L3 10-K 21 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 14, 2019	Jun. 29, 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 Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 15
Entity Common Stock, Shares Outstanding		79,368,345
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,066	$ 662
Billed receivables, net of allowances of $12 in 2018 and $18 in 2017	919	723
Contract assets	1,590	0
Contracts in process	0	1,933
Inventories	879	389
Prepaid expenses and other current assets	356	300
Assets held for sale	0	135
Assets of discontinued operations	0	306
Total current assets	4,810	4,448
Property, plant and equipment, net	1,169	1,110
Goodwill	6,808	6,615
Identifiable intangible assets	390	292
Other assets	341	264
Total assets	13,518	12,729
Current liabilities:
Accounts payable, trade	699	531
Accrued employment costs	491	493
Accrued expenses	251	217
Contract liabilities	669	0
Advance payments and billings in excess of costs incurred	0	509
Income taxes payable	49	19
Other current liabilities	288	367
Liabilities held for sale	0	17
Liabilities of discontinued operations	0	226
Total current liabilities	2,447	2,379
Pension and postretirement benefits	1,211	1,313
Deferred income taxes	196	158
Other liabilities	436	398
Long-term debt	3,321	3,330
Total liabilities	7,611	7,578
Commitments and contingencies (see Note 19)
Stockholders' Equity Attributable to Parent [Abstract]
Common stock: $.01 par value; 300,000,000 shares authorized, 78,800,714 shares outstanding at December 31, 2018 and 77,876,687 shares outstanding at December 31, 2017	6,866	6,519
Treasury stock (at cost), 84,999,711 shares at December 31, 2018 and 83,362,412 shares at December 31, 2017	(7,726)	(7,404)
Retained earnings	7,424	6,659
Accumulated other comprehensive loss	(725)	(691)
Total shareholders’ equity	5,839	5,083
Noncontrolling interests	68	68
Total equity	5,907	5,151
Total liabilities and equity	$ 13,518	$ 12,729

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Allowances for billed receivables	$ 12	$ 18
Stockholders' Equity Attributable to Parent [Abstract]
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)	78,800,714	77,876,687
Treasury stock at cost (in shares)	84,999,711	83,362,412

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total net sales	$ 10,244	$ 9,573	$ 9,210
Operating costs and expenses:
Cost of sales	(9,138)	(8,542)	(8,252)
General and administrative expenses	(1,601)	(1,520)	(1,287)
Total operating costs and expenses	(9,138)	(8,542)	(8,252)
Gain on sale of the Crestview Aerospace and TCS businesses	42	0	0
Merger and acquisition related expenses	(28)	0	0
Operating income	1,120	1,031	958
Interest expense	(164)	(169)	(164)
Interest and other income, net	37	9	17
Debt retirement charges	(69)	0	(7)
Income from continuing operations before income taxes	924	871	804
Provision for income taxes	(103)	(102)	(171)
Income from continuing operations	821	769	633
Income (loss) from discontinued operations, net of income taxes	205	(76)	91
Net income	1,026	693	724
Net income from continuing operations attributable to noncontrolling interests	(21)	(16)	(14)
Net income attributable to L3	$ 1,005	$ 677	$ 710
Basic earnings (loss) per share attributable to common shareholders:
Continuing operations (in dollars per share)	$ 10.19	$ 9.65	$ 7.99
Discontinued operations (in dollars per share)	2.61	(0.97)	1.18
Basic earnings (loss) per share (in dollars per share)	12.80	8.68	9.17
Diluted earnings (loss) per share attributable to common shareholders:
Continuing operations (in dollars per share)	10.05	9.46	7.86
Discontinued operations (in dollars per share)	2.58	(0.95)	1.15
Diluted earnings (loss) per share (in dollars per share)	12.63	8.51	9.01
Cash dividends declared per common share (in dollars per share)	$ 3.2	$ 3	$ 2.8
Weighted average common shares outstanding:
Basic (in shares)	78.5	78	77.4
Diluted (in shares)	79.6	79.6	78.8
Product [Member]
Total net sales	$ 7,165	$ 6,733	$ 6,453
Operating costs and expenses:
Cost of sales	(5,345)	(4,967)	(4,879)
Service [Member]
Total net sales	3,079	2,840	2,757
Operating costs and expenses:
Cost of sales	$ (2,192)	$ (2,055)	$ (2,086)

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income		$ 1,026	$ 693	$ 724
Other comprehensive income (loss):
Foreign currency translation adjustments		(82)	124	(77)
Unrealized (losses) gains on hedging instruments(1)	[1]	(19)	3	14
Pension and postretirement benefit plans:
Amortization of net loss and prior service cost previously recognized(2)	[2]	53	45	30
Net gain (loss) arising during the period(3)	[3]	14	(137)	(119)
Net change in pension and postretirement benefit plans		67	(92)	(89)
Total other comprehensive (loss) income		(34)	35	(152)
Comprehensive income		992	728	572
Comprehensive income attributable to noncontrolling interests		(21)	(16)	(14)
Comprehensive income attributable to L3		$ 971	$ 712	$ 558
[1]	Net of income tax benefits of $5 million in 2018, net of income taxes of $1 million in 2017 and $5 million in 2016.
[2]	Net of income taxes of $15 million in 2018, $14 million in 2017 and $18 million in 2016.
[3]	Net of income taxes of $4 million in 2018, net of income tax benefits of $42 million in 2017 and $69 million in 2016.

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Income tax expense (benefit) on unrealized gains (losses) on hedging instruments	$ 5	$ 1	$ 5
Income tax (expense) on amortization of net loss and prior service cost previously recognized	15	14	18
Income tax expense (benefit) on net (loss) gain arising during the period	$ 4	$ 42	$ 69

CONSOLIDATED STATEMENTS OF EQUI

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, 2015	$ 4,429	$ 1	$ 6,051	$ (6,851)	$ 5,728	$ (574)	$ 74
Beginning Balance (in shares) at Dec. 31, 2015		78.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	724				710		14
Other comprehensive income (loss)	(152)					(152)
Distributions to noncontrolling interests	(17)						(17)
Cash dividends declared	(220)				(220)
Shares issued:
Employee savings plans	115		115
Employee savings plans (in shares)		0.9
Exercise of stock options	53		53
Exercise of stock options (in shares)		0.6
Employee stock purchase plan	31		31
Employee stock purchase plan (in shares)		0.4
Vesting of restricted stock and performance units (in shares)		0.5
Repurchases of common stock to satisfy tax withholding obligations	(21)		(21)
Repurchases of common stock to satisfy tax withholding obligations (in shares)		(0.3)
Stock-based compensation expense	49		49
Treasury stock purchased	(373)			(373)
Treasury stock purchased (in shares)		(3)
Other	6		6
Ending Balance at Dec. 31, 2016	4,624	$ 1	6,284	(7,224)	6,218	(726)	71
Ending Balance (in shares) at Dec. 31, 2016		77.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	693				677		16
Other comprehensive income (loss)	35					35
Distributions to noncontrolling interests	(19)						(19)
Cash dividends declared	(236)				(236)
Shares issued:
Employee savings plans	113		113
Employee savings plans (in shares)		0.8
Exercise of stock options	46		46
Exercise of stock options (in shares)		0.5
Employee stock purchase plan	32		32
Employee stock purchase plan (in shares)		0.2
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	53		53
Treasury stock purchased	(180)			(180)
Treasury stock purchased (in shares)		(1)
Other	8		8
Ending Balance at Dec. 31, 2017	5,151	$ 1	6,518	(7,404)	6,659	(691)	68
Ending Balance (in shares) at Dec. 31, 2017		77.9
Cumulative Effect of New Accounting Principle in Period of Adoption	13				13
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,026				1,005		21
Other comprehensive income (loss)	(34)					(34)
Distributions to noncontrolling interests	(21)						(21)
Cash dividends declared	(253)				(253)
Shares issued:
Employee savings plans	119		119
Employee savings plans (in shares)		0.6
Exercise of stock options	149		149
Exercise of stock options (in shares)		1.5
Employee stock purchase plan	33		33
Employee stock purchase plan (in shares)		0.2
Vesting of restricted stock and performance units (in shares)		0.3
Repurchases of common stock to satisfy tax withholding obligations	(31)		(31)
Repurchases of common stock to satisfy tax withholding obligations (in shares)		(0.1)
Stock-based compensation expense	60		60
Treasury stock purchased	(322)			(322)
Treasury stock purchased (in shares)		(1.6)
Other	17		17
Ending Balance at Dec. 31, 2018	$ 5,907	$ 1	$ 6,865	$ (7,726)	$ 7,424	$ (725)	$ 68
Ending Balance (in shares) at Dec. 31, 2018		78.8

CONSOLIDATED STATEMENTS OF EQ_2

CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share (in dollars per share)	$ 3.2	$ 3	$ 2.8

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net income	$ 1,026	$ 693	$ 724
Less: (income) loss from discontinued operations, net of tax	(205)	76	(91)
Income from continuing operations	821	769	633
Depreciation of property, plant and equipment	182	172	156
Amortization of intangibles and other assets	59	53	42
Deferred income tax (benefit) provision	(7)	(8)	27
Stock-based employee compensation expense	60	53	49
Contributions to employee savings plans in common stock	115	106	102
Amortization of pension and postretirement benefit plans net loss and prior service cost	68	59	48
Loss (gain) on sale of property, plant and equipment	4	(31)	(5)
Gain on sale of the Crestview Aerospace and TCS businesses	(42)	0	0
Debt retirement charges	69	0	7
Other non-cash items	6	15	26
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables	(195)	(18)	1
Contract assets	(246)	0	0
Contracts in process	0	(70)	26
Inventories	57	(69)	22
Prepaid expenses and other current assets	(75)	(58)	(23)
Accounts payable, trade	158	99	(5)
Accrued employment costs	0	28	10
Accrued expenses	55	32	(6)
Contract liabilities	108	0	0
Advance payments and billings in excess of costs incurred	0	13	(73)
Income taxes	9	(39)	33
All other operating activities	(164)	(121)	(48)
Net cash from operating activities from continuing operations	1,042	985	1,022
Investing activities:
Business acquisitions, net of cash acquired	(369)	(316)	(388)
Proceeds from the sale of businesses, net of closing date cash balances	535	18	561
Capital expenditures	(232)	(224)	(210)
Dispositions of property, plant and equipment	3	74	21
Other investing activities	(28)	(5)	6
Net cash used in investing activities from continuing operations	(91)	(453)	(10)
Proceeds from sale of senior notes	1,798	0	547
Financing activities:
Repurchases, redemptions and maturities of senior notes	(1,865)	0	(856)
Borrowings under revolving credit facility	501	1,328	819
Repayments of borrowings under revolving credit facility	(501)	(1,328)	(819)
Common stock repurchased	(322)	(180)	(373)
Dividends paid	(254)	(236)	(220)
Proceeds from exercise of stock options	149	46	53
Proceeds from employee stock purchase plan	33	32	31
Repurchases of common stock to satisfy tax withholding obligations	(31)	(18)	(21)
Debt issue costs	(15)	0	(10)
Other financing activities	(13)	(10)	(7)
Net cash used in financing activities from continuing operations	(520)	(366)	(856)
Effect of foreign currency exchange rate changes on cash and cash equivalents	(15)	20	(13)
Net cash from (used in) discontinued operations:
Operating activities	(10)	117	19
Investing activities	(2)	(4)	(6)
Net cash (used in) from discontinued operations	(12)	113	13
Net increase in cash and cash equivalents	404	299	156
Cash and cash equivalents, beginning of the year	662	363	207
Cash and cash equivalents, end of the year	$ 1,066	$ 662	$ 363

