards	0.5
Outstanding stock option awards, exercisable	0.1
Outstanding weighted average exercise price	$ 46.83
Outstanding exercisable weighted average exercise price	$ 18.58
Outstanding intrinsic value	$ 14
Outstanding exercisable intrinsic value	$ 7
Outstanding weighted average remaining contractual live	6 years 3 months 18 days
Outstanding exercisable weighted average remaining contractual live	1 year 7 months 6 days
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, awards granted	0.4
Percentage of premium of the grant date fair market value	25.00%
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 56.19
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, grant date fair value	$ 2.3
Employee Stock Option | Exercise Prices Equal to Fair Market Value
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, awards granted	0.1
Employee Stock Option | Stock options with exercise prices at a 25% premium of the grant date fair market value
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, awards granted	0.3
Employee Stock Option | First three anniversaries of the date of grant (seven-year term option)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, award vesting percentage	0.3333%
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, options term	7 years
Employee Stock Option | Fourth, fifth and sixth anniversaries of the date of grant (ten-year term option)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, award vesting percentage	0.3333%
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, options term	10 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, other than options, awards granted	0.4	0.2	0.3
Share-Based Compensation, award vesting percentage	0.3333%
Share-Based Compensation, vesting period	3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, other than options, awards granted	1.9	1	0.9
Share-Based Compensation, award vesting percentage	0.3333%
Share-Based Compensation, vesting period	3 years
Liabilities related to share based payments	$ 70
Payment related to share-based liabilities	69	$ 85	$ 86
Equity awards fair value	$ 80	$ 92	$ 97
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation, vesting period	3 years
Share-Based Compensation, vesting date	Dec. 31, 2018
Number of days used to compute performance period average closing price of restricted stock units	20 days

Schedule of Share-Based Compens

Schedule of Share-Based Compensation Plan Cost (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	$ 70	$ 58	$ 114
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	58	52	104
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	[1]	11	$ 6	$ 10
Employee Stock Option
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 in 2014 that was recorded in integration-related costs as a component of special items.

Schedule of Share-Based Compe53

Schedule of Share-Based Compensation Plan Cost (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs	$ 60	$ 96
Special Charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Integration related costs		$ 3

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, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 65
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 49
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	$ 11
Weighted- Average Remaining Period (in years)	1 year 6 months
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation	$ 5
Weighted- Average Remaining Period (in years)	3 years 2 months 12 days

Schedule of Restricted Stock Un

Schedule of Restricted Stock Unit and Restricted Stock Activity (Detail) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	0.3	0.7	0.9
Granted, Stock	0.4	0.2	0.3
Vested, Stock	(0.1)	(0.4)	(0.4)
Forfeited, Stock	(0.1)	(0.2)	(0.1)
Non-vested at end of year, Stock	0.5	0.3	0.7
Weighted-Average Grant Price at beginning of year	$ 48.68	$ 32.55	$ 25.02
Granted, Weighted-Average Grant Price	50.63	66.53	43.33
Vested, Weighted-Average Grant Price	41.47	31.14	24.66
Forfeited, Weighted-Average Grant Price	53.42	46.23	28.88
Non-vested at end of year, Weighted-Average Grant Price	$ 52	$ 48.68	$ 32.55
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year	2.6	3.8	5.4
Granted, Stock	1.9	1	0.9
Vested, Stock	(1.4)	(1.6)	(2.2)
Forfeited, Stock	(0.2)	(0.6)	(0.3)
Non-vested at end of year, Stock	2.9	2.6	3.8

Components of Accumulated Other

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		$ 8,966	$ 2,396	$ 2,984
Comprehensive income (loss) adjustments		2	248	(1,687)
Ending Balance		8,659	8,966	2,396
Pension and Other Postretirement Liabilities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(363)	(472)	699
Other comprehensive income (loss) before reclassifications	[1]	(517)	78	(1,106)	[2]
Amounts reclassified from accumulated other comprehensive income		26	31	(65)	[2]
Comprehensive income (loss) adjustments		(491)	109	(1,171)
Ending Balance		(854)	(363)	(472)
Derivative Contracts | Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(215)	(499)	11
Other comprehensive income (loss) before reclassifications		(4)	(320)	(599)	[2]
Amounts reclassified from accumulated other comprehensive income		217	604	89	[2]
Comprehensive income (loss) adjustments		213	284	(510)
Ending Balance		(2)	(215)	(499)
Investments and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		3	7	13
Other comprehensive income (loss) before reclassifications			(4)
Amounts reclassified from accumulated other comprehensive income		(1)		(6)	[2]
Comprehensive income (loss) adjustments		(1)	(4)	(6)
Ending Balance		2	3	7
Pension and Other Postretirement Deferred Taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(154)	(115)	(115)
Other comprehensive income (loss) before reclassifications		186	(28)
Amounts reclassified from accumulated other comprehensive income		(8)	(11)
Comprehensive income (loss) adjustments		178	(39)
Ending Balance		24	(154)	(115)
Derivative Contracts Deferred Taxes | Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(102)
Other comprehensive income (loss) before reclassifications		1	115
Amounts reclassified from accumulated other comprehensive income		102	(217)
Comprehensive income (loss) adjustments		103	(102)
Ending Balance		1	(102)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(831)	(1,079)	608
Other comprehensive income (loss) before reclassifications		(334)	(159)	(1,705)	[2]
Amounts reclassified from accumulated other comprehensive income		336	407	18	[2]
Comprehensive income (loss) adjustments		2	248	(1,687)
Ending Balance		$ (829)	$ (831)	$ (1,079)
[1]	Prior service credits increased by $30 million, $0 million and $3 million and actuarial gains (losses) increased (decreased) by approximately $560 million, $78 million and $(1.1) billion for 2016, 2015 and 2014, respectively.
[2]	Income tax expense for these items 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, 2016	Dec. 31, 2015	Dec. 31, 2014
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]	$ 26	$ 31	$ (65)
Miscellaneous, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Available-for-sale securities - reclassifications of gains into earnings		(1)		(6)
Fuel Oil Contract | Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of losses into earnings		$ 217	$ 604	$ 89
[1]	This AOCI 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 Oth58

Components of Accumulated Other Comprehensive Income (Loss), Net of Tax (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Increase in prior service credits	$ 30	$ 0	$ 3
Increase (decrease) in actuarial gains (losses)	$ 560	$ 78	$ (1,100)

