L3 10-Q 26 Jul 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 29, 2018	Jul. 20, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	L3 TECHNOLOGIES, INC.
Entity Central Index Key	1,039,101
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		78,328,669
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 29, 2018

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 29, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,366	$ 662
Billed receivables, net of allowances of $18 in 2018 and 2017	863	723
Contract assets	1,611	0
Contracts in process	0	1,933
Inventories	934	389
Prepaid expenses and other current assets	332	300
Assets held for sale	0	135
Assets of discontinued operations	0	306
Total current assets	5,106	4,448
Property, plant and equipment, net	1,137	1,110
Goodwill	6,651	6,615
Identifiable intangible assets	288	292
Other assets	348	264
Total assets	13,530	12,729
Current liabilities:
Current portion of long-term debt	581	0
Accounts payable, trade	588	531
Accrued employment costs	453	493
Accrued expenses	264	217
Contract liabilities	554	0
Advance payments and billings in excess of costs incurred	0	509
Income taxes payable	25	19
Other current liabilities	338	367
Liabilities held for sale	0	17
Liabilities of discontinued operations	0	226
Total current liabilities	2,803	2,379
Pension and postretirement benefits	1,290	1,313
Deferred income taxes	190	158
Other liabilities	416	398
Long-term debt	3,319	3,330
Total liabilities	8,018	7,578
Commitments and contingencies (see Note 19)
Shareholders’ equity:
Common stock: $.01 par value; 300,000,000 shares authorized, 78,242,526 shares outstanding at June 29, 2018 and 77,876,687 shares outstanding at December 31, 2017	6,723	6,519
Treasury stock (at cost), 84,821,829 shares at June 29, 2018 and 83,362,412 shares at December 31, 2017	(7,691)	(7,404)
Retained earnings	7,126	6,659
Accumulated other comprehensive loss	(714)	(691)
Total shareholders’ equity	5,444	5,083
Noncontrolling interests	68	68
Total equity	5,512	5,151
Total liabilities and equity	$ 13,530	$ 12,729

UNAUDITED CONDENSED CONSOLIDAT3

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 29, 2018	Dec. 31, 2017
Current assets:
Allowances for billed receivables	$ 18	$ 18
Shareholders’ equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares outstanding (in shares)	78,242,526	77,876,687
Treasury stock at cost (in shares)	84,821,829	83,362,412

UNAUDITED CONDENSED CONSOLIDAT4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	May 08, 2018	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Net sales:
Products		$ 1,786	$ 1,680	$ 3,432	$ 3,284
Services		797	705	1,522	1,422
Total net sales		2,583	2,385	4,954	4,706
Operating costs and expenses:
Cost of sales — Products		(1,349)	(1,253)	(2,540)	(2,441)
Cost of sales — Services		(578)	(479)	(1,110)	(1,017)
General and administrative expenses		(383)	(359)	(780)	(717)
Total operating costs and expenses		(2,310)	(2,091)	(4,430)	(4,175)
Gain on sale of the Crestview Aerospace and TCS businesses		48	0	48	0
Operating income		321	294	572	531
Interest expense		(44)	(42)	(85)	(84)
Interest and other income, net		8	2	14	6
Debt retirement charge		(48)	0	(48)	0
Income from continuing operations before income taxes		237	254	453	453
Provision for income taxes		(48)	(59)	(72)	(101)
Income from continuing operations		189	195	381	352
Income from discontinued operations, net of income taxes		190	12	206	23
Net income		379	207	587	375
Net income from continuing operations attributable to noncontrolling interests		(4)	(5)	(9)	(9)
Net income attributable to L3		$ 375	$ 202	$ 578	$ 366
Basic earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)		$ 2.36	$ 2.44	$ 4.75	$ 4.40
Discontinued operations (in dollars per share)		2.42	0.15	2.63	0.30
Basic earnings per share (in dollars per share)		4.78	2.59	7.38	4.70
Diluted earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)		2.33	2.39	4.67	4.32
Discontinued operations (in dollars per share)		2.39	0.15	2.59	0.29
Diluted earnings per share (in dollars per share)		4.72	2.54	7.26	4.61
Cash dividends declared per common share (in dollars per share)	$ 0.80	$ 0.8	$ 0.75	$ 1.6	$ 1.50
Weighted average common shares outstanding:
Basic (in shares)		78.4	78	78.3	77.8
Diluted (in shares)		79.4	79.5	79.6	79.4

UNAUDITED CONDENSED CONSOLIDAT5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 29, 2018		Jun. 30, 2017		Jun. 29, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 379		$ 207		$ 587	$ 375
Other comprehensive income (loss):
Foreign currency translation adjustments	(72)		52		(39)	71
Unrealized lossess on hedging instruments (1)	(10)	[1]	0	[1]	(11)	0
Pension and postretirement benefit plans:
Amortization of net loss and prior service cost previously recognized (2)	13	[2]	10	[2]	27	19
Total other comprehensive (loss) income	(69)		62		(23)	90
Comprehensive income	310		269		564	465
Comprehensive income attributable to noncontrolling interests	(4)		(5)		(9)	(9)
Comprehensive income attributable to L3	$ 306		$ 264		$ 555	$ 456
[1]	Net of income tax benefit of $3 million for each of the quarterly and first half periods ended June 29, 2018.
[2]	Net of income taxes of $4 million and $5 million for the quarterly periods ended June 29, 2018 and June 30, 2017, respectively

UNAUDITED CONDENSED CONSOLIDAT6

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Income tax benefit on unrealized losses on hedging instruments	$ 3		$ 3
Income tax (expense) on amortization of net loss and prior service cost previously recognized	$ 4	$ 5	$ 8	$ 11

UNAUDITED CONDENSED CONSOLIDAT7

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2016	$ 4,624	$ 1	$ 6,284	$ (7,224)	$ 6,218	$ (726)	$ 71
Beginning Balance (in shares) at Dec. 31, 2016		77.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	375				366		9
Other comprehensive income (loss)	90					90
Distributions to noncontrolling interests	(9)						(9)
Cash dividends declared	(118)				(118)
Shares issued:
Employee savings plans	60		60
Employee savings plans (in shares)		0.4
Exercise of stock options	25		25
Exercise of stock options (in shares)		0.3
Employee stock purchase plan	16		16
Employee stock purchase plan (in shares)		0.1
Vesting of restricted stock and performance units	0
Vesting of restricted stock and performance units (in shares)		0.3
Repurchases of common stock to satisfy tax withholding obligations	(18)		(18)
Repurchases of common stock to satisfy tax withholding obligations (in shares)		(0.1)
Stock-based compensation expense	28		28
Treasury stock purchased	(26)			(26)
Treasury stock purchased (in shares)		(0.2)
Ending Balance at Jun. 30, 2017	5,047	$ 1	6,395	(7,250)	6,466	(636)	71
Ending Balance (in shares) at Jun. 30, 2017		78
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes	13				13
Beginning Balance at Dec. 31, 2017	5,151	$ 1	6,518	(7,404)	6,659	(691)	68
Beginning Balance (in shares) at Dec. 31, 2017		77.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	587				578		9
Other comprehensive income (loss)	(23)					(23)
Distributions to noncontrolling interests	(9)						(9)
Cash dividends declared	(126)				(126)
Shares issued:
Employee savings plans	72		72
Employee savings plans (in shares)		0.3
Exercise of stock options	103		103
Exercise of stock options (in shares)		1.2
Employee stock purchase plan	17		17
Employee stock purchase plan (in shares)		0.1
Vesting of restricted stock and performance units	0
Vesting of restricted stock and performance units (in shares)		0.3
Repurchases of common stock to satisfy tax withholding obligations	(24)		(24)
Repurchases of common stock to satisfy tax withholding obligations (in shares)		(0.1)
Stock-based compensation expense	34		34
Treasury stock purchased	(287)			(287)
Treasury stock purchased (in shares)		(1.5)
Other	4		2		2
Ending Balance at Jun. 29, 2018	$ 5,512	$ 1	$ 6,722	$ (7,691)	$ 7,126	$ (714)	$ 68
Ending Balance (in shares) at Jun. 29, 2018		78.2

UNAUDITED CONDENSED CONSOLIDAT8

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	May 08, 2018	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share (in dollars per share)	$ 0.80	$ 0.8	$ 0.75	$ 1.6	$ 1.50

UNAUDITED CONDENSED CONSOLIDAT9

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Operating activities:
Net income	$ 587	$ 375
Less: income from discontinued operations, net of tax	(206)	(23)
Income from continuing operations	381	352
Depreciation of property, plant and equipment	90	82
Amortization of intangibles and other assets	26	24
Deferred income tax provision	21	25
Stock-based compensation expense	34	28
Contributions to employee savings plans in L3's common stock	68	56
Amortization of pension and postretirement benefit plans net loss and prior service cost	35	30
Gain on sale of property, plant and equipment	0	(42)
Gain on sale of the Crestview Aerospace and TCS businesses	(48)	0
Debt retirement charge	48	0
Other non-cash items	1	6
Changes in operating assets and liabilities, excluding amounts from acquisitions and divestitures, and discontinued operations:
Billed receivables	(137)	(88)
Contract assets	(266)	0
Contracts in process	0	(123)
Inventories	(10)	(12)
Prepaid expenses and other current assets	(82)	(15)
Accounts payable, trade	61	(99)
Accrued employment costs	(38)	(28)
Accrued expenses	63	158
Contract liabilities	(2)	0
Advance payments and billing in excess of costs incurred	0	(10)
Income taxes	(22)	(12)
All other operating activities	(45)	(17)
Net cash from operating activities from continuing operations	178	315
Investing activities:
Business acquisitions, net of cash acquired	(69)	(191)
Proceeds from the sale of businesses, net of closing date cash balances	535	16
Capital expenditures	(108)	(96)
Dispositions of property, plant and equipment	1	65
Other investing activities	(29)	(1)
Net cash from (used in) investing activities from continuing operations	330	(207)
Financing activities:
Proceeds from sale of senior notes	1,798	0
Repurchases and redemptions of senior notes	(1,263)	0
Borrowings under revolving credit facility	501	1,158
Repayments of borrowings under revolving credit facility	(501)	(1,158)
Common stock repurchased	(287)	(26)
Dividends paid	(128)	(119)
Proceeds from exercises of stock options	103	25
Proceeds from employee stock purchase plan	17	16
Repurchases of common stock to satisfy tax withholding obligations	(24)	(18)
Debt issue costs	(13)	0
Other financing activities	(6)	(8)
Net cash from (used in) financing activities from continuing operations	197	(130)
Effect of foreign currency exchange rate changes on cash and cash equivalents	(8)	10
Net cash from (used in) discontinued operations:
Operating activities	9	36
Investing activities	(2)	(2)
Net cash from discontinued operations	7	34
Net increase in cash and cash equivalents	704	22
Cash and cash equivalents, beginning of the period	662	363
Cash and cash equivalents, end of the period	$ 1,366	$ 385

Description of Business

Description of Business	6 Months Ended
	Jun. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	. Description of Business L3 Technologies, Inc. (L3 Technologies, Inc. and, together with its subsidiaries, referred to herein as L3 or the Company) is a prime contractor in Intelligence, Surveillance and Reconnaissance (ISR) systems, aircraft sustainment (including modifications and fleet management of special mission aircraft), simulation and training, night vision and image intensification equipment and security and detection systems. L3 is also a leading provider of a broad range of communication, electronic and sensor systems used on military, homeland security and commercial platforms. The Company’s customers include the United States (U.S.) Department of Defense (DoD) and its prime contractors, U.S. Government intelligence agencies, the U.S. Department of Homeland Security (DHS), foreign governments, and domestic and foreign commercial customers. The Company has the following four reportable segments: (1) Electronic Systems, (2) Aerospace Systems, (3) Communication Systems and (4) Sensor Systems. Electronic Systems provides a broad range of products and services, including components, products, subsystems, systems and related services to military and commercial customers. These products and services serve niche markets, such as aircraft simulation and training, power and distribution, cockpit avionics, airport security and precision weapons. Electronic Systems sells these products and services primarily to the DoD and select foreign governments. The Electronic Systems business areas are Link Training & Simulation, Power & Propulsion Systems, Commercial Aviation Solutions, Precision Engagement Systems and Security & Detection Systems. Aerospace Systems provides products and services for the global ISR and Command, Control and Communications (C 3 ) markets, specializing in signals intelligence (SIGINT) and multi-intelligence platforms, including engineering, modernization and sustainment solutions for military and various government aircraft, ground support equipment and other platforms. These strategic and tactical products and services provide warfighters with the ability to detect, collect, identify, analyze and disseminate information from command centers, communication nodes and air defense systems for real-time situational awareness and response. Aerospace Systems sells these products and services primarily to the DoD and select foreign governments. The Aerospace Systems business areas are Mission Integration, MAS, Aerostructures and Advanced Systems. Communication Systems provides network and communication systems, secure communications products, radio frequency (RF) components, satellite communication terminals and space, microwave and telemetry products. These products include secure data links that are used to connect a variety of space, airborne, ground and sea-based communication systems and are used in transmission, processing, recording, monitoring and dissemination functions of these communication systems. Communication Systems sells these products and services primarily to the DoD and select foreign governments. The Communications Systems business areas are Broadband Communication Systems, Space & Power Systems and Advanced Communications. Sensor Systems provides a broad range of multi-domain ISR mission solutions from seabed to space for DoD, intelligence community, international, federal, civil and commercial customers. Major capabilities and mission solutions include networked warfighter systems, integrated ISR and targeting systems, space avionics and imaging payloads, Counter Unmanned Aircraft Systems mission solutions, integrated maritime mission solutions, directed energy, cyber and electronic warfare, special mission command & control, lightweight unmanned undersea vehicles, modeling & simulation and life cycle support. Sensor Systems sells these products and services primarily to the DoD and select foreign governments. The Sensor Systems business areas are Space & Sensor Systems, Airborne Sensor Systems, Warrior Sensor Systems, Maritime Sensor Systems, Intelligence & Mission Systems and Advanced Programs. Financial information with respect to the Company’s segments is included in Note 23 to the unaudited condensed consolidated financial statements and in Note 21 to the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . On June 29, 2018, the Company completed the sale of its Vertex Aerospace businesses for a sale price of $540 million subject to customary closing net working capital adjustments. In connection with the sale, the Company recognized: (1) a pre-tax gain from continuing operations of $48 million ( $25 million after income taxes) related to the Crestview Aerospace and TCS businesses (the "Crestview & TCS Businesses") and (2) a pre-tax gain from discontinued operations of $237 million ( $180 million after income taxes) related to the Vertex Aerospace business. The divestiture of the Vertex Aerospace business represents a strategic shift by the Company to exit the logistics solution and maintenance services business for military aircraft where the Company does not provide complex ISR systems integration and modification. The Vertex Aerospace business generated sales of $1.4 billion for the year ended December 31, 2017. The assets and liabilities and results of operations of the Vertex Aerospace business are reported as discontinued operations for all periods presented. All references made to financial data in this Quarterly Report on Form 10-Q are to the Company’s continuing operations, unless specifically noted. See Note 5 for additional information.

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 29, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These unaudited condensed consolidated financial statements for the quarterly and first half periods ended June 29, 2018 should be read in conjunction with the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Principles of Consolidation and Reporting The accompanying financial statements comprise the consolidated financial statements of L3. The consolidated financial statements of the Company include all wholly-owned and majority-owned subsidiaries and variable interest entities (VIEs) if the Company is the primary beneficiary. The Company holds interests in certain VIEs for which it was determined the Company is not the primary beneficiary. All significant intercompany transactions are eliminated in consolidation. Investments in equity securities, joint ventures and limited liability corporations over which the Company has significant influence but does not have control are accounted for using the equity method. Investments over which the Company does not have significant influence are accounted for using the cost method. For the classification of certain current assets and liabilities, the Company uses the duration of the related contract or program as its operating cycle, which may be longer than one year. Certain reclassifications have been made to conform prior-year amounts to the current-year presentation. The unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. The December 31, 2017 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. In the opinion of management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included. The results of operations for the interim periods are not necessarily indicative of results for the full year. It is generally the Company’s established practice to close its books for the quarters ending March, June and September on the Friday preceding the end of the calendar quarter. The interim unaudited condensed consolidated financial statements included herein have been prepared and are labeled based on that convention. The Company closes its books for annual periods on December 31 regardless of what day it falls on. Accounting Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of sales and costs of sales during the reporting period. The most significant of these estimates and assumptions for L3 relate to sales, profit and loss recognition related to performance obligations satisfied over time, fair values of assets acquired and liabilities assumed in business combinations and investments, market values for inventories reported at lower of cost or market, pension and postretirement benefit obligations, stock-based employee compensation expense, income taxes, including the valuations of deferred tax assets, litigation reserves, useful lives and valuation of recorded amounts of long-lived assets, identifiable intangible assets and goodwill. Changes in estimates are reflected in the periods during which they become known. Actual amounts may differ from these estimates and could differ materially. Revenue Recognition Effective January 1, 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers, as amended (commonly referred to as ASC 606) using the modified retrospective transition method. The cumulative effect of applying the standard was an increase of $13 million to shareholders' equity as of January 1, 2018. The Company’s statement of operations for the quarterly and first half periods ended June 29, 2018 and the Company’s balance sheet as of June 29, 2018 are presented under ASC 606, while the Company’s statement of operations for the quarterly and first half periods ended June 30, 2017 and the Company’s balance sheet as of December 31, 2017 are presented under ASC 605, Revenue Recognition . See Note 3 for disclosure of the impact of the adoption of ASC 606 on the Company’s statement of operations for the quarterly and first half periods ended June 29, 2018 and balance sheet as of June 29, 2018 and the effect of changes made to the Company’s consolidated balance sheet as of January 1, 2018. A substantial majority of the Company’s consolidated net sales are generated from long-term contracts with customers that require it to design, develop, manufacture, modify, upgrade, test and integrate complex aerospace and electronic equipment and to provide engineering and technical services according to the customers’ specifications. These contracts are primarily with agencies of, and prime system contractors to, the U.S. Government and foreign governments and are generally priced on a fixed-price, cost-plus or time-and-material type basis. Substantially all of the Company's cost-plus and time-and-material type contracts are with the U.S. Government, primarily the DoD. Certain of the Company’s contracts with the U.S. Government are multi-year contracts incrementally funded by the customer. The transaction price on these incrementally funded contracts includes contract value amounts not yet funded by the U.S. Government when the Company has a firm order for the goods or services and it is probable that the customer will fund such amounts. In assessing probability, the Company considers, among other factors, the period of time before contract funding is expected, communication from the customer that indicates funding will be obtained and the Company's history of receiving funding under the current contract or previous similar contracts. The Company also generates sales to a lesser extent from contracts with commercial and government customers for standard product and service offerings, which are priced on a firm fixed basis. See Note 23 for additional information regarding the composition of the Company’s net sales. The Company records sales for a contract when it has the approval and commitment of all parties, the contract identifies the rights of the parties and payment terms, the contract has commercial substance and collectibility of the consideration is probable. To determine the proper revenue recognition method, the Company first evaluates each of its contractual arrangements to identify its performance obligations. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. The majority of the Company’s contracts have a single performance obligation because the promise to transfer the individual good or service is not separately identifiable from other promises within the contract and is, therefore, not distinct. These contractual arrangements either require the use of a highly specialized manufacturing process to provide goods according to customer specifications or represent a bundle of contracted goods and services that are integrated and together represent a combined output, which may include the delivery of multiple units. Some of the Company's contracts have multiple performance obligations, primarily (i) related to the provision of multiple goods or services that have alternative use to the Company or that are not substantially the same or (ii) due to the contract covering multiple phases of the product lifecycle (development and engineering, production, maintenance and support). For contracts with more than one performance obligation, the Company allocates the total transaction price in an amount based on the estimated relative standalone selling prices underlying each performance obligation. In cases where a contract requires a customized good or service, the primary method used to estimate standalone selling price is the expected cost plus a margin approach. In cases where the Company sells a standard product or service offering, the standalone selling price is based on an observable standalone selling price. The majority of the Company's sales are from performance obligations satisfied over time and are primarily with agencies of, and prime system contractors to, the U.S. Government and foreign governments. Sales are recognized over time when control is continuously transferred to the customer during the contract. For U.S. Government contracts, the continuous transfer of control to the customer is supported by contract clauses that provide for (i) progress or performance-based payments or (ii) the unilateral right of the customer to terminate the contract for its convenience, in which case the Company has the right to receive payment for costs incurred plus a reasonable profit for products and services that do not have alternative use to the Company. Foreign government and certain commercial contracts contain similar termination for convenience clauses, or the Company has a legally enforceable right to receive payment for costs incurred and a reasonable profit for products or services that do not have alternative use to the Company. Sales on fixed price and cost-plus type contracts that include performance obligations satisfied over time are generally recorded at amounts equal to the ratio of actual cumulative costs incurred divided by total estimated costs at completion, multiplied by (i) the transaction price, less (ii) the cumulative sales recognized in prior periods (cost-to-cost method). Accounting for the sales and profits on performance obligations for which progress is measured using the cost-to-cost method involves the preparation of estimates of: (1) transaction price and (2) total costs at completion, which is equal to the sum of the actual incurred costs to date on the contract and the estimated costs to complete the contract's statement of work. Incurred costs include labor, material, overhead and, for the Company's U.S. Government contractor businesses, general and administrative (G&A) expenses. Incurred costs represent work performed, which corresponds with and thereby represents the transfer of control to the customer. The estimated profit or loss at completion on a contract is equal to the difference between the transaction price and the total estimated cost at completion. In the case of a contract related to complex aerospace or electronic equipment for which the total estimated costs exceed the total transaction price, a loss arises, and a provision for the entire loss is recorded in the period that the loss becomes evident. The unrecoverable costs on a loss contract that are expected to be incurred in the future periods are presented on the balance sheet as a component of other current liabilities entitled "Estimated cost in excess of estimated contract value to complete contracts in process in a loss position." See Note 10 for additional information. The Company’s contracts give rise to variable consideration, including award and incentive fees, as well as amounts incrementally funded by the U.S. Government, or other provisions that can either increase or decrease the transaction price. Award fees provide for a fee based on actual performance relative to contractually specified performance criteria. Incentive fees provide for a fee based on the relationship between total allowable costs and target costs. Variable consideration may require the Company to exercise significant judgment to determine the total transaction price of the contract. The Company includes variable consideration in the transaction price when there is a basis to reasonably estimate the variable amount it will be entitled to receive and it is probable that a significant reversal in revenue recognized will not be required when the uncertainty is resolved. These estimates are based on historical experience, current and forecasted performance, and the Company’s judgment at the time of the evaluation. Contract modifications routinely occur to account for changes in contract specifications or requirements. In most cases, contract modifications are for goods or services that are not distinct and, therefore, are accounted for as part of the existing contract. Transaction price estimates include additional consideration for submitted contract modifications or claims when the Company believes it has an enforceable right to the modification or claim, the amount can be reliably estimated and its realization is reasonably assured. Amounts representing modifications accounted for as part of the existing contract are included in the transaction price and recognized as an adjustment to sales on a cumulative catch-up basis. The Company’s fixed-price type contracts with the U.S. Government typically allow for progress payments or performance-based payments. Progress payments are billed to the customer as contract costs are incurred at an amount generally equal to 80% of incurred costs. Performance based payments are billed to the customer upon the achievement of predetermined performance milestones at amounts not to exceed 90% of contract price. On contracts with progress or performance-based payments, the customer often retains a small portion of the contract price until satisfactory completion of the contractual statement of work. Since a small portion of the contract price is retained, the Company generally recognizes sales in excess of billings, which are presented as contract assets on the balance sheet. The portion of the contract price retained by the customer is a normal business practice to ensure satisfactory contract completion and, therefore, is not considered a significant financing component. Contract assets also arise from cost-plus type contracts, time-and-material type contracts and fixed-price services type contracts for revenue amounts that have not been billed by the end of the accounting period due to the timing of preparation of invoices to customers. For certain fixed-price contracts with foreign governments and commercial customers, the Company receives advance payments. Advanced payments are not considered a significant financing component because they are a negotiated contract term to ensure the customer meets its financial obligation, particularly when there are significant upfront working capital requirements. The Company records a liability for advance payments received in excess of sales recognized, which is presented as a contract liability on the balance sheet. Revisions or adjustments to estimates of the transaction price, estimated costs at completion and estimated profit or loss of a performance obligation are often required as work progresses under a contract, as experience is gained, as facts and circumstances change and as new information is obtained, even though the scope of work required under the contract may not change. Revisions or adjustments may also be required if contract modifications occur. The impact of revisions in profit or loss estimates are recognized on a cumulative catch-up basis in the period in which the revisions are made. The revisions in contract estimates, if significant, can materially affect the Company’s results of operations and cash flows, as well as reduce the valuations of contract assets and inventories, and in some cases result in liabilities to complete contracts in a loss position. The aggregate impact of net changes in contract estimates is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Operating income $ 64 $ 42 $ 128 $ 84 Diluted earnings per share $ 0.61 $ 0.35 $ 1.22 $ 0.67 Net sales recognized from the Company's performance obligations satisfied in prior periods were $71 million and $139 million for the quarterly and first half periods ended June 29, 2018 , respectively, and relate to revisions in contract estimates. Sales from performance obligations satisfied at a point in time are typically for standard goods and are recognized when the customer obtains control, which is generally upon delivery and acceptance. The Company also records sales for performance obligations relating to standard services (i.e., maintenance and extended warranties covering standard goods sold by the Company) over time by using output measures of time elapsed to measure progress toward satisfying the performance obligation. Sales on time-and-material type contracts are generally recognized each period based on the amount billable to the customer, which is based on direct labor hours expended multiplied by the contractual fixed rate per hour, plus the actual costs of materials and other direct non-labor costs. The following table presents a summary of the Company’s net sales by revenue recognition method as a percentage of total net sales for the first half period ended June 29, 2018 . % of Total Net Sales Cost to cost method 76 % Point in time 18 % Output method 3 % Billing method 3 % Total 100 % Remaining Performance Obligations On June 29, 2018 , the Company had $10.2 billion of remaining performance obligations, which represents the transaction price of firm orders less inception to date sales recognized. Remaining performance obligations exclude unexercised contract options and potential orders under basic ordering agreements or master-type contracts (i.e., indefinite-delivery, indefinite-quantity (IDIQ)). The Company expects to recognize sales relating to existing performance obligations of approximately $4.7 billion during the remainder of 2018, $3.5 billion in 2019, $1.2 billion in 2020 and $0.8 billion in the periods thereafter. General and Administrative Expenses The Company’s U.S. Government contractor businesses account for the portion of their G&A, independent research and development (IRAD) and bids and proposal (B&P) costs that are allowable and reimbursable indirect contract costs under U.S. Government procurement regulations on their U.S. Government contracts as inventory. G&A, IRAD and B&P costs are allocated to contracts for which the U.S. Government is the end customer and are charged to costs of sales when sales on the related contracts are recognized. The Company’s U.S. Government contractor businesses record the unallowable portion of their G&A, IRAD and B&P costs to expense as incurred and do not include them in inventory. G&A expenses for the Company's commercial businesses are expensed as incurred. The total research and development expenses incurred were $86 million and $161 million for the quarterly and first half period s ended June 29, 2018 , respectively. The Company capitalizes the incremental costs of obtaining a contract with foreign governments and foreign and domestic commercial customers (third-party sales commissions) if the Company expects to recover the costs under the contract. The Company expenses the costs to obtain a contract as incurred when the expected amortization period is one year or less. The Company classifies the portion of capitalized costs of obtaining a contract to be amortized over the next 12 months within prepaid expense and other current assets and classifies the remaining amount within other assets in its consolidated balance sheets. Investments in and Loans to Nonconsolidated Affiliates The Company’s investments in nonconsolidated affiliates are primarily accounted for using the equity method of accounting and are carried at cost, plus or minus the Company’s share of net earnings or losses of the investment, subject to certain other adjustments. The cost of equity method investments includes transaction costs of the acquisition. As required by U.S. GAAP, to the extent that there is a basis difference between the cost and the underlying equity in the net assets of an equity investment, the Company allocates such differences between tangible and intangible assets. The Company’s share of net earnings or losses of the investment, inclusive of amortization expense for any basis difference associated with the investment, are presented in interest and other income, net, on the Company’s consolidated statements of operations. Dividends received from the investee reduce the carrying amount of the investment. Due to the timing of receiving financial information from its nonconsolidated affiliates, the Company may record its share of net earnings or losses of such affiliates on a three -month lag basis, with the exception of the amortization expense of any basis difference related to tangible and intangible assets which are recorded currently.