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 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. In the third quarter of 2018, the Company completed a realignment of its business segments to maximize growth and improve its integration and collaboration across the enterprise. As a result of the realignment, L3’s structure consists of the following three reportable segments: (1) ISR Systems (ISRS), (2) Communications and Networked Systems (C&NS) and (3) Electronic Systems. Financial information with respect to each of its segments is included in Note 22 . ISRS provides products and services for the global ISR and Command, Control and Communications (C 3 ) markets, specializing in ISR mission solutions from seabed to space, 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. Other major capabilities and mission solutions include space avionics and imaging payloads, Counter Unmanned Aircraft Systems mission solutions, cyber and electronic warfare, special mission command & control, modeling & simulation and life cycle support. ISRS sells these products and services primarily to the DoD and select foreign governments. The ISRS sectors are ISR Systems, Airborne Sensor Systems, Warrior Sensor Systems, Space & Sensor Systems, Aircraft Systems, MAS, Intelligence & Mission Systems and Advanced Programs. C&NS 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. Other major capabilities include integrated maritime mission solutions, directed energy, lightweight unmanned undersea vehicles and naval power delivery on submarines and surface ships. C&NS sells these products and services primarily to the DoD and select foreign governments. The C&NS sectors are Broadband Communication Systems, Naval Power Systems, Advanced Communications, Space & Power Systems and Maritime 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 markets, such as commercial and military aircraft simulation and training, 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 sectors are Commercial Aviation Solutions, Precision Engagement Systems, Link Training & Simulation and Security & Detection Systems. On June 29, 2018, the Company completed the sale of its Vertex Aerospace businesses for a sales 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 $42 million ( $19 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 $234 million ( $177 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 $0.6 billion in 2018, $1.4 billion in 2017 and $1.3 billion in 2016. The assets and liabilities and results of operations of the Vertex Aerospace business are reported as discontinued operations for all periods presented. See Note 3 for additional information. All references made to financial data in this Annual Report on Form 10-K are to the Company’s continuing operations, unless specifically noted. Planned Merger with Harris Corporation On October 14, 2018, L3 and Harris Corporation (“Harris”) announced an agreement to combine in an all stock merger of equals. Under the terms of the Agreement and Plan of Merger (the “Merger Agreement”) governing the proposed transaction, which was unanimously approved by the boards of directors of both companies, L3 shareholders will receive a fixed exchange ratio of 1.30 shares of Harris common stock for each share of L3 common stock they hold. Upon completion of the merger, Harris shareholders will own approximately 54% and L3 shareholders will own approximately 46% of the combined company, which will be renamed L3 Harris Technologies, Inc. The merger is expected to close in the middle of 2019, subject to customary closing conditions, including the receipt of regulatory approvals and approval by the shareholders of both L3 and Harris.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation: 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 also 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 voting 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. Accounting Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (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 cost of sales during the reporting period. The most significant of these estimates and assumptions relate to sales, profit and loss recognition for 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 post-retirement 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 year ended December 31, 2018 and the Company’s balance sheet as of December 31, 2018 are presented under ASC 606, while the Company’s statement of operations for the years ended December 31, 2017 and 2016 and the Company’s balance sheet as of December 31, 2017 are presented under ASC 605, Revenue Recognition . 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 for 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 22 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 collectability 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 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 8 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 may be 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 in some cases result in liabilities to complete contracts in a loss position. Net sales recognized from the Company's performance obligations partially satisfied in prior periods were $264 million for the year ended December 31, 2018 and relate to revisions in contract estimates. The aggregate impact of net changes in contract estimates is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Operating income $ 213 $ 185 $ 149 Diluted earnings per share $ 2.03 $ 1.49 $ 1.23 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 year ended December 31, 2018 . % of Total Net Sales Over time (cost-to-cost method) 74 % Point in time 19 % Output method 4 % Billing method 3 % Total 100 % Remaining Performance Obligations: On December 31, 2018 , the Company had $11.6 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). The Company expects to recognize sales relating to existing performance obligations of approximately $7.3 billion in 2019 , $2.7 billion in 2020 , $0.7 billion in 2021 and $0.9 billion in the periods thereafter. 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. Research and Development: Independent research and development (IRAD) costs sponsored by the Company and bid and proposal (B&P) costs relate to both U.S. Government contracts and those for international and commercial customers. The IRAD and B&P costs for certain of the Company’s businesses that are U.S. Government contractors are recoverable indirect contract costs that are allocated to U.S. Government contracts in accordance with U.S. Government procurement regulations, and are specifically excluded from research and development accounting standards. The Company includes the recoverable IRAD and B&P costs allocated to U.S. Government contracts in inventoried contract costs, and charges them to general and administrative expenses when the related contract sales are recognized as revenue. Research and development costs that are not recoverable on U.S. Government contracts are accounted for in accordance with research and development accounting standards and are expensed to general and administrative expenses as incurred. The total research and development expenses incurred were $326 million , $287 million and $258 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Customer-funded research and development costs are incurred pursuant to contracts (revenue arrangements) to perform research and development activities according to customer specifications. These direct contract costs and are charged to cost of sales when the corresponding revenue is recognized, which is generally as the research and development services are performed. Customer-funded research and development costs are substantially all incurred under cost-plus type contracts with the U.S. Government. Contract Costs: 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. Product Warranties: Product warranty costs are accrued when revenue is recognized for the covered products. Product warranty expense is recognized based on the terms of the product warranty and the related estimated costs. Accrued warranty costs are reduced as product warranty costs are incurred or as warranty periods expire. The table below presents the changes in the Company’s accrued product warranty costs. Year Ended December 31, 2018 2017 (in millions) Accrued product warranty costs (1) : Balance at January 1 $ 99 $ 109 Acquisitions during the period — 3 Accruals for product warranties issued during the period 44 52 Changes to accruals for product warranties existing before January 1 1 — Settlements made during the period (55 ) (66 ) Foreign currency translation adjustments (1 ) 1 Balance at December 31 $ 88 $ 99 __________________ (1) The balances above include both the current and non-current amounts. Deferred Debt Issue Costs: Costs to issue debt are capitalized and deferred when incurred, and subsequently amortized to interest expense over the term of the related debt using the effective interest rate method. Deferred debt issuance costs, other than for line-of-credit arrangements, are presented in the Company’s consolidated balance sheets as a direct deduction from the carrying amount of the associated debt liability. Deferred debt issue costs for line-of-credit arrangements are presented in the Company’s consolidated balance sheets in other assets. Pension Plan and Postretirement Benefit Plan Obligations: The Company maintains multiple pension plans, both contributory and non-contributory, covering employees at certain locations. Eligibility for participation in these plans varies and benefits are generally based on the participant’s compensation and/or years of service. The Company’s funding policy is generally to contribute in accordance with cost accounting standards that affect government contractors, subject to the Internal Revenue Code and regulations thereon. The Company also provides postretirement medical and life insurance benefits for retired employees and dependents at certain locations. Participants are eligible for these benefits when they retire from active service and meet the eligibility requirements for the Company’s pension plans. These benefits are funded primarily on a pay-as-you-go basis with the retiree generally paying a portion of the cost through contributions, deductibles and coinsurance provisions. In accordance with accounting standards for employee pension and postretirement benefits, the Company recognizes on a plan-by-plan basis the unfunded status of its pension and postretirement benefit plans in the consolidated financial statements and measures its pension and postretirement benefit plan assets and benefit obligations at December 31. The obligation for the Company’s pension plans and postretirement benefit plans and the related annual costs of employee benefits are calculated based on several long-term assumptions, including discount rates and expected mortality for employee benefit liabilities, and rates of return on plan assets, and expected annual rates for salary increases for employee participants in the case of pension plans, and expected annual increases in the costs of medical and other health care benefits in the case of postretirement benefit obligations. See Note 20 , Pension and Other Postretirement Benefits for additional information. Stock-Based Compensation: The Company follows the fair value based method of accounting for stock-based employee compensation, which requires the Company to expense all stock-based employee compensation. Stock-based employee compensation is primarily a non-cash expense because the Company settles these obligations by issuing shares of L3 common stock instead of settling such obligations with cash payments. Compensation expense for restricted stock unit and stock option awards is generally recognized on a straight-line basis over the requisite service period for the entire award based on the grant date fair value. All of the stock options granted to employees by the Company are non-qualified stock options under U.S. income tax regulations. Compensation expense for performance units payable in L3 common stock is based on the fair value of the units at the grant date (measurement date), adjusted each reporting period for progress towards the target award, and recognized on a straight-line basis over the requisite service period. Stock-based compensation expense is recognized net of estimated forfeitures. Income Taxes: The Company provides for income taxes using the liability method. Deferred income tax assets and liabilities reflect tax carryforwards and the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes, as determined under enacted tax laws and rates. The effect of changes in tax laws or rates is accounted for in the period of enactment. Valuation allowances for deferred tax assets are provided when it is more likely than not that the assets will not be realized, considering, when appropriate, tax planning strategies. Deferred income tax assets and liabilities are classified as noncurrent in the Company’s balance sheet. Income tax accounting standards prescribe: (1) a minimum recognition threshold that an income tax benefit arising from an uncertain income tax position taken, or expected to be taken, on an income tax return is required to meet before being recognized in the financial statements and (2) the measurement of the income tax benefits recognized from such positions. The Company’s accounting policy is to classify uncertain income tax positions that are not expected to be resolved in one year as non-current income tax liabilities and to classify potential interest and penalties on uncertain income tax positions as elements of the provision for income taxes in its financial statements. Cash and Cash Equivalents: Cash equivalents consist of highly liquid investments with an original maturity of three months or less at the time of purchase. Contract Assets and Contract Liabilities: Contract assets include unbilled contract receivables related to long-term contracts for which sales and profits are recognized primarily using cost-to-cost method of accounting and are classified as current. Unbilled contract receivables are reduced by amounts of unliquidated progress or performance-based payments. Under the terms of certain revenue arrangements (contracts) with the U.S. Government, the Company is entitled to receive progress payments as costs are incurred or performance-based payments upon the achievement of predetermined performance milestones. Unliquidated progress or performance-based payments arise from fixed-price type contracts with the U.S. Government that contain progress or performance-based payment clauses, and represent payments on invoices that have been collected in cash, but have not yet been liquidated. Progress payment invoices 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. Unliquidated progress or performance-based payments are liquidated as deliveries or other contract performance milestones are completed, at an amount equal to a percentage of the contract sales price for the items delivered or work performed, based on a contractual liquidation rate. Contract liabilities include advance payments, billings in excess of the revenue recognized and amounts received in excess of sales recognized on contracts (deferred revenue). Contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Advance payments and billings in excess of revenue recognized are classified as current, and deferred revenue as current or noncurrent based on the timing of expected revenue recognition. The noncurrent portion of deferred revenue is included in other liabilities in the Company's consolidated balance sheets. Contracts in Process: Contracts in Process include unbilled contract receivables and inventoried contract costs for which sales and profits are recognized primarily using a POC method of accounting under ASC 605. Unbilled Contract Receivables represent accumulated incurred costs and earned profits on contracts in process that have been recorded as sales, primarily using the cost-to-cost method, but have not been billed to customers. Inventoried Contract Costs primarily represent incurred costs on contracts using the units-of-delivery method of accounting and include direct costs and indirect costs, including overhead costs, and materials acquired for U.S. Government service contracts. As discussed in Note 5 , the Company’s inventoried contract costs for U.S. Government contracts, and contracts with prime contractors or subcontractors of the U.S. Government include allocated G&A, IRAD costs and B&P costs. Contracts in Process contain amounts relating to contracts and programs with long performance cycles, a portion of which may not be realized within one year. For contracts in a loss position, the unrecoverable costs expected to be incurred in future periods are recorded in Estimated Costs in Excess of Estimated Contract Value to Complete Contracts in Process in a Loss Position, which is a component of Other Current Liabilities. Under the terms of certain revenue arrangements (contracts) with the U.S. Government, the Company is entitled to receive progress payments as costs are incurred or milestone payments as work is performed. The U.S. Government has a security interest in the Unbilled Contract Receivables and Inventoried Contract Costs to which progress payments have been applied, and such progress payments are reflected as a reduction of the related amounts. Milestone payments that have been received in excess of contract costs incurred and related estimated profits are reported on the Company’s balance sheet as Advance Payments and Billings in Excess of Costs Incurred. The Company values its acquired contracts in process in connection with business acquisitions on the date of acquisition at contract value less the Company’s estimated costs to complete the contract and a reasonable profit allowance on the Company’s completion effort. Inventories: Inventories, other than Inventoried Contract Costs, are stated at cost (first-in, first-out or average cost), but not in excess of realizable value. A provision for excess, obsolete or inactive inventory is recorded based upon an analysis that considers current inventory levels, historical usage patterns and future sales expectations. Property, Plant and Equipment: Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed by generally applying the straight-line method to the estimated useful lives of the related assets. Useful lives generally range from 10 to 40 years for buildings and improvements and three to 10 years for machinery, equipment, furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. When property, plant or equipment is retired or otherwise disposed of, the net book value of the asset is removed from the Company’s balance sheet and the net gain or loss is included in the determination of operating income. Property, plant and equipment acquired as part of a business acquisition is recorded at fair value. Goodwill and Indefinite-lived Intangible Assets: The carrying value of goodwill and indefinite-lived identifiable intangible assets are not amortized, but are tested for impairment annually as of November 30 and, additionally on an interim basis, whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable. The accounting standards for goodwill allow for the assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company utilized a qualitative assessment approach for the November 30, 2018 goodwill impairment test for all of its identified reporting units. For each of the reporting units, the Company determined that it was not more likely than not that the fair values were less than their net book values. If the Company does not utilize a qualitative assessment approach, then the quantitative goodwill impairment test is utilized to identify potential impairments. The Company identifies any potential impairment by comparing the carrying value of a reporting unit to its fair value. The Company determines the fair value of its reporting units using a discounted cash flow valuation approach. If a potential impairment is identified, the Company will determine the amount of goodwill impairment by