Accumulated Other Comprehensi59

Accumulated Other Comprehensive Income (Loss) - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Valuation allowance	$ 68	$ 48		$ 68	$ 48
Income tax adjustment	$ 180	$ 88	$ (3,218)	$ 180	$ (3,130)
Valuation allowance for deferred tax assets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Valuation allowance			465
Pension and Other Postretirement Liabilities | Valuation allowance for deferred tax assets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Valuation allowance			285
Fuel | Designated as Hedging Instrument | Valuation allowance for deferred tax assets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Valuation allowance			$ 180

Components of Income Tax Expens

Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components Of Income Tax Expense Benefit [Line Items]
Current	$ (92)	$ 56	$ (17)
Deferred	1,648	(3,177)	13
Income tax expense (benefit)	1,556	(3,121)	(4)
United Airlines, Inc.
Components Of Income Tax Expense Benefit [Line Items]
Current	(92)	56	(17)
Deferred	1,650	(3,136)	13
Income tax expense (benefit)	$ 1,558	$ (3,080)	$ (4)

Income Tax Provision Differed f

Income Tax Provision Differed from Amounts Computed at Statutory Federal Income Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Income tax provision at statutory rate				$ 1,337	$ 1,477	$ 395
State income taxes, net of federal income tax				38	38	10
Foreign income taxes				3	4	2
Nondeductible employee meals				16	15	15
Income tax adjustment	$ 180	$ 88	$ (3,218)	180	(3,130)
State rate change				(12)
Valuation allowance				20	(4,662)	(435)
Other, net				(26)	7	9
Income tax expense (benefit)				1,556	(3,121)	(4)
United Airlines, Inc.
Income Taxes [Line Items]
Income tax provision at statutory rate				1,338	1,477	388
State income taxes, net of federal income tax				38	38	10
Foreign income taxes				3	4	2
Nondeductible employee meals				16	15	15
Derivative market adjustment						(7)
Income tax adjustment				180
State rate change				(12)
Valuation allowance				20	(4,621)	(421)
Other, net				(25)	7	9
Income tax expense (benefit)				$ 1,558	$ (3,080)	$ (4)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Federal statutory income tax rate					35.00%
Deferred income tax expense				$ 1,648	$ (3,177)	$ 13
Alternative minimum tax ("AMT") credit carryforwards, net of valuation allowance	$ 108			108
Alternative minimum tax ("AMT") credit carryforwards, valuation allowance	8			8
Income tax adjustments	180	$ 88	$ (3,218)	180	(3,130)
Valuation allowance	68	48		68	48
Unrecognized tax benefits	74	24		74	24	$ 9
Unrecognized tax benefits that would impact effective tax rate if recognized	20			$ 20
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
2,026
Income Taxes [Line Items]
Net operating loss expiration amount	500			$ 500
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
Fuel | Designated as Hedging Instrument
Income Taxes [Line Items]
Deferred income tax expense				180	180
State
Income Taxes [Line Items]
NOL carry forwards	56			56
NOL carry forwards, net of valuation allowance	36			36
Valuation allowance		$ 68			$ 68
Federal
Income Taxes [Line Items]
NOL carry forwards	$ 4,400			$ 4,400

Components of Deferred Tax Asse

Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	$ 1,613	$ 2,897
Deferred revenue	2,096	2,160
Employee benefits, including pension, postretirement and medical	1,662	1,662
Alternative minimum tax ("AMT") credit carryforwards	116	232
Other	523	566
Less: Valuation allowance	(68)	(48)
Total deferred tax assets	5,942	7,469
Depreciation	(3,961)	(3,921)
Intangibles	(1,326)	(1,511)
Total deferred tax liabilities	(5,287)	(5,432)
Net deferred tax asset	655	2,037
United Airlines, Inc.
Deferred income tax asset (liability):
Federal and state net operating loss ("NOL") carryforwards	1,571	2,855
Deferred revenue	2,096	2,160
Employee benefits, including pension, postretirement and medical	1,662	1,662
Alternative minimum tax ("AMT") credit carryforwards	116	232
Other	522	566
Less: Valuation allowance	(68)	(48)
Total deferred tax assets	5,899	7,427
Depreciation	(3,961)	(3,921)
Intangibles	(1,326)	(1,511)
Total deferred tax liabilities	(5,287)	(5,432)
Net deferred tax asset	$ 612	$ 1,995

Reconciliation of Change in Pro

Reconciliation of Change in Projected Benefit Obligation and Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation:	$ 4,158	$ 3,795
Benefit obligation at beginning of year	4,473	4,803
Service cost	112	124	$ 98
Interest cost	200	200	201
Actuarial (gain) loss	738	(298)
Gross benefits paid and settlements	(243)	(343)
Other	(27)	(13)
Benefit obligation at end of year	5,253	4,473	4,803
Fair value of plan assets at beginning of year	2,975	2,562
Actual gain (loss) on plan assets	230	(59)
Employer contributions	421	824
Gross benefits paid and settlements	(243)	(343)
Other	(28)	(9)
Fair value of plan assets at end of year	3,355	2,975	2,562
Funded status-Net amount recognized	(1,898)	(1,498)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	2,002	2,052
Service cost	19	21	19
Interest cost	86	82	88
Plan participants' contributions	69	68
Benefits paid	(191)	(205)
Actuarial (gain) loss	(165)	(22)
Plan amendments	(138)
Other	5	6
Benefit obligation at end of year	1,687	2,002	2,052
Fair value of plan assets at beginning of year	56	57
Actual gain (loss) on plan assets	2	1
Employer contributions	119	135
Plan participants' contributions	69	68
Benefits paid	(191)	(205)
Fair value of plan assets at end of year	55	56	$ 57
Funded status-Net amount recognized	$ (1,632)	$ (1,946)