New Accounting Standards Implem

New Accounting Standards Implemented	6 Months Ended
	Jun. 29, 2018
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards Implemented	New Accounting Standards Implemented Effective January 1, 2018, the Company adopted Financial Accounting Standards Board (FASB) ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . Defined benefit pension and postretirement benefit cost (net benefit cost) comprise several components that reflect different aspects of the Company’s financial arrangements as well as the cost of benefits provided to employees. Under previous U.S. GAAP, those components were aggregated for reporting in the financial statements and presented within the operating section of the income statement or capitalized into assets (inventories) when appropriate. The amendments in this update require the Company to report the service cost component in the same line item as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented separately from the service cost component and below income from operations. Plan administrative expenses, which were previously included in service cost, are presented together with expected return on plan assets, as a component of Interest and other income, net. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The amendments in this update have been applied retrospectively for the presentation of the components of net benefit cost and prospectively for the capitalization of the service cost component of net benefit cost. The adoption of this standard decreased operating income and increased interest and other income, net, each by $3 million and $5 million for the quarterly and first half periods ended June 29, 2018 , respectively, and increased operating income and decreased interest and other income, net, each by $2 million and $3 million for the quarterly and first half periods ended June 30, 2017 , respectively. The adoption of this standard did not impact pre-tax income for the quarterly and first half periods ended June 29, 2018 and June 30, 2017 . In January 2017, the FASB issued ASU 2017-01, Clarifying the Definition of a Business , which provides additional guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update provide new guidance to determine when an integrated set of assets and activities (collectively referred to as a ‘‘set’’) is not a business. The new guidance requires that, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. The new guidance reduces the number of transactions that need to be evaluated as a business. The Company adopted this amendment as of January 1, 2018. The adoption of ASU 2017-01 did not have a material impact on the Company's financial statements for the first half period ended June 29, 2018 . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers , as amended (commonly referred to as ASC 606), which replaces numerous requirements in U.S. GAAP, including industry-specific requirements, and provides companies with a single revenue recognition model for recognizing revenue from contracts with customers and significantly expanded the disclosure requirements for revenue arrangements. The new standard, as amended, was effective for the Company for interim and annual reporting periods beginning on January 1, 2018. As discussed in Note 2 , the Company adopted ASC 606 using the modified retrospective transition method. Results for reporting periods beginning after December 31, 2017 are presented under ASC 606, while prior period comparative information has not been restated and continues to be reported in accordance with ASC 605, Revenue Recognition, the accounting standard in effect for periods ending prior to January 1, 2018. With the adoption of ASC 606, the Company recognizes sales over time by using the cost-to-cost method on most of its (i) contracts that were covered by the contract accounting standards under ASC 605 and (ii) fixed-price type contracts that require it to perform services that are not related to the production of tangible assets. Accordingly, the adoption of ASC 606 primarily impacted certain (i) contracts previously covered by contract accounting standards that recognized revenue using the units-of-delivery method and (ii) fixed-price type contracts for services that are not related to the production of tangible assets that recognized revenue on a straight-line basis over the contractual service period. Based on contracts in process at December 31, 2017, the Company recorded, upon adoption of ASC 606, a net increase to retained earnings of $13 million , which includes the acceleration of net sales of approximately $380 million and the related cost of sales. The adjustment to retained earnings primarily relates to contracts previously accounted for under the units-of-delivery method, which is recognized under ASC 606 earlier in the performance period as costs are incurred, as opposed to when the units are delivered under ASC 605. In accordance with the modified retrospective transition provisions of ASC 606, the Company will not recognize any of the accelerated net sales and related cost of sales at January 1, 2018 in the Company’s statements of operations for any historical or future period. The Company made certain presentation changes to its consolidated balance sheet on January 1, 2018 to comply with ASC 606. The components of contracts in process as reported under ASC 605, which included unbilled contract receivables and inventoried contract costs, have been reclassified as contract assets and inventories, respectively, after certain adjustments described below under ASC 606. The adoption of ASC 606 resulted in an increase in unbilled contract receivables (referred to as contract assets under ASC 606) primarily from converting contracts previously applying the units-of-delivery method to the cost-to-cost method with a corresponding reduction in inventoried contract costs. The remainder of inventoried contract costs, primarily related to inventories not controlled by the Company's customers, were reclassified to inventories. Additionally, under ASC 606, the Company capitalizes costs to fulfill a contract (i.e., non-recurring costs for contract-related activities that do not transfer a good or service to the customer) and costs to obtain a contract (i.e., commissions paid to third-party agents or representatives) to prepaid expense and other current assets or other assets (non-current). The Company amortizes costs to obtain a contract and costs to fulfill a contract in a pattern similar to the recognition of sales on the contracts that the capitalized costs relate to. The Company previously accounted for costs to fulfill a contract either as inventoried contract costs or expensed them as incurred. Costs to obtain a contract were generally expensed as incurred. Advance payments and billings in excess of costs and deferred revenue, previously classified in other current liabilities, have been combined and are presented as contract liabilities. The table below presents the cumulative effect of the changes made to the consolidated January 1, 2018 balance sheet due to the adoption of ASC 606. BALANCE SHEET December 31, 2017 As Reported Under ASC 605 Adjustments Due to ASC 606 January 1, 2018 As Adjusted Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,349 $ 1,349 Contracts in process 1,933 (1,933 ) — Inventories 389 537 926 Prepaid expenses and other current assets 300 17 317 Assets held for sale 135 3 138 Assets of discontinued operations 306 (21 ) 285 Total current assets 4,448 (48 ) 4,400 Other assets 264 49 313 Total assets $ 12,729 $ 1 $ 12,730 Liabilities Current liabilities: Accrued expenses $ 217 $ (13 ) $ 204 Contract liabilities — 565 565 Advance payments and billing in excess of costs incurred 509 (509 ) — Other current liabilities 367 (49 ) 318 Liabilities held for sale 17 (1 ) 16 Liabilities of discontinued operations 226 (23 ) 203 Total current liabilities 2,379 (30 ) 2,349 Deferred income taxes 158 4 162 Other liabilities 398 14 412 Total liabilities 7,578 (12 ) 7,566 Shareholders' Equity Retained earnings 6,659 13 6,672 Total equity $ 5,151 $ 13 $ 5,164 The tables below present the impact of the adoption of ASC 606 on the Company's statement of operations. Second Quarter Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 1,741 $ 45 $ 1,786 Services 797 — 797 Total 2,538 45 2,583 Operating costs and expenses: Cost of sales — Products $ (1,316 ) $ (33 ) $ (1,349 ) Cost of sales — Services (561 ) (17 ) (578 ) General and administrative expenses (387 ) 4 (383 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 321 — 321 Income from continuing operations before income taxes 237 — 237 Provision for income taxes (48 ) — (48 ) Income from continuing operations 189 — 189 Income from discontinued operations, net of income taxes 191 (1 ) 190 Net income 380 (1 ) 379 Net income attributable to L3 $ 376 $ (1 ) $ 375 Basic earnings per share attributable to common shareholders: Continuing operations $ 2.36 $ — $ 2.36 Discontinued operations 2.44 (0.02 ) 2.42 Basic earnings per share $ 4.80 $ (0.02 ) $ 4.78 Diluted earnings per share attributable to common shareholders: Continuing operations $ 2.33 $ — $ 2.33 Discontinued operations 2.41 (0.02 ) 2.39 Diluted earnings per share $ 4.74 $ (0.02 ) $ 4.72 First Half Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 3,315 $ 117 $ 3,432 Services 1,518 4 1,522 Total 4,833 121 4,954 Operating costs and expenses: Cost of sales — Products $ (2,461 ) $ (79 ) $ (2,540 ) Cost of sales — Services (1,089 ) (21 ) (1,110 ) General and administrative expenses (777 ) (3 ) (780 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 553 19 572 Income from continuing operations before income taxes 434 19 453 Provision for income taxes (67 ) (5 ) (72 ) Income from continuing operations 367 14 381 Income from discontinued operations, net of income taxes 206 — 206 Net income 573 14 587 Net income attributable to L3 $ 564 $ 14 $ 578 Basic earnings per share attributable to common shareholders: Continuing operations $ 4.57 $ 0.18 $ 4.75 Discontinued operations 2.63 — 2.63 Basic earnings per share $ 7.20 $ 0.18 $ 7.38 Diluted earnings per share attributable to common shareholders: Continuing operations $ 4.50 $ 0.17 $ 4.67 Discontinued operations 2.59 — 2.59 Diluted earnings per share $ 7.09 $ 0.17 $ 7.26 The following table quantifies the impact of adopting ASC 606 on segment net sales and segment operating income for the quarterly and first half periods ended June 29, 2018 . Effect of ASC 606 Second Quarter Ended June 29, 2018 First Half Ended June 29, 2018 Sales Operating Income Sales Operating Income (in millions) Electronic Systems $ 14 $ 4 $ 44 $ 7 Aerospace Systems (2 ) (7 ) 2 (6 ) Communication Systems 21 (1 ) 41 3 Sensor Systems 12 3 34 14 Segment totals $ 45 $ (1 ) $ 121 $ 18 The table below presents the impact of the adoption of ASC 606 on the Company's balance sheet. June 29, 2018 BALANCE SHEET Under Effect of As Reported Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,611 $ 1,611 Contracts in process 2,185 (2,185 ) — Inventories 405 529 934 Prepaid expenses and other current assets 316 16 332 Assets held for sale — — — Assets of discontinued operations — — — Total current assets 5,135 (29 ) 5,106 Other assets 300 48 348 Total assets $ 13,511 $ 19 $ 13,530 Liabilities Current liabilities: Accrued expenses $ 279 $ (15 ) $ 264 Contract liabilities — 554 554 Advance payments and billings in excess of costs incurred 522 (522 ) — Other current liabilities 384 (46 ) 338 Total current liabilities 2,832 (29 ) 2,803 Deferred income taxes 181 9 190 Other liabilities 402 14 416 Total liabilities 8,024 (6 ) 8,018 Shareholders' Equity Retained earnings 7,101 25 7,126 Total equity $ 5,487 $ 25 $ 5,512

Accounting Standards Issued and

Accounting Standards Issued and Not Yet Implemented	6 Months Ended
	Jun. 29, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Standards Issued and Not Yet Implemented	Accounting Standards Issued and Not Yet Implemented In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . The amendments in this update allow a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for stranded tax effects resulting from the U.S. Tax Cuts and Jobs Act (U.S. Tax Reform). The new standard is effective for the Company beginning on January 1, 2019, with early adoption permitted. The Company will adopt ASU 2018-02 effective January 1, 2019. The Company does not expect the adoption of this standard will have a material effect on its financial position, results of operations or cash flows. In August 2017, the FASB issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this update intend to better align the Company risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedge relationships and the presentation of hedge results. The amendments in this update require the Company to present the earnings effect of the hedging instrument in the same income statement line in which the earnings effect of the hedged item is reported. Current U.S. GAAP provides for hedge accounting only for the portion of the hedge deemed to be highly effective and requires the Company to separately reflect the amount by which the hedging instrument does not offset the hedged item, which is referred to as the ineffective amount. The amendments in this update no longer require the Company to separately measure and report hedge ineffectiveness. The new standard is effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. For cash flow hedges existing at the date of adoption, the Company is required to apply a cumulative effect adjustment relating to the separate measurement of ineffectiveness to the opening balance of retained earnings. The amended presentation and disclosure guidance is required only prospectively. The Company will adopt ASU 2017-12 effective January 1, 2019. The Company does not expect the adoption of this standard to have a material effect on its financial position, results of operations or cash flows. In February 2016, the FASB issued ASU 2016-02, Leases , which updates the existing guidance on accounting for leases and requires new qualitative and quantitative disclosures about the Company’s leasing activities. The new standard requires the Company to recognize lease assets and lease liabilities on the balance sheet for all leases under which the Company is the lessee, including those classified as operating leases under previous accounting guidance. The Company will measure leases commencing after the adoption date based on the present value of the lease payments due over the lease term (as defined in ASU 2016-02), after applying the separation and allocation guidance of the new standard. The new standard, as amended, will be effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. In the adoption year, the Company will be required to (i) measure and recognize its existing leases based on the present value of the remaining minimum lease payments, as defined in existing guidance on accounting for leases, and (ii) restate each prior reporting period presented. The Company is currently evaluating the expected impact of the adoption of this standard on its consolidated financial statements and disclosures related to leasing activities. The Company plans to adopt ASU 2016-02 effective January 1, 2019. The Company has made progress in implementing the new standard by selecting a lease accounting system and assessing available practical expedients. The Company is in the process of accumulating and processing the data required to measure its existing leases and evaluating accounting policy and internal control changes to support management in the financial reporting and disclosure of leasing activities. See Note 18 to the audited consolidated financial statements for the year ended December 31, 2017 , included in the Company’s Annual Report on Form 10-K for additional information about the Company’s leases, including the future minimum lease payments of the Company's operating leases at December 31, 2017 . Other accounting standard updates effective for interim and annual periods beginning after December 31, 2018 are not expected to have a material impact on the Company’s financial position, results of operations or cash flows.

Acquisitions, Divestitures and

Acquisitions, Divestitures and Discontinued Operations	6 Months Ended
	Jun. 29, 2018
Business Combinations [Abstract]
Acquisitions, Divestitures and Discontinued Operations	Acquisitions, Divestitures and Discontinued Operations Business Acquisitions The Company continually evaluates potential acquisitions that either strategically fit within the Company’s existing portfolio or expand the Company’s portfolio into new product lines or adjacent markets. The Company has completed a number of acquisitions that have been accounted for as business combinations and have resulted in the recognition of goodwill in the Company’s financial statements. This goodwill includes the know-how of the assembled workforce, the ability of the workforce to further improve technology and product offerings and the expected cash flows resulting from these efforts. Goodwill may also include expected synergies resulting from the complementary strategic fit these businesses bring to existing operations. The business acquisitions discussed below are included in the Company’s results of operations from their respective dates of acquisition. 2018 Business Acquisitions Applied Defense Solutions, Inc. (Applied Defense Solutions). On June 29, 2018, the Company acquired Applied Defense Solutions, Inc., renamed L3 ADS, Inc., for a purchase price of $53 million , which was financed with cash on hand. Applied Defense Solutions is a leading aerospace engineering, software development and space situational awareness company. The goodwill recognized for this business was $40 million , which was assigned to the Sensor Systems segment, and is not expected to be deductible for income tax purposes. The final purchase price is subject to customary adjustments for final working capital. The final purchase price allocation, which is expected to be completed in the fourth quarter of 2018, will be based on final appraisals and other analysis of fair values of acquired assets and liabilities. The Company does not expect that differences between the preliminary and final purchase price allocation will have a material impact on its results of operations or financial position. Latitude Engineering, LLC (Latitude Engineering). On June 28, 2018, the Company acquired Latitude Engineering, LLC, renamed L3 Latitude Engineering, Inc., for a purchase price of $15 million , which was financed with cash on hand. The purchase price is subject to additional contingent consideration not to exceed $20 million , $15 million of which is based on Latitude Engineering’s post-acquisition financial performance for the four year period ended December 31, 2021, and the remaining $5 million is based on certain post-acquisition milestone achievements through December 31, 2020. Latitude Engineering is engaged in the design, manufacturing, integration, servicing, operation and support of hybrid quadrotor unmanned aerial systems. The Company recorded a $4 million liability on the acquisition date for the fair value of the contingent consideration. The goodwill recognized for this business was $14 million , which was assigned to the Electronic Systems segment and is expected to be deductible for income tax purposes. The final purchase price is subject to customary adjustments for final working capital. The final purchase price allocation, which is expected to be completed in the fourth quarter of 2018, will be based on final appraisals and other analysis of fair values of acquired assets and liabilities. The Company does not expect that differences between the preliminary and final purchase price allocation will have a material impact on its results of operations or financial position. 2017 Business Acquisitions The final purchase price and final purchase price allocations for the 2017 acquisitions of Kigre, Inc. (Kigre), Escola De Aviacao Aerocondor, S.A. (G-Air) and Adaptive Methods, Inc. (Adaptive Methods) have been finalized as of the second quarter of 2018. The final purchase price allocations resulted in a $3 million increase to goodwill. The final purchase price for Doss Aviation, Inc. (Doss Aviation) is subject to customary adjustments for final working capital. The final purchase price allocation for Doss Aviation, which is expected to be completed in the third quarter of 2018, will be based on final analysis of fair values of acquired contracts and customer relationship intangible assets. The Company does not expect that differences between the preliminary and final purchase price allocation will have a material impact on its results of operations or financial position. Business Acquisitions Announced After June 29, 2018 Azimuth Security and Linchpin Labs . On July 11, 2018, the Company entered into a definitive agreement to acquire Azimuth Security and Linchpin Labs, two information security businesses that significantly strengthen the Company's existing C 6 ISR (Command, Control, Communications, Computers, Cyber-Defense and Combat Systems, and Intelligence, Surveillance and Reconnaissance) capabilities and create synergies to drive future growth in cyber and international markets. The combined purchase price for the two businesses was approximately AUD $270 million (approximately $200 million ). The purchase price is subject to an upward adjustment of up to AUD $43 million (approximately $32 million ), payable in L3 common stock, based on the combined company’s post-acquisition sales for each of the 12-month periods ending June 30, 2019 to 2021, which would be payable in 2019 to 2021. This transaction is anticipated to be completed during the second half of 2018, subject to customary closing conditions and regulatory approvals. See Note 3 to the audited consolidated financial statements for the year ended December 31, 2017 , included in the Company’s Annual Report on Form 10-K for additional information about the Company’s 2017 business acquisitions. Unaudited Pro Forma Statements of Operations Data The following unaudited pro forma Statements of Operations data present the combined results of the Company and its business acquisitions completed during the first half period ended June 29, 2018 and the year ended December 31, 2017 , assuming that the business acquisitions completed during 2018 and 2017 had occurred on January 1, 2017 and January 1, 2016 , respectively. The unaudited pro forma Statements of Operations data below include adjustments for additional amortization expense related to acquired intangible assets and depreciation assuming the 2018 and 2017 acquisitions had occurred on January 1, 2017 and January 1, 2016 , respectively. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Pro forma net sales $ 2,592 $ 2,413 $ 4,973 $ 4,765 Pro forma income from continuing operations attributable to L3 $ 187 $ 189 $ 375 $ 343 Pro forma net income attributable to L3 $ 377 $ 201 $ 581 $ 366 Pro forma diluted earnings per share from continuing operations $ 2.36 $ 2.38 $ 4.71 $ 4.32 Pro forma diluted earnings per share $ 4.75 $ 2.53 $ 7.30 $ 4.61 The unaudited pro forma results disclosed in the table above are based on various assumptions and are not necessarily indicative of the results of operations that would have occurred had the Company completed these acquisitions on the dates indicated above. Investments in Nonconsolidated Affiliates Peak Nano Optics, LLC (Peak Nano). On February 6, 2018, the Company acquired a 25% interest in Peak Nano Optics, LLC, for a purchase price of $20 million . Peak Nano is a nanotechnology company, which allows for the design and manufacturing of polymer lenses for military, sporting and commercial optics applications using its nanolayer gradient refractive index (GRIN) technology. The purchase price is subject to a contingent payment of $30 million based upon Peak Nano meeting certain development milestones on or before August 5, 2018. The $6 million fair value of the contingent consideration liability was recorded on the investment date (See Note 16 ). The Company determined Peak Nano is a VIE as it did not have sufficient equity at risk to finance its activities. The Company, however, is not the primary beneficiary because it does not have the power to direct the activities that are most significant to the economic performance of Peak Nano. Accordingly, Peak Nano is accounted for under the equity method of accounting. As of the acquisition date, the carrying amount of the investment was greater than the Company's equity in the underlying assets of Peak Nano due primarily to the difference in the carrying amount of the indefinite-lived amortizable intangible assets including goodwill and in-process research and development (IPR&D). The basis difference attributable to goodwill and IPR&D is $11 million and $13 million , respectively. Additionally, the Company has a $5 million loan receivable from Peak Nano. Business Divestitures 2018 Divestitures As discussed in Note 1 , on June 29, 2018, the Company completed the sale of its Crestview & TCS Businesses . The assets and liabilities of the Crestview & TCS Businesses are classified as held for sale in the Company’s audited consolidated balance sheet as of December 31, 2017. The Crestview & TCS Businesses , which were within the Company’s Aerospace Segment, primarily provided aircraft fabrication and assembly of fixed and rotary wing aero structures as well as avionics hardware and software systems to address mission critical needs. The table below presents Crestview & TCS Businesses ’ results of operations and is included in continuing operations. First Half Ended June 29, 2018 (in millions) Net Sales $ 64 Gain on sale of businesses $ 48 Income from continuing operations before income taxes $ 3 Crestview & TCS Businesses . The major classes of assets and liabilities included as held for sale related to the Crestview & TCS Businesses are presented in the table below. December 31, (in millions) Assets Billed receivables $ 14 Contracts in process 33 Total current assets 47 Property, plant and equipment, net 34 Goodwill 52 Identifiable intangible assets 2 Total assets classified as held for sale $ 135 Liabilities Accounts payable, trade $ 3 Accrued employment costs 2 Accrued expenses 3 Other current liabilities 5 Total current liabilities 13 Deferred income taxes 4 Total liabilities classified as held for sale $ 17 Discontinued Operations Vertex Aerospace. As discussed in Note 1 , on June 29, 2018, the Company completed the sale of its Vertex Aerospace business. The table below presents the statements of operations data for Vertex Aerospace. The amounts presented in discontinued operations include allocated interest expenses for debt not directly attributable or related to L3’s other operations. Interest expense was allocated in accordance with the accounting standards for discontinued operations and were based on the ratio of Vertex Aerospace’s net assets to the sum of: (1) L3 consolidated total net assets and (2) L3 consolidated total debt. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Net sales $ 226 $ 351 $ 597 $ 703 Operating costs and expenses (1) (212 ) (332 ) (561 ) (667 ) Operating income from discontinued operations 14 19 36 36 Interest expense allocated to discontinued operations — — (1 ) (1 ) Gain on sale of businesses 237 — 237 — Income from discontinued operations before income taxes 251 19 272 35 Income tax expense (61 ) (7 ) (66 ) (12 ) Income from discontinued operations, net of income taxes $ 190 $ 12 $ 206 $ 23 __________________ (1) For the quarterly and first half periods ended June 29, 2018, the Company recognized $3 million of trailing expenses related to the sale of NSS. The major classes of assets and liabilities that were included in discontinued operations related to Vertex Aerospace are presented in the table below. These balances were classified as current at December 31, 2017 as the sale was expected to be completed within one year and the proceeds are not expected to be used to pay down long-term debt. December 31, (in millions) Assets Current assets $ 284 Property, plant and equipment, net 13 Other intangible assets 7 Other assets 2 Total assets of discontinued operations $ 306 Liabilities Accounts payable, trade $ 63 Other current liabilities 131 Current liabilities 194 Long-term liabilities 32 Total liabilities of discontinued operations $ 226 2017 Divestitures During the first half period ended June 30, 2017 , the Company completed the sales of the CTC Aviation Jet Services Limited (Aviation Jet Services) business, the L3 Coleman Aerospace (Coleman) business and the Display Product Line. The table below presents pre-tax (loss) gain recognized, the proceeds received and net sales included in continuing operations from these divestitures. First Half Ended June 30, 2017 Pre-Tax (Loss) gain Proceeds Received Net Sales (in millions) Aviation Jet Services divestiture $ (5 ) $ 1 $ 1 Coleman divestiture (3 ) 17 9 Display Product Line divestiture 4 7 — Total $ (4 ) $ 25 $ 10 Aviation Jet Services Divestiture. On March 1, 2017, the Company divested its Aviation Jet Services business for a sales price of £1 million (approximately $1 million ). Aviation Jet Services provided non-core aircraft management and operational services as part of commercial training solutions based in the United Kingdom and was included in the Electronic Systems segment. Coleman Divestiture. On February 24, 2017, the Company divested its Coleman business for a sales price of $15 million . Coleman provided air-launch ballistic missile targets and was included in the Electronic Systems segment. Display Product Line Divestiture. On February 23, 2017, the Company divested its Display Product Line for a sales price of $7 million . The Display Product Line provided cockpits to various military aircraft and was included in the Electronic Systems segment. Net sales and income before income taxes for Aviation Jet Services, Coleman and the Display Product Line, included in L3’s consolidated statements of operations, are presented in the table below on an aggregate basis and are included in income from continuing operations for all periods presented. First Half Ended June 30, 2017 (in millions) Net sales $ 10 Income before income taxes $ 2

Contract Assets and Contract Li

Contract Assets and Contract Liabilities	6 Months Ended
	Jun. 29, 2018
Revenue from Contract with Customer [Abstract]
Contract Assets and Contract Liabilities	Contract Assets and Contract Liabilities Contract assets represent accumulated incurred costs and earned profits on contracts with customers that have been recorded as sales but have not been billed to customers and are classified as current. Contract liabilities consist of advance payments and billings in excess of costs incurred and deferred revenue and represent amounts received in excess of sales recognized on contracts. The Company classifies advance payments and billings in excess of costs incurred as current and deferred revenue as current or non-current based on the expected timing of sales recognition. Contract assets and contract liabilities are determined on a contract by contract basis at the end of each reporting period. The non-current portion of contract liabilities is included in other liabilities in the Company's consolidated balance sheets (see Note 10 ). The table below presents the components of net contract assets (liabilities). June 29, January 1, (in millions) Contract assets $ 1,611 $ 1,349 Contract liabilities — current (554 ) (565 ) Contract liabilities — non-current (33 ) (28 ) Net contract assets (liabilities) $ 1,024 $ 756 Net contract assets (liabilities) increased from January 1, 2018 to June 29, 2018 , primarily due to sales exceeding billings due to contractual billing terms on U.S. Government contracts related to Link Training & Simulation, Space & Power Systems, Advanced Communications and Mission Integration. Contract assets increased by $262 million primarily due to the same factors as discussed above. Contract liabilities decreased by $6 million primarily due to advances received by Mission Integration for aircraft procurements related to U.S. and foreign government contracts during the first half period ended June 29, 2018 . The Company did not recognize any impairment losses on contract assets during the quarterly and first half period s ended June 29, 2018 . For the first half period ended June 29, 2018 , the Company recognized sales of $351 million related to its contract liabilities at January 1, 2018. The components of contract assets are presented in the table below. June 29, January 1, (in millions) Unbilled contract receivables, gross $ 2,643 $ 2,232 Unliquidated progress payments and advances (1,032 ) (883 ) Total contract assets $ 1,611 $ 1,349

Contracts in Process

Contracts in Process	6 Months Ended
	Jun. 29, 2018
Contractors [Abstract]
Contracts in Process	Contracts in Process The components of contracts in process are presented in the table below. December 31, (in millions) Unbilled contract receivables, gross $ 1,874 Unliquidated progress payments (761 ) Unbilled contract receivables, net 1,113 Inventoried contract costs, gross 891 Unliquidated progress payments (71 ) Inventoried contract costs, net 820 Total contracts in process $ 1,933 The table below presents a summary of G&A, IRAD and B&P costs included in inventoried contract costs and the changes to them, including amounts charged to operating costs and expenses by the Company’s U.S. Government contractor businesses for the quarterly and first half periods ended June 30, 2017 . Second Quarter Ended First Half Ended June 30, 2017 June 30, 2017 (in millions) Amounts included in inventoried contract costs at beginning of the period $ 177 $ 173 Contract costs incurred: IRAD and B&P 78 154 Other G&A 199 399 Total 277 553 Amounts charged to operating costs and expenses (280 ) (552 ) Amounts included in inventoried contract costs at end of the period $ 174 $ 174

Inventories

Inventories	6 Months Ended
	Jun. 29, 2018
Inventory Disclosure [Abstract]
Inventories	. Inventories Inventories at Lower of Cost or Realizable Value. The table below presents the components of inventories at the lower of cost (first-in, first-out or average cost) or realizable value. The Company's inventories at December 31, 2017 were comprised primarily of amounts related to standard products. In addition, the Company classified inventories related to contracts for complex aerospace and electronic equipment and engineering and technical services according to the customers' specifications as inventoried contract costs, which was a component of contracts in process on the consolidated balance sheet at December 31, 2017. See Note 7 for additional information. In accordance with ASC 606, all inventories that customers do not currently control are classified within inventories on the Company's consolidated balance sheet at June 29, 2018 , without regard to whether the goods promised to the customer are standard or customized. June 29, December 31, (in millions) Raw materials, components and sub-assemblies $ 318 $ 184 Work in process 430 98 Finished goods 186 107 Total $ 934 $ 389 Inventories at June 29, 2018 included G&A costs of $62 million . G&A costs incurred and recorded in inventories totaled $597 million during the first half period ended June 29, 2018 , and G&A costs charged to expense from inventories totaled $585 million during the first half period ended June 29, 2018 . See Note 7 for information on G&A costs included in contracts in process for the quarterly and first half periods ended June 30, 2017 .

Goodwill and Identifiable Intan

Goodwill and Identifiable Intangible Assets	6 Months Ended
	Jun. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Identifiable Intangible Assets	. Goodwill and Identifiable Intangible Assets Goodwill. In accordance with the accounting standards for business combinations, the Company records the assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition (commonly referred to as the purchase price allocation). The table below presents the changes in goodwill allocated to the Company’s reporting units in each reportable segment. Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated Total (in millions) Goodwill $ 2,856 $ 1,146 $ 1,058 $ 1,659 $ 6,719 Accumulated impairment losses (43 ) — (35 ) (26 ) (104 ) December 31, 2017 2,813 1,146 1,023 1,633 6,615 Business acquisitions (1) 16 — — 43 59 Foreign currency translation adjustments (15 ) (3 ) — (5 ) (23 ) June 29, 2018 2,814 1,143 1,023 1,671 6,651 Goodwill 2,857 1,143 1,058 1,697 6,755 Accumulated impairment losses (43 ) — (35 ) (26 ) (104 ) $ 2,814 $ 1,143 $ 1,023 $ 1,671 $ 6,651 __________________ (1) The increase for the Electronic Systems segment was due to the acquisition of the Latitude Engineering business and the purchase price allocation adjustments for the Doss Aviation and G-Air business acquisitions. The increase for the Sensor Systems segment was due to the acquisition of the Applied Defense Solutions business and the purchase price allocation adjustments for the Adaptive Methods and Kigre business acquisitions. Identifiable Intangible Assets. The most significant identifiable intangible asset that is separately recognized for the Company’s business acquisitions is customer contractual relationships. All of the Company’s customer relationships are established through written customer contracts (revenue arrangements). The fair value for customer contractual relationships is determined, as of the date of acquisition, based on estimates and judgments regarding expectations for the estimated future after-tax earnings and cash flows (including cash flows for working capital) arising from the follow-on sales on contract (revenue arrangement) renewals expected from the customer contractual relationships over their estimated lives, including the probability of expected future contract renewals and sales, less a contributory assets charge, all of which is discounted to present value. The Company’s indefinite-lived intangible assets include IPR&D. The table below presents information for the Company’s identifiable intangible assets that are subject to amortization and indefinite-lived intangible assets. June 29, 2018 December 31, 2017 Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in years) (in millions) Customer contractual relationships 15 $ 406 $ 273 $ 133 $ 393 $ 257 $ 136 Technology 10 190 121 69 189 114 75 Other 14 34 14 20 29 14 15 Total subject to amortization 630 408 222 611 385 226 IPR&D indefinite 66 — 66 66 — 66 Total $ 696 $ 408 $ 288 $ 677 $ 385 $ 292 The table below presents amortization expense recorded by the Company for its identifiable intangible assets. Second Quarter Ended First Half Ended June 29, June 30, June 29, 2018 June 30, 2017 (in millions) Amortization expense $ 11 $ 10 22 20 Based on gross carrying amounts at June 29, 2018 , the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2018 through 2022 is presented in the table below. Year Ending December 31, 2018 2019 2020 2021 2022 (in millions) Estimated amortization expense $ 44 $ 42 $ 33 $ 27 $ 23

Other Current Liabilities and O

Other Current Liabilities and Other Liabilities	6 Months Ended
	Jun. 29, 2018
Other Liabilities Disclosure [Abstract]
Other Current Liabilities and Other Liabilities	. Other Current Liabilities and Other Liabilities The table below presents the components of other current liabilities. June 29, December 31, (in millions) Other Current Liabilities: Accrued product warranty costs $ 75 $ 69 Estimated costs in excess of estimated contract value to complete contracts in process in a loss position 55 63 Accrued interest 28 43 Estimated contingent purchase price payable for acquired businesses and other investments (see Note 16) 17 11 Deferred revenues — 38 Other 163 143 Total other current liabilities $ 338 $ 367 The table below presents the components of other liabilities. June 29, December 31, (in millions) Other Liabilities: Non-current income taxes payable (see Note 12) $ 179 $ 164 Deferred compensation 53 49 Contract liabilities (see Note 6) 33 — Accrued workers' compensation 24 23 Accrued product warranty costs 23 30 Notes payable and capital lease obligations 19 16 Estimated contingent purchase price payable for acquired businesses (see Note 16) 10 20 Deferred revenues — 19 Other 75 77 Total other liabilities $ 416 $ 398 The table below presents the changes in the Company’s accrued product warranty costs. First Half Ended June 29, June 30, (in millions) Accrued product warranty costs: Balance at January 1 $ 99 $ 109 Acquisitions during the period — 3 Accruals for product warranties issued during the period 25 22 Changes to accruals for product warranties existing before January 1 1 — Settlements made during the period (26 ) (29 ) Foreign currency translation adjustments (1 ) 1 Balance at end of period $ 98 $ 106