Acquisitions, Divestitures and

Acquisitions, Divestitures and Discontinued Operations	12 Months Ended
	Dec. 31, 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 ASV Global, L.L.C. (ASV Global). On September 20, 2018, the Company acquired ASV Global, L.L.C., renamed L3 ASV, for a purchase price of $94 million , excluding adjustments for approximately $1 million of cash acquired, which was financed with cash on hand. ASV Global is a leading unmanned surface vessel (USV) and autonomous vessel control systems company. The goodwill recognized for this business was $54 million , of which $16 million is expected to be deductible for income tax purposes and was assigned to the C&NS segment. The Company also recognized a preliminary estimate for technology intangible assets of $30 million . 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 second quarter of 2019, 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. C.K. Industrial Engineers Limited. (C.K. Industrial Engineers). On September 18, 2018, the Company acquired C.K. Industrial Engineers Limited, for a purchase price of £18 million (approximately $24 million ), excluding adjustments for £4 million (approximately $5 million ) of cash acquired, which was financed with cash on hand. C.K. Industrial Engineers is a U.K.-based provider of specialized tooling and equipment used primarily in robotic solutions for automotive manufacturing. The goodwill recognized for this business was $13 million , which was assigned to the Electronic 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 second quarter of 2019, 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. Azimuth Security and Linchpin Labs . (Azimuth Security and Linchpin Labs). On August 31, 2018, the Company acquired Azimuth Security and Linchpin Labs, renamed L3 Trenchant, for a combined purchase price of AUD $249 million (approximately $185 million ), net of cash acquired of AUD $21 million (approximately $15 million ), which was financed with cash on hand. The purchase price is subject to an upward adjustment for contingent consideration of up to AUD $43 million (approximately $31 million ), payable in a fixed number of shares of L3 common stock not to exceed 161,087 shares, based on L3 Trenchant's post-acquisition sales for each of the 12-month periods ending June 30, 2019, 2020 and 2021. Azimuth Security and Linchpin Labs are 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 Company recorded a $6 million increase to equity for the preliminary acquisition date fair value of the contingent consideration. The goodwill recognized for this business was $117 million , of which $20 million is expected to be deductible for income tax purposes and was assigned to the ISRS segment. The Company also recognized a preliminary estimate for intangible assets of $90 million , primarily relating to technology and customer relationships. The technology and customer relationship intangibles are expected to be amortized over 4 years and 20 years, respectively. 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 third quarter of 2019, 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. 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 , excluding adjustments for approximately $1 million of cash acquired, 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 ISRS segment, and is not expected to be deductible for income tax purposes. The final purchase price and purchase price allocation of L3 ADS was finalized as of December 31, 2018, with no significant changes to preliminary amounts. 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 ending 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 $6 million liability as of the acquisition date for the fair value of the contingent consideration. The goodwill recognized for this business was $15 million , all of which is expected to be deductible for income tax purposes and was assigned to the Electronic Systems segment. The final purchase price and purchase price allocation of Latitude Engineering was finalized as of December 31, 2018, with no significant changes to preliminary amounts. Net sales and income before income taxes for ASV Global, C.K. Industrial Engineers, Azimuth Security, Linchpin Labs, Applied Defense Solutions and Latitude Engineering, included in L3’s consolidated statement of operations for the year ended December 31, 2018 , are presented in the table below. Year Ended (in millions) Net sales $ 46 Loss before income taxes (1) $ (7 ) __________________ (1) Includes intangible amortization of $7 million and IRAD expense of $1 million . 2017 Business Acquisitions Kigre, Inc. (Kigre) . On December 18, 2017, the Company acquired Kigre, Inc., renamed L3 Kigre, Inc., for a purchase price of $13 million , which was financed with cash on hand. Kigre designs, manufactures, markets and distributes laser glass, filter glass and laser transmitter solutions involving rare earth elements. The goodwill recognized for this business was $9 million , which was assigned to the ISRS segment, and is not expected to be deductible for income tax purposes. The purchase price and purchase price allocation of Kigre was finalized as of June 29, 2018, with no significant changes to preliminary amounts. Escola De Aviacao Aerocondor, S.A. (G-Air) . On October 27, 2017, the Company acquired Escola De Aviacao Aerocondor, S.A., renamed G-Air, Inc., for a purchase price of $13 million , which was financed with cash on hand. G-Air is a European airplane and helicopter training academy located in Cascais, Portugal. The goodwill recognized for this business was $12 million , which was assigned to the Electronic Systems segment, and is not expected to be deductible for income tax purposes. The purchase price and purchase price allocation of G-Air was finalized as of June 29, 2018, with no significant changes to preliminary amounts. Doss Aviation, Inc. (Doss Aviation). On September 12, 2017, the Company acquired Doss Aviation, Inc., which has been renamed L3 Doss Aviation, Inc. Doss Aviation is the sole provider of initial flight training for U.S. Air Force (USAF) pilots and offers curriculum coursework and flight training for both fixed-wing and unmanned aircraft pilots and weapons officers from its full-service, turnkey training facility. Doss Aviation also provides instructor pilots for rotary-wing aircraft for the U.S. Army, as well as global airfield service support activities at U.S. government bases, including aircraft and bulk refueling services and aircraft component repair and modification. The strength of Doss Aviation’s military training, combined with the Company’s existing training solutions, increases the Company’s position to support customers’ growing demand for trained international military and commercial pilots. The acquisition was financed with cash on hand. The goodwill recognized for this business was $37 million , which was assigned to the Electronic Systems segment, of which $13 million is expected to be deductible for income tax purposes. The purchase price and purchase price allocation of Doss Aviation was finalized as of September 28, 2018, with no significant changes to preliminary amounts. Adaptive Methods, Inc. (Adaptive Methods). On September 8, 2017, the Company acquired Adaptive Methods, Inc., renamed L3 Adaptive Methods, Inc., for a purchase price of $33 million , which was financed with cash on hand. Adaptive Methods delivers Undersea Warfare (USW) and Anti-Submarine Warfare capabilities for U.S. military customers and develops autonomy and sensor payload solutions for use by Unmanned Undersea Vehicles (UUVs). The acquisition provides the Company with an innovative UUV autonomy technology that will broaden its capabilities in the dynamic and growing undersea market. The acquisition was financed with cash on hand. The goodwill recognized for this business was $28 million , which was assigned to the C&NS segment, all of which is expected to be deductible for income tax purposes. The purchase price and purchase price allocation of Adaptive Methods was finalized as of June 29, 2018, with no significant changes to preliminary amounts. Open Water Power, Inc. (Open Water Power) . On May 19, 2017, the Company acquired Open Water Power, Inc., which has been renamed L3 Open Water Power, Inc. Open Water Power develops safe and high-energy-density undersea power generation technologies for use by UUVs and other maritime platforms. The acquisition enhances the Company’s growing portfolio of innovative undersea capabilities. The acquisition was financed with cash on hand. The purchase price is subject to additional contingent consideration not to exceed $17 million and is based on Open Water Power’s post-acquisition milestone achievements for the four-year period ending December 31, 2021. The Company recorded a $14 million liability on the acquisition date for the fair value of the contingent consideration. The goodwill recognized for this business was $25 million , which was assigned to the C&NS segment, and is not expected to be deductible for income tax purposes. The Company also recognized indefinite-lived intangible assets of $65 million for IPR&D costs. The purchase price and purchase price allocation of Open Water Power was finalized as of December 31, 2017, with no significant changes to preliminary amounts. OceanServer Technology, Inc. (OceanServer) . On March 17, 2017, the Company acquired OceanServer Technology, Inc., which has been renamed L3 OceanServer, Inc. OceanServer develops and manufactures autonomous, lightweight UUVs. OceanServer provides highly capable UUVs to a wide array of military, commercial and international customers. The acquisition was financed with cash on hand. The goodwill recognized for this business was $19 million , which was assigned to the C&NS segment, all of which is expected to be deductible for income tax purposes. The purchase price and purchase price allocation of OceanServer was finalized as of September 29, 2017, with no significant changes to preliminary amounts. Explosive Trace Detection business of Implant Sciences . On October 10, 2016, the Company entered into an asset purchase agreement (APA) to acquire the explosive trace detection (ETD) business of Implant Sciences Corporation (Implant), at which time Implant entered into Chapter 11 bankruptcy protection of the U.S. Bankruptcy Code. In December 2016, Implant received U.S. Bankruptcy Court approval to consummate the APA. The ETD business bolsters the Company’s leadership in efficient, scalable security solutions and greatly enhances its capabilities in the global aviation security and national security markets. On January 5, 2017, the Company completed the acquisition of the ETD business for a purchase price of $118 million , in addition to the assumption of specified liabilities, which was financed with cash on hand. The goodwill recognized for this business was $80 million , which was assigned to the Electronic Systems segment, all of which is expected to be deductible for income tax purposes. The purchase price and purchase price allocation of the ETD business was finalized as of December 31, 2017, with no significant changes to preliminary amounts. 