Amounts Recognized in Consolida

Amounts Recognized in Consolidated Balance Sheet and Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits
Amounts recognized in the consolidated balance sheets consist of:
Noncurrent asset	$ 2	$ 2
Current liability	(8)	(12)
Noncurrent liability	(1,892)	(1,488)
Total liability	(1,898)	(1,498)
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	(1,482)	(844)
Prior service credit (loss)	(1)	(1)
Total accumulated other comprehensive income (loss)	(1,483)	(845)
Other Postretirement Benefits
Amounts recognized in the consolidated balance sheets consist of:
Current liability	(51)	(64)
Noncurrent liability	(1,581)	(1,882)
Total liability	(1,632)	(1,946)
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net actuarial gain (loss)	384	236
Prior service credit (loss)	245	246
Total accumulated other comprehensive income (loss)	$ 629	$ 482

Accumulated Benefit Obligation

Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 5,025	$ 4,292
Accumulated benefit obligation	3,985	3,655
Fair value of plan assets	$ 3,164	$ 2,794

Components of Net Periodic Bene

Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 112	$ 124	$ 98
Interest cost	200	200	201
Expected return on plan assets	(216)	(194)	(180)
Amortization of unrecognized actuarial (gain) loss	76	85	12
Other	5	4	1
Net periodic benefit cost	177	219	132
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	19	21	19
Interest cost	86	82	88
Expected return on plan assets	(2)	(2)	(2)
Curtailment gain	(107)
Amortization of unrecognized actuarial (gain) loss	(19)	(22)	(47)
Amortization of prior service credits	(31)	(32)	(31)
Net periodic benefit cost	$ (54)	$ 47	$ 27

Pension and Other Postretirem68

Pension and Other Postretirement Plans (Defined Pension and Other Postretirement Plans) - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Effect on post retirement benefit obligation, 1% Decrease		$ 181
Effect on total service and interest cost, 1% Decrease		11
Postretirement Medical Plan | Flight Attendant Postretirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain recognition of prior service credit		47
Postretirement Medical Plan | Technicians and Related Employees Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain recognition of prior service credit		60
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain recognition of prior service credit		107
Effect on post retirement benefit obligation, 1% Decrease		149
Effect on total service and interest cost, 1% Decrease		11
Employer contributions		$ 119	$ 135
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		$ 421	$ 824
United Airlines, Inc. | Other Postretirement Benefits | Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 108
United Airlines, Inc. | Pension Benefits | Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 400

Amortized Accumulated Other Com

Amortized Accumulated Other Comprehensive Income (Loss) Into Net Periodic Benefit Cost (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$ 127
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	(36)
Prior service credit	$ (37)

Assumptions Used for Benefit Pl

Assumptions Used for Benefit Plans (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits
Assumptions used to determine benefit obligations
Discount rate	4.18%	4.58%
Rate of compensation increase	3.54%	3.66%
Assumptions used to determine net expense
Discount rate	4.58%	4.20%
Expected return on plan assets	7.04%	7.40%
Rate of compensation increase	3.53%	3.51%
Other Postretirement Benefits
Assumptions used to determine benefit obligations
Discount rate	4.07%	4.49%
Assumptions used to determine net expense
Discount rate	4.49%	4.07%
Expected return on plan assets	3.00%	3.00%
Health care cost trend rate assumed for next year	6.50%	6.75%
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, 2016
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%

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, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest cost,1% Decrease	$ (11)
Effect on post retirement benefit obligation, 1% Decrease	(181)
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	169
Effect on total service and interest cost,1% Decrease	(11)
Effect on post retirement benefit obligation, 1% Decrease	$ (149)

Pension and Other Postretirem73

Pension and Other Postretirement Plan Assets (Detail) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		$ 3,355	$ 2,975	$ 2,562
Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		1,173	1,135
Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		1,298	1,109
Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		586	527
Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		298	204
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		55	56	57
Other Postretirement Benefits | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		55	56
Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		277	291
Level 1 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		230	254
Level 1 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		47	37
Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		1,003	1,069
Level 2 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		111	135
Level 2 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		824	877
Level 2 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets			1
Level 2 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		68	56
Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		287	208	$ 188
Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		232	152
Level 3 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		11	9
Level 3 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		134	125
Level 3 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		87	18
Level 3 | Other Postretirement Benefits | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets		55	56
Assets Measured at NAV | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	[1]	1,843	1,463
Assets Measured at NAV | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	[1]	832	746
Assets Measured at NAV | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	[1]	463	223
Assets Measured at NAV | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	[1]	452	401
Assets Measured at NAV | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	[1]	$ 96	$ 93
[1]	In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) have not been classified in the fair value hierarchy. These investments are commingled funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. Redemption periods for these investments range from daily to annually.

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, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 208	$ 188
Actual return on plan assets, Sold during the year	4	8
Actual return on plan assets, Held at year end	3	(1)
Purchases, sales, issuances and settlements (net)	72	13
Fair value of plan assets at end of year	$ 287	$ 208

Estimated Future Benefit Paymen

Estimated Future Benefit Payments (Detail) $ in Millions	Dec. 31, 2016USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 303
2,018	300
2,019	310
2,020	319
2,021	337
Years 2022 - 2026	1,782
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2,017	112
2,018	117
2,019	122
2,020	126
2,021	130
Years 2022 - 2026	682
Other Postretirement-Subsidy Receipts
Defined Benefit Plan Disclosure [Line Items]
2,017	6
2,018	6
2,019	7
2,020	7
2,021	8
Years 2022 - 2026	$ 44

Pension and Other Postretirem76

Pension and Other Postretirement Plans (Defined Contribution Plans) - Additional Information (Detail) - United Airlines, Inc. - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer	$ 592	$ 522	$ 503
Minimum
Defined Contribution Plan Disclosure [Line Items]
Employer contribution, percentage	1.00%
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer contribution, percentage	16.00%

Pension and Other Postretirem77

Pension and Other Postretirement Plans (Multi-Employer Plans) - Additional Information (Detail) - Multiemployer Plans, Pension - IAM National Pension Plan $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Multiemployer Plans [Line Items]
Multi-employer plan contributions	$ 395
Minimum
Multiemployer Plans [Line Items]
Percent of company's contribution to plan	5.00%

Multi-Employer Plans (Detail)

Multi-Employer Plans (Detail) - Multiemployer Plans, Pension - IAM National Pension Plan - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Multiemployer Plans [Line Items]
EIN		516,031,295
Pension Plan Number		2
Pension Protection Act Zone Status (2016 and 2015)	[1]	Green
FIP/RP Status Pending/Implemented		No
United's Contributions			$ 395
Surcharge Imposed		No
United Airlines, Inc.
Multiemployer Plans [Line Items]
United's Contributions		$ 41	$ 40	$ 39
[1]	At the date the financial statements were issued, Forms 5500 were not available for the plan year ending in 2016.