Debt

Debt	6 Months Ended
	Jun. 29, 2018
Debt Disclosure [Abstract]
Debt	. Debt The components of debt and a reconciliation to the carrying amount of current and long-term debt are presented in the table below. June 29, December 31, (in millions) Borrowings under Revolving Credit Facility (1) $ — $ — 5.20% Senior Notes due 2019 317 1,000 4.75% Senior Notes due 2020 265 800 4.95% Senior Notes due 2021 650 650 3.85% Senior Notes due 2023 800 — 3.95% Senior Notes due 2024 350 350 3.85% Senior Notes due 2026 550 550 4.40% Senior Notes due 2028 1,000 — Principal amount of long-term debt 3,932 3,350 Unamortized discounts (8 ) (7 ) Deferred debt issue costs (24 ) (13 ) Carrying amount of long-term debt 3,900 3,330 Current portion of long-term debt (581 ) — Carrying amount of long-term debt, excluding current portion $ 3,319 $ 3,330 __________________ (1) During the first half period ended June 29, 2018 , L3’s aggregate borrowings and repayments under the Credit Facility were $501 million . At June 29, 2018 , L3 had the full availability of its $1 billion Credit Facility. Issuance of Senior Notes On June 6, 2018, L3 issued two series of senior notes, which are unsecured senior obligations of L3. The terms of each series of senior notes are presented in the table below. Note Date of Issuance Amount Issued Discount (1) Net Proceeds (2) Effective Interest Rate Redemption at Treasury Rate (3)(4) (dollars in millions) 3.85% Senior Notes due June 15, 2023 (the 2023 Notes) June 6, 2018 $ 800 $ 2 $ 792 3.89 % 20 bps 4.40% Senior Notes due June 15, 2028 (the 2028 Notes) June 6, 2018 $ 1,000 $ 1 $ 990 4.41 % 25 bps __________________ (1) Bond discounts are recorded as a reduction to the principal amount of the notes and are amortized as interest expense over the term of the notes. (2) The net cash proceeds of $1,782 million (after deduction of the discount, underwriting expenses and commissions and other related expenses) plus cash on hand were used to fund the concurrent cash tender offers (the Tender Offers) for any and all of $1 billion aggregate principal amount of 5.20% Senior Notes due October 15, 2019 (the 2019 Notes) and $800 million aggregate principal amount of 4.75% Senior Notes due July 15, 2020 (the 2020 Notes) and any related redemption of notes not tendered in the Tender Offers. (3) The 2023 Notes may be redeemed at any time prior to May 15, 2023 (one month prior to maturity) and the 2028 Notes may be redeemed at any time prior to March 15, 2028 (three months prior to maturity), at the option of L3, in whole or in part, at a redemption price equal to the greater of: (i) 100% of the principal amount, or (ii) the present value of the remaining principal and interest payments discounted to the date of redemption, on a semi-annual basis, at the Treasury Rate (as defined in the indentures governing the senior notes), plus the spread indicated in the table above. In addition, if the 2023 Notes and the 2028 Notes are redeemed at any time on or after May 15, 2023 and March 15, 2028, respectively, the redemption price would be equal to 100% of the principal amount. (4) Upon the occurrence of a change in control (as defined in the indentures governing the senior notes), each holder of the notes will have the right to require L3 to repurchase all or any part of such holder’s notes at an offer price in cash equal to 101% of the aggregate principal amount plus accrued and unpaid interest, if any, to the date of purchase. Repurchases and Redemptions of Senior Notes The table below summarizes the 2019 Notes and the 2020 Notes Tender Offers. Note Settlement Type Date Settled Aggregate Principal Principal Tendered Tender Premium Cash Tendered (1) Interest Total Cash Payments Debt Charge (2) (dollars in millions) 5.20% Senior Notes due 2019 Tender Offer June 6, 2018 $ 1,000 $ 683 103.282 % $ 705 $ 5 $ 710 $ 24 4.75% Senior Notes due 2020 Tender Offer June 6, 2018 $ 800 $ 535 104.092 % $ 557 $ 10 $ 567 $ 24 __________________ (1) Excludes $1 million of tender offer fees. (2) The debt retirement charge includes $1 million of tender offer fees and $3 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts. On June 6, 2018, the Company initiated the redemption of the 2019 Notes and the 2020 Notes that remained outstanding subsequent to the expiration of the Tender Offers. On July 6, 2018, the Company completed the redemption of the 2019 Notes and the 2020 Notes. The terms of the 2019 Notes and the 2020 Notes redemption are presented in the table below. Note Settlement Type Date Settled Principal Redemption Premium Cash Payments Interest Total Cash Payments Debt Charge (1) (dollars in millions) 5.20% Senior Notes due 2019 Redemption July 6, 2018 $ 317 103.048 % $ 327 $ 4 $ 331 $ 10 4.75% Senior Notes due 2020 Redemption July 6, 2018 $ 265 103.818 % $ 275 $ 6 $ 281 $ 11 __________________ (1) The debt retirement charge includes $1 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts. Guarantees. The borrowings under the Credit Facility are fully and unconditionally guaranteed by L3 and by substantially all of the material 100% owned domestic subsidiaries of L3 on an unsecured senior basis. The payment of principal and premium, if any, and interest on the senior notes is fully and unconditionally guaranteed, jointly and severally, by L3’s material 100% owned domestic subsidiaries that guarantee any of its other indebtedness. The guarantees of the Credit Facility and the senior notes rank pari passu with each other.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 29, 2018
Income Tax Disclosure [Abstract]
Income Taxes	. Income Taxes The Company and its subsidiaries file income tax returns in the U.S. Federal jurisdiction, which is the Company’s primary tax jurisdiction, and various state and foreign jurisdictions. At June 29, 2018 , the statutes of limitations for the Company’s U.S. Federal income tax returns for the years ended December 31, 2012 through 2016 were open. The U.S. Internal Revenue Service (IRS) is auditing the Company’s U.S. Federal income tax returns for the years ended 2012 and 2013. The Company expects the audits to conclude within the next 12 months. The Company cannot predict the outcome of the audits at this time. The U.S. Government enacted U.S. Tax Reform on December 22, 2017, which made significant changes to the U.S. tax system. Significant changes under U.S. Tax Reform included, among other things, the reduction of the U.S. corporate income tax rate from 35% to 21%, the implementation of a modified territorial tax system and the imposition of a one-time repatriation tax on deemed repatriated earnings and profits of U.S. owned foreign subsidiaries (Toll Charge). As a result, the Company recorded an estimated tax benefit (Preliminary Net Tax Benefit) from U.S. Tax Reform in its consolidated financial statements for the year ended December 31, 2017. The Company did not record any change to the Preliminary Net Tax Benefit on the unaudited condensed consolidated financial statements for the quarterly and first half periods ended June 29, 2018 . The Preliminary Net Tax Benefit ultimately recorded may differ in the future due principally to changes to the interpretations of U.S. Tax Reform, legislative action to clarify the interpretation of U.S. Tax Reform and changes to estimates the Company has utilized to calculate the tax benefit. The Company expects to finalize the tax benefit from U.S. Tax Reform with the filing of its tax return and at that time will record the difference between the final benefit and the Preliminary Net Tax Benefit previously recorded, if any, in accordance with the Securities and Exchange Commission Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act . Additionally, the Company is still evaluating the Global Intangible Low-Taxed Income (GILTI) provisions enacted under U.S. Tax Reform, and the associated election to record its effects as a period cost or as a component of deferred taxes. The effective income tax rate for the quarterly period ended June 29, 2018 was 20.3% . Excluding the sale of the Crestview & TCS Businesses, the debt retirement charge and the related income tax impacts of each, the effective income tax rate would have decreased to 15.6% from 23.2% for the quarterly period ended June 30, 2017 . The decrease was primarily driven by an increase in tax benefits from equity compensation and the reduction of the U.S. corporate income tax rate enacted under U.S. Tax Reform. The effective income tax rate for the first half period ended June 29, 2018 was 15.9% . Excluding the sale of the Crestview & TCS Businesses, the debt retirement charge and the related income tax impacts of each, the effective income tax rate would have decreased to 13.5% from 22.3% for the same period last year. The decrease was primarily driven by trends similar to the quarterly period ended June 29, 2018 . At June 29, 2018 , the Company anticipates that unrecognized tax benefits will decrease by approximately $44 million over the next 12 months due to the potential resolution of unrecognized tax benefits involving several jurisdictions and tax periods. The actual amount of the decrease over the next 12 months could vary significantly depending on the ultimate timing and nature of any settlements. Current and non-current income taxes payable include accrued potential interest of $17 million ( $13 million after income taxes) at June 29, 2018 and $15 million ( $11 million after income taxes) at December 31, 2017 , and potential penalties of $9 million at June 29, 2018 and $8 million at December 31, 2017 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income (AOCI)	6 Months Ended
	Jun. 29, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive (Loss) Income (AOCI)	. Accumulated Other Comprehensive (Loss) Income (AOCI) The changes in the AOCI balances, including amounts reclassified from AOCI into net income, are presented in the table below. Foreign currency translation Unrealized gains (losses) on hedging instruments Unrecognized (losses) gains and prior service cost, net Total accumulated other comprehensive loss (in millions) Balance at December 31, 2017 $ (54 ) $ 9 $ (646 ) $ (691 ) Other comprehensive loss before reclassifications, net of tax (39 ) (10 ) — (49 ) Amounts reclassified from AOCI, net of tax — (1 ) 27 26 Net current period other comprehensive (loss) income (39 ) (11 ) 27 (23 ) Balance at June 29, 2018 $ (93 ) $ (2 ) $ (619 ) $ (714 ) Balance at December 31, 2016 $ (178 ) $ 6 $ (554 ) $ (726 ) Other comprehensive income before reclassifications, net of tax 71 1 — 72 Amounts reclassified from AOCI, net of tax — (1 ) 19 18 Net current period other comprehensive income 71 — 19 90 Balance at June 30, 2017 $ (107 ) $ 6 $ (535 ) $ (636 ) Further details regarding the amounts reclassified from AOCI into net income are presented in the table below. Amount Reclassified from AOCI (a) Affected Line Item in the Unaudited Condensed Consolidated Statements of Operations Second Quarter Ended First Half Ended Details About AOCI Components June 29, June 30, June 29, June 30, (in millions) Gain on hedging instruments $ — $ 1 $ 1 $ 1 Income from continuing operations before income taxes $ — $ 1 $ 1 $ 1 Income from continuing operations Amortization of defined benefit pension and postretirement items: Net loss (b) $ (17 ) $ (15 ) $ (35 ) $ (30 ) Income from continuing operations before income taxes 4 5 8 11 Provision for income taxes $ (13 ) $ (10 ) $ (27 ) $ (19 ) Income from continuing operations Total reclassification for the period $ (13 ) $ (9 ) $ (26 ) $ (18 ) Income from continuing operations __________________ (a) Amounts in parenthesis indicate charges to the unaudited condensed consolidated statements of operations. (b) Amounts related to pension and postretirement benefit plans were reclassified from AOCI and recorded as a component of net periodic benefit cost (see Note 20 for additional information).

Equity

Equity	6 Months Ended
	Jun. 29, 2018
Equity [Abstract]
Equity	. Equity On May 8, 2017, L3’s Board of Directors approved a share repurchase program that authorizes L3 to repurchase up to an additional $1.5 billion of its common stock. The program became effective on July 1, 2017 and has no set expiration date. Repurchases of L3’s common stock are made from time to time at management’s discretion in accordance with applicable U.S. Federal securities laws. The timing and actual number of shares to be repurchased in the future will depend on a variety of factors, including, but not limited to, the Company’s financial position, earnings, legal requirements, other investment opportunities (including acquisitions) and market conditions. L3 repurchased 1,459,417 shares of its common stock at an average price of $196.97 per share for an aggregate amount of $287 million from January 1, 2018 through June 29, 2018 . All share repurchases of L3’s common stock have been recorded as treasury shares. From June 30, 2018 through July 20, 2018 , L3 repurchased 172,082 shares of its common stock at an average price of $193.85 per share for an aggregate amount of approximately $34 million . On May 8, 2018 , L3’s Board of Directors declared a quarterly cash dividend of $ 0.80 per share, paid on June 15, 2018 to shareholders of record at the close of business on May 18, 2018 . During the first half period ended June 29, 2018 , the Company paid $128 million of cash dividends, including a $2 million net reduction of previously accrued dividends for employee-held stock awards.

L3's Earnings Per Common Share

L3's Earnings Per Common Share	6 Months Ended
	Jun. 29, 2018
Earnings Per Share [Abstract]
L3's Earnings Per Common Share	. L3’s Earnings Per Share A reconciliation of basic and diluted Earnings Per Share (EPS) is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Reconciliation of net income: Net income $ 379 $ 207 $ 587 $ 375 Net income from continuing operations attributable to noncontrolling interests (4 ) (5 ) (9 ) (9 ) Net income attributable to L3’s common shareholders $ 375 $ 202 $ 578 $ 366 Earnings attributable to L3’s common shareholders: Continuing operations $ 185 $ 190 $ 372 $ 343 Discontinued operations, net of income tax 190 12 206 23 Net income attributable to L3’s common shareholders $ 375 $ 202 $ 578 $ 366 Earnings per share attributable to L3’s common shareholders: Basic: Weighted average common shares outstanding 78.4 78.0 78.3 77.8 Basic earnings per share: Continuing operations $ 2.36 $ 2.44 $ 4.75 $ 4.40 Discontinued operations, net of income tax 2.42 0.15 2.63 0.30 Net income $ 4.78 $ 2.59 $ 7.38 $ 4.70 Diluted: Common and potential common shares: Weighted average common shares outstanding 78.4 78.0 78.3 77.8 Effect of dilutive securities 1.0 1.5 1.3 1.6 Common and potential common shares 79.4 79.5 79.6 79.4 Diluted earnings per share: Continuing operations $ 2.33 $ 2.39 $ 4.67 $ 4.32 Discontinued operations, net of income tax 2.39 0.15 2.59 0.29 Net income $ 4.72 $ 2.54 $ 7.26 $ 4.61 The computation of diluted EPS excludes 0.3 million shares for each of the quarterly and first half periods ended June 29, 2018 and 0.4 million shares and 0.3 million shares for the quarterly and first half periods ended June 30, 2017 , respectively, for share-based payment awards as they were anti-dilutive.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 29, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	. Fair Value Measurements Fair value is defined as the price that would be received for an asset or the exit price that would be paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants. The standards establish a fair value hierarchy that gives the highest priority to observable inputs and the lowest priority to unobservable inputs. The following table presents the fair value hierarchy level for each of the Company’s assets and liabilities that are measured and recorded at fair value on a recurring basis. June 29, 2018 December 31, 2017 Description Level 1 (1) Level 2 (2) Level 3 (3) Level 1 (1) Level 2 (2) Level 3 (3) (in millions) Assets Cash equivalents $ 955 $ — $ — $ 310 $ — $ — Derivatives (foreign currency forward contracts) — 3 — — 11 — Total assets $ 955 $ 3 $ — $ 310 $ 11 $ — Liabilities Derivatives (foreign currency forward contracts) $ — $ 8 $ — $ — $ 1 $ — Contingent consideration — — 27 — — 31 Total liabilities $ — $ 8 $ 27 $ — $ 1 $ 31 __________________ (1) Level 1 is based on quoted market prices available in active markets for identical assets or liabilities as of the reporting date. Cash equivalents are primarily held in registered money market funds, which are valued using quoted market prices. (2) Level 2 is based on pricing inputs other than quoted prices in active markets, which are either directly or indirectly observable. The fair value is determined using a valuation model based on observable market inputs, including quoted foreign currency forward exchange rates and consideration of non-performance risk. (3) Level 3 is based on pricing inputs that are not observable and not corroborated by market data. The contingent consideration liabilities represent the future potential earn-out payments relating to the acquisitions of MacDonald Humfrey (Automation) Limited, renamed L3 MacDonald Humfrey (MacH), on November 22, 2016, Open Water Power, Inc., renamed L3 Open Water Power, Inc. (Open Water Power), on May 19, 2017 and Latitude Engineering, LLC, renamed L3 Latitude Engineering, Inc. (Latitude Engineering) on June 28, 2018 and achieving certain milestones related to the Peak Nano investment. The fair value of the MacH contingent consideration liability, and a portion of the Latitude Engineering contingent consideration liability is based on a Monte Carlo Simulation of the aggregate revenue of MacH for the three-year period ending December 31, 2019, and the aggregate revenue of Latitude Engineering as of each year within the four-year period ended December 31, 2021. The significant unobservable inputs used in calculating the fair value of the MacH contingent consideration and a portion of the Latitude Engineering contingent consideration include: (i) projected revenues of the acquired businesses, (ii) company specific risk premium, which is a component of the discount rate applied to the revenue projections and (iii) volatility. The fair value of the Open Water Power contingent consideration liability and a portion of the Latitude Engineering contingent consideration liability is based on the Scenario-Based Method of the income approach using post-acquisition milestone achievements of Open Water Power and Latitude Engineering through December 31, 2020. The significant unobservable inputs used in calculating the fair value of the Open Water Power contingent consideration and a portion of the Latitude Engineering contingent consideration include: (i) timing of achieving the milestones associated with the contingent consideration arrangement, (ii) probabilities of achieving each milestone and (iii) discount rate. The fair value of the contingent consideration for potential earn-out payments is reassessed quarterly, including an analysis of the significant inputs used in the evaluation, as well as the accretion of the present value discount. Changes are reflected within operating costs and expenses in the unaudited condensed consolidated statements of operations. The Peak Nano contingent consideration liability was recorded at fair value on the acquisition date based on a probability assessment of the likelihood of achieving certain development milestones on or before August 5, 2018. The fair value of the contingent consideration liability is reassessed quarterly and changes are reflected within interest and other income, net, in the unaudited condensed consolidated statements of operations. The table below presents the changes to contingent consideration obligations during the first half period ended June 29, 2018 . June 29, 2018 (in millions) Balance at beginning of period $ 31 Acquisitions and investments 10 Cash payments (2 ) Changes in fair value of contingent consideration, net (12 ) Balance at end of period $ 27

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 29, 2018
Investments, All Other Investments [Abstract]
Financial Instruments	. Financial Instruments At June 29, 2018 and December 31, 2017 , the Company’s financial instruments consisted primarily of cash and cash equivalents, billed receivables, trade accounts payable, senior notes and foreign currency forward contracts. The carrying amounts of cash and cash equivalents, billed receivables and trade accounts payable are representative of their respective fair values because of the short-term maturities or the expected settlement dates of these instruments. The carrying amounts and estimated fair values of the Company’s other financial instruments are presented in the table below. June 29, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value (in millions) Senior notes (1) $ 3,900 $ 3,944 $ 3,330 $ 3,502 Foreign currency forward contracts (2) $ (5 ) $ (5 ) $ 10 $ 10 __________________ (1) The Company measures the fair value of its senior notes using Level 2 inputs based primarily on current market yields for its existing debt traded in the secondary market. (2) The Company measures the fair values of foreign currency forward contracts based on forward exchange rates. See Note 18 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	. Derivative Financial Instruments The Company’s derivative financial instruments include foreign currency forward contracts, which are entered into for risk management purposes, as well as the Peak Nano contingent consideration liability. See Note 16 for further information on the contingent consideration liability. Foreign Currency Forward Contracts. The Company’s U.S. and foreign businesses enter into contracts with customers, subcontractors or vendors that are denominated in currencies other than their functional currencies. To protect the functional currency equivalent cash flows associated with certain of these contracts, the Company enters into foreign currency forward contracts. The Company’s activities involving foreign currency forward contracts are designed to hedge the changes in the functional currency equivalent cash flows due to movements in foreign exchange rates compared to the functional currency. The foreign currencies hedged are primarily the Canadian dollar, the U.S. dollar, the Euro, the United Arab Emirates dirham, the British pound and the New Zealand dollar. The Company manages exposure to counterparty non-performance credit risk by entering into foreign currency forward contracts only with major financial institutions that are expected to fully perform under the terms of such contracts. Foreign currency forward contracts are recorded in the Company’s condensed consolidated balance sheets at fair value and are generally designated and accounted for as cash flow hedges in accordance with the accounting standards for derivative instruments and hedging activities. Gains and losses on designated foreign currency forward contracts that are highly effective in offsetting the corresponding change in the cash flows of the hedged transactions are recorded net of income taxes in AOCI and then recognized in income when the underlying hedged transaction affects income. Gains and losses on foreign currency forward contracts that do not meet hedge accounting criteria are recognized in income immediately. Notional amounts are used to measure the volume of foreign currency forward contracts and do not represent exposure to foreign currency losses. The table below presents the notional amounts of the Company’s outstanding foreign currency forward contracts by currency at June 29, 2018 . Currency Notional Amounts (in millions) Canadian dollar $ 183 U.S. dollar 145 Euro 80 United Arab Emirates dirham 12 British pound 11 New Zealand dollar 7 Total $ 438 At June 29, 2018 , the Company’s foreign currency forward contracts had maturities through 2023 . The table below presents the location of the Company’s derivative instruments recorded at fair value on the condensed consolidated balance sheets. June 29, 2018 December 31, 2017 Other Current Assets Other Assets Other Current Liabilities Other Liabilities Other Current Assets Other Assets Other Current Liabilities Other Liabilities (in millions) Derivatives designated as hedging instruments: Foreign currency forward contracts (1) $ 3 $ — $ 6 $ 2 $ 11 $ — $ 1 $ — Derivatives not designated as hedging instruments: Contingent consideration (2) — — 6 — — — — — Total derivative instruments $ 3 $ — $ 12 $ 2 $ 11 $ — $ 1 $ — __________________ (1) See Note 16 for a description of the fair value hierarchy related to the Company’s foreign currency forward contracts. (2) See Note 16 for additional information on Peak Nano contingent consideration liability. The effects from foreign currency forward contracts on the unaudited condensed consolidated statements of operations were a pre-tax gain of $1 million for the quarterly period ended June 30, 2017 and pre-tax gain s of $1 million for each of the first half period s ended June 29, 2018 and June 30, 2017 . At June 29, 2018 , the estimated net amount of existing losses that are expected to be reclassified into income within the next 12 months was $5 million .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 29, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	. Commitments and Contingencies Procurement Regulations A substantial majority of the Company’s revenues are generated from providing products and services under legally binding agreements or contracts with the U.S. Government, foreign government customers and state and local governments. U.S. Government contracts are subject to extensive legal and regulatory requirements, and, from time to time, agencies of the U.S. Government investigate whether such contracts were and are being conducted in accordance with these requirements. The Company is currently cooperating with the U.S. Government on several investigations from which civil, criminal or administrative proceedings have or could result and give rise to fines, penalties, compensatory and treble damages, restitution and/or forfeitures, including investigations into the pricing of certain contracts entered into by the Communication Systems segment. The Company does not currently anticipate that any of these investigations will have a material adverse effect, individually or in the aggregate, on its consolidated financial position, results of operations or cash flows. However, under U.S. Government regulations, an indictment of the Company by a federal grand jury, or an administrative finding against the Company as to its present responsibility to be a U.S. Government contractor or subcontractor, could result in the Company being suspended for a period of time from eligibility for awards of new government contracts or task orders or in a loss of export privileges. A conviction, or an administrative finding against the Company that satisfies the requisite level of seriousness, could result in debarment from contracting with the federal government for a specified term. In addition, all of the Company’s U.S. Government contracts: (1) are subject to audit and various pricing and cost controls, (2) include standard provisions for termination for the convenience of the U.S. Government or for default and (3) are subject to cancellation if funds for contracts become unavailable. Foreign government contracts generally include comparable provisions relating to terminations for convenience or default, as well as other procurement clauses relevant to the foreign government. Litigation Matters The Company is also subject to litigation, proceedings, claims or assessments and various contingent liabilities incidental to its businesses, including the matter specified below. Furthermore, in connection with certain business acquisitions, the Company has assumed some or all claims against, and liabilities of, such acquired businesses, including both asserted and unasserted claims and liabilities. In accordance with the accounting standard for contingencies, the Company records a liability when management believes that it is both probable that a liability has been incurred and the Company can reasonably estimate the amount of the loss. Generally, the loss is recorded at the amount the Company expects to resolve the liability. Amounts recoverable from insurance contracts or third parties are recorded as assets when deemed probable. At June 29, 2018 , the Company recorded approximately $2 million of receivables for recoveries from insurance contracts or third parties in connection with the amount of liabilities recorded for pending and threatened litigation. Legal defense costs are expensed as incurred. The Company believes it has recorded adequate provisions for its litigation matters. The Company reviews these provisions to reflect the impact of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular matter. While it is reasonably possible that an unfavorable outcome may occur in the matter set forth below, unless otherwise stated, the Company believes that it is not probable that a loss has been incurred in such matter. With respect to any litigation matter below for which it is reasonably possible that an unfavorable outcome may occur, an estimate of loss or range of loss is disclosed when such amount or amounts can be reasonably estimated. Although the Company believes that it has valid defenses with respect to legal matters and investigations pending against it, the results of litigation can be difficult to predict, particularly those involving jury trials. Therefore, it is possible that any of the following or other contingencies could have a material impact on the financial position, results of operations or cash flows of the Company in future periods. HVC Alkmaar . On July 23, 2014, a notice of claim was received by the Company’s former JovyAtlas business unit. The notice relates to losses resulting from a fire that occurred at an HVC Alkmaar bio-energy plant on July 21, 2013. The notice states that the fire resulted from the failure of an uninterruptible power supply (UPS) to provide sufficient power to act as a back-up energy supply, alleges that JovyAtlas was the manufacturer and service provider for the UPS and claims €11 million in estimated property damages and €35 million in estimated business interruption damages. The Company has tendered the notice of claim to its insurance carriers.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	6 Months Ended
	Jun. 29, 2018
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	. Pension and Other Postretirement Benefits The following table summarizes the components of net periodic benefit cost for the Company’s pension and other postretirement benefit plans. Pension Plans Postretirement Benefit Plans Second Quarter Ended First Half Ended Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, June 29, June 30, June 29, June 30, (in millions) Components of net periodic benefit cost: Service cost $ 26 $ 25 $ 52 $ 50 $ 1 $ — $ 1 $ 1 Interest cost 36 36 72 71 1 1 2 2 Expected return on plan assets (56 ) (49 ) (112 ) (98 ) (1 ) (1 ) (2 ) (2 ) Amortization of net loss (gains) 18 15 37 31 (1 ) — (2 ) (1 ) Net periodic benefit cost $ 24 $ 27 $ 49 $ 54 $ — $ — $ (1 ) $ — The components of net periodic benefit cost other than the service cost component are included in interest and other income, net, in the unaudited condensed consolidated statements of operations. Service cost is included in operating costs and expenses in the unaudited condensed consolidated statements of operations. Contributions. The Company contributed cash of $28 million to its pension plans and $3 million to its other postretirement benefit plans during the first half period ended June 29, 2018 . The Company expects to contribute an additional $72 million to its pension plans and $7 million to its other postretirement benefit plans during the remainder of 2018 .

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 29, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	. Stock-Based Compensation During the first half period ended June 29, 2018 , the Company granted stock-based awards under the Amended and Restated 2008 Long Term Performance Plan in the form of stock options, restricted stock units and performance units. The stock-based compensation awards granted during the first half period ended June 29, 2018 are further discussed below. Stock Options. The Company granted 201,041 stock options with a weighted average exercise price of $210.60 per option, which was equal to the closing price of L3’s common stock on the date of grant. Options expire 10 years after the date of grant and vest ratably over a three -year period on the annual anniversary of the date of grant. The options granted to the Company’s Chairman, Chief Executive Officer and President are also subject to performance-based vesting conditions. The weighted average grant date fair value for the options of $38.02 per option was estimated using the Black-Scholes option-pricing model. The weighted average assumptions used in the valuation model for this grant are presented in the table below. Expected holding period (in years) 5.2 Expected volatility 19.8 % Expected dividend yield 1.8 % Risk-free interest rate 2.7 % Restricted Stock Units. The Company granted 246,342 restricted stock units with a weighted average grant date fair value of $210.39 per share. Restricted stock units typically vest three years after the grant date for employees and one year after the grant date for non-employee directors, or if earlier, on the date of the first annual stockholders meeting held after the grant date. The restricted stock units automatically convert into shares of L3’s common stock upon vesting. The grant date fair value of the restricted stock unit awards is based on L3’s closing stock price at the date of grant and is generally recognized as compensation expense on a straight-line basis over the vesting period. However, for employees who attain retirement eligibility status prior to the end of the three -year cliff vesting period and who have provided at least one year of service after the date of grant, compensation expense is recognized over the shorter period from the date of grant to the retirement eligibility date. For grants of restricted stock units made during the first half period ended June 29, 2018 , retirement eligible employees are those employees that either: (1) have attained the age of 60 and completed at least five years of service (which service must be continuous through the date of termination except for a single break in service that does not exceed one year in length) or (2) have attained the age of 65 (without regard to their length of service at L3). Performance Units. The Company granted 21,546 performance units with a weighted average grant date fair value per unit of $210.54 . The final payout for these units is based on the achievement of pre-determined EPS goals established by the Compensation Committee of the Company’s Board of Directors for the three -year period ending December 31, 2020 . Units earned can range from zero to 200% of the original number of units awarded, which are converted into shares of L3’s common stock.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 29, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	. Supplemental Cash Flow Information First Half Ended June 29, June 30, (in millions) Interest paid $ 97 $ 83 Income tax payments $ 54 $ 96 Income tax refunds $ 3 $ 7

Segment Information

Segment Information	6 Months Ended
	Jun. 29, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information The Company has four reportable segments, which are described in Note 1 . The Company evaluates the performance of its operating segments and reportable segments based on their sales, operating income and operating margin. Corporate expenses are allocated to the Company’s operating segments using an allocation methodology prescribed by U.S. Government regulations for government contractors. Accordingly, segment results include all costs and expenses, except for goodwill impairment charges and certain other items that are excluded by management for purposes of evaluating the operating performance of the Company’s business segments. The tables below present net sales, operating income, depreciation and amortization and total assets by reportable segment. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Net Sales: Electronic Systems $ 828 $ 789 $ 1,630 $ 1,549 Aerospace Systems 751 681 1,450 1,382 Communication Systems 563 555 1,062 1,098 Sensor Systems 482 394 894 748 Elimination of intercompany sales (41 ) (34 ) (82 ) (71 ) Consolidated total $ 2,583 $ 2,385 $ 4,954 $ 4,706 Operating Income: Electronic Systems $ 113 $ 103 $ 221 $ 193 Aerospace Systems 61 56 118 112 Communication Systems 45 84 82 126 Sensor Systems 54 51 103 100 Segment total 273 294 524 531 Gain on sale of the Crestview & TCS Businesses 48 — 48 — Consolidated total $ 321 $ 294 $ 572 $ 531 Depreciation and amortization: Electronic Systems $ 24 $ 17 $ 43 $ 35 Aerospace Systems 12 13 24 24 Communication Systems 11 12 24 24 Sensor Systems 13 12 25 23 Consolidated total $ 60 $ 54 $ 116 $ 106 June 29, December 31, (in millions) Total Assets: Electronic Systems $ 4,990 $ 4,796 Aerospace Systems 2,200 2,014 Communication Systems 2,142 2,063 Sensor Systems 2,890 2,706 Corporate 1,308 709 Assets held for sale — 135 Assets of discontinued operations — 306 Consolidated total $ 13,530 $ 12,729 Disaggregation of Total Net Sales . The Company disaggregates its sales from contracts with customers by end customer, contract type, deliverable type and revenue recognition method for each of its segments, as the Company believes these factors affect the nature, amount, timing and uncertainty of the Company’s revenue and cash flows. Sales by End Customer. Direct sales to the end customer represented approximately 64% of the Company’s consolidated sales for each of the quarterly and first half periods ended June 29, 2018 , and indirect sales as a subcontractor or supplier represented the remaining 36% . The tables below present total net sales disaggregated by end customer. Second Quarter Ended June 29, 2018 End Customer Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Total DoD $ 443 $ 624 $ 426 $ 240 $ 1,733 Other U.S. Government 40 7 24 22 93 Total U.S. Government 483 631 450 262 1,826 Foreign governments (1) 74 103 39 155 371 Commercial — foreign 177 6 25 14 222 Commercial — domestic 78 1 40 45 164 Total $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 End Customer Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Total DoD $ 860 $ 1,192 $ 797 $ 446 $ 3,295 Other U.S. Government 79 12 48 47 186 Total U.S. Government 939 1,204 845 493 3,481 Foreign governments (1) 142 206 73 281 702 Commercial — foreign 344 14 46 35 439 Commercial — domestic 172 3 83 74 332 Total $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954 __________________ (1) Includes sales under foreign military sales agreements, which are made directly between the U.S. Government and foreign governments. Sales by Contract Type. Generally, the sales price arrangements for the Company’s contracts are either fixed-price, cost-plus or time-and-material type. Fixed-price type contracts generally offer higher profit margin potential than cost-plus type or time-and-material type contracts due to the greater levels of risk assumed on a fixed-price type contract. On a fixed-price type contract, the Company agrees to perform the contractual statement of work for a predetermined sales price. On a cost-plus type contract, the Company is paid its allowable incurred costs plus a profit which can be fixed or variable depending on the contract’s fee arrangement up to predetermined funding levels determined by the customer. Cost-plus type contracts with award and incentive fee provisions are the Company’s primary variable contract fee arrangement. On a time-and-material type contract, the Company is paid on the basis of direct labor hours expended at specified fixed-price hourly rates (that include wages, overhead, allowable general and administrative expenses and profit) and materials at cost. Substantially all of the Company’s cost-plus type contracts and time-and-material type contracts are with U.S. Government customers, while sales to foreign government and commercial customers are generally transacted under fixed-price sales arrangements and are included in the Company’s fixed-price contract type sales. The tables below present total net sales disaggregated by contract type. Second Quarter Ended June 29, 2018 Contract Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Fixed-price (1) $ 680 $ 398 $ 403 $ 391 $ 1,872 Cost-plus (2) 118 292 133 83 626 Time-and-material 14 51 18 2 85 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Contract Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Fixed-price (1) $ 1,344 $ 764 $ 732 $ 724 $ 3,564 Cost-plus (2) 226 561 281 154 1,222 Time-and-material 27 102 34 5 168 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954 __________________ (1) Includes fixed-price incentive fee type contracts, which contributed approximately 1% to the Company's total net sales for quarterly period ended June 29, 2018 and 2% for the first half period ended June 29, 2018 . (2) Includes cost-plus award and incentive fee type contracts, which contributed approximately 4% to the Company's total net sales for each of the quarterly and first half periods ended June 29, 2018 . Sales by Deliverable Type: The tables below present total net sales disaggregated by the type of deliverable, which is determined by the Company at the performance obligation level. Second Quarter Ended June 29, 2018 Sales by Deliverable Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Products $ 578 $ 405 $ 397 $ 406 $ 1,786 Services 234 336 157 70 797 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Sales by Deliverable Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Products $ 1,138 $ 777 $ 761 $ 756 $ 3,432 Services 459 650 286 127 1,522 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954 Revenue Recognition Method: The tables below present total net sales disaggregated based on the revenue recognition method applied. Second Quarter Ended June 29, 2018 Revenue Recognition Method Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Cost to cost method $ 548 $ 713 $ 455 $ 226 $ 1,942 Point in time 175 11 76 222 484 Output method 71 1 5 11 88 Billing method 18 16 18 17 69 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Revenue Recognition Method Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Cost to cost method $ 1,081 $ 1,379 $ 845 $ 439 $ 3,744 Point in time 369 13 153 381 916 Output method 122 1 12 27 162 Billing method 25 34 37 36 132 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954