2016 Business Acquisitions MacDonald Humfrey (Automation) Limited. On November 22, 2016, the Company acquired MacDonald Humfrey (Automation) Limited, which has been renamed L3 MacDonald Humfrey (MacH), for a purchase price of £263 million (approximately $327 million ). The purchase price is subject to additional, contingent consideration not to exceed £30 million (approximately $38 million ) and is based on MacH’s post-acquisition financial performance for the three-year period ending December 31, 2019. The Company recorded a £21 million (approximately $26 million ) liability on the acquisition date for the fair value of the contingent consideration. The acquisition was funded from cash on hand and revolving credit borrowings that were repaid before the end of 2016. The purchase price and purchase price allocation of MacH was finalized as of December 31, 2017, with no significant changes to preliminary amounts. MacH is a globally recognized leader in the deployment of operationally effective and efficient aviation checkpoint security solutions, as well as in the development of state-of-the-art process automation and collaborative robotic capabilities supporting aviation and other adjacent markets. The goodwill recognized for this business was £204 million (approximately $255 million ), which was assigned to the Electronics Systems reportable segment, and is not expected to be deductible for income tax purposes. The Company also recognized identifiable intangible assets of £45 million (approximately $56 million ) in the aggregate, which consisted of £6 million (approximately $8 million ) for trade name, £10 million (approximately $12 million ) for technology and £29 million (approximately $36 million ) for customer relationships. Identifiable intangible assets will be amortized over a weighted average useful life of 10 years. Micreo Limited and Aerosim. On September 30, 2016, the Company acquired Micreo Limited (Micreo) and Flight Training Acquisitions LLC (Aerosim), in separate transactions, for an aggregate purchase price of approximately $86 million , which was financed with cash on hand. The purchase price and purchase price allocation of Micreo and Aersoim was finalized as of September 29, 2017, with no significant changes to preliminary amounts. Micreo specializes in solutions that utilize high-performance microwave, millimeter wave and photonic technology that complements the Company’s wide range of sensor products and is expected to strengthen the development of the Company’s future products in the higher Electronic Warfare (EW) radio frequency (RF) bandwidth. Micreo currently supports a variety of airborne, land and security programs in Australia. Aerosim provides innovative, portable and flexible pilot and maintenance technician training products and provides a flight school for prospective airline pilots. Aerosim’s commercial training capabilities are complementary to those offered by L3 Commercial Training Solutions. The aggregate goodwill recognized for these businesses was $59 million , which was assigned to the Electronic Systems and ISRS reportable segments, of which $6 million is expected to be deductible for income tax purposes. Advanced Technical Materials, Inc. (ATM) Acquisition. On January 22, 2016, the Company acquired the assets of ATM for a purchase price of $27 million , which was financed with cash on hand. The purchase price and purchase price allocation of ATM was finalized as of September 23, 2016, with no significant changes to preliminary amounts. ATM develops and manufactures a broad product line of passive microwave waveguides and specialized coaxial components. The goodwill recognized for this business was $20 million , which was assigned to the C&NS reportable segment, all of which is expected to be deductible for income tax purposes. 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 years ended December 31, 2018 and 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. Year Ended December 31, 2018 2017 (in millions, except per share data) Pro forma net sales $ 10,324 $ 9,741 Pro forma income from continuing operations attributable to L3 $ 805 $ 756 Pro forma net income attributable to L3 $ 1,010 $ 680 Pro forma diluted earnings per share from continuing operations $ 10.11 $ 9.50 Pro forma diluted earnings per share $ 12.69 $ 8.54 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 technology. 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 IPR&D. The basis difference attributable to goodwill and IPR&D is $11 million and $13 million , respectively. 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 were 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 ISRS 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, which is included in continuing operations. Year Ended December 31, 2018 2017 2016 (in millions) Net sales $ 64 $ 119 $ 166 Gain on sale of businesses $ 42 $ — $ — Income from continuing operations before income taxes $ 45 $ (2 ) $ 12 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 businesses for a sales 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 $42 million ( $19 million after income taxes) related to the Crestview & TCS Businesses and (2) a pre-tax gain from discontinued operations of $234 million ( $177 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 $0.6 billion in 2018, $1.4 billion in 2017 and $1.3 billion in 2016. The assets and liabilities and results of operations of the Vertex Aerospace business are reported as discontinued operations for all periods presented. NSS . On February 1, 2016, the Company completed the sale of its NSS segment to CACI International Inc. for a sales price of $547 million . The results of operations of NSS are reported as discontinued operations for all periods presented. The table below presents the statements of operations data for Vertex Aerospace and NSS. 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 their net assets to the sum of: (1) total L3 consolidated net assets and (2) L3 consolidated total debt. Year Ended December 31, 2018 2017 2016 (in millions) Net sales $ 597 $ 1,429 $ 1,402 Operating costs and expenses (1) (561 ) (1,531 ) (1,357 ) Operating income (loss) from discontinued operations 36 (102 ) 45 Interest expense allocated to discontinued operations (1 ) (2 ) (5 ) Gain on sale of businesses 234 — 64 Income (loss) from discontinued operations before income taxes 269 (104 ) 104 Income tax (expense) benefit (64 ) 28 (13 ) Income (loss) from discontinued operations, net of income taxes $ 205 $ (76 ) $ 91 __________________ (1) Due to a decline in estimated fair value, the Company recorded a goodwill impairment charge of $187 million during 2017 related to Vertex Aerospace. The major classes of assets and liabilities 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 were not expected to be used to pay down long-term debt. As discussed above, since the sale of NSS was completed on February 1, 2016, the balances below exclude NSS. 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 year ended December 31, 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. Year Ended December 31, 2017 Pre-Tax Proceeds 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. 2016 Divestitures NSS . On February 1, 2016, the Company completed the sale of its NSS segment to CACI International Inc. for a sales price of $547 million . See Discontinued Operations above for additional information. 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. Year Ended December 31, 2017 2016 (in millions) Net sales $ 10 $ 59 Income before income taxes $ 2 $ 8

Contract Assets and Contract Li

Contract Assets and Contract Liabilities (Notes)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Contract Assets and Contract Liabilities The table below presents the components of net contract assets. December 31, January 1, (in millions) Contract assets $ 1,590 $ 1,349 Contract liabilities — current (669 ) (565 ) Contract liabilities — non-current (31 ) (28 ) Net contract assets $ 890 $ 756 Contract assets increased from January 1, 2018 to December 31, 2018 by $241 million primarily due to sales exceeding billings due to contractual billing terms on U.S. Government contracts across all business areas, with the largest increases from ISR Systems, Commercial Aviation Solutions, and Space & Power Systems. Contract liabilities increased by $107 million primarily due to advances received by ISR Systems, Commercial Aviation Solutions and Warrior Sensor Systems related to U.S. and foreign government contracts and deferred revenue on software licensing and support services for Trenchant, which was acquired on August 31, 2018, partially offset by decreases due to the liquidation of advances received by Link Training & Simulation resulting from performance on customer contracts. The Company did not recognize any impairment losses on contract assets during the year ended December 31, 2018 . For the year ended December 31, 2018 , the Company recognized sales of $457 million related to its contract liabilities at January 1, 2018. The components of contract assets are presented in the table below. December 31, January 1, (in millions) Unbilled contract receivables, gross $ 2,716 $ 2,232 Unliquidated progress payments and advances (1,126 ) (883 ) Total contract assets $ 1,590 $ 1,349