Pension and Other Postretirem79

Pension and Other Postretirement Plans (Profit Sharing) - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Profit sharing and payroll tax expense	$ 628	$ 698	$ 235
Minimum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Percentage of pre-tax earnings paid for profit sharing plan	5.00%
Maximum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Percentage of pre-tax earnings paid for profit sharing plan	20.00%

Financial Assets and Liabilitie

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		$ 2,179	$ 3,006
Restricted cash		124	206
Enhanced equipment trust certificates ("EETC")		23	26
Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		835	891
Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		792	710
CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		246	281
U.S. Government and Agency Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		140	72
Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			9
Other Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		54	26
Other Investments Measured At NAV
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	[1]	182	201
Fuel Derivatives Liability, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net			124
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		2,179	3,006
Restricted cash		124	206
Level 2 | Corporate Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		835	891
Level 2 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		792	710
Level 2 | CDARS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		246	281
Level 2 | U.S. Government and Agency Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		140	72
Level 2 | Other Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		54	26
Level 2 | Fuel Derivatives Liability, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, net			124
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Enhanced equipment trust certificates ("EETC")		$ 23	26
Level 3 | Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			$ 9
[1]	In accordance with the relevant accounting standards, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statement of financial position. The investments measured using NAV are shares of mutual funds that invest in fixed-income instruments including bonds, debt securities, and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The Company can redeem its shares at any time at NAV subject to a three-day settlement period.

Financial Assets and Liabilit81

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Redeemable shares, settlement period	3 days

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
EETC
Fair Value [Line Items]
Available-for-sale securities remaining maturities	2,019
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	30 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	5 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

Carrying Values and Estimated F

Carrying Values and Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Carrying (Reported) Amount, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 10,767	$ 10,897
Estimate of Fair Value, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	11,055	11,371
Estimate of Fair Value, Fair Value Disclosure | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	8,184	8,646
Estimate of Fair Value, Fair Value Disclosure | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value	$ 2,871	$ 2,725

Hedging Activities - Additional

Hedging Activities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016Contract
Fuel Contract
Derivatives And Hedging Activities [Line Items]
Fuel hedging contracts outstanding	0
Fuel Contract | Cash Flow Hedging | Designated as Hedging Instrument
Derivatives And Hedging Activities [Line Items]
Fuel hedges expiration date	2016-12
Foreign Currency Derivatives
Derivatives And Hedging Activities [Line Items]
Foreign currency contracts outstanding	0
Foreign Currency Derivatives | Cash Flow Hedging | Designated as Hedging Instrument
Derivatives And Hedging Activities [Line Items]
Derivative instrument expiration date	2016-12

Description of Derivative Instr

Description of Derivative Instruments (Detail) - Cash Flow Hedging $ in Millions	Dec. 31, 2015USD ($)
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	$ 124
Designated as Hedging Instrument | Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	119
Not Designated as Hedging Instrument | Fuel Derivative Instruments
Derivatives, Fair Value [Line Items]
Fuel contracts, liabilities	$ 5

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, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Recognized in AOCI on Derivatives (Effective Portion)	$ (4)	$ (320)
Loss Reclassified from AOCI into Income (Fuel Expense) (Effective Portion)	(217)	(604)
Amount of Loss Recognized in Nonoperating income (expense): Miscellaneous, net (Ineffective Portion)	$ 0	$ 0

Schedule of Derivative Instrume

Schedule of Derivative Instruments not Designated as Hedges Losses (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss recognized in Nonoperating income (expense): Miscellaneous, net	$ 0	$ (80)	$ (462)

Debt (Detail)

Debt (Detail) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Less: current portion of long-term debt		$ (849)	$ (1,224)
Long-term debt, net		9,918	9,673
United Airlines, Inc.
Debt Instrument [Line Items]
Less: current portion of long-term debt		(849)	(1,224)
Long-term debt, net		9,918	9,673
UAL and United
Debt Instrument [Line Items]
Long-term Debt, Gross		10,891	11,042
Less: unamortized debt discount, premiums and debt issuance costs		(124)	(145)
Less: current portion of long-term debt		(849)	(1,224)
Long-term debt, net		9,918	9,673
Secured Debt | Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		7,586	7,971
Secured Debt | Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2028 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		1,546	1,302
Secured Debt | Term Loan Facility Due April 2019 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		866	875
Secured Debt | Term Loan Facility Due September 2021 | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		192	194
Unsecured Debt | 6% Senior Notes due 2020
Debt Instrument [Line Items]
Long-term Debt, Gross	[1]	300	300
Unsecured Debt | 6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Long-term Debt, Gross	[1]	300	300
Unsecured Debt | Other Debt | United Airlines, Inc.
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 101	$ 100
[1]	UAL is the issuer of this debt. United is a guarantor.

Debt (Parenthetical) (Detail)

Debt (Parenthetical) (Detail)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
United Airlines, Inc. | Minimum
Debt Instrument [Line Items]
Debt instrument, maturity date		2,026
United Airlines, Inc. | Maximum
Debt Instrument [Line Items]
Debt instrument, maturity date		2,028
Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 | United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Weighted average interest rate		4.85%	4.85%
Debt instrument, maturity date		2,028	2,028
Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 | United Airlines, Inc. | Secured Debt | Minimum
Debt Instrument [Line Items]
Debt instrument stated interest rate		1.42%	1.42%
Notes payable, fixed interest rates of 1.42% to 9.75% (weighted average rate of 4.85% as of December 31, 2016), payable through 2028 | United Airlines, Inc. | Secured Debt | Maximum
Debt Instrument [Line Items]
Debt instrument stated interest rate		9.75%	9.75%
Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2028 | United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Debt instrument, maturity date		2,028	2,028
Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2028 | United Airlines, Inc. | Secured Debt | LIBOR | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.20%	0.20%
Notes payable, floating interest rates of the London Interbank Offered Rate ("LIBOR") plus 0.20% to 2.85%, payable through 2028 | United Airlines, Inc. | Secured Debt | LIBOR | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.85%	2.85%
Term Loan Facility Due April 2019 | United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Debt instrument, maturity date		2,019	2,019
Term Loan Facility Due April 2019 | United Airlines, Inc. | Secured Debt | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.50%	2.50%
Term Loan Facility Due April 2019 | United Airlines, Inc. | Secured Debt | Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.75%	0.75%
Term Loan Facility Due April 2019 | United Airlines, Inc. | Secured Debt | Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.50%	1.50%
Term Loan Facility Due September 2021 | United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Debt instrument, maturity date		2,021	2,021
Term Loan Facility Due September 2021 | United Airlines, Inc. | Secured Debt | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.75%	2.75%
Term Loan Facility Due September 2021 | United Airlines, Inc. | Secured Debt | Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.75%	0.75%
Term Loan Facility Due September 2021 | United Airlines, Inc. | Secured Debt | Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.75%	1.75%
6% Senior Notes due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate		6.00%
6% Senior Notes due 2020 | Unsecured Debt
Debt Instrument [Line Items]
Debt instrument stated interest rate	[1]	6.00%	6.00%
Debt instrument, maturity date	[1]	2,020	2,020
6.375% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument stated interest rate		6.375%
6.375% Senior Notes due 2018 | Unsecured Debt
Debt Instrument [Line Items]
Debt instrument stated interest rate	[1]	6.375%	6.375%
Debt instrument, maturity date	[1]	2,018	2,018
[1]	UAL is the issuer of this debt. United is a guarantor.