Severance and Restructuring Rel

Severance and Restructuring Related Costs	6 Months Ended
	Jun. 29, 2018
Restructuring and Related Activities [Abstract]
Severance and Restructuring Related Costs	. Severance and Restructuring Related Costs Consistent with the Company’s strategy to continuously improve its cost structure and right-size its businesses, L3 is completing employment reduction actions across several of its businesses to reduce both direct and indirect costs, including overhead and general and administrative costs. As a result of these initiatives, the Company recorded a total of $6 million and $14 million of severance and restructuring related costs with respect to approximately 400 employees during the quarterly and first half periods ended June 29, 2018 , respectively. During the year ended December 31, 2017 , the Company recorded a total of $101 million of severance and restructuring related costs with respect to approximately 1,500 employees. Severance and restructuring related costs are reported within operating costs and expenses on the unaudited condensed consolidated statements of operations. Severance and restructuring related costs incurred by reportable segment are presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Reportable Segment Electronic Systems $ 2 $ 2 $ 4 $ 5 Aerospace Systems — 1 1 1 Communication Systems 3 9 8 18 Sensor Systems 1 — 1 2 Consolidated $ 6 $ 12 $ 14 $ 26 The Company had severance and restructuring related liabilities of $15 million and $23 million included in other current liabilities on the Company’s balance sheets at June 29, 2018 and December 31, 2017 , respectively. The remaining liability balance at June 29, 2018 is expected to be paid primarily by the second quarter of 2019. The table below presents the change to the Company’s severance and restructuring related liability during the first half period ended June 29, 2018 . June 29, 2018 (in millions) Balance at beginning of period $ 23 Additional provisions 14 Cash payments (22 ) Balance at end of period $ 15

Condensed Combining Financial I

Condensed Combining Financial Information of L3 and Its Subsidiaries	6 Months Ended
	Jun. 29, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Combining Financial Information of L3 and Its Subsidiaries	. Condensed Combining Financial Information of L3 and Its Subsidiaries The debt of L3, including the senior notes and borrowings under amounts drawn against the Credit Facility, are guaranteed, on a joint and several, full and unconditional basis, by certain of its 100% owned domestic subsidiaries (the Guarantor Subsidiaries). See Note 9 to the audited consolidated financial statements for the year ended December 31, 2017 , included in the Company’s Annual Report on Form 10-K for additional information. The foreign subsidiaries and certain domestic subsidiaries of L3 (the Non-Guarantor Subsidiaries) do not guarantee the debt of L3. None of the debt of L3 has been issued by its subsidiaries. Under the terms of the indentures governing the senior notes, the guarantees of the senior notes will automatically and unconditionally be released and discharged: (1) upon the release of all guarantees of all other outstanding indebtedness of L3 or (2) upon the determination that such guarantor is no longer a “domestic subsidiary.” In addition, the guarantees of the senior notes will be automatically and unconditionally released and discharged in the event of a sale or other disposition of all of the assets of any guarantor, by way of merger, consolidation or otherwise, or a sale of all of the capital stock of such guarantor. There are no restrictions on the payment of dividends from the Guarantor Subsidiaries to L3. The following unaudited condensed combining financial information presents the results of operations, financial position and cash flows of: (1) L3 excluding its consolidated subsidiaries (the Parent), (2) the Guarantor Subsidiaries, (3) the Non-Guarantor Subsidiaries and (4) the eliminations to arrive at the information for L3 on a consolidated basis. L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Balance Sheets: At June 29, 2018 Current assets: Cash and cash equivalents $ 1,055 $ 19 $ 307 $ (15 ) $ 1,366 Billed receivables, net 285 315 263 — 863 Contract assets 616 810 185 — 1,611 Inventories 393 315 226 — 934 Prepaid expenses and other current assets 112 150 70 — 332 Total current assets 2,461 1,609 1,051 (15 ) 5,106 Goodwill 2,273 2,828 1,550 — 6,651 Other assets 707 712 354 — 1,773 Investment in and amounts due from consolidated subsidiaries 5,668 6,614 — (12,282 ) — Total assets $ 11,109 $ 11,763 $ 2,955 $ (12,297 ) $ 13,530 Current portion of long-term debt $ 581 $ — $ — $ — $ 581 Current liabilities 774 864 599 (15 ) 2,222 Amounts due to consolidated subsidiaries — — 426 (426 ) — Other long-term liabilities 991 757 148 — 1,896 Long-term debt 3,319 — — — 3,319 Total liabilities 5,665 1,621 1,173 (441 ) 8,018 L3 shareholders’ equity 5,444 10,142 1,782 (11,924 ) 5,444 Noncontrolling interests — — — 68 68 Total equity 5,444 10,142 1,782 (11,856 ) 5,512 Total liabilities and equity $ 11,109 $ 11,763 $ 2,955 $ (12,297 ) $ 13,530 L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) At December 31, 2017 Current assets: Cash and cash equivalents $ 432 $ 16 $ 285 $ (71 ) $ 662 Billed receivables, net 266 244 213 — 723 Contracts in process 706 912 315 — 1,933 Prepaid expenses and other current assets 330 235 124 — 689 Assets held for sale — 135 — — 135 Assets of discontinued operations 306 — — — 306 Total current assets 2,040 1,542 937 (71 ) 4,448 Goodwill 2,248 2,844 1,523 — 6,615 Other assets 658 687 321 — 1,666 Investment in and amounts due from consolidated subsidiaries 5,513 6,398 — (11,911 ) — Total assets $ 10,459 $ 11,471 $ 2,781 $ (11,982 ) $ 12,729 Current liabilities $ 811 $ 832 $ 564 $ (71 ) $ 2,136 Liabilities held for sale — 17 — — 17 Liabilities of discontinued operations 226 — — — 226 Amounts due to consolidated subsidiaries — — 330 (330 ) — Other long-term liabilities 1,009 729 131 — 1,869 Long-term debt 3,330 — — — 3,330 Total liabilities 5,376 1,578 1,025 (401 ) 7,578 L3 shareholders’ equity 5,083 9,893 1,756 (11,649 ) 5,083 Noncontrolling interests — — — 68 68 Total equity 5,083 9,893 1,756 (11,581 ) 5,151 Total liabilities and equity $ 10,459 $ 11,471 $ 2,781 $ (11,982 ) $ 12,729 L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Statements of Operations: For the quarter ended June 29, 2018: Total net sales $ 919 $ 1,328 $ 431 $ (95 ) $ 2,583 Total operating costs and expenses (819 ) (1,239 ) (347 ) 95 (2,310 ) Gain on sale of the Crestview & TCS Businesses — 48 — — 48 Operating income 100 137 84 — 321 Interest expense (43 ) — (1 ) — (44 ) Interest and other income, net 6 1 1 — 8 Debt retirement charge (48 ) — — — (48 ) Income from continuing operations before income taxes 15 138 84 — 237 Provision for income taxes (4 ) (26 ) (18 ) — (48 ) Equity in net income of consolidated subsidiaries 174 47 — (221 ) — Income from continuing operations 185 159 66 (221 ) 189 Income from discontinued operations, net of income taxes 190 — — — 190 Net income 375 159 66 (221 ) 379 Net income attributable to noncontrolling interests — — — (4 ) (4 ) Net income attributable to L3 $ 375 $ 159 $ 66 $ (225 ) $ 375 Comprehensive income attributable to L3 $ 306 $ 85 $ (11 ) $ (74 ) $ 306 For the quarter ended June 30, 2017: Total net sales $ 894 $ 1,193 $ 399 $ (101 ) $ 2,385 Total operating costs and expenses (810 ) (1,049 ) (333 ) 101 (2,091 ) Operating income 84 144 66 — 294 Interest expense (42 ) — — — (42 ) Interest and other income, net 2 — — — 2 Income from continuing operations before income taxes 44 144 66 — 254 Provision for income taxes (10 ) (34 ) (15 ) — (59 ) Equity in net income of consolidated subsidiaries 156 35 — (191 ) — Income from continuing operations 190 145 51 (191 ) 195 Income from discontinued operations, net of income taxes 12 — — — 12 Net income 202 145 51 (191 ) 207 Net income attributable to noncontrolling interests — — — (5 ) (5 ) Net income attributable to L3 $ 202 $ 145 $ 51 $ (196 ) $ 202 Comprehensive income attributable to L3 $ 264 $ 192 $ 104 $ (296 ) $ 264 L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Statements of Cash Flows For the first half period ended June 29, 2018: Operating activities: Net cash from (used in) operating activities from continuing operations $ 195 $ (100 ) $ 88 $ (5 ) $ 178 Investing activities: Business acquisitions, net of cash acquired (69 ) — — — (69 ) Proceeds from sale of businesses, net of closing date cash balances 360 175 — — 535 Other investing activities (79 ) (38 ) (19 ) — (136 ) Net cash from (used in) investing activities from continuing operations 212 137 (19 ) — 330 Financing activities: Proceeds from sale of senior notes 1,798 — — — 1,798 Repurchases and redemptions of senior notes (1,263 ) — — — (1,263 ) Common stock repurchased (287 ) — — — (287 ) Dividends paid (128 ) — — — (128 ) Other financing activities 89 (34 ) (39 ) 61 77 Net cash from (used in) financing activities from continuing operations 209 (34 ) (39 ) 61 197 Effect of foreign currency exchange rate changes on cash — — (8 ) — (8 ) Net increase in cash and cash equivalents of discontinued operations 7 — — — 7 Net increase in cash 623 3 22 56 704 Cash and cash equivalents, beginning of the period 432 16 285 (71 ) 662 Cash and cash equivalents, end of the period $ 1,055 $ 19 $ 307 $ (15 ) $ 1,366 For the first half period ended June 30, 2017: Operating activities: Net cash from operating activities from continuing operations $ 137 $ 101 $ 118 $ (41 ) $ 315 Investing activities: Business acquisitions, net of cash acquired (191 ) — — — (191 ) Proceeds from sale of businesses, net of closing date cash balances 15 — 1 — 16 Other investing activities (33 ) 11 (10 ) — (32 ) Net cash (used in) from investing activities from continuing operations (209 ) 11 (9 ) — (207 ) Financing activities: Common stock repurchased (26 ) — — — (26 ) Dividends paid (119 ) — — — (119 ) Other financing activities 164 (117 ) (124 ) 92 15 Net cash from (used in) financing activities from continuing operations 19 (117 ) (124 ) 92 (130 ) Effect of foreign currency exchange rate changes on cash — — 10 — 10 Net increase in cash and cash equivalents of discontinued operations 34 — — — 34 Net decrease in cash (19 ) (5 ) (5 ) 51 22 Cash and cash equivalents, beginning of the period 291 5 203 (136 ) 363 Cash and cash equivalents, end of the period $ 272 $ — $ 198 $ (85 ) $ 385 During the preparation of the condensed consolidating financial information of the Company and its subsidiaries for the quarter ended June 29, 2018, the Company determined the Guarantor Subsidiaries and Non-Guarantor Subsidiaries columns of the Condensed Combining Balance Sheet at December 31, 2017 and March 30, 2018 contained errors which understated total assets, total liabilities and equity of the guarantor subsidiaries reflected as non-guarantor subsidiaries and overstated total assets, total liabilities and equity of the non-guarantor subsidiaries. The errors related to certain guarantor subsidiaries reflected as non-guarantor subsidiaries and understating the equity in net income of certain guarantor subsidiaries. As a result of these errors, the guarantor subsidiaries and non-guarantor subsidiaries columns of the Condensed Combining Statements of Operations for the quarter ended June 30, 2017 and for the half year ended June 30, 2017 understated net income of the guarantor subsidiaries and overstated net income of the non-guarantor subsidiaries. The errors did not impact the Condensed Combining Statement of Cash Flows. The Company assessed the materiality of these items on previously issued annual and interim financial statements in accordance with SEC Staff Accounting Bulletin No. 99 and No. 108, and concluded that the disclosure errors were not material to the Company's previously issued annual and quarter financial statements taken as a whole. The Company has revised the reported amounts for Guarantor Subsidiaries, Non-Guarantor Subsidiaries and Eliminations in the December 31, 2017 Condensed Combining Balance Sheet, and the Condensed Combining Statements of Operations for the quarterly period ended June 30, 2017 and for the first half period ended June 30, 2017 , to correct for these errors as enumerated below. Additionally, the effect of changes in the guarantor subsidiaries resulting from the sale of Vertex Aerospace which occurred on June 29, 2018 are being retrospectively reflected in the below guarantor adjustment column. Condensed Combining Balance Sheet (at December 31, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Total assets $ 10,270 $ 3,156 $ (10,930 ) $ 1,201 $ (375 ) $ (1,052 ) $ 11,471 $ 2,781 $ (11,982 ) Total liabilities $ 1,756 $ 1,091 $ (419 ) $ (178 ) $ (66 ) $ 18 $ 1,578 $ 1,025 $ (401 ) Total equity $ 8,514 $ 2,065 $ (10,511 ) $ 1,379 $ (309 ) $ (1,070 ) $ 9,893 $ 1,756 $ (11,581 ) Condensed Combining Statement of Operations ( Second Quarter Ended June 30, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Net income $ 117 $ 52 $ (164 ) $ 28 $ (1 ) $ (27 ) $ 145 $ 51 $ (191 ) Condensed Combining Statement of Operations ( First Half Ended June 30, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Net Income $ 201 $ 100 $ (292 ) $ 47 $ (3 ) $ (44 ) $ 248 $ 97 $ (336 )

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 29, 2018
Accounting Policies [Abstract]
Principles of Consolidation and Reporting	Principles of Consolidation and Reporting The accompanying financial statements comprise the consolidated financial statements of L3. The consolidated financial statements of the Company include all wholly-owned and majority-owned subsidiaries and variable interest entities (VIEs) if the Company is the primary beneficiary. The Company holds interests in certain VIEs for which it was determined the Company is not the primary beneficiary. All significant intercompany transactions are eliminated in consolidation. Investments in equity securities, joint ventures and limited liability corporations over which the Company has significant influence but does not have control are accounted for using the equity method. Investments over which the Company does not have significant influence are accounted for using the cost method. For the classification of certain current assets and liabilities, the Company uses the duration of the related contract or program as its operating cycle, which may be longer than one year. Certain reclassifications have been made to conform prior-year amounts to the current-year presentation. The unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. The December 31, 2017 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. In the opinion of management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included. The results of operations for the interim periods are not necessarily indicative of results for the full year. It is generally the Company’s established practice to close its books for the quarters ending March, June and September on the Friday preceding the end of the calendar quarter. The interim unaudited condensed consolidated financial statements included herein have been prepared and are labeled based on that convention. The Company closes its books for annual periods on December 31 regardless of what day it falls on.
Accounting Estimates	Accounting Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of sales and costs of sales during the reporting period. The most significant of these estimates and assumptions for L3 relate to sales, profit and loss recognition related to performance obligations satisfied over time, fair values of assets acquired and liabilities assumed in business combinations and investments, market values for inventories reported at lower of cost or market, pension and postretirement benefit obligations, stock-based employee compensation expense, income taxes, including the valuations of deferred tax assets, litigation reserves, useful lives and valuation of recorded amounts of long-lived assets, identifiable intangible assets and goodwill. Changes in estimates are reflected in the periods during which they become known. Actual amounts may differ from these estimates and could differ materially.
Revenue Recognition	Revenue Recognition Effective January 1, 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers, as amended (commonly referred to as ASC 606) using the modified retrospective transition method. The cumulative effect of applying the standard was an increase of $13 million to shareholders' equity as of January 1, 2018. The Company’s statement of operations for the quarterly and first half periods ended June 29, 2018 and the Company’s balance sheet as of June 29, 2018 are presented under ASC 606, while the Company’s statement of operations for the quarterly and first half periods ended June 30, 2017 and the Company’s balance sheet as of December 31, 2017 are presented under ASC 605, Revenue Recognition . See Note 3 for disclosure of the impact of the adoption of ASC 606 on the Company’s statement of operations for the quarterly and first half periods ended June 29, 2018 and balance sheet as of June 29, 2018 and the effect of changes made to the Company’s consolidated balance sheet as of January 1, 2018. A substantial majority of the Company’s consolidated net sales are generated from long-term contracts with customers that require it to design, develop, manufacture, modify, upgrade, test and integrate complex aerospace and electronic equipment and to provide engineering and technical services according to the customers’ specifications. These contracts are primarily with agencies of, and prime system contractors to, the U.S. Government and foreign governments and are generally priced on a fixed-price, cost-plus or time-and-material type basis. Substantially all of the Company's cost-plus and time-and-material type contracts are with the U.S. Government, primarily the DoD. Certain of the Company’s contracts with the U.S. Government are multi-year contracts incrementally funded by the customer. The transaction price on these incrementally funded contracts includes contract value amounts not yet funded by the U.S. Government when the Company has a firm order for the goods or services and it is probable that the customer will fund such amounts. In assessing probability, the Company considers, among other factors, the period of time before contract funding is expected, communication from the customer that indicates funding will be obtained and the Company's history of receiving funding under the current contract or previous similar contracts. The Company also generates sales to a lesser extent from contracts with commercial and government customers for standard product and service offerings, which are priced on a firm fixed basis. See Note 23 for additional information regarding the composition of the Company’s net sales. The Company records sales for a contract when it has the approval and commitment of all parties, the contract identifies the rights of the parties and payment terms, the contract has commercial substance and collectibility of the consideration is probable. To determine the proper revenue recognition method, the Company first evaluates each of its contractual arrangements to identify its performance obligations. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. The majority of the Company’s contracts have a single performance obligation because the promise to transfer the individual good or service is not separately identifiable from other promises within the contract and is, therefore, not distinct. These contractual arrangements either require the use of a highly specialized manufacturing process to provide goods according to customer specifications or represent a bundle of contracted goods and services that are integrated and together represent a combined output, which may include the delivery of multiple units. Some of the Company's contracts have multiple performance obligations, primarily (i) related to the provision of multiple goods or services that have alternative use to the Company or that are not substantially the same or (ii) due to the contract covering multiple phases of the product lifecycle (development and engineering, production, maintenance and support). For contracts with more than one performance obligation, the Company allocates the total transaction price in an amount based on the estimated relative standalone selling prices underlying each performance obligation. In cases where a contract requires a customized good or service, the primary method used to estimate standalone selling price is the expected cost plus a margin approach. In cases where the Company sells a standard product or service offering, the standalone selling price is based on an observable standalone selling price. The majority of the Company's sales are from performance obligations satisfied over time and are primarily with agencies of, and prime system contractors to, the U.S. Government and foreign governments. Sales are recognized over time when control is continuously transferred to the customer during the contract. For U.S. Government contracts, the continuous transfer of control to the customer is supported by contract clauses that provide for (i) progress or performance-based payments or (ii) the unilateral right of the customer to terminate the contract for its convenience, in which case the Company has the right to receive payment for costs incurred plus a reasonable profit for products and services that do not have alternative use to the Company. Foreign government and certain commercial contracts contain similar termination for convenience clauses, or the Company has a legally enforceable right to receive payment for costs incurred and a reasonable profit for products or services that do not have alternative use to the Company. Sales on fixed price and cost-plus type contracts that include performance obligations satisfied over time are generally recorded at amounts equal to the ratio of actual cumulative costs incurred divided by total estimated costs at completion, multiplied by (i) the transaction price, less (ii) the cumulative sales recognized in prior periods (cost-to-cost method). Accounting for the sales and profits on performance obligations for which progress is measured using the cost-to-cost method involves the preparation of estimates of: (1) transaction price and (2) total costs at completion, which is equal to the sum of the actual incurred costs to date on the contract and the estimated costs to complete the contract's statement of work. Incurred costs include labor, material, overhead and, for the Company's U.S. Government contractor businesses, general and administrative (G&A) expenses. Incurred costs represent work performed, which corresponds with and thereby represents the transfer of control to the customer. The estimated profit or loss at completion on a contract is equal to the difference between the transaction price and the total estimated cost at completion. In the case of a contract related to complex aerospace or electronic equipment for which the total estimated costs exceed the total transaction price, a loss arises, and a provision for the entire loss is recorded in the period that the loss becomes evident. The unrecoverable costs on a loss contract that are expected to be incurred in the future periods are presented on the balance sheet as a component of other current liabilities entitled "Estimated cost in excess of estimated contract value to complete contracts in process in a loss position." See Note 10 for additional information. The Company’s contracts give rise to variable consideration, including award and incentive fees, as well as amounts incrementally funded by the U.S. Government, or other provisions that can either increase or decrease the transaction price. Award fees provide for a fee based on actual performance relative to contractually specified performance criteria. Incentive fees provide for a fee based on the relationship between total allowable costs and target costs. Variable consideration may require the Company to exercise significant judgment to determine the total transaction price of the contract. The Company includes variable consideration in the transaction price when there is a basis to reasonably estimate the variable amount it will be entitled to receive and it is probable that a significant reversal in revenue recognized will not be required when the uncertainty is resolved. These estimates are based on historical experience, current and forecasted performance, and the Company’s judgment at the time of the evaluation. Contract modifications routinely occur to account for changes in contract specifications or requirements. In most cases, contract modifications are for goods or services that are not distinct and, therefore, are accounted for as part of the existing contract. Transaction price estimates include additional consideration for submitted contract modifications or claims when the Company believes it has an enforceable right to the modification or claim, the amount can be reliably estimated and its realization is reasonably assured. Amounts representing modifications accounted for as part of the existing contract are included in the transaction price and recognized as an adjustment to sales on a cumulative catch-up basis. The Company’s fixed-price type contracts with the U.S. Government typically allow for progress payments or performance-based payments. Progress payments are billed to the customer as contract costs are incurred at an amount generally equal to 80% of incurred costs. Performance based payments are billed to the customer upon the achievement of predetermined performance milestones at amounts not to exceed 90% of contract price. On contracts with progress or performance-based payments, the customer often retains a small portion of the contract price until satisfactory completion of the contractual statement of work. Since a small portion of the contract price is retained, the Company generally recognizes sales in excess of billings, which are presented as contract assets on the balance sheet. The portion of the contract price retained by the customer is a normal business practice to ensure satisfactory contract completion and, therefore, is not considered a significant financing component. Contract assets also arise from cost-plus type contracts, time-and-material type contracts and fixed-price services type contracts for revenue amounts that have not been billed by the end of the accounting period due to the timing of preparation of invoices to customers. For certain fixed-price contracts with foreign governments and commercial customers, the Company receives advance payments. Advanced payments are not considered a significant financing component because they are a negotiated contract term to ensure the customer meets its financial obligation, particularly when there are significant upfront working capital requirements. The Company records a liability for advance payments received in excess of sales recognized, which is presented as a contract liability on the balance sheet. Revisions or adjustments to estimates of the transaction price, estimated costs at completion and estimated profit or loss of a performance obligation are often required as work progresses under a contract, as experience is gained, as facts and circumstances change and as new information is obtained, even though the scope of work required under the contract may not change. Revisions or adjustments may also be required if contract modifications occur. The impact of revisions in profit or loss estimates are recognized on a cumulative catch-up basis in the period in which the revisions are made. The revisions in contract estimates, if significant, can materially affect the Company’s results of operations and cash flows, as well as reduce the valuations of contract assets and inventories, and in some cases result in liabilities to complete contracts in a loss position. The aggregate impact of net changes in contract estimates is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Operating income $ 64 $ 42 $ 128 $ 84 Diluted earnings per share $ 0.61 $ 0.35 $ 1.22 $ 0.67 Net sales recognized from the Company's performance obligations satisfied in prior periods were $71 million and $139 million for the quarterly and first half periods ended June 29, 2018 , respectively, and relate to revisions in contract estimates. Sales from performance obligations satisfied at a point in time are typically for standard goods and are recognized when the customer obtains control, which is generally upon delivery and acceptance. The Company also records sales for performance obligations relating to standard services (i.e., maintenance and extended warranties covering standard goods sold by the Company) over time by using output measures of time elapsed to measure progress toward satisfying the performance obligation. Sales on time-and-material type contracts are generally recognized each period based on the amount billable to the customer, which is based on direct labor hours expended multiplied by the contractual fixed rate per hour, plus the actual costs of materials and other direct non-labor costs. The following table presents a summary of the Company’s net sales by revenue recognition method as a percentage of total net sales for the first half period ended June 29, 2018 . % of Total Net Sales Cost to cost method 76 % Point in time 18 % Output method 3 % Billing method 3 % Total 100 % Remaining Performance Obligations On June 29, 2018 , the Company had $10.2 billion of remaining performance obligations, which represents the transaction price of firm orders less inception to date sales recognized. Remaining performance obligations exclude unexercised contract options and potential orders under basic ordering agreements or master-type contracts (i.e., indefinite-delivery, indefinite-quantity (IDIQ)). The Company expects to recognize sales relating to existing performance obligations of approximately $4.7 billion during the remainder of 2018, $3.5 billion in 2019, $1.2 billion in 2020 and $0.8 billion in the periods thereafter.
Investments in and Loans to Nonconsolidated Affiliates	Investments in and Loans to Nonconsolidated Affiliates The Company’s investments in nonconsolidated affiliates are primarily accounted for using the equity method of accounting and are carried at cost, plus or minus the Company’s share of net earnings or losses of the investment, subject to certain other adjustments. The cost of equity method investments includes transaction costs of the acquisition. As required by U.S. GAAP, to the extent that there is a basis difference between the cost and the underlying equity in the net assets of an equity investment, the Company allocates such differences between tangible and intangible assets. The Company’s share of net earnings or losses of the investment, inclusive of amortization expense for any basis difference associated with the investment, are presented in interest and other income, net, on the Company’s consolidated statements of operations. Dividends received from the investee reduce the carrying amount of the investment. Due to the timing of receiving financial information from its nonconsolidated affiliates, the Company may record its share of net earnings or losses of such affiliates on a three -month lag basis, with the exception of the amortization expense of any basis difference related to tangible and intangible assets which are recorded currently.