Contracts in Process

Contracts in Process	12 Months Ended
	Dec. 31, 2018
Contractors [Abstract]
Contracts in Process	Contracts in Process The components of contracts in process are presented in the table below. The unbilled contract receivables, inventoried contract costs and unliquidated progress payments principally relate to contracts with the U.S. Government and prime contractors or subcontractors of the U.S. Government. 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 Unbilled Contract Receivables. Unbilled contract receivables represent accumulated incurred costs and earned profits on contracts (revenue arrangements), which have been recorded as sales, but have not yet been billed to customers. Unbilled contract receivables arise from the cost-to-cost method of revenue recognition that is used to record sales on certain fixed-price contracts. Unbilled contract receivables from fixed-price type contracts are converted to billed receivables when amounts are invoiced to customers according to contractual billing terms, which generally occur when deliveries or other performance milestones are completed. Unbilled contract receivables also arise from cost-plus type contracts, time-and-material type contracts and fixed-price service 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. Unliquidated Progress Payments. Unliquidated progress payments are a contra asset account, and are classified against unbilled contract receivables if revenue for the underlying contract is recorded using the cost-to-cost method, and against inventoried contract costs if revenue is recorded using the units-of-delivery method. Inventoried Contract Costs. In accordance with contract accounting standards, the Company’s U.S. Government contractor businesses account for the portion of their G&A, IRAD and B&P costs that are allowable and reimbursable indirect contract costs under U.S. Government procurement regulations on their U.S. Government contracts (revenue arrangements) as inventoried contract costs. 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 inventoried contract 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 periods presented. Year Ended December 31, 2017 2016 (in millions) Amounts included in inventoried contract costs at beginning of the year $ 173 $ 137 Contract costs incurred: IRAD and B&P 333 304 Other G&A 842 749 Total 1,175 1,053 Amounts charged to operating costs and expenses (1,179 ) (1,017 ) Amounts included in inventoried contract costs at end of the year $ 169 $ 173

Inventories

Inventories	12 Months Ended
	Dec. 31, 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 5 for additional information. In accordance with ASC 606, all work in process relating to goods that customers do not currently control are classified within inventories on the Company's consolidated balance sheet at December 31, 2018 , without regard to whether the goods are standard or customized. December 31, 2018 2017 (in millions) Raw materials, components and sub-assemblies $ 351 $ 184 Work in process 330 98 Finished goods 198 107 Total $ 879 $ 389 Inventories at December 31, 2018 included G&A costs of $31 million . G&A costs incurred and recorded in inventories totaled $1,181 million during the year ended December 31, 2018 , and G&A costs charged to expense from inventories totaled $1,221 million during the year ended December 31, 2018 . See Note 5 for information on G&A costs included in contracts in process for the years ended December 31, 2017 and 2016.

Goodwill and Identifiable Intan

Goodwill and Identifiable Intangible Assets	12 Months Ended
	Dec. 31, 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). Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. As part of the purchase price allocations for the Company’s business acquisitions, identifiable intangible assets are recognized as assets apart from goodwill if they arise from contractual or other legal rights, or if they are capable of being separated or divided from the acquired business and sold, transferred, licensed, rented or exchanged. However, the Company does not recognize any intangible assets apart from goodwill for the assembled workforces of its business acquisitions. At December 31, 2018 , the Company had approximately 31,000 employees, and the substantial majority of the sales generated by the Company’s businesses were from the productive labor efforts of its employees, as compared to selling manufactured products or right-to-use technology. Generally, the largest intangible assets from the businesses that the Company acquires are the assembled workforces, which includes the human capital of the management, administrative, marketing and business development, scientific, engineering and technical employees of the acquired businesses. The success of the Company’s businesses, including their ability to retain existing business (revenue arrangements) and to successfully compete for and win new business (revenue arrangements), is primarily dependent on the management, marketing and business development, contracting, engineering and technical skills and knowledge of its employees, rather than on productive capital (plant and equipment, and technology and intellectual property). Additionally, for a significant portion of its businesses, the Company’s ability to attract and retain employees who have U.S. Government security clearances, particularly those of top-secret and above, is critical to its success, and is often a prerequisite for retaining existing revenue arrangements and pursuing new ones. Generally, patents, trademarks and licenses are not material for the Company’s acquired businesses. Furthermore, the Company’s U.S. Government contracts (revenue arrangements) generally permit other companies to use the Company’s patents in most domestic work performed by such other companies for the U.S. Government. Therefore, because intangible assets for assembled workforces are part of goodwill in accordance with the accounting standards for business combinations, the substantial majority of the intangible assets for the Company’s business acquisitions is recognized as goodwill. Additionally, the value assigned to goodwill for the Company’s business acquisitions also includes the value that the Company expects to realize from cost reduction measures that it implements for its acquired businesses. The table below presents the changes in goodwill allocated to the Company’s reporting units in each reportable segment. ISRS C&NS Electronic Consolidated (in millions) December 31, 2016 Goodwill $ 2,512 $ 1,883 $ 2,083 $ 6,478 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) 2,466 1,868 2,040 6,374 Business acquisitions (1) 8 73 131 212 Business divestitures (2) — — (12 ) (12 ) Foreign currency translation adjustments 26 21 46 93 Assets held for sale (3) (42 ) — (10 ) (52 ) December 31, 2017 Goodwill 2,504 1,977 2,238 6,719 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) 2,458 1,962 2,195 6,615 Business acquisitions (1) 158 56 33 247 Foreign currency translation adjustments (20 ) (11 ) (23 ) (54 ) December 31, 2018 Goodwill 2,634 2,022 2,248 6,904 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) $ 2,596 $ 2,007 $ 2,205 $ 6,808 __________________ (1) For the year ended December 31, 2018 , business acquisitions for the ISRS segment included the acquisitions of the Azimuth Security and Linchpin Labs and Applied Defense Solutions businesses and the purchase price allocation adjustments for the Kigre business acquisition. Business acquisitions for the C&NS segment included the acquisitions of the ASV Global business and purchase price allocation adjustments for the Adaptive Methods business acquisition. Business acquisitions for the Electronic Systems segment included the acquisitions of the Latitude Engineering and C.K. Industrial Engineers businesses and purchase price allocation adjustments for the G-Air and Doss Aviation business acquisitions. For the year ended December 31, 2017 , business acquisitions for the ISRS segment included primarily the Kigre business acquisition. Business acquisitions for the C&NS segment included primarily the Adaptive Methods, Open Water Power, and OceanServer business acquisitions. Business acquisitions for the Electronic Systems segment included the acquisitions of the ETD, Doss Aviation and G-Air businesses and purchase price allocation adjustments for the MacH and Aerosim business acquisitions. (2) The decrease for the Electronic Systems segment was due to the divestitures of Coleman and Aviation Jet Services during the quarterly period ended March 31, 2017. (3) The Crestview & TCS businesses from the Company’s ISRS segment were classified as held for sale as of December 31, 2017. 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 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. December 31, 2018 December 31, 2017 Weighted Average Gross Accumulated Net Gross Accumulated Net (in years) (in millions) Customer contractual relationships 16 $ 468 $ 288 $ 180 $ 393 $ 257 $ 136 Technology 9 245 132 113 189 114 75 Other 9 49 18 31 29 14 15 Total subject to amortization 762 438 324 611 385 226 IPR&D indefinite 66 — 66 66 — 66 Total $ 828 $ 438 $ 390 $ 677 $ 385 $ 292 The table below presents amortization expense recorded by the Company for its identifiable intangible assets. Year Ended December 31, 2018 2017 2016 (in millions) Amortization expense $ 49 $ 43 $ 33 Based on gross carrying amounts at December 31, 2018 , the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2019 through 2023 is presented in the table below. Year Ending December 31, 2019 2020 2021 2022 2023 (in millions) Estimated amortization expense $ 51 $ 47 $ 42 $ 37 $ 28

Other Current Liabilities and O

Other Current Liabilities and Other Liabilities	12 Months Ended
	Dec. 31, 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. December 31, 2018 2017 (in millions) Other Current Liabilities: Accrued product warranty costs $ 66 $ 69 Estimated costs in excess of estimated contract value to complete contracts in process in a loss position 40 63 Accrued interest 18 43 Estimated contingent purchase price payable for acquired businesses (see Note 13) 10 11 Deferred revenues — 38 Other 154 143 Total other current liabilities $ 288 $ 367 The table below presents the components of other liabilities. December 31, 2018 2017 (in millions) Other Liabilities: Non-current income taxes payable (see Note 17) $ 161 $ 164 Deferred compensation 53 49 Notes payable and capital lease obligations 40 16 Contract liabilities (see Note 4) 31 — Accrued product warranty costs 22 30 Accrued workers’ compensation 20 23 Estimated contingent purchase price payable for acquired businesses (see Note 13) 10 20 Deferred revenues — 19 Other 99 77 Total other liabilities $ 436 $ 398

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment The table below presents the components of property, plant and equipment. December 31, 2018 2017 (in millions) Land $ 34 $ 34 Buildings and improvements 428 404 Machinery, equipment, furniture and fixtures 2,081 1,959 Leasehold improvements 407 376 Gross property, plant and equipment 2,950 2,773 Accumulated depreciation and amortization (1,781 ) (1,663 ) Property, plant and equipment, net $ 1,169 $ 1,110