Contractual Principal Payments

Contractual Principal Payments (Detail) - UAL and United - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2,017	$ 849
2,018	1,427
2,019	1,852
2,020	1,007
2,021	1,174
After 2,021	4,582
Long-term debt	$ 10,891	$ 11,042

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 30, 2017	Dec. 31, 2016
5% Senior Notes due 2024
Debt Instrument [Line Items]
Debt instrument stated interest rate		5.00%
United Airlines, Inc.
Debt Instrument [Line Items]
Borrowed principal amount		$ 369,000,000
United Airlines, Inc. | Minimum
Debt Instrument [Line Items]
Debt instrument maturity year		2,026
United Airlines, Inc. | Maximum
Debt Instrument [Line Items]
Debt instrument maturity year		2,028
United Airlines, Inc. | Surety Bond
Debt Instrument [Line Items]
Credit facility outstanding amount		$ 383,000,000
Credit facility expiration year		2,021
United Airlines, Inc. | Pass-through certificates
Debt Instrument [Line Items]
Long term debt		$ 7,500,000,000
United Airlines, Inc. | 5% Senior Notes due 2024 | Subsequent Event
Debt Instrument [Line Items]
Borrowed principal amount	$ 300,000,000
Debt instrument maturity date	Feb. 1, 2024
Debt instrument stated interest rate	5.00%
Notes repurchase price	101.00%
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		$ 72,000,000
United Airlines, Inc. | Secured Debt
Debt Instrument [Line Items]
Quarterly principal repayment amount		0.25%
United Airlines, Inc. | Secured Debt | Term Loan Facility Due April 2019
Debt Instrument [Line Items]
Borrowed principal amount		$ 900,000,000
Long term debt		$ 866,000,000
Debt instrument maturity date		Apr. 1, 2019
United Airlines, Inc. | Secured Debt | Term Loan Facility Due September 2021
Debt Instrument [Line Items]
Borrowed principal amount		$ 500,000,000
Long term debt		$ 192,000,000
Debt instrument maturity date		Sep. 15, 2021
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 | Revolving Credit Facility | Term Loan, due 2021 | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		3.00%
United Airlines, Inc. | Secured Debt | Revolving Credit Facility | Term Loan, due 2021 | Certain Market Interest Rates
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.00%
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

Details of Pass Through Trusts

Details of Pass Through Trusts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total debt recorded			$ 248
Proceeds received from issuance of debt	$ 808	$ 1,073	1,432
United Airlines, Inc.
Debt Instrument [Line Items]
Principal	369
Proceeds received from issuance of debt	808	$ 1,073	$ 1,432
United Airlines, Inc. | Class AA Pass Through Certificates | September 2016
Debt Instrument [Line Items]
Principal	$ 637
Final expected distribution date	2028-10
Stated interest rate	2.875%
Total debt recorded	$ 80
Proceeds received from issuance of debt	80
Remaining proceeds from issuance of debt to be received in future periods	557
United Airlines, Inc. | Class AA Pass Through Certificates | June 2016
Debt Instrument [Line Items]
Principal	$ 729
Final expected distribution date	2028-07
Stated interest rate	3.10%
Total debt recorded	$ 410
Proceeds received from issuance of debt	410
Remaining proceeds from issuance of debt to be received in future periods	319
United Airlines, Inc. | Class A Pass Through Certificates | September 2016
Debt Instrument [Line Items]
Principal	$ 283
Final expected distribution date	2028-10
Stated interest rate	3.10%
Total debt recorded	$ 36
Proceeds received from issuance of debt	36
Remaining proceeds from issuance of debt to be received in future periods	247
United Airlines, Inc. | Class A Pass Through Certificates | June 2016
Debt Instrument [Line Items]
Principal	$ 324
Final expected distribution date	2028-07
Stated interest rate	3.45%
Total debt recorded	$ 182
Proceeds received from issuance of debt	182
Remaining proceeds from issuance of debt to be received in future periods	142
United Airlines, Inc. | EETC
Debt Instrument [Line Items]
Principal	1,973
Total debt recorded	708
Proceeds received from issuance of debt	708
Remaining proceeds from issuance of debt to be received in future periods	$ 1,265

Summary of Collateral Covenants

Summary of Collateral Covenants and Cross Default Provisions (Detail)	12 Months Ended
	Dec. 31, 2016
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.
6% Senior Notes 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.
5% Senior Notes due 2024
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.