New Accounting Standards Impl36

New Accounting Standards Implemented (Policies)	6 Months Ended
	Jun. 29, 2018
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards Implemented	Effective January 1, 2018, the Company adopted Financial Accounting Standards Board (FASB) ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . Defined benefit pension and postretirement benefit cost (net benefit cost) comprise several components that reflect different aspects of the Company’s financial arrangements as well as the cost of benefits provided to employees. Under previous U.S. GAAP, those components were aggregated for reporting in the financial statements and presented within the operating section of the income statement or capitalized into assets (inventories) when appropriate. The amendments in this update require the Company to report the service cost component in the same line item as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented separately from the service cost component and below income from operations. Plan administrative expenses, which were previously included in service cost, are presented together with expected return on plan assets, as a component of Interest and other income, net. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The amendments in this update have been applied retrospectively for the presentation of the components of net benefit cost and prospectively for the capitalization of the service cost component of net benefit cost. The adoption of this standard decreased operating income and increased interest and other income, net, each by $3 million and $5 million for the quarterly and first half periods ended June 29, 2018 , respectively, and increased operating income and decreased interest and other income, net, each by $2 million and $3 million for the quarterly and first half periods ended June 30, 2017 , respectively. The adoption of this standard did not impact pre-tax income for the quarterly and first half periods ended June 29, 2018 and June 30, 2017 . In January 2017, the FASB issued ASU 2017-01, Clarifying the Definition of a Business , which provides additional guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update provide new guidance to determine when an integrated set of assets and activities (collectively referred to as a ‘‘set’’) is not a business. The new guidance requires that, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. The new guidance reduces the number of transactions that need to be evaluated as a business. The Company adopted this amendment as of January 1, 2018. The adoption of ASU 2017-01 did not have a material impact on the Company's financial statements for the first half period ended June 29, 2018 . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers , as amended (commonly referred to as ASC 606), which replaces numerous requirements in U.S. GAAP, including industry-specific requirements, and provides companies with a single revenue recognition model for recognizing revenue from contracts with customers and significantly expanded the disclosure requirements for revenue arrangements. The new standard, as amended, was effective for the Company for interim and annual reporting periods beginning on January 1, 2018. As discussed in Note 2 , the Company adopted ASC 606 using the modified retrospective transition method. Results for reporting periods beginning after December 31, 2017 are presented under ASC 606, while prior period comparative information has not been restated and continues to be reported in accordance with ASC 605, Revenue Recognition, the accounting standard in effect for periods ending prior to January 1, 2018. With the adoption of ASC 606, the Company recognizes sales over time by using the cost-to-cost method on most of its (i) contracts that were covered by the contract accounting standards under ASC 605 and (ii) fixed-price type contracts that require it to perform services that are not related to the production of tangible assets. Accordingly, the adoption of ASC 606 primarily impacted certain (i) contracts previously covered by contract accounting standards that recognized revenue using the units-of-delivery method and (ii) fixed-price type contracts for services that are not related to the production of tangible assets that recognized revenue on a straight-line basis over the contractual service period. Based on contracts in process at December 31, 2017, the Company recorded, upon adoption of ASC 606, a net increase to retained earnings of $13 million , which includes the acceleration of net sales of approximately $380 million and the related cost of sales. The adjustment to retained earnings primarily relates to contracts previously accounted for under the units-of-delivery method, which is recognized under ASC 606 earlier in the performance period as costs are incurred, as opposed to when the units are delivered under ASC 605. In accordance with the modified retrospective transition provisions of ASC 606, the Company will not recognize any of the accelerated net sales and related cost of sales at January 1, 2018 in the Company’s statements of operations for any historical or future period. The Company made certain presentation changes to its consolidated balance sheet on January 1, 2018 to comply with ASC 606. The components of contracts in process as reported under ASC 605, which included unbilled contract receivables and inventoried contract costs, have been reclassified as contract assets and inventories, respectively, after certain adjustments described below under ASC 606. The adoption of ASC 606 resulted in an increase in unbilled contract receivables (referred to as contract assets under ASC 606) primarily from converting contracts previously applying the units-of-delivery method to the cost-to-cost method with a corresponding reduction in inventoried contract costs. The remainder of inventoried contract costs, primarily related to inventories not controlled by the Company's customers, were reclassified to inventories. Additionally, under ASC 606, the Company capitalizes costs to fulfill a contract (i.e., non-recurring costs for contract-related activities that do not transfer a good or service to the customer) and costs to obtain a contract (i.e., commissions paid to third-party agents or representatives) to prepaid expense and other current assets or other assets (non-current). The Company amortizes costs to obtain a contract and costs to fulfill a contract in a pattern similar to the recognition of sales on the contracts that the capitalized costs relate to. The Company previously accounted for costs to fulfill a contract either as inventoried contract costs or expensed them as incurred. Costs to obtain a contract were generally expensed as incurred. Advance payments and billings in excess of costs and deferred revenue, previously classified in other current liabilities, have been combined and are presented as contract liabilities. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . The amendments in this update allow a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for stranded tax effects resulting from the U.S. Tax Cuts and Jobs Act (U.S. Tax Reform). The new standard is effective for the Company beginning on January 1, 2019, with early adoption permitted. The Company will adopt ASU 2018-02 effective January 1, 2019. The Company does not expect the adoption of this standard will have a material effect on its financial position, results of operations or cash flows. In August 2017, the FASB issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this update intend to better align the Company risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedge relationships and the presentation of hedge results. The amendments in this update require the Company to present the earnings effect of the hedging instrument in the same income statement line in which the earnings effect of the hedged item is reported. Current U.S. GAAP provides for hedge accounting only for the portion of the hedge deemed to be highly effective and requires the Company to separately reflect the amount by which the hedging instrument does not offset the hedged item, which is referred to as the ineffective amount. The amendments in this update no longer require the Company to separately measure and report hedge ineffectiveness. The new standard is effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. For cash flow hedges existing at the date of adoption, the Company is required to apply a cumulative effect adjustment relating to the separate measurement of ineffectiveness to the opening balance of retained earnings. The amended presentation and disclosure guidance is required only prospectively. The Company will adopt ASU 2017-12 effective January 1, 2019. The Company does not expect the adoption of this standard to have a material effect on its financial position, results of operations or cash flows. In February 2016, the FASB issued ASU 2016-02, Leases , which updates the existing guidance on accounting for leases and requires new qualitative and quantitative disclosures about the Company’s leasing activities. The new standard requires the Company to recognize lease assets and lease liabilities on the balance sheet for all leases under which the Company is the lessee, including those classified as operating leases under previous accounting guidance. The Company will measure leases commencing after the adoption date based on the present value of the lease payments due over the lease term (as defined in ASU 2016-02), after applying the separation and allocation guidance of the new standard. The new standard, as amended, will be effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. In the adoption year, the Company will be required to (i) measure and recognize its existing leases based on the present value of the remaining minimum lease payments, as defined in existing guidance on accounting for leases, and (ii) restate each prior reporting period presented. The Company is currently evaluating the expected impact of the adoption of this standard on its consolidated financial statements and disclosures related to leasing activities. The Company plans to adopt ASU 2016-02 effective January 1, 2019. The Company has made progress in implementing the new standard by selecting a lease accounting system and assessing available practical expedients. The Company is in the process of accumulating and processing the data required to measure its existing leases and evaluating accounting policy and internal control changes to support management in the financial reporting and disclosure of leasing activities. See Note 18 to the audited consolidated financial statements for the year ended December 31, 2017 , included in the Company’s Annual Report on Form 10-K for additional information about the Company’s leases, including the future minimum lease payments of the Company's operating leases at December 31, 2017 . Other accounting standard updates effective for interim and annual periods beginning after December 31, 2018 are not expected to have a material impact on the Company’s financial position, results of operations or cash flows.

Accounting Standards Issued a37

Accounting Standards Issued and Not Yet Implemented (Policies)	6 Months Ended
	Jun. 29, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Standards Implemented	Effective January 1, 2018, the Company adopted Financial Accounting Standards Board (FASB) ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . Defined benefit pension and postretirement benefit cost (net benefit cost) comprise several components that reflect different aspects of the Company’s financial arrangements as well as the cost of benefits provided to employees. Under previous U.S. GAAP, those components were aggregated for reporting in the financial statements and presented within the operating section of the income statement or capitalized into assets (inventories) when appropriate. The amendments in this update require the Company to report the service cost component in the same line item as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented separately from the service cost component and below income from operations. Plan administrative expenses, which were previously included in service cost, are presented together with expected return on plan assets, as a component of Interest and other income, net. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The amendments in this update have been applied retrospectively for the presentation of the components of net benefit cost and prospectively for the capitalization of the service cost component of net benefit cost. The adoption of this standard decreased operating income and increased interest and other income, net, each by $3 million and $5 million for the quarterly and first half periods ended June 29, 2018 , respectively, and increased operating income and decreased interest and other income, net, each by $2 million and $3 million for the quarterly and first half periods ended June 30, 2017 , respectively. The adoption of this standard did not impact pre-tax income for the quarterly and first half periods ended June 29, 2018 and June 30, 2017 . In January 2017, the FASB issued ASU 2017-01, Clarifying the Definition of a Business , which provides additional guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update provide new guidance to determine when an integrated set of assets and activities (collectively referred to as a ‘‘set’’) is not a business. The new guidance requires that, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. The new guidance reduces the number of transactions that need to be evaluated as a business. The Company adopted this amendment as of January 1, 2018. The adoption of ASU 2017-01 did not have a material impact on the Company's financial statements for the first half period ended June 29, 2018 . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers , as amended (commonly referred to as ASC 606), which replaces numerous requirements in U.S. GAAP, including industry-specific requirements, and provides companies with a single revenue recognition model for recognizing revenue from contracts with customers and significantly expanded the disclosure requirements for revenue arrangements. The new standard, as amended, was effective for the Company for interim and annual reporting periods beginning on January 1, 2018. As discussed in Note 2 , the Company adopted ASC 606 using the modified retrospective transition method. Results for reporting periods beginning after December 31, 2017 are presented under ASC 606, while prior period comparative information has not been restated and continues to be reported in accordance with ASC 605, Revenue Recognition, the accounting standard in effect for periods ending prior to January 1, 2018. With the adoption of ASC 606, the Company recognizes sales over time by using the cost-to-cost method on most of its (i) contracts that were covered by the contract accounting standards under ASC 605 and (ii) fixed-price type contracts that require it to perform services that are not related to the production of tangible assets. Accordingly, the adoption of ASC 606 primarily impacted certain (i) contracts previously covered by contract accounting standards that recognized revenue using the units-of-delivery method and (ii) fixed-price type contracts for services that are not related to the production of tangible assets that recognized revenue on a straight-line basis over the contractual service period. Based on contracts in process at December 31, 2017, the Company recorded, upon adoption of ASC 606, a net increase to retained earnings of $13 million , which includes the acceleration of net sales of approximately $380 million and the related cost of sales. The adjustment to retained earnings primarily relates to contracts previously accounted for under the units-of-delivery method, which is recognized under ASC 606 earlier in the performance period as costs are incurred, as opposed to when the units are delivered under ASC 605. In accordance with the modified retrospective transition provisions of ASC 606, the Company will not recognize any of the accelerated net sales and related cost of sales at January 1, 2018 in the Company’s statements of operations for any historical or future period. The Company made certain presentation changes to its consolidated balance sheet on January 1, 2018 to comply with ASC 606. The components of contracts in process as reported under ASC 605, which included unbilled contract receivables and inventoried contract costs, have been reclassified as contract assets and inventories, respectively, after certain adjustments described below under ASC 606. The adoption of ASC 606 resulted in an increase in unbilled contract receivables (referred to as contract assets under ASC 606) primarily from converting contracts previously applying the units-of-delivery method to the cost-to-cost method with a corresponding reduction in inventoried contract costs. The remainder of inventoried contract costs, primarily related to inventories not controlled by the Company's customers, were reclassified to inventories. Additionally, under ASC 606, the Company capitalizes costs to fulfill a contract (i.e., non-recurring costs for contract-related activities that do not transfer a good or service to the customer) and costs to obtain a contract (i.e., commissions paid to third-party agents or representatives) to prepaid expense and other current assets or other assets (non-current). The Company amortizes costs to obtain a contract and costs to fulfill a contract in a pattern similar to the recognition of sales on the contracts that the capitalized costs relate to. The Company previously accounted for costs to fulfill a contract either as inventoried contract costs or expensed them as incurred. Costs to obtain a contract were generally expensed as incurred. Advance payments and billings in excess of costs and deferred revenue, previously classified in other current liabilities, have been combined and are presented as contract liabilities. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . The amendments in this update allow a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for stranded tax effects resulting from the U.S. Tax Cuts and Jobs Act (U.S. Tax Reform). The new standard is effective for the Company beginning on January 1, 2019, with early adoption permitted. The Company will adopt ASU 2018-02 effective January 1, 2019. The Company does not expect the adoption of this standard will have a material effect on its financial position, results of operations or cash flows. In August 2017, the FASB issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this update intend to better align the Company risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedge relationships and the presentation of hedge results. The amendments in this update require the Company to present the earnings effect of the hedging instrument in the same income statement line in which the earnings effect of the hedged item is reported. Current U.S. GAAP provides for hedge accounting only for the portion of the hedge deemed to be highly effective and requires the Company to separately reflect the amount by which the hedging instrument does not offset the hedged item, which is referred to as the ineffective amount. The amendments in this update no longer require the Company to separately measure and report hedge ineffectiveness. The new standard is effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. For cash flow hedges existing at the date of adoption, the Company is required to apply a cumulative effect adjustment relating to the separate measurement of ineffectiveness to the opening balance of retained earnings. The amended presentation and disclosure guidance is required only prospectively. The Company will adopt ASU 2017-12 effective January 1, 2019. The Company does not expect the adoption of this standard to have a material effect on its financial position, results of operations or cash flows. In February 2016, the FASB issued ASU 2016-02, Leases , which updates the existing guidance on accounting for leases and requires new qualitative and quantitative disclosures about the Company’s leasing activities. The new standard requires the Company to recognize lease assets and lease liabilities on the balance sheet for all leases under which the Company is the lessee, including those classified as operating leases under previous accounting guidance. The Company will measure leases commencing after the adoption date based on the present value of the lease payments due over the lease term (as defined in ASU 2016-02), after applying the separation and allocation guidance of the new standard. The new standard, as amended, will be effective for the Company for interim and annual reporting periods beginning on January 1, 2019, with early adoption permitted. In the adoption year, the Company will be required to (i) measure and recognize its existing leases based on the present value of the remaining minimum lease payments, as defined in existing guidance on accounting for leases, and (ii) restate each prior reporting period presented. The Company is currently evaluating the expected impact of the adoption of this standard on its consolidated financial statements and disclosures related to leasing activities. The Company plans to adopt ASU 2016-02 effective January 1, 2019. The Company has made progress in implementing the new standard by selecting a lease accounting system and assessing available practical expedients. The Company is in the process of accumulating and processing the data required to measure its existing leases and evaluating accounting policy and internal control changes to support management in the financial reporting and disclosure of leasing activities. See Note 18 to the audited consolidated financial statements for the year ended December 31, 2017 , included in the Company’s Annual Report on Form 10-K for additional information about the Company’s leases, including the future minimum lease payments of the Company's operating leases at December 31, 2017 . Other accounting standard updates effective for interim and annual periods beginning after December 31, 2018 are not expected to have a material impact on the Company’s financial position, results of operations or cash flows.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	6 Months Ended
	Jun. 29, 2018
Accounting Policies [Abstract]
Aggregate Impact of Net Changes in Contract Estimates	The aggregate impact of net changes in contract estimates is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Operating income $ 64 $ 42 $ 128 $ 84 Diluted earnings per share $ 0.61 $ 0.35 $ 1.22 $ 0.67
Summary of Net Sales by Revenue Recognition Method as Percentage of Total Net Sales	The following table presents a summary of the Company’s net sales by revenue recognition method as a percentage of total net sales for the first half period ended June 29, 2018 . % of Total Net Sales Cost to cost method 76 % Point in time 18 % Output method 3 % Billing method 3 % Total 100 %
Impact of Adoption of New Accounting Pronouncement	The aggregate impact of net changes in contract estimates is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Operating income $ 64 $ 42 $ 128 $ 84 Diluted earnings per share $ 0.61 $ 0.35 $ 1.22 $ 0.67 The table below presents the cumulative effect of the changes made to the consolidated January 1, 2018 balance sheet due to the adoption of ASC 606. BALANCE SHEET December 31, 2017 As Reported Under ASC 605 Adjustments Due to ASC 606 January 1, 2018 As Adjusted Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,349 $ 1,349 Contracts in process 1,933 (1,933 ) — Inventories 389 537 926 Prepaid expenses and other current assets 300 17 317 Assets held for sale 135 3 138 Assets of discontinued operations 306 (21 ) 285 Total current assets 4,448 (48 ) 4,400 Other assets 264 49 313 Total assets $ 12,729 $ 1 $ 12,730 Liabilities Current liabilities: Accrued expenses $ 217 $ (13 ) $ 204 Contract liabilities — 565 565 Advance payments and billing in excess of costs incurred 509 (509 ) — Other current liabilities 367 (49 ) 318 Liabilities held for sale 17 (1 ) 16 Liabilities of discontinued operations 226 (23 ) 203 Total current liabilities 2,379 (30 ) 2,349 Deferred income taxes 158 4 162 Other liabilities 398 14 412 Total liabilities 7,578 (12 ) 7,566 Shareholders' Equity Retained earnings 6,659 13 6,672 Total equity $ 5,151 $ 13 $ 5,164 The tables below present the impact of the adoption of ASC 606 on the Company's statement of operations. Second Quarter Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 1,741 $ 45 $ 1,786 Services 797 — 797 Total 2,538 45 2,583 Operating costs and expenses: Cost of sales — Products $ (1,316 ) $ (33 ) $ (1,349 ) Cost of sales — Services (561 ) (17 ) (578 ) General and administrative expenses (387 ) 4 (383 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 321 — 321 Income from continuing operations before income taxes 237 — 237 Provision for income taxes (48 ) — (48 ) Income from continuing operations 189 — 189 Income from discontinued operations, net of income taxes 191 (1 ) 190 Net income 380 (1 ) 379 Net income attributable to L3 $ 376 $ (1 ) $ 375 Basic earnings per share attributable to common shareholders: Continuing operations $ 2.36 $ — $ 2.36 Discontinued operations 2.44 (0.02 ) 2.42 Basic earnings per share $ 4.80 $ (0.02 ) $ 4.78 Diluted earnings per share attributable to common shareholders: Continuing operations $ 2.33 $ — $ 2.33 Discontinued operations 2.41 (0.02 ) 2.39 Diluted earnings per share $ 4.74 $ (0.02 ) $ 4.72 First Half Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 3,315 $ 117 $ 3,432 Services 1,518 4 1,522 Total 4,833 121 4,954 Operating costs and expenses: Cost of sales — Products $ (2,461 ) $ (79 ) $ (2,540 ) Cost of sales — Services (1,089 ) (21 ) (1,110 ) General and administrative expenses (777 ) (3 ) (780 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 553 19 572 Income from continuing operations before income taxes 434 19 453 Provision for income taxes (67 ) (5 ) (72 ) Income from continuing operations 367 14 381 Income from discontinued operations, net of income taxes 206 — 206 Net income 573 14 587 Net income attributable to L3 $ 564 $ 14 $ 578 Basic earnings per share attributable to common shareholders: Continuing operations $ 4.57 $ 0.18 $ 4.75 Discontinued operations 2.63 — 2.63 Basic earnings per share $ 7.20 $ 0.18 $ 7.38 Diluted earnings per share attributable to common shareholders: Continuing operations $ 4.50 $ 0.17 $ 4.67 Discontinued operations 2.59 — 2.59 Diluted earnings per share $ 7.09 $ 0.17 $ 7.26 The following table quantifies the impact of adopting ASC 606 on segment net sales and segment operating income for the quarterly and first half periods ended June 29, 2018 . Effect of ASC 606 Second Quarter Ended June 29, 2018 First Half Ended June 29, 2018 Sales Operating Income Sales Operating Income (in millions) Electronic Systems $ 14 $ 4 $ 44 $ 7 Aerospace Systems (2 ) (7 ) 2 (6 ) Communication Systems 21 (1 ) 41 3 Sensor Systems 12 3 34 14 Segment totals $ 45 $ (1 ) $ 121 $ 18 The table below presents the impact of the adoption of ASC 606 on the Company's balance sheet. June 29, 2018 BALANCE SHEET Under Effect of As Reported Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,611 $ 1,611 Contracts in process 2,185 (2,185 ) — Inventories 405 529 934 Prepaid expenses and other current assets 316 16 332 Assets held for sale — — — Assets of discontinued operations — — — Total current assets 5,135 (29 ) 5,106 Other assets 300 48 348 Total assets $ 13,511 $ 19 $ 13,530 Liabilities Current liabilities: Accrued expenses $ 279 $ (15 ) $ 264 Contract liabilities — 554 554 Advance payments and billings in excess of costs incurred 522 (522 ) — Other current liabilities 384 (46 ) 338 Total current liabilities 2,832 (29 ) 2,803 Deferred income taxes 181 9 190 Other liabilities 402 14 416 Total liabilities 8,024 (6 ) 8,018 Shareholders' Equity Retained earnings 7,101 25 7,126 Total equity $ 5,487 $ 25 $ 5,512

New Accounting Standards Impl39

New Accounting Standards Implemented (Tables)	6 Months Ended
	Jun. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Impact of Adoption of New Accounting Pronouncement	The aggregate impact of net changes in contract estimates is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Operating income $ 64 $ 42 $ 128 $ 84 Diluted earnings per share $ 0.61 $ 0.35 $ 1.22 $ 0.67 The table below presents the cumulative effect of the changes made to the consolidated January 1, 2018 balance sheet due to the adoption of ASC 606. BALANCE SHEET December 31, 2017 As Reported Under ASC 605 Adjustments Due to ASC 606 January 1, 2018 As Adjusted Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,349 $ 1,349 Contracts in process 1,933 (1,933 ) — Inventories 389 537 926 Prepaid expenses and other current assets 300 17 317 Assets held for sale 135 3 138 Assets of discontinued operations 306 (21 ) 285 Total current assets 4,448 (48 ) 4,400 Other assets 264 49 313 Total assets $ 12,729 $ 1 $ 12,730 Liabilities Current liabilities: Accrued expenses $ 217 $ (13 ) $ 204 Contract liabilities — 565 565 Advance payments and billing in excess of costs incurred 509 (509 ) — Other current liabilities 367 (49 ) 318 Liabilities held for sale 17 (1 ) 16 Liabilities of discontinued operations 226 (23 ) 203 Total current liabilities 2,379 (30 ) 2,349 Deferred income taxes 158 4 162 Other liabilities 398 14 412 Total liabilities 7,578 (12 ) 7,566 Shareholders' Equity Retained earnings 6,659 13 6,672 Total equity $ 5,151 $ 13 $ 5,164 The tables below present the impact of the adoption of ASC 606 on the Company's statement of operations. Second Quarter Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 1,741 $ 45 $ 1,786 Services 797 — 797 Total 2,538 45 2,583 Operating costs and expenses: Cost of sales — Products $ (1,316 ) $ (33 ) $ (1,349 ) Cost of sales — Services (561 ) (17 ) (578 ) General and administrative expenses (387 ) 4 (383 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 321 — 321 Income from continuing operations before income taxes 237 — 237 Provision for income taxes (48 ) — (48 ) Income from continuing operations 189 — 189 Income from discontinued operations, net of income taxes 191 (1 ) 190 Net income 380 (1 ) 379 Net income attributable to L3 $ 376 $ (1 ) $ 375 Basic earnings per share attributable to common shareholders: Continuing operations $ 2.36 $ — $ 2.36 Discontinued operations 2.44 (0.02 ) 2.42 Basic earnings per share $ 4.80 $ (0.02 ) $ 4.78 Diluted earnings per share attributable to common shareholders: Continuing operations $ 2.33 $ — $ 2.33 Discontinued operations 2.41 (0.02 ) 2.39 Diluted earnings per share $ 4.74 $ (0.02 ) $ 4.72 First Half Ended June 29, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 3,315 $ 117 $ 3,432 Services 1,518 4 1,522 Total 4,833 121 4,954 Operating costs and expenses: Cost of sales — Products $ (2,461 ) $ (79 ) $ (2,540 ) Cost of sales — Services (1,089 ) (21 ) (1,110 ) General and administrative expenses (777 ) (3 ) (780 ) Gain on sale of the Crestview & TCS Businesses 47 1 48 Operating income 553 19 572 Income from continuing operations before income taxes 434 19 453 Provision for income taxes (67 ) (5 ) (72 ) Income from continuing operations 367 14 381 Income from discontinued operations, net of income taxes 206 — 206 Net income 573 14 587 Net income attributable to L3 $ 564 $ 14 $ 578 Basic earnings per share attributable to common shareholders: Continuing operations $ 4.57 $ 0.18 $ 4.75 Discontinued operations 2.63 — 2.63 Basic earnings per share $ 7.20 $ 0.18 $ 7.38 Diluted earnings per share attributable to common shareholders: Continuing operations $ 4.50 $ 0.17 $ 4.67 Discontinued operations 2.59 — 2.59 Diluted earnings per share $ 7.09 $ 0.17 $ 7.26 The following table quantifies the impact of adopting ASC 606 on segment net sales and segment operating income for the quarterly and first half periods ended June 29, 2018 . Effect of ASC 606 Second Quarter Ended June 29, 2018 First Half Ended June 29, 2018 Sales Operating Income Sales Operating Income (in millions) Electronic Systems $ 14 $ 4 $ 44 $ 7 Aerospace Systems (2 ) (7 ) 2 (6 ) Communication Systems 21 (1 ) 41 3 Sensor Systems 12 3 34 14 Segment totals $ 45 $ (1 ) $ 121 $ 18 The table below presents the impact of the adoption of ASC 606 on the Company's balance sheet. June 29, 2018 BALANCE SHEET Under Effect of As Reported Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,611 $ 1,611 Contracts in process 2,185 (2,185 ) — Inventories 405 529 934 Prepaid expenses and other current assets 316 16 332 Assets held for sale — — — Assets of discontinued operations — — — Total current assets 5,135 (29 ) 5,106 Other assets 300 48 348 Total assets $ 13,511 $ 19 $ 13,530 Liabilities Current liabilities: Accrued expenses $ 279 $ (15 ) $ 264 Contract liabilities — 554 554 Advance payments and billings in excess of costs incurred 522 (522 ) — Other current liabilities 384 (46 ) 338 Total current liabilities 2,832 (29 ) 2,803 Deferred income taxes 181 9 190 Other liabilities 402 14 416 Total liabilities 8,024 (6 ) 8,018 Shareholders' Equity Retained earnings 7,101 25 7,126 Total equity $ 5,487 $ 25 $ 5,512

Acquisitions, Divestitures an40

Acquisitions, Divestitures and Discontinued Operations (Tables)	6 Months Ended
	Jun. 29, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Components of Pre-tax (Loss) Gain Recognized, Proceeds Received and Net Sales Included in Continuing Operations from Business Divestitures Of Business Divestitures	The table below presents pre-tax (loss) gain recognized, the proceeds received and net sales included in continuing operations from these divestitures. First Half Ended June 30, 2017 Pre-Tax (Loss) gain Proceeds Received Net Sales (in millions) Aviation Jet Services divestiture $ (5 ) $ 1 $ 1 Coleman divestiture (3 ) 17 9 Display Product Line divestiture 4 7 — Total $ (4 ) $ 25 $ 10
Unaudited Pro Forma Statements of Operations Data	The following unaudited pro forma Statements of Operations data present the combined results of the Company and its business acquisitions completed during the first half period ended June 29, 2018 and the year ended December 31, 2017 , assuming that the business acquisitions completed during 2018 and 2017 had occurred on January 1, 2017 and January 1, 2016 , respectively. The unaudited pro forma Statements of Operations data below include adjustments for additional amortization expense related to acquired intangible assets and depreciation assuming the 2018 and 2017 acquisitions had occurred on January 1, 2017 and January 1, 2016 , respectively. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Pro forma net sales $ 2,592 $ 2,413 $ 4,973 $ 4,765 Pro forma income from continuing operations attributable to L3 $ 187 $ 189 $ 375 $ 343 Pro forma net income attributable to L3 $ 377 $ 201 $ 581 $ 366 Pro forma diluted earnings per share from continuing operations $ 2.36 $ 2.38 $ 4.71 $ 4.32 Pro forma diluted earnings per share $ 4.75 $ 2.53 $ 7.30 $ 4.61
Disposal Groups, Including Discontinued Operations	As discussed in Note 1 , on June 29, 2018, the Company completed the sale of its Vertex Aerospace business. The table below presents the statements of operations data for Vertex Aerospace. The amounts presented in discontinued operations include allocated interest expenses for debt not directly attributable or related to L3’s other operations. Interest expense was allocated in accordance with the accounting standards for discontinued operations and were based on the ratio of Vertex Aerospace’s net assets to the sum of: (1) L3 consolidated total net assets and (2) L3 consolidated total debt. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Net sales $ 226 $ 351 $ 597 $ 703 Operating costs and expenses (1) (212 ) (332 ) (561 ) (667 ) Operating income from discontinued operations 14 19 36 36 Interest expense allocated to discontinued operations — — (1 ) (1 ) Gain on sale of businesses 237 — 237 — Income from discontinued operations before income taxes 251 19 272 35 Income tax expense (61 ) (7 ) (66 ) (12 ) Income from discontinued operations, net of income taxes $ 190 $ 12 $ 206 $ 23 __________________ (1) For the quarterly and first half periods ended June 29, 2018, the Company recognized $3 million of trailing expenses related to the sale of NSS. The major classes of assets and liabilities that were included in discontinued operations related to Vertex Aerospace are presented in the table below. These balances were classified as current at December 31, 2017 as the sale was expected to be completed within one year and the proceeds are not expected to be used to pay down long-term debt. December 31, (in millions) Assets Current assets $ 284 Property, plant and equipment, net 13 Other intangible assets 7 Other assets 2 Total assets of discontinued operations $ 306 Liabilities Accounts payable, trade $ 63 Other current liabilities 131 Current liabilities 194 Long-term liabilities 32 Total liabilities of discontinued operations $ 226
Schedule Of Results Of Operations Of Business Divestitures	Net sales and income before income taxes for Aviation Jet Services, Coleman and the Display Product Line, included in L3’s consolidated statements of operations, are presented in the table below on an aggregate basis and are included in income from continuing operations for all periods presented. First Half Ended June 30, 2017 (in millions) Net sales $ 10 Income before income taxes $ 2
Assets Held for Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Components of Pre-tax (Loss) Gain Recognized, Proceeds Received and Net Sales Included in Continuing Operations from Business Divestitures Of Business Divestitures	The table below presents Crestview & TCS Businesses ’ results of operations and is included in continuing operations. First Half Ended June 29, 2018 (in millions) Net Sales $ 64 Gain on sale of businesses $ 48 Income from continuing operations before income taxes $ 3
Disposal Groups, Including Discontinued Operations	The major classes of assets and liabilities included as held for sale related to the Crestview & TCS Businesses are presented in the table below. December 31, (in millions) Assets Billed receivables $ 14 Contracts in process 33 Total current assets 47 Property, plant and equipment, net 34 Goodwill 52 Identifiable intangible assets 2 Total assets classified as held for sale $ 135 Liabilities Accounts payable, trade $ 3 Accrued employment costs 2 Accrued expenses 3 Other current liabilities 5 Total current liabilities 13 Deferred income taxes 4 Total liabilities classified as held for sale $ 17

Contract Assets and Contract 41

Contract Assets and Contract Liabilities (Tables)	6 Months Ended
	Jun. 29, 2018
Revenue from Contract with Customer [Abstract]
Rollforward of Net Contract Assets (Liabilities)	The table below presents the components of net contract assets (liabilities). June 29, January 1, (in millions) Contract assets $ 1,611 $ 1,349 Contract liabilities — current (554 ) (565 ) Contract liabilities — non-current (33 ) (28 ) Net contract assets (liabilities) $ 1,024 $ 756
Components of Contract Assets	The components of contract assets are presented in the table below. June 29, January 1, (in millions) Unbilled contract receivables, gross $ 2,643 $ 2,232 Unliquidated progress payments and advances (1,032 ) (883 ) Total contract assets $ 1,611 $ 1,349

Contracts in Process (Tables)

Contracts in Process (Tables)	6 Months Ended
	Jun. 29, 2018
Contractors [Abstract]
Components of Contracts in Process	The components of contracts in process are presented in the table below. December 31, (in millions) Unbilled contract receivables, gross $ 1,874 Unliquidated progress payments (761 ) Unbilled contract receivables, net 1,113 Inventoried contract costs, gross 891 Unliquidated progress payments (71 ) Inventoried contract costs, net 820 Total contracts in process $ 1,933
General and Administrative, Independent Research and Development and Bid and Proposal Costs	The table below presents a summary of G&A, IRAD and B&P costs included in inventoried contract costs and the changes to them, including amounts charged to operating costs and expenses by the Company’s U.S. Government contractor businesses for the quarterly and first half periods ended June 30, 2017 . Second Quarter Ended First Half Ended June 30, 2017 June 30, 2017 (in millions) Amounts included in inventoried contract costs at beginning of the period $ 177 $ 173 Contract costs incurred: IRAD and B&P 78 154 Other G&A 199 399 Total 277 553 Amounts charged to operating costs and expenses (280 ) (552 ) Amounts included in inventoried contract costs at end of the period $ 174 $ 174

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 29, 2018
Inventory Disclosure [Abstract]
Inventories at Lower of Cost or Realizable Value	The table below presents the components of inventories at the lower of cost (first-in, first-out or average cost) or realizable value. The Company's inventories at December 31, 2017 were comprised primarily of amounts related to standard products. In addition, the Company classified inventories related to contracts for complex aerospace and electronic equipment and engineering and technical services according to the customers' specifications as inventoried contract costs, which was a component of contracts in process on the consolidated balance sheet at December 31, 2017. See Note 7 for additional information. In accordance with ASC 606, all inventories that customers do not currently control are classified within inventories on the Company's consolidated balance sheet at June 29, 2018 , without regard to whether the goods promised to the customer are standard or customized. June 29, December 31, (in millions) Raw materials, components and sub-assemblies $ 318 $ 184 Work in process 430 98 Finished goods 186 107 Total $ 934 $ 389