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	Debt The components of debt and a reconciliation to the carrying amount of long-term debt is presented in the table below. December 31, 2018 2017 (in millions) Borrowings under Revolving Credit Facility (1) $ — $ — 5.20% Senior Notes due 2019 — 1,000 4.75% Senior Notes due 2020 — 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 3,350 3,350 Unamortized discounts (7 ) (7 ) Deferred debt issue costs (22 ) (13 ) Carrying amount of long-term debt $ 3,321 $ 3,330 __________________ (1) During 2018 , L3's aggregate borrowings and repayments under the Credit Facility were $501 million . L3 had the full availability of its $1 billion Credit Facility at December 31, 2018 and December 31, 2017 . L3 Revolving Credit Facility On October 31, 2016, L3 entered into a new five -year unsecured revolving credit facility (Credit Facility), which replaced its amended and restated revolving credit agreement dated February 3, 2012. The Credit Facility provides for total aggregate borrowings of $1 billion and any outstanding borrowings under the Credit Facility are due and payable on October 31, 2021 . Borrowings under the Credit Facility may consist of: (1) base rate loans, which shall bear interest at a rate equal to the sum of the applicable rate (as defined in the Credit Facility), and the “base rate” (as defined in the Credit Facility) and/or (2) eurodollar loans, which shall bear interest at a rate equal to the sum of the applicable rate plus the “Eurodollar rate” (as defined in the Credit Facility). The applicable rate for base rate loans under the Credit Facility ranges from 0.125% to 1.000% , and the applicable rate for eurodollar loans ranges from 1.125% to 2.000% , in each case based on the long-term debt rating of L3. In addition, the Credit Facility provides for uncommitted incremental revolving facilities and additional term loan facilities in an aggregate principal amount of up to $600 million . L3 Senior Notes The senior notes are unsecured senior obligations of L3. The terms of each outstanding senior note are presented in the table below. Note Date of Issuance Amount Issued Discount (1) Net Cash Proceeds Effective Interest Rate Redemption at Treasury Rate (2)(3) (dollars in millions) 4.95% Senior Notes due February 15, 2021 February 7, 2011 $ 650 $ 4 $ 639 5.02 % 25 bps 3.85% Senior Notes due June 15, 2023 (4) June 6, 2018 $ 800 $ 2 $ 792 3.89 % 20 bps 3.95% Senior Notes due May 28, 2024 (5) May 28, 2014 $ 650 $ 3 $ 641 4.02 % 20 bps 3.85% Senior Notes due December 15, 2026 December 5, 2016 $ 550 $ 3 $ 542 3.91 % 25 bps 4.40% Senior Notes due June 15, 2028 (4) 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 senior notes maturing in 2023 may be redeemed at any time prior to May 15, 2023 (one month prior to maturity) and the senior notes maturing in 2021, 2024, 2026 and 2028 may be redeemed at any time prior to November 15, 2020, February 28, 2024, September 15, 2026 and March 15, 2028, respectively, (three months prior to their 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 senior notes maturing in 2021, 2023, 2024, 2026 and 2028 are redeemed at any time on or after November 15, 2020, May 15, 2023, February 28, 2024, September 15, 2026 and March 15, 2028, respectively, the redemption price would be equal to 100% of the principal amount. (3) Upon the occurrence of a change in control (as defined in the indentures governing the senior notes) along with a “change of control triggering event” (generally described as the applicable series of senior notes ceasing to be rated investment grade, 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. (4) 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. (5) On December 22, 2015, the Company repurchased $300 million of the 3.95% Senior Notes due May 28, 2024. Repurchases, Redemptions and Maturities of Senior Notes The repurchases, redemptions and maturities of senior notes are presented in the table below. Note Settlement Type Date Settled Aggregate Amount Premium Cash Payments Interest Total Cash Payments Debt Charge (dollars in millions) 5.20% Senior Notes due 2019 (1) Redemption July 6, 2018 $ 317 103.048 % $ 327 $ 4 $ 331 $ 10 4.75% Senior Notes due 2020 (1) Redemption July 6, 2018 $ 265 103.818 % $ 275 $ 6 $ 281 $ 11 5.20% Senior Notes due 2019 (2) Tender Offer June 6, 2018 $ 683 103.282 % $ 705 $ 5 $ 710 $ 24 4.75% Senior Notes due 2020 (2) Tender Offer June 6, 2018 $ 535 104.092 % $ 557 $ 10 $ 567 $ 24 1.50% Senior Notes due 2017 Redemption December 30, 2016 $ 350 100.323 % $ 351 $ 1 $ 352 $ 2 3.95% Senior Notes due 2016 Maturity November 15, 2016 $ 200 100.000 % $ 200 $ — $ 200 $ — 3.95% Senior Notes due 2016 Redemption May 20, 2016 $ 300 101.475 % $ 305 $ — $ 305 $ 5 __________________ (1) The debt retirement charge includes $1 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts. (2) Cash payments exclude $1 million of tender offer fees. 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. 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. See Note 25 . Subordination The guarantees of the Credit Facility and the senior notes rank pari passu with each other. Covenants Financial and other restrictive covenants. The Credit Facility contains financial and other restrictive covenants that limit, among other things, the ability of the subsidiaries of L3 to borrow additional funds, and the ability of L3 and its subsidiaries to incur liens, make investments, merge or consolidate or dispose of assets. The Company’s Credit Facility contains covenants that require that: (1) the Company’s consolidated interest coverage ratio be greater than or equal to 3.0 to 1.0, (2) the Company’s consolidated leverage ratio be less than or equal to 3.75 to 1.0, provided that the foregoing consolidated leverage ratio shall be increased to 4.0 to 1.0 as of the end of each of the four fiscal quarters immediately following a material acquisition (as defined in the Credit Facility). Calculations of the financial covenants are to exclude, among other things, certain items such as impairment losses on goodwill or other intangible assets, non-cash gains or losses from discontinued operations, gains or losses in connection with asset dispositions, and gains or losses with respect to judgments or settlements in connection with litigation matters. At December 31, 2018 , the Company was in compliance with its financial and other restrictive covenants. The indentures governing the senior notes (Senior Indentures) contain covenants customary for investment grade notes, including covenants that restrict the ability of L3 and its 100% owned domestic subsidiaries to create, incur, assume or permit to exist any lien, except permitted liens (as defined in the Senior Indentures) and restrict the ability of L3 and its subsidiaries to enter into certain sale and leaseback transactions (as defined in the Senior Indentures). Cross default provisions. The Credit Facility contains cross default provisions that are triggered when a payment default occurs or certain other defaults occur that would allow the acceleration of indebtedness, swap contracts or guarantees of L3 or its subsidiaries, so long as the aggregate amount of such indebtedness, swap contracts or guarantees is at least $75 million and such defaults (other than payment defaults and defaults that have resulted in acceleration) have not been cured within 10 days . The senior notes indenture contains a cross acceleration provision that is triggered when a default or acceleration occurs under any indenture or instrument of L3 or its subsidiaries or the payment of which is guaranteed by L3 or its subsidiaries in an aggregate amount of at least $100 million .

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income (AOCI)	12 Months Ended
	Dec. 31, 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 Unrealized Unrecognized Total (in millions) Balance at December 31, 2015 $ (101 ) $ (8 ) $ (465 ) $ (574 ) Other comprehensive (loss) income before reclassifications, net of tax (77 ) 3 (119 ) (193 ) Amounts reclassified from AOCI, net of tax — 11 30 41 Net current period other comprehensive (loss) income (77 ) 14 (89 ) (152 ) Balance at December 31, 2016 $ (178 ) $ 6 $ (554 ) $ (726 ) Other comprehensive income (loss) before reclassifications, net of tax 124 7 (137 ) (6 ) Amounts reclassified from AOCI, net of tax — (4 ) 45 41 Net current period other comprehensive income (loss) 124 3 (92 ) 35 Balance at December 31, 2017 $ (54 ) $ 9 $ (646 ) $ (691 ) Other comprehensive loss before reclassifications, net of tax (82 ) (17 ) 14 (85 ) Amounts reclassified from AOCI, net of tax — (2 ) 53 51 Net current period other comprehensive (loss) income (82 ) (19 ) 67 (34 ) Balance at December 31, 2018 $ (136 ) $ (10 ) $ (579 ) $ (725 ) 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 Year Ended December 31, Details About AOCI Components 2018 2017 2016 (in millions) Gain (loss) on hedging instruments $ 3 $ 5 $ (13 ) Cost of sales-products 3 5 (13 ) Income from continuing operations before income taxes (1 ) (1 ) 2 Provision for income taxes $ 2 $ 4 $ (11 ) Income from continuing operations Amortization of defined benefit pension and postretirement items: Net loss (b) $ (68 ) $ (59 ) $ (48 ) Income from continuing operations before income taxes 15 14 18 Provision for income taxes $ (53 ) $ (45 ) $ (30 ) Income from continuing operations Total reclassification for the period $ (51 ) $ (41 ) $ (41 ) Income from continuing operations __________________ (a) Amounts in parentheses indicate charges to the 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	12 Months Ended
	Dec. 31, 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 1.6 million shares of its common stock at an average price of $196.64 per share for an aggregate amount of $322 million from January 1, 2018 through September 28, 2018. All share repurchases of L3’s common stock have been recorded as treasury shares. The Company did not repurchase any shares of common stock from September 29, 2018 through February 14, 2019 . The last repurchase of shares was in July 2018. In connection with the planned merger with Harris Corporation (see Note 1 ), the Company suspended the share repurchase program. On February 12, 2019 , L3’s Board of Directors declared a quarterly cash dividend of $0.85 per share, payable on March 15, 2019 to shareholders of record at the close of business on March 1, 2019 . During the year ended December 31, 2018 , the Company paid $254 million of cash dividends, offset by a $1 million net reduction of previously accrued dividends for employee-held stock awards.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 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. December 31, 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 $ 660 $ — $ — $ 310 $ — $ — Derivatives (foreign currency forward contracts) — 1 — — 11 — Total assets $ 660 $ 1 $ — $ 310 $ 11 $ — Liabilities Derivatives (foreign currency forward contracts) $ — $ 17 $ — $ — $ 1 $ — Contingent consideration — — 20 — — 31 Total liabilities $ — $ 17 $ 20 $ — $ 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 MacH on November 22, 2016, Open Water Power on May 19, 2017 and Latitude Engineering on June 28, 2018. 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) the 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 cost of sales in the consolidated statements of operations. The fair value of the contingent consideration liability has been reassessed quarterly. The table below presents the changes to contingent consideration obligations during the year ended December 31, 2018 . December 31, 2018 (in millions) Balance at beginning of period $ 31 Acquisitions and investments 11 Cash payments (7 ) Changes in fair value of contingent consideration, net (15 ) Balance at end of period $ 20

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2018
Investments, All Other Investments [Abstract]
Financial Instruments	Financial Instruments At December 31, 2018 and 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 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. December 31, 2018 December 31, 2017 Carrying Estimated Carrying Estimated (in millions) Senior notes (1) $ 3,321 $ 3,355 $ 3,330 $ 3,502 Foreign currency forward contracts (2) $ (16 ) $ (16 ) $ 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 15 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments 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 December 31, 2018 . Currency Notional Amounts (in millions) U.S. dollar $ 204 Canadian dollar 123 Euro 67 United Arab Emirates dirham 12 British pound 9 Total $ 415 At December 31, 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 consolidated balance sheets. December 31, 2018 December 31, 2017 Other Other Other Other Other Other Other Other (in millions) Derivatives designated as hedging instruments: Foreign currency forward contracts (1) $ 1 $ — $ 13 $ 4 $ 11 $ — $ 1 $ — Total derivative instruments $ 1 $ — $ 13 $ 4 $ 11 $ — $ 1 $ — __________________ (1) See Note 13 for a description of the fair value hierarchy related to the Company's foreign currency forward contracts. The effects from foreign currency forward contracts on the consolidated statements of operations were a pre-tax gain of $3 million for the year ended December 31, 2018 , a pre-tax gain of $5 million for the year ended December 31, 2017 , and a pre-tax loss of $13 million for the year ended December 31, 2016 . At December 31, 2018 , the estimated net amount of existing losses that are expected to be reclassified into income within the next 12 months is $10 million .