Summary of Collateral Covenan94

Summary of Collateral Covenants and Cross Default Provisions (Parenthetical) (Detail) $ in Billions	12 Months Ended
	Dec. 31, 2016USD ($)
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
6% Senior Notes due 2020
Debt Instrument [Line Items]
Debt instrument stated interest rate	6.00%
Debt instrument maturity year	2,020
5% Senior Notes due 2024
Debt Instrument [Line Items]
Debt instrument stated interest rate	5.00%
Debt instrument maturity year	2,024

Future Minimum Lease Payments f

Future Minimum Lease Payments for Capital and Operating Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Capital Leases
2,017	$ 183
2,018	170
2,019	105
2,020	85
2,021	84
After 2,021	915
Minimum lease payments	1,542
Imputed interest	(604)
Present value of minimum lease payments	938
Current portion	(116)	$ (135)
Long-term obligations under capital leases	822	$ 727
Present value of minimum lease payments	938
Facility and Other Operating Leases
Operating Leases
2,017	1,256
2,018	1,106
2,019	991
2,020	1,104
2,021	888
After 2,021	6,702
Minimum lease payments	12,047
Aircraft Operating Leases
Operating Leases
2,017	1,271
2,018	1,074
2,019	894
2,020	669
2,021	551
After 2,021	2,049
Minimum lease payments	$ 6,508

Leases and Capacity Purchase 96

Leases and Capacity Purchase Agreements - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)Aircraft	Dec. 31, 2015USD ($)Aircraft	Dec. 31, 2014USD ($)
Capital Leased Assets [Line Items]
Regional capacity purchase expense | $		$ 2,197	$ 2,290	$ 2,344
Capacity Purchase Agreements | Scenario Forecast
Capital Leased Assets [Line Items]
Scheduled block hours increase (decrease) percentage	10.00%
Change in cash obligation | $	$ 147
Metropolitan Washington Airports Authority
Capital Leased Assets [Line Items]
Operating lease expiration date, in years		2,024
Lease extension term		7 years
Aircraft Operating Leases
Capital Leased Assets [Line Items]
Operating leases obligations | $		$ 6,508
Facility and Other Operating Leases
Capital Leased Assets [Line Items]
Operating lease extended expiration year		2,041
Operating leases obligations | $		$ 12,047
Minimum | Aircraft Operating Leases
Capital Leased Assets [Line Items]
Operating lease term		5 years
Operating lease expiration date, in years		2,017
Maximum | Aircraft Operating Leases
Capital Leased Assets [Line Items]
Operating lease term		26 years
Operating lease expiration date, in years		2,028
United Airlines, Inc.
Capital Leased Assets [Line Items]
Nonaircraft rent expense | $		$ 1,200	1,300	1,400
Regional capacity purchase expense | $		$ 2,197	2,290	2,344
United Airlines, Inc. | Capacity Purchase Agreements
Capital Leased Assets [Line Items]
Number of aircraft operated		494
Airline capacity purchase arrangements, expiration year		2,029
United Airlines, Inc. | Revaluation of Liabilities
Capital Leased Assets [Line Items]
Net accretion amounts | $		$ 82	107	160
United Airlines, Inc. | Regional Aircraft
Capital Leased Assets [Line Items]
Regional capacity purchase expense | $		439	$ 461	$ 442
United Airlines, Inc. | Variable Interest Entity, Not Primary Beneficiary
Capital Leased Assets [Line Items]
Operating leases obligations | $		$ 1,400
United Airlines, Inc. | Minimum
Capital Leased Assets [Line Items]
Imputed interest rate		3.50%
Lease Fair Value Adjustment, Remaining Lease Term		1 year
United Airlines, Inc. | Maximum
Capital Leased Assets [Line Items]
Imputed interest rate		20.80%
Lease Fair Value Adjustment, Remaining Lease Term		8 years
United Airlines, Inc. | Mainline
Capital Leased Assets [Line Items]
Number of assets subject to lease		38
United Airlines, Inc. | Regional Carrier
Capital Leased Assets [Line Items]
Number of assets subject to lease		29
AerCap Holdings N.V. | A319 aircraft | Capital Addition Purchase Commitments
Capital Leased Assets [Line Items]
Number of aircraft expected to be delivered		5
AerCap Holdings N.V. | Maximum | A319 aircraft | Capital Addition Purchase Commitments
Capital Leased Assets [Line Items]
Number of used aircraft expected to be delivered over the next five years			14
SkyWest | Embraer E175 Aircraft | Capital Addition Purchase Commitments | Capacity Purchase Arrangement
Capital Leased Assets [Line Items]
Number of aircraft expected to be delivered		7
Number of aircraft operated			25
Mesa | Embraer E175 Aircraft | Capital Addition Purchase Commitments | Capacity Purchase Arrangement
Capital Leased Assets [Line Items]
Number of aircraft committed to purchase		12
Number of aircraft to be acquired		12
CommutAir | Embraer ERJ145 Aircraft | Capacity Purchase Arrangement
Capital Leased Assets [Line Items]
Number of aircraft operated			40
Used aircraft, scheduled transfer end date			2,018
Number of aircrafts to be transferred		28
Republic | Embraer E175 Aircraft | Capital Addition Purchase Commitments | Capacity Purchase Arrangement
Capital Leased Assets [Line Items]
Number of aircraft expected to be delivered		12
Number of aircraft operated		28	28
Number of aircraft Purchased		16
Number of aircraft delivered		16
Number of aircraft owned		12

Future Lease Payment Under Term

Future Lease Payment Under Terms of Capacity Purchase Agreement (Detail) $ in Billions	Dec. 31, 2016USD ($)
Long-term Purchase Commitment [Line Items]
2,017	$ 1.9
2,018	1.9
2,019	1.3
2,020	1
2,021	1
After 2,021	4.3
Contractual Obligation, Total	$ 11.4

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Detail) - Variable Interest Entity, Not Primary Beneficiary	Dec. 31, 2016Aircraft
Mainline
Variable Interest Entity [Line Items]
Aircraft under operating lease, fixed purchase options	37
Regional Carrier
Variable Interest Entity [Line Items]
Aircraft under operating lease	192