Goodwill and Identifiable Int44

Goodwill and Identifiable Intangible Assets (Tables)	6 Months Ended
	Jun. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill by Segment	The table below presents the changes in goodwill allocated to the Company’s reporting units in each reportable segment. Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated Total (in millions) Goodwill $ 2,856 $ 1,146 $ 1,058 $ 1,659 $ 6,719 Accumulated impairment losses (43 ) — (35 ) (26 ) (104 ) December 31, 2017 2,813 1,146 1,023 1,633 6,615 Business acquisitions (1) 16 — — 43 59 Foreign currency translation adjustments (15 ) (3 ) — (5 ) (23 ) June 29, 2018 2,814 1,143 1,023 1,671 6,651 Goodwill 2,857 1,143 1,058 1,697 6,755 Accumulated impairment losses (43 ) — (35 ) (26 ) (104 ) $ 2,814 $ 1,143 $ 1,023 $ 1,671 $ 6,651 __________________ (1) The increase for the Electronic Systems segment was due to the acquisition of the Latitude Engineering business and the purchase price allocation adjustments for the Doss Aviation and G-Air business acquisitions. The increase for the Sensor Systems segment was due to the acquisition of the Applied Defense Solutions business and the purchase price allocation adjustments for the Adaptive Methods and Kigre business acquisitions.
Identifiable Intangible Assets	The table below presents information for the Company’s identifiable intangible assets that are subject to amortization and indefinite-lived intangible assets. June 29, 2018 December 31, 2017 Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in years) (in millions) Customer contractual relationships 15 $ 406 $ 273 $ 133 $ 393 $ 257 $ 136 Technology 10 190 121 69 189 114 75 Other 14 34 14 20 29 14 15 Total subject to amortization 630 408 222 611 385 226 IPR&D indefinite 66 — 66 66 — 66 Total $ 696 $ 408 $ 288 $ 677 $ 385 $ 292
Amortization Expense	The table below presents amortization expense recorded by the Company for its identifiable intangible assets. Second Quarter Ended First Half Ended June 29, June 30, June 29, 2018 June 30, 2017 (in millions) Amortization expense $ 11 $ 10 22 20
Estimated Amortization Expense	Based on gross carrying amounts at June 29, 2018 , the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2018 through 2022 is presented in the table below. Year Ending December 31, 2018 2019 2020 2021 2022 (in millions) Estimated amortization expense $ 44 $ 42 $ 33 $ 27 $ 23

Other Current Liabilities and45

Other Current Liabilities and Other Liabilities (Tables)	6 Months Ended
	Jun. 29, 2018
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	The table below presents the components of other current liabilities. June 29, December 31, (in millions) Other Current Liabilities: Accrued product warranty costs $ 75 $ 69 Estimated costs in excess of estimated contract value to complete contracts in process in a loss position 55 63 Accrued interest 28 43 Estimated contingent purchase price payable for acquired businesses and other investments (see Note 16) 17 11 Deferred revenues — 38 Other 163 143 Total other current liabilities $ 338 $ 367
Other Liabilities	The table below presents the components of other liabilities. June 29, December 31, (in millions) Other Liabilities: Non-current income taxes payable (see Note 12) $ 179 $ 164 Deferred compensation 53 49 Contract liabilities (see Note 6) 33 — Accrued workers' compensation 24 23 Accrued product warranty costs 23 30 Notes payable and capital lease obligations 19 16 Estimated contingent purchase price payable for acquired businesses (see Note 16) 10 20 Deferred revenues — 19 Other 75 77 Total other liabilities $ 416 $ 398
Changes in Company's Accrued Product Warranty Costs	The table below presents the changes in the Company’s accrued product warranty costs. First Half Ended June 29, June 30, (in millions) Accrued product warranty costs: Balance at January 1 $ 99 $ 109 Acquisitions during the period — 3 Accruals for product warranties issued during the period 25 22 Changes to accruals for product warranties existing before January 1 1 — Settlements made during the period (26 ) (29 ) Foreign currency translation adjustments (1 ) 1 Balance at end of period $ 98 $ 106

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 29, 2018
Debt Disclosure [Abstract]
Components of Debt and Reconciliation to Carrying Amount of Current and Long-Term Debt	The components of debt and a reconciliation to the carrying amount of current and long-term debt are presented in the table below. June 29, December 31, (in millions) Borrowings under Revolving Credit Facility (1) $ — $ — 5.20% Senior Notes due 2019 317 1,000 4.75% Senior Notes due 2020 265 800 4.95% Senior Notes due 2021 650 650 3.85% Senior Notes due 2023 800 — 3.95% Senior Notes due 2024 350 350 3.85% Senior Notes due 2026 550 550 4.40% Senior Notes due 2028 1,000 — Principal amount of long-term debt 3,932 3,350 Unamortized discounts (8 ) (7 ) Deferred debt issue costs (24 ) (13 ) Carrying amount of long-term debt 3,900 3,330 Current portion of long-term debt (581 ) — Carrying amount of long-term debt, excluding current portion $ 3,319 $ 3,330 __________________ (1) During the first half period ended June 29, 2018 , L3’s aggregate borrowings and repayments under the Credit Facility were $501 million . At June 29, 2018 , L3 had the full availability of its $1 billion Credit Facility.
Information Regarding Outstanding Senior Subordinated Notes	Issuance of Senior Notes On June 6, 2018, L3 issued two series of senior notes, which are unsecured senior obligations of L3. The terms of each series of senior notes are presented in the table below. Note Date of Issuance Amount Issued Discount (1) Net Proceeds (2) Effective Interest Rate Redemption at Treasury Rate (3)(4) (dollars in millions) 3.85% Senior Notes due June 15, 2023 (the 2023 Notes) June 6, 2018 $ 800 $ 2 $ 792 3.89 % 20 bps 4.40% Senior Notes due June 15, 2028 (the 2028 Notes) June 6, 2018 $ 1,000 $ 1 $ 990 4.41 % 25 bps __________________ (1) Bond discounts are recorded as a reduction to the principal amount of the notes and are amortized as interest expense over the term of the notes. (2) The net cash proceeds of $1,782 million (after deduction of the discount, underwriting expenses and commissions and other related expenses) plus cash on hand were used to fund the concurrent cash tender offers (the Tender Offers) for any and all of $1 billion aggregate principal amount of 5.20% Senior Notes due October 15, 2019 (the 2019 Notes) and $800 million aggregate principal amount of 4.75% Senior Notes due July 15, 2020 (the 2020 Notes) and any related redemption of notes not tendered in the Tender Offers. (3) The 2023 Notes may be redeemed at any time prior to May 15, 2023 (one month prior to maturity) and the 2028 Notes may be redeemed at any time prior to March 15, 2028 (three months prior to maturity), at the option of L3, in whole or in part, at a redemption price equal to the greater of: (i) 100% of the principal amount, or (ii) the present value of the remaining principal and interest payments discounted to the date of redemption, on a semi-annual basis, at the Treasury Rate (as defined in the indentures governing the senior notes), plus the spread indicated in the table above. In addition, if the 2023 Notes and the 2028 Notes are redeemed at any time on or after May 15, 2023 and March 15, 2028, respectively, the redemption price would be equal to 100% of the principal amount. (4) Upon the occurrence of a change in control (as defined in the indentures governing the senior notes), each holder of the notes will have the right to require L3 to repurchase all or any part of such holder’s notes at an offer price in cash equal to 101% of the aggregate principal amount plus accrued and unpaid interest, if any, to the date of purchase.
Repurchases, Redemptions and Maturities of Senior Notes	Repurchases and Redemptions of Senior Notes The table below summarizes the 2019 Notes and the 2020 Notes Tender Offers. Note Settlement Type Date Settled Aggregate Principal Principal Tendered Tender Premium Cash Tendered (1) Interest Total Cash Payments Debt Charge (2) (dollars in millions) 5.20% Senior Notes due 2019 Tender Offer June 6, 2018 $ 1,000 $ 683 103.282 % $ 705 $ 5 $ 710 $ 24 4.75% Senior Notes due 2020 Tender Offer June 6, 2018 $ 800 $ 535 104.092 % $ 557 $ 10 $ 567 $ 24 __________________ (1) Excludes $1 million of tender offer fees. (2) The debt retirement charge includes $1 million of tender offer fees and $3 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts. On June 6, 2018, the Company initiated the redemption of the 2019 Notes and the 2020 Notes that remained outstanding subsequent to the expiration of the Tender Offers. On July 6, 2018, the Company completed the redemption of the 2019 Notes and the 2020 Notes. The terms of the 2019 Notes and the 2020 Notes redemption are presented in the table below. Note Settlement Type Date Settled Principal Redemption Premium Cash Payments Interest Total Cash Payments Debt Charge (1) (dollars in millions) 5.20% Senior Notes due 2019 Redemption July 6, 2018 $ 317 103.048 % $ 327 $ 4 $ 331 $ 10 4.75% Senior Notes due 2020 Redemption July 6, 2018 $ 265 103.818 % $ 275 $ 6 $ 281 $ 11 __________________ (1) The debt retirement charge includes $1 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts.

Accumulated Other Comprehensi47

Accumulated Other Comprehensive (Loss) Income (AOCI) (Tables)	6 Months Ended
	Jun. 29, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Summary of AOCI Balances Including Amounts Reclassified from AOCI into Net Income	The changes in the AOCI balances, including amounts reclassified from AOCI into net income, are presented in the table below. Foreign currency translation Unrealized gains (losses) on hedging instruments Unrecognized (losses) gains and prior service cost, net Total accumulated other comprehensive loss (in millions) Balance at December 31, 2017 $ (54 ) $ 9 $ (646 ) $ (691 ) Other comprehensive loss before reclassifications, net of tax (39 ) (10 ) — (49 ) Amounts reclassified from AOCI, net of tax — (1 ) 27 26 Net current period other comprehensive (loss) income (39 ) (11 ) 27 (23 ) Balance at June 29, 2018 $ (93 ) $ (2 ) $ (619 ) $ (714 ) Balance at December 31, 2016 $ (178 ) $ 6 $ (554 ) $ (726 ) Other comprehensive income before reclassifications, net of tax 71 1 — 72 Amounts reclassified from AOCI, net of tax — (1 ) 19 18 Net current period other comprehensive income 71 — 19 90 Balance at June 30, 2017 $ (107 ) $ 6 $ (535 ) $ (636 )
Summary of Amounts Reclassified from AOCI into Net Income	Further details regarding the amounts reclassified from AOCI into net income are presented in the table below. Amount Reclassified from AOCI (a) Affected Line Item in the Unaudited Condensed Consolidated Statements of Operations Second Quarter Ended First Half Ended Details About AOCI Components June 29, June 30, June 29, June 30, (in millions) Gain on hedging instruments $ — $ 1 $ 1 $ 1 Income from continuing operations before income taxes $ — $ 1 $ 1 $ 1 Income from continuing operations Amortization of defined benefit pension and postretirement items: Net loss (b) $ (17 ) $ (15 ) $ (35 ) $ (30 ) Income from continuing operations before income taxes 4 5 8 11 Provision for income taxes $ (13 ) $ (10 ) $ (27 ) $ (19 ) Income from continuing operations Total reclassification for the period $ (13 ) $ (9 ) $ (26 ) $ (18 ) Income from continuing operations __________________ (a) Amounts in parenthesis indicate charges to the unaudited condensed consolidated statements of operations. (b) Amounts related to pension and postretirement benefit plans were reclassified from AOCI and recorded as a component of net periodic benefit cost (see Note 20 for additional information).

L3's Earnings Per Common Share

L3's Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 29, 2018
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Earnings per Share (EPS)	A reconciliation of basic and diluted Earnings Per Share (EPS) is presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions, except per share data) Reconciliation of net income: Net income $ 379 $ 207 $ 587 $ 375 Net income from continuing operations attributable to noncontrolling interests (4 ) (5 ) (9 ) (9 ) Net income attributable to L3’s common shareholders $ 375 $ 202 $ 578 $ 366 Earnings attributable to L3’s common shareholders: Continuing operations $ 185 $ 190 $ 372 $ 343 Discontinued operations, net of income tax 190 12 206 23 Net income attributable to L3’s common shareholders $ 375 $ 202 $ 578 $ 366 Earnings per share attributable to L3’s common shareholders: Basic: Weighted average common shares outstanding 78.4 78.0 78.3 77.8 Basic earnings per share: Continuing operations $ 2.36 $ 2.44 $ 4.75 $ 4.40 Discontinued operations, net of income tax 2.42 0.15 2.63 0.30 Net income $ 4.78 $ 2.59 $ 7.38 $ 4.70 Diluted: Common and potential common shares: Weighted average common shares outstanding 78.4 78.0 78.3 77.8 Effect of dilutive securities 1.0 1.5 1.3 1.6 Common and potential common shares 79.4 79.5 79.6 79.4 Diluted earnings per share: Continuing operations $ 2.33 $ 2.39 $ 4.67 $ 4.32 Discontinued operations, net of income tax 2.39 0.15 2.59 0.29 Net income $ 4.72 $ 2.54 $ 7.26 $ 4.61

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 29, 2018
Fair Value Disclosures [Abstract]
Company's Assets and Liabilities at Fair Value on Recurring Basis	The following table presents the fair value hierarchy level for each of the Company’s assets and liabilities that are measured and recorded at fair value on a recurring basis. June 29, 2018 December 31, 2017 Description Level 1 (1) Level 2 (2) Level 3 (3) Level 1 (1) Level 2 (2) Level 3 (3) (in millions) Assets Cash equivalents $ 955 $ — $ — $ 310 $ — $ — Derivatives (foreign currency forward contracts) — 3 — — 11 — Total assets $ 955 $ 3 $ — $ 310 $ 11 $ — Liabilities Derivatives (foreign currency forward contracts) $ — $ 8 $ — $ — $ 1 $ — Contingent consideration — — 27 — — 31 Total liabilities $ — $ 8 $ 27 $ — $ 1 $ 31 __________________ (1) Level 1 is based on quoted market prices available in active markets for identical assets or liabilities as of the reporting date. Cash equivalents are primarily held in registered money market funds, which are valued using quoted market prices. (2) Level 2 is based on pricing inputs other than quoted prices in active markets, which are either directly or indirectly observable. The fair value is determined using a valuation model based on observable market inputs, including quoted foreign currency forward exchange rates and consideration of non-performance risk. (3) Level 3 is based on pricing inputs that are not observable and not corroborated by market data.
Changes to Contingent Consideration Obligations	The table below presents the changes to contingent consideration obligations during the first half period ended June 29, 2018 . June 29, 2018 (in millions) Balance at beginning of period $ 31 Acquisitions and investments 10 Cash payments (2 ) Changes in fair value of contingent consideration, net (12 ) Balance at end of period $ 27

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 29, 2018
Investments, All Other Investments [Abstract]
Carrying Amounts and Estimated Fair Values of Company's Long-Term Debt and Foreign Currency Forward Contracts	The carrying amounts and estimated fair values of the Company’s other financial instruments are presented in the table below. June 29, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value (in millions) Senior notes (1) $ 3,900 $ 3,944 $ 3,330 $ 3,502 Foreign currency forward contracts (2) $ (5 ) $ (5 ) $ 10 $ 10 __________________ (1) The Company measures the fair value of its senior notes using Level 2 inputs based primarily on current market yields for its existing debt traded in the secondary market. (2) The Company measures the fair values of foreign currency forward contracts based on forward exchange rates. See Note 18 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative Financial Instrume51

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Company's Outstanding Foreign Currency Forward Contracts by Currency	The table below presents the notional amounts of the Company’s outstanding foreign currency forward contracts by currency at June 29, 2018 . Currency Notional Amounts (in millions) Canadian dollar $ 183 U.S. dollar 145 Euro 80 United Arab Emirates dirham 12 British pound 11 New Zealand dollar 7 Total $ 438
Location of Company's Derivative Instruments Recorded at Fair Value on the Condensed Consolidated Balance Sheets	The table below presents the location of the Company’s derivative instruments recorded at fair value on the condensed consolidated balance sheets. June 29, 2018 December 31, 2017 Other Current Assets Other Assets Other Current Liabilities Other Liabilities Other Current Assets Other Assets Other Current Liabilities Other Liabilities (in millions) Derivatives designated as hedging instruments: Foreign currency forward contracts (1) $ 3 $ — $ 6 $ 2 $ 11 $ — $ 1 $ — Derivatives not designated as hedging instruments: Contingent consideration (2) — — 6 — — — — — Total derivative instruments $ 3 $ — $ 12 $ 2 $ 11 $ — $ 1 $ — __________________ (1) See Note 16 for a description of the fair value hierarchy related to the Company’s foreign currency forward contracts. (2) See Note 16 for additional information on Peak Nano contingent consideration liability.

Pension and Other Postretirem52

Pension and Other Postretirement Benefits (Tables)	6 Months Ended
	Jun. 29, 2018
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Cost	The following table summarizes the components of net periodic benefit cost for the Company’s pension and other postretirement benefit plans. Pension Plans Postretirement Benefit Plans Second Quarter Ended First Half Ended Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, June 29, June 30, June 29, June 30, (in millions) Components of net periodic benefit cost: Service cost $ 26 $ 25 $ 52 $ 50 $ 1 $ — $ 1 $ 1 Interest cost 36 36 72 71 1 1 2 2 Expected return on plan assets (56 ) (49 ) (112 ) (98 ) (1 ) (1 ) (2 ) (2 ) Amortization of net loss (gains) 18 15 37 31 (1 ) — (2 ) (1 ) Net periodic benefit cost $ 24 $ 27 $ 49 $ 54 $ — $ — $ (1 ) $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 29, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted Average Assumptions in Valuation Model	The weighted average assumptions used in the valuation model for this grant are presented in the table below. Expected holding period (in years) 5.2 Expected volatility 19.8 % Expected dividend yield 1.8 % Risk-free interest rate 2.7 %

Supplemental Cash Flow Inform54

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 29, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	First Half Ended June 29, June 30, (in millions) Interest paid $ 97 $ 83 Income tax payments $ 54 $ 96 Income tax refunds $ 3 $ 7

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 29, 2018
Disaggregation of Revenue [Line Items]
Summary of Segment Information	The tables below present net sales, operating income, depreciation and amortization and total assets by reportable segment. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Net Sales: Electronic Systems $ 828 $ 789 $ 1,630 $ 1,549 Aerospace Systems 751 681 1,450 1,382 Communication Systems 563 555 1,062 1,098 Sensor Systems 482 394 894 748 Elimination of intercompany sales (41 ) (34 ) (82 ) (71 ) Consolidated total $ 2,583 $ 2,385 $ 4,954 $ 4,706 Operating Income: Electronic Systems $ 113 $ 103 $ 221 $ 193 Aerospace Systems 61 56 118 112 Communication Systems 45 84 82 126 Sensor Systems 54 51 103 100 Segment total 273 294 524 531 Gain on sale of the Crestview & TCS Businesses 48 — 48 — Consolidated total $ 321 $ 294 $ 572 $ 531 Depreciation and amortization: Electronic Systems $ 24 $ 17 $ 43 $ 35 Aerospace Systems 12 13 24 24 Communication Systems 11 12 24 24 Sensor Systems 13 12 25 23 Consolidated total $ 60 $ 54 $ 116 $ 106 June 29, December 31, (in millions) Total Assets: Electronic Systems $ 4,990 $ 4,796 Aerospace Systems 2,200 2,014 Communication Systems 2,142 2,063 Sensor Systems 2,890 2,706 Corporate 1,308 709 Assets held for sale — 135 Assets of discontinued operations — 306 Consolidated total $ 13,530 $ 12,729
Revenue by End Customer [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The tables below present total net sales disaggregated by end customer. Second Quarter Ended June 29, 2018 End Customer Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Total DoD $ 443 $ 624 $ 426 $ 240 $ 1,733 Other U.S. Government 40 7 24 22 93 Total U.S. Government 483 631 450 262 1,826 Foreign governments (1) 74 103 39 155 371 Commercial — foreign 177 6 25 14 222 Commercial — domestic 78 1 40 45 164 Total $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 End Customer Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Total DoD $ 860 $ 1,192 $ 797 $ 446 $ 3,295 Other U.S. Government 79 12 48 47 186 Total U.S. Government 939 1,204 845 493 3,481 Foreign governments (1) 142 206 73 281 702 Commercial — foreign 344 14 46 35 439 Commercial — domestic 172 3 83 74 332 Total $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954 __________________ (1) Includes sales under foreign military sales agreements, which are made directly between the U.S. Government and foreign governments.
Revenue by Contract Type [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The tables below present total net sales disaggregated by contract type. Second Quarter Ended June 29, 2018 Contract Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Fixed-price (1) $ 680 $ 398 $ 403 $ 391 $ 1,872 Cost-plus (2) 118 292 133 83 626 Time-and-material 14 51 18 2 85 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Contract Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Fixed-price (1) $ 1,344 $ 764 $ 732 $ 724 $ 3,564 Cost-plus (2) 226 561 281 154 1,222 Time-and-material 27 102 34 5 168 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954 __________________ (1) Includes fixed-price incentive fee type contracts, which contributed approximately 1% to the Company's total net sales for quarterly period ended June 29, 2018 and 2% for the first half period ended June 29, 2018 . (2) Includes cost-plus award and incentive fee type contracts, which contributed approximately 4% to the Company's total net sales for each of the quarterly and first half periods ended June 29, 2018 .
Revenue by Deliverable Type [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The tables below present total net sales disaggregated by the type of deliverable, which is determined by the Company at the performance obligation level. Second Quarter Ended June 29, 2018 Sales by Deliverable Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Products $ 578 $ 405 $ 397 $ 406 $ 1,786 Services 234 336 157 70 797 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Sales by Deliverable Type Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Products $ 1,138 $ 777 $ 761 $ 756 $ 3,432 Services 459 650 286 127 1,522 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954
Revenue by Revenue Recognition Method [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The tables below present total net sales disaggregated based on the revenue recognition method applied. Second Quarter Ended June 29, 2018 Revenue Recognition Method Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Cost to cost method $ 548 $ 713 $ 455 $ 226 $ 1,942 Point in time 175 11 76 222 484 Output method 71 1 5 11 88 Billing method 18 16 18 17 69 Total sales $ 812 $ 741 $ 554 $ 476 $ 2,583 First Half Ended June 29, 2018 Revenue Recognition Method Electronic Systems Aerospace Systems Communication Systems Sensor Systems Consolidated L3 (in millions) Cost to cost method $ 1,081 $ 1,379 $ 845 $ 439 $ 3,744 Point in time 369 13 153 381 916 Output method 122 1 12 27 162 Billing method 25 34 37 36 132 Total sales $ 1,597 $ 1,427 $ 1,047 $ 883 $ 4,954

Severance and Restructuring R56

Severance and Restructuring Related Costs (Tables)	6 Months Ended
	Jun. 29, 2018
Restructuring and Related Activities [Abstract]
Severance and Restructuring Costs Incurred by Reportable Segment	Severance and restructuring related costs incurred by reportable segment are presented in the table below. Second Quarter Ended First Half Ended June 29, June 30, June 29, June 30, (in millions) Reportable Segment Electronic Systems $ 2 $ 2 $ 4 $ 5 Aerospace Systems — 1 1 1 Communication Systems 3 9 8 18 Sensor Systems 1 — 1 2 Consolidated $ 6 $ 12 $ 14 $ 26
Schedule of Restructuring Reserve	The table below presents the change to the Company’s severance and restructuring related liability during the first half period ended June 29, 2018 . June 29, 2018 (in millions) Balance at beginning of period $ 23 Additional provisions 14 Cash payments (22 ) Balance at end of period $ 15

Condensed Combining Financial57

Condensed Combining Financial Information of L3 and Its Subsidiaries (Tables)	6 Months Ended
	Jun. 29, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Combining Balance Sheets	The following unaudited condensed combining financial information presents the results of operations, financial position and cash flows of: (1) L3 excluding its consolidated subsidiaries (the Parent), (2) the Guarantor Subsidiaries, (3) the Non-Guarantor Subsidiaries and (4) the eliminations to arrive at the information for L3 on a consolidated basis. L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Balance Sheets: At June 29, 2018 Current assets: Cash and cash equivalents $ 1,055 $ 19 $ 307 $ (15 ) $ 1,366 Billed receivables, net 285 315 263 — 863 Contract assets 616 810 185 — 1,611 Inventories 393 315 226 — 934 Prepaid expenses and other current assets 112 150 70 — 332 Total current assets 2,461 1,609 1,051 (15 ) 5,106 Goodwill 2,273 2,828 1,550 — 6,651 Other assets 707 712 354 — 1,773 Investment in and amounts due from consolidated subsidiaries 5,668 6,614 — (12,282 ) — Total assets $ 11,109 $ 11,763 $ 2,955 $ (12,297 ) $ 13,530 Current portion of long-term debt $ 581 $ — $ — $ — $ 581 Current liabilities 774 864 599 (15 ) 2,222 Amounts due to consolidated subsidiaries — — 426 (426 ) — Other long-term liabilities 991 757 148 — 1,896 Long-term debt 3,319 — — — 3,319 Total liabilities 5,665 1,621 1,173 (441 ) 8,018 L3 shareholders’ equity 5,444 10,142 1,782 (11,924 ) 5,444 Noncontrolling interests — — — 68 68 Total equity 5,444 10,142 1,782 (11,856 ) 5,512 Total liabilities and equity $ 11,109 $ 11,763 $ 2,955 $ (12,297 ) $ 13,530 L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) At December 31, 2017 Current assets: Cash and cash equivalents $ 432 $ 16 $ 285 $ (71 ) $ 662 Billed receivables, net 266 244 213 — 723 Contracts in process 706 912 315 — 1,933 Prepaid expenses and other current assets 330 235 124 — 689 Assets held for sale — 135 — — 135 Assets of discontinued operations 306 — — — 306 Total current assets 2,040 1,542 937 (71 ) 4,448 Goodwill 2,248 2,844 1,523 — 6,615 Other assets 658 687 321 — 1,666 Investment in and amounts due from consolidated subsidiaries 5,513 6,398 — (11,911 ) — Total assets $ 10,459 $ 11,471 $ 2,781 $ (11,982 ) $ 12,729 Current liabilities $ 811 $ 832 $ 564 $ (71 ) $ 2,136 Liabilities held for sale — 17 — — 17 Liabilities of discontinued operations 226 — — — 226 Amounts due to consolidated subsidiaries — — 330 (330 ) — Other long-term liabilities 1,009 729 131 — 1,869 Long-term debt 3,330 — — — 3,330 Total liabilities 5,376 1,578 1,025 (401 ) 7,578 L3 shareholders’ equity 5,083 9,893 1,756 (11,649 ) 5,083 Noncontrolling interests — — — 68 68 Total equity 5,083 9,893 1,756 (11,581 ) 5,151 Total liabilities and equity $ 10,459 $ 11,471 $ 2,781 $ (11,982 ) $ 12,729
Condensed Combining Statements of Operations	L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Statements of Operations: For the quarter ended June 29, 2018: Total net sales $ 919 $ 1,328 $ 431 $ (95 ) $ 2,583 Total operating costs and expenses (819 ) (1,239 ) (347 ) 95 (2,310 ) Gain on sale of the Crestview & TCS Businesses — 48 — — 48 Operating income 100 137 84 — 321 Interest expense (43 ) — (1 ) — (44 ) Interest and other income, net 6 1 1 — 8 Debt retirement charge (48 ) — — — (48 ) Income from continuing operations before income taxes 15 138 84 — 237 Provision for income taxes (4 ) (26 ) (18 ) — (48 ) Equity in net income of consolidated subsidiaries 174 47 — (221 ) — Income from continuing operations 185 159 66 (221 ) 189 Income from discontinued operations, net of income taxes 190 — — — 190 Net income 375 159 66 (221 ) 379 Net income attributable to noncontrolling interests — — — (4 ) (4 ) Net income attributable to L3 $ 375 $ 159 $ 66 $ (225 ) $ 375 Comprehensive income attributable to L3 $ 306 $ 85 $ (11 ) $ (74 ) $ 306 For the quarter ended June 30, 2017: Total net sales $ 894 $ 1,193 $ 399 $ (101 ) $ 2,385 Total operating costs and expenses (810 ) (1,049 ) (333 ) 101 (2,091 ) Operating income 84 144 66 — 294 Interest expense (42 ) — — — (42 ) Interest and other income, net 2 — — — 2 Income from continuing operations before income taxes 44 144 66 — 254 Provision for income taxes (10 ) (34 ) (15 ) — (59 ) Equity in net income of consolidated subsidiaries 156 35 — (191 ) — Income from continuing operations 190 145 51 (191 ) 195 Income from discontinued operations, net of income taxes 12 — — — 12 Net income 202 145 51 (191 ) 207 Net income attributable to noncontrolling interests — — — (5 ) (5 ) Net income attributable to L3 $ 202 $ 145 $ 51 $ (196 ) $ 202 Comprehensive income attributable to L3 $ 264 $ 192 $ 104 $ (296 ) $ 264
Condensed Combining Statements of Cash Flows	L3 Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated L3 (in millions) Condensed Combining Statements of Cash Flows For the first half period ended June 29, 2018: Operating activities: Net cash from (used in) operating activities from continuing operations $ 195 $ (100 ) $ 88 $ (5 ) $ 178 Investing activities: Business acquisitions, net of cash acquired (69 ) — — — (69 ) Proceeds from sale of businesses, net of closing date cash balances 360 175 — — 535 Other investing activities (79 ) (38 ) (19 ) — (136 ) Net cash from (used in) investing activities from continuing operations 212 137 (19 ) — 330 Financing activities: Proceeds from sale of senior notes 1,798 — — — 1,798 Repurchases and redemptions of senior notes (1,263 ) — — — (1,263 ) Common stock repurchased (287 ) — — — (287 ) Dividends paid (128 ) — — — (128 ) Other financing activities 89 (34 ) (39 ) 61 77 Net cash from (used in) financing activities from continuing operations 209 (34 ) (39 ) 61 197 Effect of foreign currency exchange rate changes on cash — — (8 ) — (8 ) Net increase in cash and cash equivalents of discontinued operations 7 — — — 7 Net increase in cash 623 3 22 56 704 Cash and cash equivalents, beginning of the period 432 16 285 (71 ) 662 Cash and cash equivalents, end of the period $ 1,055 $ 19 $ 307 $ (15 ) $ 1,366 For the first half period ended June 30, 2017: Operating activities: Net cash from operating activities from continuing operations $ 137 $ 101 $ 118 $ (41 ) $ 315 Investing activities: Business acquisitions, net of cash acquired (191 ) — — — (191 ) Proceeds from sale of businesses, net of closing date cash balances 15 — 1 — 16 Other investing activities (33 ) 11 (10 ) — (32 ) Net cash (used in) from investing activities from continuing operations (209 ) 11 (9 ) — (207 ) Financing activities: Common stock repurchased (26 ) — — — (26 ) Dividends paid (119 ) — — — (119 ) Other financing activities 164 (117 ) (124 ) 92 15 Net cash from (used in) financing activities from continuing operations 19 (117 ) (124 ) 92 (130 ) Effect of foreign currency exchange rate changes on cash — — 10 — 10 Net increase in cash and cash equivalents of discontinued operations 34 — — — 34 Net decrease in cash (19 ) (5 ) (5 ) 51 22 Cash and cash equivalents, beginning of the period 291 5 203 (136 ) 363 Cash and cash equivalents, end of the period $ 272 $ — $ 198 $ (85 ) $ 385
Revised Amounts for Guarantor Subsidiaries, Non-Guarantor Subsidiaries and Eliminations	The Company has revised the reported amounts for Guarantor Subsidiaries, Non-Guarantor Subsidiaries and Eliminations in the December 31, 2017 Condensed Combining Balance Sheet, and the Condensed Combining Statements of Operations for the quarterly period ended June 30, 2017 and for the first half period ended June 30, 2017 , to correct for these errors as enumerated below. Additionally, the effect of changes in the guarantor subsidiaries resulting from the sale of Vertex Aerospace which occurred on June 29, 2018 are being retrospectively reflected in the below guarantor adjustment column. Condensed Combining Balance Sheet (at December 31, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Total assets $ 10,270 $ 3,156 $ (10,930 ) $ 1,201 $ (375 ) $ (1,052 ) $ 11,471 $ 2,781 $ (11,982 ) Total liabilities $ 1,756 $ 1,091 $ (419 ) $ (178 ) $ (66 ) $ 18 $ 1,578 $ 1,025 $ (401 ) Total equity $ 8,514 $ 2,065 $ (10,511 ) $ 1,379 $ (309 ) $ (1,070 ) $ 9,893 $ 1,756 $ (11,581 ) Condensed Combining Statement of Operations ( Second Quarter Ended June 30, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Net income $ 117 $ 52 $ (164 ) $ 28 $ (1 ) $ (27 ) $ 145 $ 51 $ (191 ) Condensed Combining Statement of Operations ( First Half Ended June 30, 2017 ) As Reported Adjustment As Adjusted Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination Guarantor Subsidiaries Non-Guarantor Subsidiaries Elimination (in millions) Net Income $ 201 $ 100 $ (292 ) $ 47 $ (3 ) $ (44 ) $ 248 $ 97 $ (336 )