Schedule of Commitments to Purc

Schedule of Commitments to Purchase Aircrafts (Detail) - United Airlines, Inc. - Capital Addition Purchase Commitments	Dec. 31, 2016Aircraft	[1]
Airbus A350-1000 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	35
Boeing 737NG/737 MAX Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	165
Boeing 777-300ER Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	12
Boeing 787-8/-9/-10 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	21
Embraer E175 Aircraft
Long-term Purchase Commitment [Line Items]
Number of new aircraft committed to purchase	24
[1]	United also has options and purchase rights for additional aircraft.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) Employee in Thousands	1 Months Ended					12 Months Ended
	Dec. 31, 2016USD ($)Employee	Aug. 31, 2016	Apr. 30, 2016Contract	Mar. 31, 2016	Jan. 31, 2016	Dec. 31, 2016USD ($)EmployeeContractOption	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						223
Int'1 Brotherhood of Teamsters
Commitments and Contingencies [Line Items]
Service contract extended year	2,022
Contract period	6 years
Air Line Pilots Association International
Commitments and Contingencies [Line Items]
Service contract extended year					Jan. 31, 2019
Professional Airline Flight Control Association
Commitments and Contingencies [Line Items]
Service contract extended year				2,021
Int'1 Association of Machinists
Commitments and Contingencies [Line Items]
Service contract extended year			2,021			2,021
Number of new contracts extended | Contract			7			7
United And The Association Of Flight Attendants
Commitments and Contingencies [Line Items]
Contract period		5 years
Aircraft Mortgage Debt
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	$ 168,000,000					$ 168,000,000
Floating Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	2,600,000,000					2,600,000,000
Fixed Rate Debt
Commitments and Contingencies [Line Items]
Debt instrument principal amount	90,000,000					90,000,000
Loans And Leases From Non U S Entities
Commitments and Contingencies [Line Items]
Debt instrument principal amount	2,600,000,000					2,600,000,000
Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	1,900,000,000					1,900,000,000
Operating leases obligations	1,400,000,000					1,400,000,000
Capital leases obligations	400,000,000					400,000,000
Tax-exempt special facilities revenue bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	234,000,000					234,000,000
Contingent liabilities based on participation	1,500,000,000					$ 1,500,000,000
Maximum
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms (years)						12 years
Maximum | Loans And Leases From Non U S Entities
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms (years)						12 years
Maximum | Tax-exempt special facilities revenue bonds
Commitments and Contingencies [Line Items]
Debt instrument maturity year						2,038
Maximum | Tax-exempt special facilities revenue bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Debt instrument maturity year						2,049
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
United Airlines, Inc.
Commitments and Contingencies [Line Items]
Borrowed principal amount	$ 369,000,000					$ 369,000,000
Number of employees | Employee	88					88
Percentage of employees represented by various U.S. labor organizations						80.00%
United Airlines, Inc. | EETC
Commitments and Contingencies [Line Items]
Borrowed principal amount	$ 1,973,000,000					$ 1,973,000,000
Debt instrument principal amount	$ 708,000,000					$ 708,000,000
United Airlines, Inc. | Maximum
Commitments and Contingencies [Line Items]
Debt instrument maturity year						2,028
United Airlines, Inc. | Minimum
Commitments and Contingencies [Line Items]
Debt instrument maturity year						2,026
Capital Addition Purchase Commitments | United Airlines, Inc. | Maximum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date						2,027
Capital Addition Purchase Commitments | United Airlines, Inc. | Minimum
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date						2,017

Schedule of Acquisition of Airc

Schedule of Acquisition of Aircrafts and Related Spare Engines (Detail) $ in Billions	Dec. 31, 2016USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
2,017	$ 4.5
2,018	3.2
2,019	3.1
2,020	2.5
2,021	2.2
After 2,021	7.8
Total commitments	$ 23.3

Components of Special Items (De

Components of Special Items (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating:
Impairment of assets			$ 412		$ 48	$ 18	$ 11	$ 2	$ 412	$ 79	$ 49
Cleveland airport lease restructuring				$ 74					74
Labor agreement costs	$ (60)	$ 14	10	100	18				64	18
Severance and benefit costs	10	13	6	8	4	28	25	50	37	107	199
(Gains) losses on sale of assets and other special charges	19	18	6	8	61	30	19	12	51	122	195
Special charges	(31)	45	434	190	131	76	55	64	638	326	443
Nonoperating and income taxes:
Losses (gain) on extinguishment of debt and other			(9)	8	7	61	128	6	(1)	202	74
Income tax benefit related to special charges	12	(16)	(153)	(72)	(11)				(229)	(11)	(10)
Income tax adjustments (Notes 6 and 7)	180				88	(3,218)			180	(3,130)
Total operating and nonoperating special items, net of income taxes	$ 161	$ 29	$ 272	$ 126	$ 215	$ (3,081)	$ 183	$ 70	$ 588	$ (2,613)	$ 507