Description of Business (Detail

Description of Business (Details) $ in Millions	Jun. 29, 2018USD ($)	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 29, 2018USD ($)Segment	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of reportable segments | Segment				4
Gain on sale of businesses		$ 48	$ 0	$ 48	$ 0
Gain from discontinued operation	$ 237
Total sales		2,583	$ 2,385	4,954	$ 4,706
Vertex Aerospace [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of business, base sales price	540	$ 540		$ 540
Gain from discontinued operation, after tax	180
Total sales						$ 1,400
Crestview Aerospace and TCS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of businesses	48
Gain on sale of businesses, after tax	$ 25

Basis of Presentation - Impact

Basis of Presentation - Impact of Adoption of New Accounting Pronouncement (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes						$ 13
Progress billings as percent of incurred costs (percent)			80.00%
Performance-based billings as percent of contract price, maximum (percent)			90.00%
Operating income	$ 321	$ 294	$ 572	$ 531
Diluted earnings per share (in dollars per share)	$ 4.72	$ 2.54	$ 7.26	$ 4.61
Performance obligations satisfied in prior periods	$ 71		$ 139
Research and development expense	$ 86		161
Lag basis for reporting income (loss) from nonconsolidated affiliates	3 months
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating income	$ 64	$ 42	$ 128	$ 84
Diluted earnings per share (in dollars per share)	$ 0.61	$ 0.35	$ 1.22	$ 0.67
Shareholders' Equity [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes					$ 13

Basis of Presentation - Remaini

Basis of Presentation - Remaining Performance Obligations (Details) $ in Billions	Jun. 29, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-03-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 4.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	3.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	1.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	0.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 10.2

Basis of Presentation - Summary

Basis of Presentation - Summary of Net Sales by Revenue Recognition Method as Percentage of Total Net Sales (Details)	3 Months Ended
	Jun. 29, 2018
Revenue from Contract with Customer [Abstract]
Cost to cost method	76.00%
Point in time	18.00%
Billing method	3.00%
Output method	3.00%
Total	100.00%

New Accounting Standards Impl62

New Accounting Standards Implemented (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating income	$ 321	$ 294	$ 572	$ 531
Interest and other income, net	8	2	14	6
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes					$ 13
Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating income	(3)	2	(5)	3
Retained Earnings [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest and other income, net	$ 3	$ (2)	$ 5	$ (3)
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes					13
Net Sales [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment of ASC 606 on January 1, 2018, net of taxes					$ 380

New Accounting Standards Impl63

New Accounting Standards Implemented - Impact of Adoption of ASC 606 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Contract assets	$ 1,611		$ 1,611		$ 1,349	$ 0
Contracts in process	0		0		0	1,933
Inventories	934		934		926	389
Prepaid expenses and other current assets	332		332		317	300
Assets held for sale	0		0		138	135
Assets of discontinued operations	0		0		285	306
Total current assets	5,106		5,106		4,400	4,448
Other assets	348		348		313	264
Total assets	13,530		13,530		12,730	12,729
Liabilities
Accrued expenses	264		264		204	217
Contract liabilities	554		554		565	0
Advance payments and billings in excess of costs incurred	0		0		0	509
Other current liabilities	338		338		318	367
Liabilities held for sale	0		0		16	17
Liabilities of discontinued operations	0		0		203	226
Total current liabilities	2,803		2,803		2,349	2,379
Deferred income taxes	190		190		162	158
Other liabilities	416		416		412	398
Total liabilities	8,018		8,018		7,566	7,578
Shareholders' Equity
Retained earnings	7,126		7,126		6,672	6,659
Total equity	5,512	$ 5,047	5,512	$ 5,047	5,164	5,151	$ 4,624
Net Sales:
Products	1,786	1,680	3,432	3,284
Services	797	705	1,522	1,422
Total net sales	2,583	2,385	4,954	4,706
Operating costs and expenses:
Cost of sales — Products	(1,349)	(1,253)	(2,540)	(2,441)
Cost of sales — Services	(578)	(479)	(1,110)	(1,017)
General and administrative expenses	(383)	(359)	(780)	(717)
Gain on sale of the Crestview Aerospace and TCS businesses	48	0	48	0
Operating income	321	294	572	531
Income from continuing operations before income taxes	237	254	453	453
Provision for income taxes	(48)	(59)	(72)	(101)
Income from continuing operations	189	195	381	352
Income from discontinued operations, net of income taxes	190	12	206	23
Net income	379	207	587	375
Net income attributable to L3	$ 375	$ 202	$ 578	$ 366
Basic earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	$ 2.36	$ 2.44	$ 4.75	$ 4.40
Discontinued operations (in dollars per share)	2.42	0.15	2.63	0.30
Basic earnings per share (in dollars per share)	4.78	2.59	7.38	4.70
Diluted earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	2.33	2.39	4.67	4.32
Discontinued operations (in dollars per share)	2.39	0.15	2.59	0.29
Diluted earnings per share (in dollars per share)	$ 4.72	$ 2.54	$ 7.26	$ 4.61
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Assets
Contract assets	$ 0		$ 0			0
Contracts in process	2,185		2,185			1,933
Inventories	405		405			389
Prepaid expenses and other current assets	316		316			300
Assets held for sale	0		0			135
Assets of discontinued operations	0		0			306
Total current assets	5,135		5,135			4,448
Other assets	300		300			264
Total assets	13,511		13,511			12,729
Liabilities
Accrued expenses	279		279			217
Contract liabilities	0		0			0
Advance payments and billings in excess of costs incurred	522		522			509
Other current liabilities	384		384			367
Liabilities held for sale						17
Liabilities of discontinued operations						226
Total current liabilities	2,832		2,832			2,379
Deferred income taxes	181		181			158
Other liabilities	402		402			398
Total liabilities	8,024		8,024			7,578
Shareholders' Equity
Retained earnings	7,101		7,101			6,659
Total equity	5,487		5,487			5,151
Net Sales:
Products	1,741		3,315
Services	797		1,518
Total net sales	2,538		4,833
Operating costs and expenses:
Cost of sales — Products	(1,316)		(2,461)
Cost of sales — Services	(561)		(1,089)
General and administrative expenses	(387)		(777)
Gain on sale of the Crestview Aerospace and TCS businesses	47		47
Operating income	321		553
Income from continuing operations before income taxes	237		434
Provision for income taxes	(48)		(67)
Income from continuing operations	189		367
Income from discontinued operations, net of income taxes	191		206
Net income	380		573
Net income attributable to L3	$ 376		$ 564
Basic earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	$ 2.36		$ 4.57
Discontinued operations (in dollars per share)	2.44		2.63
Basic earnings per share (in dollars per share)	4.80		7.20
Diluted earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	2.33		4.50
Discontinued operations (in dollars per share)	2.41		2.59
Diluted earnings per share (in dollars per share)	$ 4.74		$ 7.09
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Assets
Contract assets	$ 1,611		$ 1,611		1,349
Contracts in process	(2,185)		(2,185)		(1,933)
Inventories	529		529		537
Prepaid expenses and other current assets	16		16		17
Assets held for sale	0		0		3
Assets of discontinued operations	0		0		(21)
Total current assets	(29)		(29)		(48)
Other assets	48		48		49
Total assets	19		19		1
Liabilities
Accrued expenses	(15)		(15)		(13)
Contract liabilities	554		554		565
Advance payments and billings in excess of costs incurred	(522)		(522)		(509)
Other current liabilities	(46)		(46)		(49)
Liabilities held for sale					(1)
Liabilities of discontinued operations					(23)
Total current liabilities	(29)		(29)		(30)
Deferred income taxes	9		9		4
Other liabilities	14		14		14
Total liabilities	(6)		(6)		(12)
Shareholders' Equity
Retained earnings	25		25		13
Total equity	25		25		$ 13
Net Sales:
Products	45		117
Services	0		4
Total net sales	45		121
Operating costs and expenses:
Cost of sales — Products	(33)		(79)
Cost of sales — Services	(17)		(21)
General and administrative expenses	4		(3)
Gain on sale of the Crestview Aerospace and TCS businesses	1		1
Operating income	0		19
Income from continuing operations before income taxes	0		19
Provision for income taxes	0		(5)
Income from continuing operations	0		14
Income from discontinued operations, net of income taxes	(1)		0
Net income	(1)		14
Net income attributable to L3	$ (1)		$ 14
Basic earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	$ 0		$ 0.18
Discontinued operations (in dollars per share)	(0.02)		0
Basic earnings per share (in dollars per share)	(0.02)		0.18
Diluted earnings per share attributable to common shareholders:
Continuing operations (in dollars per share)	0		0.17
Discontinued operations (in dollars per share)	(0.02)		0
Diluted earnings per share (in dollars per share)	$ (0.02)		$ 0.17
Electronic Systems [Member]
Net Sales:
Total net sales	$ 812		$ 1,597
Electronic Systems [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating costs and expenses:
Operating income	4		7
Diluted earnings per share attributable to common shareholders:
Sales	14		44
Aerospace Systems [Member]
Net Sales:
Total net sales	741		1,427
Aerospace Systems [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating costs and expenses:
Operating income	(7)		(6)
Diluted earnings per share attributable to common shareholders:
Sales	(2)		2
Communication Systems [Member]
Net Sales:
Total net sales	554		1,047
Communication Systems [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating costs and expenses:
Operating income	(1)		3
Diluted earnings per share attributable to common shareholders:
Sales	21		41
Sensor Systems [Member]
Net Sales:
Total net sales	476		883
Sensor Systems [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating costs and expenses:
Operating income	3		14
Diluted earnings per share attributable to common shareholders:
Sales	12		34
Operating Segments [Member]
Operating costs and expenses:
Operating income	273	$ 294	524	$ 531
Operating Segments [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating costs and expenses:
Operating income	(1)		18
Diluted earnings per share attributable to common shareholders:
Sales	45		121
Operating Segments [Member] | Electronic Systems [Member]
Assets
Total assets	4,990		4,990			4,796
Net Sales:
Total net sales	828	789	1,630	1,549
Operating costs and expenses:
Operating income	113	103	221	193
Operating Segments [Member] | Aerospace Systems [Member]
Assets
Total assets	2,200		2,200			2,014
Net Sales:
Total net sales	751	681	1,450	1,382
Operating costs and expenses:
Operating income	61	56	118	112
Operating Segments [Member] | Communication Systems [Member]
Assets
Total assets	2,142		2,142			2,063
Net Sales:
Total net sales	563	555	1,062	1,098
Operating costs and expenses:
Operating income	45	84	82	126
Operating Segments [Member] | Sensor Systems [Member]
Assets
Total assets	2,890		2,890			$ 2,706
Net Sales:
Total net sales	482	394	894	748
Operating costs and expenses:
Operating income	$ 54	$ 51	$ 103	$ 100

Acquisitions and Divestitures,

Acquisitions and Divestitures, Business Acquisitions (Details) $ in Millions, $ in Millions	Jul. 11, 2018USD ($)acquisition	Jul. 11, 2018AUD ($)acquisition	Jun. 29, 2018USD ($)	Jun. 28, 2018USD ($)	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jul. 11, 2018AUD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Contingent consideration			$ 27		$ 27		$ 27			$ 31
Goodwill recognized			6,651		6,651		6,651			6,615
Pro forma net sales					2,592	$ 2,413	4,973	$ 4,765
Applied Defense Solutions [Member]
Business Acquisition [Line Items]
Purchase price			53
Goodwill recognized			40		40		40
L3 Latitude Engineering [Member]
Business Acquisition [Line Items]
Purchase price				$ 15
Contingent consideration				20
Liability for the fair value of contingent consideration at acquisition				4
Kigre, G-Air and Adaptive Methods [Member]
Business Acquisition [Line Items]
Increase to goodwill					3
Electronic Systems [Member]
Business Acquisition [Line Items]
Goodwill recognized			$ 2,814		$ 2,814		$ 2,814			$ 2,813
Electronic Systems [Member] | L3 Latitude Engineering [Member]
Business Acquisition [Line Items]
Goodwill recognized				14
Subsequent Event [Member] | Azimuth Security and Linchpin Labs [Member]
Business Acquisition [Line Items]
Purchase price	$ 200	$ 270
Contingent consideration	$ 32								$ 43
Number of Businesses Acquired | acquisition	2	2
Post-acquisition Performance through December 2021 [Member] | L3 Latitude Engineering [Member]
Business Acquisition [Line Items]
Contingent consideration				15
Post-acquisition Milestone Achievements through December 2020 [Member] | L3 Latitude Engineering [Member]
Business Acquisition [Line Items]
Contingent consideration				$ 5

Acquisitions and Divestitures65

Acquisitions and Divestitures, Unaudited Pro Forma Statements of Operations Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Pro forma net sales	$ 2,592	$ 2,413	$ 4,973	$ 4,765
Pro forma income from continuing operations attributable to L3	187	189	375	343
Pro forma net income attributable to L3	$ 377	$ 201	$ 581	$ 366
Pro forma diluted earnings per share from continuing operations (in dollars per share)	$ 2.36	$ 2.38	$ 4.71	$ 4.32
Pro forma diluted earnings per share (in dollars per share)	$ 4.75	$ 2.53	$ 7.30	$ 4.61

Acquisitions, Divestitures an66

Acquisitions, Divestitures and Discontinued Operations Acquisitions and Divestitures, Investments in Unconsolidated Affiliates (Details) - USD ($) $ in Millions	Jun. 29, 2018	Feb. 16, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Contingent consideration	$ 27		$ 31
Goodwill recognized	6,651		$ 6,615
Variable Interest Entity, Not Primary Beneficiary [Member] | Peak Nano [Member]
Schedule of Equity Method Investments [Line Items]
Investment in nonconsolidated affiliate (percent)		25.00%
Purchase price		$ 20
Contingent milestone payment		30
Contingent consideration		6
Goodwill recognized		11
Loan receivable	$ 5
IPR&D [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Peak Nano [Member]
Schedule of Equity Method Investments [Line Items]
Indefinite-lived intangible assets		$ 13

Acquisitions and Divestitures67

Acquisitions and Divestitures, Business Divestitures (Details) £ in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Mar. 01, 2017USD ($)	Mar. 01, 2017GBP (£)	Feb. 24, 2017USD ($)	Feb. 23, 2017USD ($)
Business Acquisition [Line Items]
Pre-Tax (Loss) gain				$ (4)
Proceeds Received				25
Net Sales				10
Net sales	$ 2,583	$ 2,385	$ 4,954	4,706
Gain on sale of businesses	48	0	48	0
Income from continuing operations before income taxes	237	$ 254	453	453
Aerostructures [Member]
Business Acquisition [Line Items]
Net sales			64
Gain on sale of businesses	$ 48
Income from continuing operations before income taxes			$ 3
Aviation Jet Services divestiture [Member]
Business Acquisition [Line Items]
Pre-Tax (Loss) gain				(5)
Proceeds Received				1
Net Sales				1
Sale of business, base sales price					$ 1	£ 1
Coleman divestiture [Member]
Business Acquisition [Line Items]
Pre-Tax (Loss) gain				(3)
Proceeds Received				17
Net Sales				9
Sale of business, base sales price							$ 15
Display Product Line divestiture [Member]
Business Acquisition [Line Items]
Pre-Tax (Loss) gain				4
Proceeds Received				7
Net Sales				0
Sale of business, base sales price								$ 7
Discontinued Operations [Member]
Business Acquisition [Line Items]
Net sales				10
Income from continuing operations before income taxes				$ 2

Acquisitions and Divestitures68

Acquisitions and Divestitures, Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Discontinued Operations, Income Statement Disclosures [Abstract]
Net Sales				$ 10
Gain on sale of businesses	$ 48	$ 0	$ 48	0
Income from discontinued operations, net of income taxes	190	12	206	23
Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total assets of discontinued operations	0		0		$ 285	$ 306
Current liabilities	0		0		$ 203	226
Vertex Aerospace [Member] | Discontinued Operations [Member]
Discontinued Operations, Income Statement Disclosures [Abstract]
Net Sales	226	351	597	703
Operating costs and expenses (1)	(212)	(332)	(561)	(667)
Operating income from discontinued operations	14	19	36	36
Interest expense allocated to discontinued operations	0	0	(1)	(1)
Gain on sale of businesses	237	0	237	0
Income from discontinued operations before income taxes	251	19	272	35
Income tax expense	(61)	(7)	(66)	(12)
Income from discontinued operations, net of income taxes	$ 190	$ 12	$ 206	$ 23
Discontinued Operation, Balance Sheet Disclosures [Abstract]
Current assets						284
Property, plant and equipment, net						13
Other intangible assets						7
Other assets						2
Total assets of discontinued operations						306
Accounts payable, trade						63
Other current liabilities						131
Other current liabilities						194
Long-term liabilities						32
Current liabilities						$ 226

Acquisitions, Divestitures an69

Acquisitions, Divestitures and Discontinued Operations Acquisitions and Divestitures, Assets Held for Sale (Details) - USD ($) $ in Millions	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets classified as held for sale	$ 0		$ 135
Total liabilities classified as held for sale	$ 0	$ 16	17
Assets Held for Sale [Member] | Aerostructures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Billed receivables			14
Contracts in process			33
Total current assets			47
Property, plant and equipment, net			34
Goodwill			52
Identifiable intangible assets			2
Total assets classified as held for sale			135
Accounts payable, trade			3
Accrued employment costs			2
Accrued expenses			3
Other current liabilities			5
Total current liabilities			13
Deferred income taxes			4
Total liabilities classified as held for sale			$ 17

Contract Assets and Contract 70

Contract Assets and Contract Liabilities - Components of Net Contract Assets (Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 29, 2018	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract assets	$ 1,611	$ 1,611	$ 1,349	$ 0
Contract liabilities — current	(554)	(554)	(565)	0
Contract liabilities — non-current	(33)	(33)	(28)	$ 0
Net contract assets (liabilities)	1,024	1,024	$ 756
Increase in contract assets	262
Increase in contract liability	$ (6)
Revenue recognized related to contract liabilities		$ 351

Components of Contract Assets (

Components of Contract Assets (Details) - USD ($) $ in Millions	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Contracts Receivable [Abstract]
Unbilled contract receivables, gross	$ 2,643	$ 2,232	$ 1,874
Unliquidated progress payments and advances	(1,032)	(883)	(761)
Total contract assets	$ 1,611	$ 1,349	$ 0

Contracts in Process (Details)

Contracts in Process (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Contractors [Abstract]
Unbilled contract receivables, gross			$ 2,643	$ 2,232	$ 1,874
Unliquidated progress payments			(1,032)	(883)	(761)
Unbilled contract receivables, net					1,113
Inventoried contract costs, gross					891
Unliquidated progress payments					(71)
Inventoried contract costs, net					820
Total contracts in process			$ 0	$ 0	$ 1,933
Summary Of Inventory For Long Term Contracts Or Programs [Roll Forward]
Amounts included in inventoried contract costs at beginning of the period	$ 177	$ 173
Contract Costs Incurred [Abstract]
IRAD and B&P	78	154
Other G&A	199	399
Total	277	553
Amounts charged to operating costs and expenses	(280)	(552)
Amounts included in inventoried contract costs at end of the period	$ 174	$ 174

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials, components and sub-assemblies	$ 318		$ 184
Work in process	430		98
Finished goods	186		107
Total	934	$ 926	$ 389
G&A costs included in inventory	62
G&A costs incurred and recorded in inventories	597
G&A costs charged to expense from inventories	$ 585

Goodwill and Identifiable Int74

Goodwill and Identifiable Intangible Assets - Allocated by Reportable Segment (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 6,755	$ 6,719
Accumulated impairment losses	(104)	(104)
Balance	6,615
Business acquisitions	59
Foreign currency translation adjustments	(23)
Balance	6,651
Electronic Systems [Member]
Goodwill [Line Items]
Goodwill	2,857	2,856
Accumulated impairment losses	(43)	(43)
Balance	2,813
Business acquisitions	16
Foreign currency translation adjustments	(15)
Balance	2,814
Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill	1,143	1,146
Accumulated impairment losses	0	0
Balance	1,146
Business acquisitions	0
Foreign currency translation adjustments	(3)
Balance	1,143
Communication Systems [Member]
Goodwill [Line Items]
Goodwill	1,058	1,058
Accumulated impairment losses	(35)	(35)
Balance	1,023
Business acquisitions	0
Foreign currency translation adjustments	0
Balance	1,023
Sensor Systems [Member]
Goodwill [Line Items]
Goodwill	1,697	1,659
Accumulated impairment losses	(26)	$ (26)
Balance	1,633
Business acquisitions	43
Foreign currency translation adjustments	(5)
Balance	$ 1,671

Goodwill and Identifiable Int75

Goodwill and Identifiable Intangible Assets - Identifiable Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period
Finite-lived intangible assets, gross carrying amount	$ 630		$ 630		$ 611
Finite-lived intangible assets, accumulated amortization	408		408		385
Finite-lived intangible assets, net carrying amount	222		222		226
Amortization expense	11	$ 10	22	$ 20
Estimated Amortization Expense for Identifiable Intangible Assets [Abstract]
Estimated amortization expense, 2018	44		44
Estimated amortization expense, 2019	42		42
Estimated amortization expense, 2020	33		33
Estimated amortization expense, 2021	27		27
Estimated amortization expense, 2022	23		23
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	696		696		677
Intangible assets, net carrying amount	288		288		292
IPR&D [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	66		$ 66		66
Customer Contractual Relationships [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period			15 years
Finite-lived intangible assets, gross carrying amount	406		$ 406		393
Finite-lived intangible assets, accumulated amortization	273		273		257
Finite-lived intangible assets, net carrying amount	133		$ 133		136
Technology [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period			10 years
Finite-lived intangible assets, gross carrying amount	190		$ 190		189
Finite-lived intangible assets, accumulated amortization	121		121		114
Finite-lived intangible assets, net carrying amount	69		$ 69		75
Other [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period			14 years
Finite-lived intangible assets, gross carrying amount	34		$ 34		29
Finite-lived intangible assets, accumulated amortization	14		14		14
Finite-lived intangible assets, net carrying amount	$ 20		$ 20		$ 15

Other Current Liabilities and76

Other Current Liabilities and Other Liabilities (Details) - USD ($) $ in Millions	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Current Liabilities [Abstract]
Accrued product warranty costs	$ 75		$ 69
Estimated costs in excess of estimated contract value to complete contracts in process in a loss position	55		63
Accrued interest	28		43
Estimated contingent purchase price payable for acquired businesses and other investments	17		11
Deferred revenues	0		38
Other	163		143
Total other current liabilities	338	$ 318	367
Other Liabilities [Abstract]
Non-current income taxes payable (see Note 12)	179		164
Deferred compensation	53		49
Contract liabilities	33	28	0
Accrued workers' compensation	24		23
Accrued product warranty costs	23		30
Notes payable and capital lease obligations	19		16
Estimated contingent purchase price payable for acquired businesses	10		20
Deferred revenues	0		19
Other	75		77
Total other liabilities	$ 416	$ 412	$ 398

Other Current Liabilities and77

Other Current Liabilities and Other Liabilities - Changes in Company's Accrued Product Warranty Costs (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Accrued product warranty costs [Roll Forward]:
Balance at January 1	$ 99	$ 109
Acquisitions during the period	0	3
Accruals for product warranties issued during the period	25	22
Changes to accruals for product warranties existing before January 1	1	0
Settlements made during the period	(26)	(29)
Foreign currency translation adjustments	(1)	1
Balance at end of period	$ 98	$ 106

Debt (Details)

Debt (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 06, 2018	Dec. 31, 2017
Components of Debt [Abstract]
Current portion of long-term debt	$ (581)			$ 0
Carrying amount of long-term debt, excluding current portion	3,319			3,330
Long-term debt, current and noncurrent [Abstract]
Repayments under the credit facility	501	$ 1,158
Proceeds under the credit facility	501	$ 1,158
5.20% Senior Notes due 2019 [Member]
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes			5.20%
4.75% Senior Notes due 2020 [Member]
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes			4.75%
3.85% Senior Notes due 2023 [Member]
Components of Debt [Abstract]
Unamortized discounts	(2)
4.40% Senior Notes due 2028 [Member]
Components of Debt [Abstract]
Unamortized discounts	(1)
Subsidiaries [Member]
Components of Debt [Abstract]
Borrowings under Revolving Credit Facility	0			0
Principal amount of long-term debt	3,932			3,350
Unamortized discounts	(8)			(7)
Deferred debt issue costs	(24)			(13)
Carrying amount of long-term debt	3,900			3,330
Subsidiaries [Member] | Revolving Credit Facility [Member]
Long-term debt, current and noncurrent [Abstract]
Available borrowings under credit facility	1,000
Repayments under the credit facility	501
Proceeds under the credit facility	501
Senior Notes [Member] | Subsidiaries [Member] | 5.20% Senior Notes due 2019 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 317			1,000
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	5.20%
Debt instrument maturity period	2,019
Senior Notes [Member] | Subsidiaries [Member] | 4.75% Senior Notes due 2020 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 265			800
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	4.75%
Debt instrument maturity period	2,020
Senior Notes [Member] | Subsidiaries [Member] | 4.95% Senior Notes due 2021 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 650			650
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	4.95%
Debt instrument maturity period	2,021
Senior Notes [Member] | Subsidiaries [Member] | 3.85% Senior Notes due 2023 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 800			0
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	3.85%
Debt instrument maturity period	2,023
Senior Notes [Member] | Subsidiaries [Member] | 3.95% Senior Notes due 2024 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 350			350
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	3.95%
Debt instrument maturity period	2,024
Senior Notes [Member] | Subsidiaries [Member] | 3.85% Senior Notes due 2026 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 550			550
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	3.85%
Debt instrument maturity period	2,026
Senior Notes [Member] | Subsidiaries [Member] | 4.40% Senior Notes due 2028 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 1,000			$ 0
Long-term debt, current and noncurrent [Abstract]
Interest rate on senior notes	4.40%
Debt instrument maturity period	2,028

Debt - Debt Outstanding, Senior

Debt - Debt Outstanding, Senior Subordinated Notes (Details) - USD ($)	Jul. 06, 2018	Jun. 06, 2018	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Debt Instrument [Line Items]
Interest					$ 97,000,000	$ 83,000,000
Principal Tendered			$ (48,000,000)	$ 0	$ (48,000,000)	$ 0
Redemption price of senior notes as percentage of principal amount redeemed (percent)					101.00%
3.85% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Date of Issuance		Jun. 6, 2018
Amount Issued			800,000,000		$ 800,000,000
Discount			$ 2,000,000		2,000,000
Net Cash Proceeds(2)					$ 792,000,000
Effective Interest Rate			3.89%		3.89%
Redemption at Treasury Rate(3)(4)		0.20%
4.40% Senior Notes due 2028 [Member]
Debt Instrument [Line Items]
Date of Issuance		Jun. 6, 2018
Amount Issued			$ 1,000,000,000		$ 1,000,000,000
Discount			$ 1,000,000		1,000,000
Net Cash Proceeds(2)					$ 990,000,000
Effective Interest Rate			4.41%		4.41%
Redemption at Treasury Rate(3)(4)		0.25%
Notes due 2023 and 2028 [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,782,000,000
5.20% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Interest rate on senior notes		5.20%
Aggregate principal included in tender offer		$ 1,000,000,000
4.75% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Interest rate on senior notes		4.75%
Aggregate principal included in tender offer		$ 800,000,000
5.20% Senior Notes due 2019, Settled under Tender Offers [Member]
Debt Instrument [Line Items]
Tender Offer Date		Jun. 6, 2018
Aggregate principal included in tender offer		$ 1,000,000,000
Principal Tendered		$ 683,000,000
Tender Premium		103.282%
Cash Tendered		$ 705,000,000
Interest		5,000,000
Total Cash Payments Tendered		710,000,000
Principal Tendered		$ 24,000,000
4.75% Senior Notes due 2020, Settled under Tender Offers [Member]
Debt Instrument [Line Items]
Tender Offer Date		Jun. 6, 2018
Aggregate principal included in tender offer		$ 800,000,000
Principal Tendered		$ 535,000,000
Tender Premium		104.092%
Cash Tendered		$ 557,000,000
Interest		10,000,000
Total Cash Payments Tendered		567,000,000
Principal Tendered		24,000,000
Notes Settled under Tender Offers [Member]
Debt Instrument [Line Items]
Tender offer fees included in debt retirement charge		1,000,000
Non-cash portion of debt retirement charge		$ 3,000,000
Minimum [Member] | Prior to May 15, 2023 and March 15, 2028 [Member]
Debt Instrument [Line Items]
Redemption price of senior notes as percentage of principal amount redeemed (percent)					100.00%
Minimum [Member] | On or After May 15, 2023 and March 15, 2028 [Member]
Debt Instrument [Line Items]
Redemption price of senior notes as percentage of principal amount redeemed (percent)					100.00%
Subsequent Event [Member] | 5.20% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Interest	$ 4,000,000
Principal Tendered	$ 10,000,000
Redemption Date	Jul. 6, 2018
Aggregate Amount, Redemption	$ 317,000,000
Redemption price of senior notes as percentage of principal amount redeemed (percent)	103.048%
Redemption Cash Payments	$ 327,000,000
Total Cash Payments for Redemptions	331,000,000
Subsequent Event [Member] | 4.75% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Interest	6,000,000
Principal Tendered	$ 11,000,000
Redemption Date	Jul. 6, 2018
Aggregate Amount, Redemption	$ 265,000,000
Redemption price of senior notes as percentage of principal amount redeemed (percent)	103.818%
Redemption Cash Payments	$ 275,000,000
Total Cash Payments for Redemptions	281,000,000
Subsequent Event [Member] | Redemption of Senior Notes [Member]
Debt Instrument [Line Items]
Non-cash portion of debt retirement charge	$ 1,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	20.30%	23.20%	15.90%	22.30%
Effective tax rate, excluding sale of the Crestview & TCS Businesses		15.60%		13.50%
Anticipated decrease in unrecognized tax benefits over the next 12 months	$ 44		$ 44
Accrued potential interest included within current and non-current income taxes payable	17		17		$ 15
Accrued potential interest included within current and non-current income taxes payable, after income taxes	13		13		11
Potential penalties	$ 9		$ 9		$ 8

Accumulated Other Comprehensi81

Accumulated Other Comprehensive (Loss) Income (AOCI), Summary of AOCI Balances Including Amounts Reclassified from AOCI into Net Income (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	$ 5,083
Other comprehensive (loss) income before reclassifications, net of tax	(49)	$ 72
Amounts reclassified from AOCI, net of tax	26	18
Net current period other comprehensive (loss) income	(23)	90
Ending Balance	5,444
Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(691)	(726)
Ending Balance	(714)	(636)
Foreign Currency Translation [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(54)	(178)
Other comprehensive (loss) income before reclassifications, net of tax	(39)	71
Amounts reclassified from AOCI, net of tax	0	0
Net current period other comprehensive (loss) income	(39)	71
Ending Balance	(93)	(107)
Unrealized Gains (Losses) on Hedging Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	9	6
Other comprehensive (loss) income before reclassifications, net of tax	(10)	1
Amounts reclassified from AOCI, net of tax	(1)	(1)
Net current period other comprehensive (loss) income	(11)	0
Ending Balance	(2)	6
Unrecognized (Losses) Gains and Prior Service Cost, Net [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(646)	(554)
Other comprehensive (loss) income before reclassifications, net of tax	0	0
Amounts reclassified from AOCI, net of tax	27	19
Net current period other comprehensive (loss) income	27	19
Ending Balance	$ (619)	$ (535)

Accumulated Other Comprehensi82

Accumulated Other Comprehensive (Loss) Income (AOCI), Summary of Amounts Reclassified from AOCI into Net Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	$ 237	$ 254	$ 453	$ 453
Provision for income taxes	(48)	(59)	(72)	(101)
Income from continuing operations	189	195	381	352
Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations	(13)	(9)	(26)	(18)
Unrealized Gains (Losses) on Hedging Instruments [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	0	1	1	1
Income from continuing operations	0	1	1	1
Amortization of Defined Benefit Pension and Postretirement Items [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net loss	(17)	(15)	(35)	(30)
Provision for income taxes	4	5	8	11
Income from continuing operations	$ (13)	$ (10)	$ (27)	$ (19)

Equity (Details)

Equity (Details) - USD ($)	Jul. 10, 2018	May 08, 2018	Jul. 20, 2018	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	May 08, 2017
Class of Stock [Line Items]
Aggregate amount of repurchased shares						$ 287,000,000	$ 26,000,000
Cash dividends declared per common share (in dollars per share)		$ 0.80		$ 0.8	$ 0.75	$ 1.6	$ 1.50
Dividend declared date						May 8, 2018
Dividend paid date						Jun. 15, 2018
Dividend paid, record date						May 18, 2018
Cash dividends						$ 128,000,000
Accrued dividends through payment						2,000,000
Subsequent Event [Member]
Class of Stock [Line Items]
Cash dividends declared per common share (in dollars per share)	$ 0.80
Treasury Stock [Member]
Class of Stock [Line Items]
Aggregate amount of repurchased shares						$ 287,000,000	$ 26,000,000
Treasury Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Aggregate amount of repurchased shares			$ 34,000,000
Share Repurchase Program May 8, 2017 [Member]
Class of Stock [Line Items]
Amount of shares authorized to be repurchased								$ 1,500,000,000
Share Repurchase Program December 4, 2014 [Member] | Treasury Stock [Member]
Class of Stock [Line Items]
Number of common shares repurchased (in shares)						1,459,417
Average price per share of repurchased shares (in dollars per share)						$ 196.97
Share Repurchase Program December 4, 2014 [Member] | Treasury Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Number of common shares repurchased (in shares)			172,082
Average price per share of repurchased shares (in dollars per share)			$ 193.85

L3's Earnings Per Common Shar84

L3's Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Reconciliation of Net Income [Abstract]
Net income	$ 379	$ 207	$ 587	$ 375
Net income from continuing operations attributable to noncontrolling interests	(4)	(5)	(9)	(9)
Net income attributable to L3	375	202	578	366
Earnings attributable to L3' s common shareholders [Abstract]
Continuing operations	185	190	372	343
Discontinued operations, net of income tax	190	12	206	23
Net income attributable to L3	$ 375	$ 202	$ 578	$ 366
Basic [Abstract]
Weighted average common shares outstanding (in shares)	78.4	78	78.3	77.8
Basic earnings (loss) per share [Abstract]
Continuing operations (in dollars per share)	$ 2.36	$ 2.44	$ 4.75	$ 4.40
Discontinued operations (in dollars per share)	2.42	0.15	2.63	0.30
Basic earnings per share (in dollars per share)	$ 4.78	$ 2.59	$ 7.38	$ 4.70
Common and potential common shares [Abstract]
Weighted average common shares outstanding (in shares)	78.4	78	78.3	77.8
Effect of dilutive securities (in shares)	1	1.5	1.3	1.6
Common and potential common shares (in shares)	79.4	79.5	79.6	79.4
Diluted earnings (loss) per share [Abstract]
Continuing operations (in dollars per share)	$ 2.33	$ 2.39	$ 4.67	$ 4.32
Discontinued operations, net of income tax (in dollars per share)	2.39	0.15	2.59	0.29
Diluted earnings per share (in dollars per share)	$ 4.72	$ 2.54	$ 7.26	$ 4.61
Shares excluded from computation of diluted earnings per share (in shares)	0.3	0.4	0.3	0.3

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 29, 2018	Dec. 31, 2017
Liabilities [Abstract]
Contingent consideration	$ 31	$ 27	$ 31
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	31
Acquisitions and investments	10
Cash payments	(2)
Changes in fair value of contingent consideration, net	(12)
Balance at end of period	27
Recurring [Member] | Level 1 [Member]
Assets [Abstract]
Cash equivalents		955	310
Derivatives (foreign currency forward contracts)		0	0
Total assets		955	310
Liabilities [Abstract]
Derivatives (foreign currency forward contracts)		0	0
Contingent consideration	0	0	0
Total liabilities		0	0
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	0
Balance at end of period	0
Recurring [Member] | Level 2 [Member]
Assets [Abstract]
Cash equivalents		0	0
Derivatives (foreign currency forward contracts)		3	11
Total assets		3	11
Liabilities [Abstract]
Derivatives (foreign currency forward contracts)		8	1
Contingent consideration	0	0	0
Total liabilities		8	1
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	0
Balance at end of period	0
Recurring [Member] | Level 3 [Member]
Assets [Abstract]
Cash equivalents		0	0
Derivatives (foreign currency forward contracts)		0	0
Total assets		0	0
Liabilities [Abstract]
Derivatives (foreign currency forward contracts)		0	0
Contingent consideration	31	27	31
Total liabilities		$ 27	$ 31
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	31
Balance at end of period	$ 27

Financial Instruments (Details)

Financial Instruments (Details) - USD ($) $ in Millions	Jun. 29, 2018	Dec. 31, 2017
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	$ 3,900	$ 3,330
Foreign currency forward contracts	(5)	10
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	3,944	3,502
Foreign currency forward contracts	$ (5)	$ 10

Derivative Financial Instrume87

Derivative Financial Instruments, Outstanding Forward Contracts by Currency (Details) - Foreign Currency Forward Contracts [Member] $ in Millions	Jun. 29, 2018USD ($)
Derivative [Line Items]
Notional amounts	$ 438
Canadian Dollar [Member]
Derivative [Line Items]
Notional amounts	183
U.S. Dollar [Member]
Derivative [Line Items]
Notional amounts	145
Euro [Member]
Derivative [Line Items]
Notional amounts	80
United Arab Emirates Dirham [Member]
Derivative [Line Items]
Notional amounts	12
British Pound [Member]
Derivative [Line Items]
Notional amounts	11
New Zealand Dollar
Derivative [Line Items]
Notional amounts	$ 7

Derivative Financial Instrume88

Derivative Financial Instruments, Fair Value on Consolidated Balance Sheet (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 29, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Pre-tax gain on foreign currency forward contracts	$ 1	$ 1
Estimated net amount of existing gains expected to be reclassified into income within the next 12 months			$ 5
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			3	$ 11
Other Current Assets [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			3	11
Other Current Assets [Member] | Contingent Consideration [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			0	0
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			0	0
Other Assets [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			0	0
Other Assets [Member] | Contingent Consideration [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets			0	0
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			12	1
Other Current Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			6	1
Other Current Liabilities [Member] | Contingent Consideration [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			6	0
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			2	0
Other Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			2	0
Other Liabilities [Member] | Contingent Consideration [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities			$ 0	$ 0

Commitments and Contingencies (

Commitments and Contingencies (Details) € in Millions, $ in Millions	Jul. 23, 2014EUR (€)	Jun. 29, 2018USD ($)
Contingencies And Commitments [Line Items]
Receivables for recoveries from insurance contracts or third parties | $		$ 2
Property Damages [Member] | HVC Alkmaar [Member]
Contingencies And Commitments [Line Items]
Claims for estimated damages	€ 11
Business Interruption [Member] | HVC Alkmaar [Member]
Contingencies And Commitments [Line Items]
Claims for estimated damages	€ 35

Pension and Other Postretirem90

Pension and Other Postretirement Benefits, Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 26	$ 25	$ 52	$ 50
Interest cost	36	36	72	71
Expected return on plan assets	(56)	(49)	(112)	(98)
Amortization of net loss (gains)	18	15	37	31
Net periodic benefit cost	24	27	49	54
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	1	0	1	1
Interest cost	1	1	2	2
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of net loss (gains)	(1)	0	(2)	(1)
Net periodic benefit cost	$ 0	$ 0	$ (1)	$ 0

Pension and Other Postretirem91

Pension and Other Postretirement Benefits, Contributions (Details) $ in Millions	6 Months Ended
	Jun. 29, 2018USD ($)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to defined benefit plans	$ 28
Expected contributions to plans during the remainder of fiscal year	72
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to defined benefit plans	3
Expected contributions to plans during the remainder of fiscal year	$ 7

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Options (Details) - Stock Options [Member] - $ / shares	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 29, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	201,041
Weighted average exercise price (in dollars per share)	$ 210.60
Expiration period of stock options granted from date of grant		10 years
Vesting period		3 years
Weighted average grant date fair value of stock options (in dollars per share)	$ 38.02
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected holding period	5 years 2 months 12 days
Expected volatility	19.80%
Expected dividend yield	1.80%
Risk-free interest rate	2.70%

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Units (Details) - Unvested Restricted Stock Awards [Member] - $ / shares	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted (in shares)		246,342
Weighted average grant date fair value (in dollars per share)		$ 210.39
Vesting period	3 years
Retirement eligibility, employee age	60 years
Service period, minimum	5 years
Retirement eligibility, employee age requirement, without minimum service period	65 years
Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Stock-Based Compensation, Perfo

Stock-Based Compensation, Performance Units (Details) - Performance Unit Awards [Member] - $ / shares	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 29, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted (in shares)	21,546
Weighted average grant date fair value (in dollars per share)	$ 210.54
Length of service after grant date		3 years
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	200.00%

Supplemental Cash Flow Inform95

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Interest	$ 97	$ 83
Income tax payments	54	96
Income tax refunds	$ 3	$ 7

Segment Information (Details)

Segment Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 29, 2018USD ($)Segment	Jun. 30, 2017USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			4
Net Sales [Abstract]
Net sales	$ 2,583	$ 2,385	$ 4,954	$ 4,706
Operating Income [Abstract]
Gain on the sale of the Crestview & TCS Businesses	48	0	48	0
Operating income	321	294	572	531
Depreciation and amortization [Abstract]
Depreciation and amortization	60	54	116	106
Total Assets:
Assets held for sale	0		0		$ 138	$ 135
Assets of discontinued operations	0		0		285	306
Total assets	13,530		13,530		$ 12,730	12,729
Electronic Systems [Member]
Net Sales [Abstract]
Net sales	812		1,597
Aerospace Systems [Member]
Net Sales [Abstract]
Net sales	741		1,427
Communication Systems [Member]
Net Sales [Abstract]
Net sales	554		1,047
Sensor Systems [Member]
Net Sales [Abstract]
Net sales	476		883
Operating Segments [Member]
Operating Income [Abstract]
Operating income	273	294	524	531
Operating Segments [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	828	789	1,630	1,549
Operating Income [Abstract]
Operating income	113	103	221	193
Depreciation and amortization [Abstract]
Depreciation and amortization	24	17	43	35
Total Assets:
Total assets	4,990		4,990			4,796
Operating Segments [Member] | Aerospace Systems [Member]
Net Sales [Abstract]
Net sales	751	681	1,450	1,382
Operating Income [Abstract]
Operating income	61	56	118	112
Depreciation and amortization [Abstract]
Depreciation and amortization	12	13	24	24
Total Assets:
Total assets	2,200		2,200			2,014
Operating Segments [Member] | Communication Systems [Member]
Net Sales [Abstract]
Net sales	563	555	1,062	1,098
Operating Income [Abstract]
Operating income	45	84	82	126
Depreciation and amortization [Abstract]
Depreciation and amortization	11	12	24	24
Total Assets:
Total assets	2,142		2,142			2,063
Operating Segments [Member] | Sensor Systems [Member]
Net Sales [Abstract]
Net sales	482	394	894	748
Operating Income [Abstract]
Operating income	54	51	103	100
Depreciation and amortization [Abstract]
Depreciation and amortization	13	12	25	23
Total Assets:
Total assets	2,890		2,890			2,706
Corporate [Member]
Total Assets:
Total assets	1,308		1,308			$ 709
Elimination of Intercompany Sales [Member]
Net Sales [Abstract]
Net sales	(41)	$ (34)	(82)	$ (71)
Department of Defense [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	443		860
Other U.S. Government [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	40		79
Total U. S. Government [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	483		939
Foreign Government Debt [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	74		142
Commercial - Foreign [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	177		344
Commercial - Domestic [Member] | Electronic Systems [Member]
Net Sales [Abstract]
Net sales	$ 78		$ 172

Segment Information - Disaggreg

Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Direct sales to end customer as percent of consolidated sales (percent)	64.00%
Indirect sales as subcontractor or supplier as percent of consolidated sales (percent)	36.00%
Fixed price incentive fee type contracts as percent of net sales (percent)	1.00%		2.00%
Cost-plus and incentive fee type contracts as percent of net sales (percent)	4.00%		4.00%
Total sales	$ 2,583	$ 2,385	$ 4,954	$ 4,706
Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	812		1,597
Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	741		1,427
Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	554		1,047
Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	476		883
Department of Defense [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	443		860
Other U.S. Government [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	40		79
Total U. S. Government [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	483		939
Foreign Government Debt [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	74		142
Commercial - Foreign [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	177		344
Commercial - Domestic [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	78		172
Product [Member]
Disaggregation of Revenue [Line Items]
Total sales	1,786		3,432
Product [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	578		1,138
Product [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	405		777
Product [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	397		761
Product [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	406		756
Services [Member]
Disaggregation of Revenue [Line Items]
Total sales	797		1,522
Services [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	234		459
Services [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	336		650
Services [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	157		286
Services [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	70		127
Fixed-price Contract [Member]
Disaggregation of Revenue [Line Items]
Total sales	1,872		3,564
Fixed-price Contract [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	680		1,344
Fixed-price Contract [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	398		764
Fixed-price Contract [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	403		732
Fixed-price Contract [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	391		724
Cost-plus Contract [Member]
Disaggregation of Revenue [Line Items]
Total sales	626		1,222
Cost-plus Contract [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	118		226
Cost-plus Contract [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	292		561
Cost-plus Contract [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	133		281
Cost-plus Contract [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	83		154
Time-and-materials Contract [Member]
Disaggregation of Revenue [Line Items]
Total sales	85		168
Time-and-materials Contract [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	14		27
Time-and-materials Contract [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	51		102
Time-and-materials Contract [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	18		34
Time-and-materials Contract [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	2		5
Cost to Cost Method [Member]
Disaggregation of Revenue [Line Items]
Total sales	1,942		3,744
Cost to Cost Method [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	548		1,081
Cost to Cost Method [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	713		1,379
Cost to Cost Method [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	455		845
Cost to Cost Method [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	226		439
Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total sales	484		916
Point in Time [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	175		369
Point in Time [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	11		13
Point in Time [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	76		153
Point in Time [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	222		381
Output Method [Member]
Disaggregation of Revenue [Line Items]
Total sales	88		162
Output Method [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	71		122
Output Method [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	1		1
Output Method [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	5		12
Output Method [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	11		27
Billing Method [Member]
Disaggregation of Revenue [Line Items]
Total sales	69		132
Billing Method [Member] | Electronic Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	18		25
Billing Method [Member] | Aerospace Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	16		34
Billing Method [Member] | Communication Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	18		37
Billing Method [Member] | Sensor Systems [Member]
Disaggregation of Revenue [Line Items]
Total sales	$ 17		$ 36

Severance and Restructuring R98

Severance and Restructuring Related Costs (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 29, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 29, 2018USD ($)Employees	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)Employees
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs			$ 14		$ 101
Number of employees of restructuring costs | Employees			400		1,500
Remaining balance of employee severance and restructuring costs	$ 15		$ 15		$ 23
Electronic Systems [Member]
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs	2	$ 2	4	$ 5
Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs	0	1	1	1
Communication Systems [Member]
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs	3	9	8	18
Sensor Systems [Member]
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs	1	0	1	2
Consolidated [Member]
Restructuring Cost and Reserve [Line Items]
Severance and restructuring related costs	$ 6	$ 12	$ 14	$ 26

Severance and Restructuring R99

Severance and Restructuring Related Costs - Restructuring Reserve (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 29, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Balance at beginning of period	$ 23
Additional provisions	14	$ 101
Cash payments	(22)
Balance at end of period	$ 15	$ 23

Condensed Combining Financia100

Condensed Combining Financial Information of L3 and Its Subsidiaries- Condensed Combining Balance Sheets (Details) - USD ($) $ in Millions	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Current assets [Abstract]
Cash and cash equivalents	$ 1,366		$ 662	$ 385	$ 363
Billed receivables, net	863		723
Contract assets	1,611	$ 1,349	0
Contracts in process	0	0	1,933
Inventories	934	926	389
Prepaid expenses and other current assets	332	317	300
Prepaid expenses and other current assets			689
Assets held for sale	0		135
Assets of discontinued operations	0	285	306
Total current assets	5,106	4,400	4,448
Goodwill	6,651		6,615
Other assets	1,773		1,666
Investment in and amounts due from consolidated subsidiaries	0		0
Total assets	13,530	12,730	12,729
Current portion of long-term debt	581		0
Current liabilities	2,222		2,136
Liabilities held for sale	0	16	17
Liabilities of discontinued operations	0	203	226
Amounts due to consolidated subsidiaries	0		0
Other long-term liabilities	1,896		1,869
Long-term debt	3,319		3,330
Total liabilities	8,018	7,566	7,578
L3 shareholders' equity	5,444		5,083
Noncontrolling interests	68		68
Total equity	5,512	$ 5,164	5,151	5,047	4,624
Total liabilities and equity	13,530		12,729
Eliminations [Member]
Current assets [Abstract]
Cash and cash equivalents	(15)		(71)	(85)	(136)
Billed receivables, net	0		0
Contract assets	0
Contracts in process			0
Inventories	0
Prepaid expenses and other current assets	0
Prepaid expenses and other current assets			0
Assets held for sale			0
Assets of discontinued operations			0
Total current assets	(15)		(71)
Goodwill	0		0
Other assets	0		0
Investment in and amounts due from consolidated subsidiaries	(12,282)		(11,911)
Total assets	(12,297)		(11,982)
Current portion of long-term debt	0
Current liabilities	(15)		(71)
Liabilities held for sale			0
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	(426)		(330)
Other long-term liabilities	0		0
Long-term debt	0		0
Total liabilities	(441)		(401)
L3 shareholders' equity	(11,924)		(11,649)
Noncontrolling interests	68		68
Total equity	(11,856)		(11,581)
Total liabilities and equity	(12,297)		(11,982)
L-3 [Member]
Current assets [Abstract]
Cash and cash equivalents	1,055		432	272	291
Billed receivables, net	285		266
Contract assets	616
Contracts in process			706
Inventories	393
Prepaid expenses and other current assets	112
Prepaid expenses and other current assets			330
Assets held for sale			0
Assets of discontinued operations			306
Total current assets	2,461		2,040
Goodwill	2,273		2,248
Other assets	707		658
Investment in and amounts due from consolidated subsidiaries	5,668		5,513
Total assets	11,109		10,459
Current portion of long-term debt	581
Current liabilities	774		811
Liabilities held for sale			0
Liabilities of discontinued operations			226
Amounts due to consolidated subsidiaries	0		0
Other long-term liabilities	991		1,009
Long-term debt	3,319		3,330
Total liabilities	5,665		5,376
L3 shareholders' equity	5,444		5,083
Noncontrolling interests	0		0
Total equity	5,444		5,083
Total liabilities and equity	11,109		10,459
Guarantor Subsidiaries [Member]
Current assets [Abstract]
Cash and cash equivalents	19		16	0	5
Billed receivables, net	315		244
Contract assets	810
Contracts in process			912
Inventories	315
Prepaid expenses and other current assets	150
Prepaid expenses and other current assets			235
Assets held for sale			135
Assets of discontinued operations			0
Total current assets	1,609		1,542
Goodwill	2,828		2,844
Other assets	712		687
Investment in and amounts due from consolidated subsidiaries	6,614		6,398
Total assets	11,763		11,471
Current portion of long-term debt	0
Current liabilities	864		832
Liabilities held for sale			17
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	0		0
Other long-term liabilities	757		729
Long-term debt	0		0
Total liabilities	1,621		1,578
L3 shareholders' equity	10,142		9,893
Noncontrolling interests	0		0
Total equity	10,142		9,893
Total liabilities and equity	11,763		11,471
Non-Guarantor Subsidiaries [Member]
Current assets [Abstract]
Cash and cash equivalents	307		285	$ 198	$ 203
Billed receivables, net	263		213
Contract assets	185
Contracts in process			315
Inventories	226
Prepaid expenses and other current assets	70
Prepaid expenses and other current assets			124
Assets held for sale			0
Assets of discontinued operations			0
Total current assets	1,051		937
Goodwill	1,550		1,523
Other assets	354		321
Investment in and amounts due from consolidated subsidiaries	0		0
Total assets	2,955		2,781
Current portion of long-term debt	0
Current liabilities	599		564
Liabilities held for sale			0
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	426		330
Other long-term liabilities	148		131
Long-term debt	0		0
Total liabilities	1,173		1,025
L3 shareholders' equity	1,782		1,756
Noncontrolling interests	0		0
Total equity	1,782		1,756
Total liabilities and equity	$ 2,955		$ 2,781

Condensed Combining Financia101

Condensed Combining Financial Information of L3 and Its Subsidiaries- Condensed Combining Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Total net sales	$ 2,583	$ 2,385	$ 4,954	$ 4,706
Total operating costs and expenses	(2,310)	(2,091)	(4,430)	(4,175)
Gain on sale of the Crestview Aerospace and TCS businesses	48	0	48	0
Operating income	321	294	572	531
Interest expense	(44)	(42)	(85)	(84)
Interest and other income, net	8	2	14	6
Debt retirement charge	(48)	0	(48)	0
Income from continuing operations before income taxes	237	254	453	453
Provision (benefit) for income taxes	(48)	(59)	(72)	(101)
Equity in net loss of consolidated subsidiaries	0	0	0	0
Income from continuing operations	189	195	381	352
Loss from discontinued operations, net of income taxes	190	12	206	23
Net income	379	207	587	375
Net income attributable to noncontrolling interests	(4)	(5)	(9)	(9)
Net income attributable to L3	375	202	578	366
Comprehensive income attributable to L3	306	264	555	456
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales	(95)	(101)	(192)	(177)
Total operating costs and expenses	95	101	192	177
Gain on sale of the Crestview Aerospace and TCS businesses	0		0
Operating income	0	0	0	0
Interest expense	0	0	0	0
Interest and other income, net	0	0	0	0
Debt retirement charge	0		0
Income from continuing operations before income taxes	0	0	0	0
Provision (benefit) for income taxes	0	0	0	0
Equity in net loss of consolidated subsidiaries	(221)	(191)	(411)	(336)
Income from continuing operations	(221)	(191)	(411)	(336)
Loss from discontinued operations, net of income taxes	0	0	0	0
Net income	(221)	(191)	(411)	(336)
Net income attributable to noncontrolling interests	(4)	(5)	(9)	(9)
Net income attributable to L3	(225)	(196)	(420)	(345)
Comprehensive income attributable to L3	(74)	(296)	(333)	(478)
L-3 [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales	919	894	1,726	1,744
Total operating costs and expenses	(819)	(810)	(1,541)	(1,581)
Gain on sale of the Crestview Aerospace and TCS businesses	0		0
Operating income	100	84	185	163
Interest expense	(43)	(42)	(84)	(84)
Interest and other income, net	6	2	11	5
Debt retirement charge	(48)		(48)
Income from continuing operations before income taxes	15	44	64	84
Provision (benefit) for income taxes	(4)	(10)	(10)	(19)
Equity in net loss of consolidated subsidiaries	174	156	318	278
Income from continuing operations	185	190	372	343
Loss from discontinued operations, net of income taxes	190	12	206	23
Net income	375	202	578	366
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to L3	375	202	578	366
Comprehensive income attributable to L3	306	264	555	456
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales	1,328	1,193	2,567	2,389
Total operating costs and expenses	(1,239)	(1,049)	(2,394)	(2,145)
Gain on sale of the Crestview Aerospace and TCS businesses	48		48
Operating income	137	144	221	244
Interest expense	0	0	0	0
Interest and other income, net	1	0	1	0
Debt retirement charge	0		0
Income from continuing operations before income taxes	138	144	222	244
Provision (benefit) for income taxes	(26)	(34)	(35)	(54)
Equity in net loss of consolidated subsidiaries	47	35	93	58
Income from continuing operations	159	145	280	248
Loss from discontinued operations, net of income taxes	0	0	0	0
Net income	159	145	280	248
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to L3	159	145	280	248
Comprehensive income attributable to L3	85	192	237	308
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales	431	399	853	750
Total operating costs and expenses	(347)	(333)	(687)	(626)
Gain on sale of the Crestview Aerospace and TCS businesses	0		0
Operating income	84	66	166	124
Interest expense	(1)	0	(1)	0
Interest and other income, net	1	0	2	1
Debt retirement charge	0		0
Income from continuing operations before income taxes	84	66	167	125
Provision (benefit) for income taxes	(18)	(15)	(27)	(28)
Equity in net loss of consolidated subsidiaries	0	0	0	0
Income from continuing operations	66	51	140	97
Loss from discontinued operations, net of income taxes	0	0	0	0
Net income	66	51	140	97
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to L3	66	51	140	97
Comprehensive income attributable to L3	$ (11)	$ 104	$ 96	$ 170

Condensed Combining Financia102

Condensed Combining Financial Information of L3 and Its Subsidiaries- Condensed Combining Statements of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017
Operating activities [Abstract]
Net cash from operating activities from continuing operations	$ 178	$ 315
Investing activities [Abstract]
Business acquisitions, net of cash acquired	(69)	(191)
Proceeds from sale of businesses, net of closing date cash balances	535	16
Other investing activities	(136)	(32)
Net cash from (used in) investing activities from continuing operations	330	(207)
Financing activities [Abstract]
Proceeds from sale of senior notes	1,798	0
Repurchases and redemptions of senior notes	(1,263)	0
Common stock repurchased	(287)	(26)
Dividends paid on L3's common stock	(128)	(119)
Other financing activities	77	15
Net cash from (used in) financing activities from continuing operations	197	(130)
Effect of foreign currency exchange rate changes on cash	(8)	10
Net decrease in cash and cash equivalents of discontinued operations	7	34
Net decrease (increase) in cash	704	22
Cash and cash equivalents, beginning of the period	662	363
Cash and cash equivalents, end of the period	1,366	385
Eliminations [Member]
Operating activities [Abstract]
Net cash from operating activities from continuing operations	(5)	(41)
Investing activities [Abstract]
Business acquisitions, net of cash acquired	0	0
Proceeds from sale of businesses, net of closing date cash balances	0	0
Other investing activities	0	0
Net cash from (used in) investing activities from continuing operations	0	0
Financing activities [Abstract]
Proceeds from sale of senior notes	0
Repurchases and redemptions of senior notes	0
Common stock repurchased	0	0
Dividends paid on L3's common stock	0	0
Other financing activities	61	92
Net cash from (used in) financing activities from continuing operations	61	92
Effect of foreign currency exchange rate changes on cash	0	0
Net decrease in cash and cash equivalents of discontinued operations	0	0
Net decrease (increase) in cash	56	51
Cash and cash equivalents, beginning of the period	(71)	(136)
Cash and cash equivalents, end of the period	(15)	(85)
L-3 [Member]
Operating activities [Abstract]
Net cash from operating activities from continuing operations	195	137
Investing activities [Abstract]
Business acquisitions, net of cash acquired	(69)	(191)
Proceeds from sale of businesses, net of closing date cash balances	360	15
Other investing activities	(79)	(33)
Net cash from (used in) investing activities from continuing operations	212	(209)
Financing activities [Abstract]
Proceeds from sale of senior notes	1,798
Repurchases and redemptions of senior notes	(1,263)
Common stock repurchased	(287)	(26)
Dividends paid on L3's common stock	(128)	(119)
Other financing activities	89	164
Net cash from (used in) financing activities from continuing operations	209	19
Effect of foreign currency exchange rate changes on cash	0	0
Net decrease in cash and cash equivalents of discontinued operations	7	34
Net decrease (increase) in cash	623	(19)
Cash and cash equivalents, beginning of the period	432	291
Cash and cash equivalents, end of the period	1,055	272
Guarantor Subsidiaries [Member]
Operating activities [Abstract]
Net cash from operating activities from continuing operations	(100)	101
Investing activities [Abstract]
Business acquisitions, net of cash acquired	0	0
Proceeds from sale of businesses, net of closing date cash balances	175	0
Other investing activities	(38)	11
Net cash from (used in) investing activities from continuing operations	137	11
Financing activities [Abstract]
Proceeds from sale of senior notes	0
Repurchases and redemptions of senior notes	0
Common stock repurchased	0	0
Dividends paid on L3's common stock	0	0
Other financing activities	(34)	(117)
Net cash from (used in) financing activities from continuing operations	(34)	(117)
Effect of foreign currency exchange rate changes on cash	0	0
Net decrease in cash and cash equivalents of discontinued operations	0	0
Net decrease (increase) in cash	3	(5)
Cash and cash equivalents, beginning of the period	16	5
Cash and cash equivalents, end of the period	19	0
Non-Guarantor Subsidiaries [Member]
Operating activities [Abstract]
Net cash from operating activities from continuing operations	88	118
Investing activities [Abstract]
Business acquisitions, net of cash acquired	0	0
Proceeds from sale of businesses, net of closing date cash balances	0	1
Other investing activities	(19)	(10)
Net cash from (used in) investing activities from continuing operations	(19)	(9)
Financing activities [Abstract]
Proceeds from sale of senior notes	0
Repurchases and redemptions of senior notes	0
Common stock repurchased	0	0
Dividends paid on L3's common stock	0	0
Other financing activities	(39)	(124)
Net cash from (used in) financing activities from continuing operations	(39)	(124)
Effect of foreign currency exchange rate changes on cash	(8)	10
Net decrease in cash and cash equivalents of discontinued operations	0	0
Net decrease (increase) in cash	22	(5)
Cash and cash equivalents, beginning of the period	285	203
Cash and cash equivalents, end of the period	$ 307	$ 198

Condensed Combining Financia103

Condensed Combining Financial Information of L3 and Its Subsidiaries - Financial Statement Revisions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Total assets	$ 13,530		$ 13,530		$ 12,730	$ 12,729
Total liabilities	8,018		8,018		7,566	7,578
Total equity	5,512	$ 5,047	5,512	$ 5,047	$ 5,164	5,151	$ 4,624
Net income	379	207	587	375
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets	(12,297)		(12,297)			(11,982)
Total liabilities	(441)		(441)			(401)
Total equity	(11,856)		(11,856)			(11,581)
Net income	(221)	(191)	(411)	(336)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets	11,763		11,763			11,471
Total liabilities	1,621		1,621			1,578
Total equity	10,142		10,142			9,893
Net income	159	145	280	248
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets	2,955		2,955			2,781
Total liabilities	1,173		1,173			1,025
Total equity	1,782		1,782			1,756
Net income	$ 66	51	$ 140	97
As Reported [Member] | Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						(10,930)
Total liabilities						(419)
Total equity						(10,511)
Net income		(164)		(292)
As Reported [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						10,270
Total liabilities						1,756
Total equity						8,514
Net income		117		201
As Reported [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						3,156
Total liabilities						1,091
Total equity						2,065
Net income		52		100
Adjustment [Member] | Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						(1,052)
Total liabilities						18
Total equity						(1,070)
Net income		(27)		(44)
Adjustment [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						1,201
Total liabilities						(178)
Total equity						1,379
Net income		28		47
Adjustment [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total assets						(375)
Total liabilities						(66)
Total equity						$ (309)
Net income		$ (1)		$ (3)