Special Items - Additional Info

Special Items - Additional Information (Detail)	1 Months Ended	3 Months Ended								12 Months Ended
	Apr. 30, 2016Contract	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)VEF / $	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)Contractplan	Dec. 31, 2015USD ($)VEF / $	Dec. 31, 2014USD ($)AircraftAttendant
Special Charges [Line Items]
Impairment of indefinite-lived intangible assets						$ 33,000,000						$ 16,000,000
Impairment of indefinite-lived intangible assets, net of tax benefits						22,000,000						10,000,000
Lease maturity year										2,029
Cleveland airport lease restructuring					$ 74,000,000					$ 74,000,000
Cleveland airport lease restructuring, net of taxes										47,000,000
Labor agreement costs		$ (60,000,000)	$ 14,000,000	$ 10,000,000	100,000,000	18,000,000				64,000,000	$ 18,000,000
Severance and benefits		10,000,000	13,000,000	6,000,000	8,000,000	4,000,000	$ 28,000,000	$ 25,000,000	$ 50,000,000	37,000,000	107,000,000	199,000,000
Severance and benefits costs net of tax										24,000,000
(Gains) losses on sale of assets and other miscellaneous (gains) losses, net		19,000,000	$ 18,000,000	6,000,000	8,000,000	61,000,000	30,000,000	19,000,000	12,000,000	51,000,000	122,000,000	195,000,000
(Gains) losses on sale of assets and other special charges, net of tax										33,000,000
Venezuela local currency loss										8,000,000	61,000,000
Venezuela local currency loss, net of tax										5,000,000
Sale of an affiliate										9,000,000
Sale of an affiliate, net of tax										6,000,000
Costs associated with aircraft						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 of assets held for disposal											10,000,000
Charges for legal matters											32,000,000
Collective bargaining agreements											18,000,000
Integration-related costs											60,000,000	96,000,000
Cease use of an aircraft under lease											$ 16,000,000
Foreign currency exchange rate per US dollar, description											200 Venezuelan bolivars to one U.S. dollar
Foreign currency exchange rate | VEF / $						200					200
Losses (gain) on extinguishment of debt and other				$ (9,000,000)	$ 8,000,000	$ 7,000,000	$ 61,000,000	$ 128,000,000	$ 6,000,000	(1,000,000)	$ 202,000,000	$ 74,000,000
Number of leased aircraft | Aircraft												21
Lease expiry year												2,018
Debt instrument principal amount												$ 248,000,000
Unsecured Debt
Special Charges [Line Items]
Venezuela local currency loss												10,000,000
Losses (gain) on extinguishment of debt and other												64,000,000
Cleveland
Special Charges [Line Items]
Severance and benefits												58,000,000
Boeing 737-300 and 737-500 fleets
Special Charges [Line Items]
Impairment of assets held for disposal												$ 33,000,000
6% Convertible Junior Subordinated Debentures
Special Charges [Line Items]
Debt instrument stated interest rate												6.00%
6% Convertible preferred securities
Special Charges [Line Items]
Debt instrument stated interest rate												6.00%
Newark Liberty International Airport
Special Charges [Line Items]
Impairment of indefinite-lived intangible assets										412,000,000
Impairment of indefinite-lived intangible assets, net of tax benefits										$ 264,000,000
United Airlines, Inc. | 6% Notes due 2026 and 2028
Special Charges [Line Items]
Write off of unamortized discount											134,000,000
Venezuelan bolivars
Special Charges [Line Items]
Unrestricted cash balance held as Venezuelan bolivars						$ 13,000,000					$ 13,000,000
Flight Attendant Postretirement Medical Plan | Postretirement Medical Plan
Special Charges [Line Items]
Number of plans amended | plan										2
Curtailment gain recognition of prior service credit										$ 47,000,000
Curtailment gain recognition of prior service credit,net of tax										30,000,000
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
Int'1 Association of Machinists
Special Charges [Line Items]
Curtailment gain recognition of prior service credit										60,000,000
Curtailment gain recognition of prior service credit,net of tax										$ 38,000,000
Number of new contracts extended | Contract	7									7
Service contract extended year	2,021									2,021
Labor agreement costs										$ 171,000,000
Labor agreement costs net of tax										110,000,000
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	$ 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

Schedule of Severance Related A

Schedule of Severance Related Accruals (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Severance and Benefits Costs
Schedule Of Accrual Activity [Line Items]
Beginning Balance	$ 27	$ 109	$ 91
Accrual	37	107	199
Payments	(50)	(189)	(181)
Ending Balance	14	27	109
Permanently Grounded Aircraft
Schedule Of Accrual Activity [Line Items]
Beginning Balance	78	102	11
Accrual	(17)	30	102
Payments	(20)	(54)	(11)
Ending Balance	$ 41	$ 78	$ 102

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016Segment
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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenues	$ 9,052	$ 9,913	$ 9,396	$ 8,195	$ 9,036	$ 10,306	$ 9,914	$ 8,608	$ 36,556	$ 37,864	$ 38,901
Domestic (U.S. and Canada)
Segment Reporting Information [Line Items]
Total revenues									22,202	21,931	22,320
Pacific
Segment Reporting Information [Line Items]
Total revenues									4,959	5,498	5,767
Atlantic
Segment Reporting Information [Line Items]
Total revenues									6,157	7,068	7,321
Latin America
Segment Reporting Information [Line Items]
Total revenues									$ 3,238	$ 3,367	$ 3,493

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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Selected Quarterly Financial Data [Line Items]
Operating revenue	$ 9,052	$ 9,913	$ 9,396	$ 8,195	$ 9,036	$ 10,306	$ 9,914	$ 8,608	$ 36,556	$ 37,864	$ 38,901
Income from operations	1,005	1,624	1,060	649	1,081	1,899	1,445	741	4,338	5,166	2,373
Net income	$ 397	$ 965	$ 588	$ 313	$ 823	$ 4,816	$ 1,193	$ 508	$ 2,263	$ 7,340	$ 1,132
Basic earnings per share	$ 1.26	$ 3.02	$ 1.78	$ 0.88	$ 2.24	$ 12.83	$ 3.14	$ 1.33	$ 6.86	$ 19.52	$ 3.05
Diluted earnings per share	$ 1.26	$ 3.01	$ 1.78	$ 0.88	$ 2.24	$ 12.82	$ 3.14	$ 1.32	$ 6.85	$ 19.47	$ 2.93

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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating:
Impairment of assets			$ 412		$ 48	$ 18	$ 11	$ 2	$ 412	$ 79	$ 49
Cleveland airport lease restructuring				$ 74					74
Labor agreement costs and related items	$ (60)	$ 14	10	100	18				64	18
Severance and benefit costs	10	13	6	8	4	28	25	50	37	107	199
(Gains) losses on sale of assets and other special charges	19	18	6	8	61	30	19	12	51	122	195
Special charges	(31)	45	434	190	131	76	55	64	638	326	443
Nonoperating and income taxes:
Losses (gain) on extinguishment of debt and other			(9)	8	7	61	128	6	(1)	202	74
Income tax expense (benefit) related to special charges	12	(16)	(153)	(72)	(11)				(229)	(11)	(10)
Income tax adjustments (Note 6)	180				88	(3,218)			180	(3,130)
Total operating and nonoperating special items, net of income taxes	$ 161	$ 29	$ 272	$ 126	$ 215	$ (3,081)	$ 183	$ 70	$ 588	$ (2,613)	$ 507

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 48	$ 4,751	$ 4,591
Additions Charged to Costs and Expenses		47		156
Deductions	[1]	27	4,703
Other				4
Balance at End of Period		68	48	4,751
UAL and United | Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		18	22	13
Additions Charged to Costs and Expenses		18	25	45
Deductions	[1]	26	29	36
Balance at End of Period		10	18	22
UAL and United | Obsolescence allowance-spare parts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		235	169	162
Additions Charged to Costs and Expenses		61	38	35
Deductions	[1]	16		28
Other		15	28
Balance at End of Period		295	235	169
United Airlines, Inc. | Valuation allowance for deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		48	4,721	4,561
Additions Charged to Costs and Expenses		47		167
Deductions	[1]	27	4,673
Other				(7)
Balance at End of Period		$ 68	$ 48	$ 4,721
[1]	Deduction from reserve for purpose for which reserve was created.