L3's Earnings Per Share

L3's Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
L3's Earnings Per Share	L3’s Earnings Per Share A reconciliation of basic and diluted Earnings Per Share (EPS) is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Reconciliation of net income: Net income $ 1,026 $ 693 $ 724 Net income from continuing operations attributable to noncontrolling interests (21 ) (16 ) (14 ) Net income attributable to L3’s common shareholders $ 1,005 $ 677 $ 710 Earnings (loss) attributable to L3’s common shareholders: Continuing operations $ 800 $ 753 $ 619 Discontinued operations, net of income tax 205 (76 ) 91 Net income attributable to L3’s common shareholders $ 1,005 $ 677 $ 710 Earnings per share attributable to L3’s common shareholders: Basic: Weighted average common shares outstanding 78.5 78.0 77.4 Basic earnings (loss) per share: Continuing operations $ 10.19 $ 9.65 $ 7.99 Discontinued operations, net of income tax 2.61 (0.97 ) 1.18 Net income $ 12.80 $ 8.68 $ 9.17 Diluted: Common and potential common shares: Weighted average common shares outstanding 78.5 78.0 77.4 Effect of dilutive securities 1.1 1.6 1.4 Common and potential common shares 79.6 79.6 78.8 Diluted earnings (loss) per share: Continuing operations $ 10.05 $ 9.46 $ 7.86 Discontinued operations, net of income tax 2.58 (0.95 ) 1.15 Net income $ 12.63 $ 8.51 $ 9.01 The computation of diluted EPS excludes 0.3 million , 0.3 million and 0.4 million shares for the years ended December 31, 2018 , 2017 and 2016 , respectively, for share-based payment awards as they were anti-dilutive.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes 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). The Securities and Exchange Commission issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Job Act (SAB 118), which allowed companies to record provisional impacts of U.S. Tax Reform during a measurement period not extending beyond one year from the enactment date. As a result, the Company recorded an estimated tax benefit (Preliminary Net Tax Benefit) of $79 million from U.S. Tax Reform in its consolidated financial statements for the year ended December 31, 2017. For the year ended December 31, 2018, the SAB 118 measurement period closed and the Company recorded an additional $1 million net tax benefit related to U.S. Tax Reform. The final cumulative benefit of $80 million includes a $98 million estimated tax benefit related to the remeasurement of deferred taxes partially offset by an estimated tax provision of $18 million related to the Toll Charge. The implementation of a modified territorial tax system under U.S. Tax Reform subjects the Company to tax on its Global Intangible Low-Taxed Income (GILTI) starting with the year ended December 31, 2018. The FASB has permitted companies to make an accounting policy decision to either: (1) treat taxes due on future GILTI inclusions in U.S. taxable income as a current-period expense when incurred (“period cost method”) or (2) factor such amounts into the measurement of its deferred taxes (“deferred method”). The Company has elected to use the period cost method. As of December 31, 2018, the Company has completed the accounting for all impacts of U.S. Tax Reform. Income from continuing operations before income taxes is summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Domestic $ 630 $ 649 $ 608 Foreign 294 222 196 Income from continuing operations before income taxes $ 924 $ 871 $ 804 The components of the Company’s current and deferred portions of the provision for income taxes on continuing operations are presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Current income tax provision: Federal $ 30 $ 44 $ 88 State and local 18 10 8 Foreign 62 56 48 Subtotal 110 110 144 Deferred income tax provision/(benefit): Federal (7 ) (16 ) 25 State and local — 6 2 Foreign — 2 — Subtotal (7 ) (8 ) 27 Total provision for income taxes $ 103 $ 102 $ 171 A reconciliation of the statutory federal income tax rate to the effective income tax rate on continuing operations of the Company is presented in the table below. Year Ended December 31, 2018 2017 2016 Statutory federal income tax rate 21.0 % 35.0 % 35.0 % State and local income taxes, net of federal income tax benefit 2.6 2.0 2.0 Foreign income taxes (0.9 ) (6.7 ) (3.0 ) Manufacturing benefits — (1.4 ) (2.2 ) Research and experimentation and other tax credits (5.2 ) (4.1 ) (4.6 ) Resolution of tax contingencies (3.8 ) (0.4 ) (3.1 ) Tax deductible dividends (0.5 ) (0.9 ) (1.0 ) Equity compensation - excess income tax benefits (4.0 ) (2.3 ) (2.1 ) Mergers, acquisitions and divestitures 1.3 — — Tax reform (0.1 ) (9.1 ) — Other, net 0.7 (0.4 ) 0.3 Effective income tax rate on continuing operations 11.1 % 11.7 % 21.3 % The significant components of the Company’s net deferred tax assets and liabilities are presented in the table below. December 31, 2018 2017 (in millions) Deferred tax assets: Inventoried costs $ 47 $ 44 Compensation and benefits 90 94 Pension and postretirement benefits 271 281 Loss carryforwards 13 12 Tax credit carryforwards 4 5 Other 67 57 Deferred tax assets 492 493 Less: valuation allowance (14 ) (10 ) Deferred tax assets, net of valuation allowance 478 483 Deferred tax liabilities: Goodwill and other intangible assets $ (549 ) $ (514 ) Income recognition on contracts in process (18 ) (24 ) Property, plant and equipment (66 ) (59 ) Other (36 ) (41 ) Deferred tax liabilities (669 ) (638 ) Total deferred tax liabilities, net of valuation allowance $ (191 ) $ (155 ) The classification of the Company’s deferred tax assets and liabilities are presented in the table below. December 31, 2018 2017 (in millions) Non-current deferred tax assets $ 5 $ 3 Non-current deferred tax liabilities (196 ) (158 ) Total net deferred tax liabilities $ (191 ) $ (155 ) Non-current deferred tax assets are presented in other assets on the consolidated balance sheets. The following table presents the Company’s loss and tax credit carryforwards at December 31, 2018 on a tax-return basis. The Company has established a valuation allowance as indicated in those instances in which it does not believe that it is more likely than not it will generate sufficient taxable income, of the appropriate character and in the applicable subsidiary, to utilize the carryforwards. Year Ended December 31, 2018 Carryforwards Valuation Allowances Gross Tax Gross Tax Expiration (in millions) Federal net operating loss carryforwards $ 23 $ 5 $ (5 ) $ (1 ) 2026-2034 Foreign net operating loss carryforwards 18 4 (10 ) (3 ) Indefinite State net operating loss carryforwards 291 4 (131 ) (3 ) 2019-2038 Total loss carryforwards $ 13 $ (7 ) State tax credit carryforwards 5 4 (4 ) (3 ) 2019-2033 Total tax credit carryforwards $ 4 $ (3 ) At December 31, 2018 , the total amount of unrecognized tax benefits was $183 million , $150 million of which would reduce the effective income tax rate, if recognized. A reconciliation of the change in unrecognized income tax benefits, excluding potential interest and penalties, is presented in the table below. 2018 2017 2016 (in millions) Balance at January 1 $ 178 $ 110 $ 124 Additions for tax positions related to the current year 13 14 16 Additions for tax positions related to prior years 37 66 2 Reductions for tax positions related to prior years (20 ) (4 ) (24 ) Reductions for tax positions related to settlements with taxing authorities (7 ) — (1 ) Reduction for tax positions related to prior years as a result of a lapse of statute of limitations (18 ) (8 ) (7 ) Balance at December 31 $ 183 $ 178 $ 110 At December 31, 2018 , the Company anticipates that unrecognized tax benefits will decrease by approximately $27 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. 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 December 31, 2018 , the statutes of limitations for the Company’s U.S. Federal income tax returns for the years ended December 31, 2012, 2013, 2015, 2016 and 2017 were open. During the year ended December 31, 2018 , the Company reached an agreement with the U.S. Internal Revenue Service (IRS) relating to the audit of the Company’s 2012 and 2013 U.S. Federal income tax returns and extended the statute of limitations to September 2019. The Company also reached agreement on several state and foreign audits. In addition, the statute of limitations expired for several of the Company’s tax returns, including the Company’s 2014 U.S. Federal income tax return as well as certain state and foreign tax returns. As a result, the Company reduced its income tax provision by $35 million , including interest and penalties. During the years ended 2017 and 2016 , the Company effectively settled various Federal, state and local and foreign audits. As a result of these settlements, the Company reversed previously accrued income tax expense of $4 million and $25 million , including interest and penalties. At December 31, 2018 and 2017 , current and non-current income taxes payable include accrued potential interest of $15 million ( $11 million after income taxes) for each of the years, and potential penalties of $9 million and $8 million , respectively. With respect to the interest related items, the Company’s income tax expense included expenses of $2 million and $5 million for the years ended December 31, 2018 and 2017 , respectively. At December 31, 2018 , the Company had not provided deferred income taxes and foreign withholding taxes for approximately $1 billion of undistributed earnings by its non-U.S. subsidiaries as such earnings are intended to be reinvested indefinitely. Although U.S. Tax Reform imposed the Toll Charge on accumulated earnings through December 31, 2017 and introduced a GILTI tax on foreign earnings beginning in 2018, undistributed earnings may still be subject to additional taxes upon repatriation, including foreign withholding taxes. Quantification of additional taxes that may be payable on distribution is not practicable.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock-Based Compensation Plans. The Company has adopted stock-based compensation plans in order to provide incentives to directors, officers, employees and other individuals providing services to or on behalf of the Company and its subsidiaries. The Company believes that its stock-based compensation awards encourage high levels of performance by individuals who contribute to the success of the Company and enable the Company to attract, retain and reward talented and experienced individuals. This is accomplished by providing eligible individuals with an opportunity to obtain or increase a proprietary interest in the Company and/or by providing eligible individuals with additional incentives to join or remain with the Company. The stock-based compensation plans serve to better align the interests of management and its employees with those of the Company’s shareholders. During the year ended December 31, 2018 , the Company awarded stock-based compensation under its Amended and Restated 2008 Long Term Performance Plan (2008 LTPP). Awards under the 2008 LTPP may be granted to any officer or employee of the Company or any of its subsidiaries, non-employee directors, or to any other individual who provides services to or on behalf of the Company or any of its subsidiaries. To date, awards under the 2008 LTPP have been in the form of L3’s restricted stock, restricted stock units, performance units and options to purchase L3’s common stock. The Company's share-based compensation awards typically accelerate vesting upon a change in control. On May 3, 2016, the stockholders of L3 approved an amendment to the 2008 LTPP to increase the number of shares authorized for issuance by 6.8 million shares to approximately 26.0 million shares. Each share of L3’s common stock issued under a full value award (that is, awards other than stock options and stock appreciation rights) granted on or after February 23, 2016 is counted as 4.26 shares for purposes of this share limit. Each share issued under full value awards granted between February 26, 2013 and February 22, 2016 is counted as 3.69 shares for purposes of the share limit. At December 31, 2018 , 7.0 million shares of L3’s common stock remained available for future awards under the 2008 LTPP. The Company’s stock-based compensation expense by form of award, including stock-based compensation recorded in discontinued operations related to Vertex Aerospace and NSS, is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Stock options $ 7 $ 7 $ 10 Restricted stock units 43 43 35 Performance units 10 7 4 Total before income taxes 60 57 49 Income taxes (13 ) (12 ) (18 ) Total after income taxes 47 45 31 Less: Stock-based compensation recorded in discontinued operations, net of income taxes — 1 1 Stock-based compensation recorded in continuing operations, net of income taxes $ 47 $ 44 $ 30 Stock Options. The exercise price of stock options granted under the 2008 LTPP may not be less than the fair market value 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. All unvested options are subject to forfeiture upon termination of employment (subject to customary exceptions for death or disability). All of the stock option awards issued under the 2008 LTPP are non-qualified stock options for U.S. income tax regulations. The table below presents a summary of the Company’s stock option activity at December 31, 2018 and changes during the year then ended. Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in thousands) (in years) (in millions) Number of shares under option: Outstanding at January 1, 2018 2,698.9 $ 113.67 5.7 $ 227 Options granted 221.9 208.92 Options exercised (1,533.4 ) 97.49 Options forfeited (175.7 ) 147.37 Outstanding at December 31, 2018 1,211.7 $ 146.70 6.4 $ 42 Vested and expected to vest at December 31, 2018 (1) 1,205.6 $ 146.48 6.4 $ 42 Exercisable at December 31, 2018 666.1 $ 119.03 4.7 $ 37 __________________ (1) Represents outstanding options reduced by expected forfeitures for options not fully vested. The weighted average grant date fair value of the stock options awarded during 2018 , 2017 and 2016 was $37.72 , $28.35 and $15.90 , respectively. The aggregate intrinsic value, disclosed in the table above, represents the difference between L3’s closing stock price on the last trading day for the period, and the exercise price, multiplied by the number of in-the-money stock options. The total intrinsic value of stock options exercised, based on the difference between the L3’s stock price at the time of exercise and the related exercise price, was $165 million , $44 million and $34 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. At December 31, 2018 , unrecognized compensation cost related to stock options was $8 million ( $7 million after income taxes), which is expected to be recognized over a weighted average remaining period of 1.5 years . The actual income tax benefit realized related to compensation deductions arising from the exercise of stock options by the Company’s employees totaled $40 million , $16 million and $12 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Stock Option Fair Value Estimation Assumptions. The Company estimates the fair value of its stock options at the date of grant using the Black-Scholes option-pricing valuation model. The Company’s valuation model is affected by L3’s stock price as well as weighted average assumptions for a number of subjective variables described below. • Expected Holding Period. The expected holding period represents the period of time that granted stock options are expected to be outstanding until they are exercised. The Company uses historical stock option exercise data to estimate the expected holding period. • Expected Volatility. Expected volatility is based on L3’s historical share price volatility matching the expected holding period. • Expected Dividend Yield. Expected dividend yield is based on L3’s anticipated dividend payments and historical pattern of dividend increases over the expected holding period. • Risk-Free Interest Rates. The risk-free interest rates for stock options are based on U.S. Treasuries for a maturity period matching the expected holding period. Changes in assumptions can materially impact the estimated fair value of stock options. The weighted average assumptions used in the valuation model are presented in the table below. 2018 Grants 2017 Grants 2016 Grants Expected holding period (in years) 5.2 5.2 5.0 Expected volatility 19.8 % 19.9 % 21.3 % Expected dividend yield 1.8 % 2.0 % 2.8 % Risk-free interest rate 2.7 % 2.0 % 1.1 % Restricted Stock Units. The Company awards restricted stock units that automatically convert into shares of L3’s common stock upon vesting (in the case of awards granted to employees) or upon the date on which the recipient ceases to be a director (in the case of awards granted to directors). 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 weighted average grant date fair value of the restricted stock units awarded during 2018 , 2017 and 2016 was $205.73 , $169.23 and $116.72 , respectively. 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 year ended December 31, 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). The table below presents a summary of the Company’s nonvested restricted stock unit awards at December 31, 2018 and changes during the year then ended. Number of Shares Weighted Average Grant Date Fair Value (in thousands) Nonvested balance at January 1, 2018 902.7 $ 137.12 Granted 317.9 205.73 Vested (320.7 ) 137.00 Forfeited (86.2 ) 142.21 Nonvested balance at December 31, 2018 813.7 $ 163.44 At December 31, 2018 , total unrecognized compensation costs related to nonvested restricted stock unit and restricted stock awards were $46 million ( $36 million after income taxes) and are expected to be recognized over a weighted average remaining period of 1.4 years . The total fair value of restricted stock unit and restricted stock awards vested during the years ended December 31, 2018 , 2017 and 2016 as of their vesting dates was $67 million , $53 million and $57 million , respectively. Restricted Stock . The Company also awarded shares of restricted stock to certain employees having general vesting terms (including with respect to retirement eligibility) similar to the vesting terms described above for restricted stock units. Shares of restricted stock are issued to employees immediately upon grant, but remain subject to potential forfeiture in the event of the employee’s termination of employment prior to the scheduled vesting date (other than in the case of retirement or certain other qualifying terminations of employment). The employees who received restricted stock grants during 2018 made elections under Section 83(b) of the Internal Revenue Code to be taxed on the value of such awards at the time of grant and, accordingly, a portion of the shares initially awarded to them was withheld by the Company to satisfy tax withholding obligations (and therefore such withheld shares of restricted stock were no longer outstanding as of December 31, 2018). Performance Units. The Company grants performance unit awards, with each unit having a value at the time of grant equal to a share of L3’s common stock. The number of units ultimately earned can range from zero to 200% of the original award based upon the level of performance achieved by the Company over the associated performance period in relation to pre-determined performance goals. Units earned under the program are converted into shares of L3’s common stock, or are paid in cash based on the closing price of L3’s common stock at the end of the performance period, as determined at the time of grant by the Compensation Committee of the Board of Directors. During the years ended December 31, 2018 , 2017 , and 2016 , the Company granted performance unit awards with a weighted average grant date fair value per unit of $209.91 , $168.80 and $116.20 , respectively. All the awards granted in 2018 , 2017 , and 2016 have performance conditions based on L3’s diluted EPS. The performance periods for the awards began on January 1 of the applicable grant year and end on December 31 of the year corresponding to a three -year performance period. Units earned under the awards are convertible into shares of L3’s common stock. At December 31, 2018 , total unrecognized compensation costs related to the awards were $10 million ( $10 million after income taxes) and are expected to be recognized over a weighted average remaining period of 1.5 years . The table below presents a summary of the Company’s performance unit awards based on expected performance at December 31, 2018 and changes during the year then ended. Payable in Shares (EPS) Number of Weighted Average (in thousands) Outstanding at January 1, 2018 132.1 $ 135.99 Granted 22.1 209.91 Increase due to expected performance 25.3 38.96 Vested (57.5 ) 116.20 Forfeited (27.0 ) 133.41 Outstanding at December 31, 2018 95.0 $ 140.14 The performance period for awards granted in 2016 ended on December 31, 2018 . Based on L3’s cumulative diluted EPS during the performance period, a total of 57,508 performance units having a fair market value of $11 million as of their vesting date were earned by the participants on December 31, 2018 . Employee Stock Purchase Plan. Effective July 1, 2009, the Company adopted the 2009 Employee Stock Purchase Plan (2009 ESPP). Under the 2009 ESPP, eligible employees are offered options to purchase shares of L3’s common stock at the end of each six -month offering period at 95% of fair market value based on the average of the highest and lowest sales prices for the stock on the purchase date. Eligible employees generally include all employees of the Company and each subsidiary or affiliate of the Company that has been designated to participate in the 2009 ESPP. Offering periods begin on the first trading day in January and July of each calendar year and end on the last trading day in June and December of each calendar year. Share purchases are funded through payroll deductions of up to 10% of an employee’s eligible compensation for each payroll period, or $21,250 each calendar year. At December 31, 2018 , 3.3 million shares were available for future issuance under the 2009 ESPP (i.e., excluding the effect of shares issued in January 2019 as described below). In July 2018 , the Company issued 0.1 million shares under the 2009 ESPP at an average price of $192.96 per share, which covered employee contributions for the six months ended June 29, 2018 . In January 2019 , the Company issued 0.1 million shares under the 2009 ESPP at an average price of $162.91 per share, which covered employee contributions for the six months ended December 31, 2018 . The 5% discount is not recognized as compensation expense in accordance with the accounting standard for share-based compensation expense. In anticipation of the merger with Harris, the Company has amended the 2009 ESPP to provide that the offering period that ended December 31, 2018 will be the final offering period for the plan. At the effective time of the merger, the 2009 ESPP will terminate in its entirety.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Non-Cancelable Operating Leases The Company leases certain facilities and equipment under agreements expiring at various dates through 2046. Certain leases contain renewal options or escalation clauses providing for increased rental payments based upon maintenance, utility and tax increases. No lease agreement imposes a restriction on the Company’s ability to pay dividends, engage in debt or equity financing transactions, or enter into further lease agreements. The following table presents future minimum payments under non-cancelable operating leases with initial or remaining terms in excess of one year at December 31, 2018 . Real Estate Equipment Total (in millions) 2019 $ 111 $ 4 $ 115 2020 132 2 134 2021 81 1 82 2022 73 — 73 2023 65 — 65 Thereafter 506 — 506 Total minimum payments required 968 7 975 Sublease rentals under non-cancelable leases (7 ) — (7 ) Net minimum payments required $ 961 $ 7 $ 968 Rent expense was $105 million for 2018 , $103 million for 2017 and $97 million for 2016 . Sublease rental income was $2 million for 2018 , $1 million for 2017 and $2 million for 2016 . Letters of Credit The Company enters into standby letters of credit with financial institutions covering performance and financial guarantees pursuant to contractual arrangements with certain customers. The Company had total outstanding letters of credit aggregating to $410 million and $416 million at December 31, 2018 and 2017 , respectively. The Company had the full availability of its $1 billion Credit Facility at December 31, 2018 . These letters of credit may be drawn upon in the event of the Company’s nonperformance. Guarantees The Company, from time to time, enters into contractual guarantees that arise in connection with its business acquisitions, dispositions, and other contractual arrangements in the normal course of business. In connection with the spin-off of Engility in 2012, L3 entered into a Distribution Agreement and several other agreements that govern certain aspects of L3’s relationship with Engility, including employee matters, tax matters, transition services, and the future supplier/customer relationship between L3 and Engility. These agreements generally provide cross-indemnities that, except as otherwise provided, are principally designed to place the financial responsibility for the obligations and liabilities of each entity with that respective entity. Engility has joint and several liability with L3 to the U.S. IRS for the consolidated U.S. Federal income taxes of L3’s consolidated group for taxable periods in which Engility was a part of that group. However, the Tax Matters Agreement specifies the portion of this tax liability for which L3 and Engility will each bear responsibility, and L3 and Engility have agreed to indemnify each other against any amounts for which the other is not responsible. The Tax Matters Agreement also allocates responsibility between L3 and Engility for other taxes, including special rules for allocating tax liabilities in the event that the spin-off is determined not to be tax-free. Though valid as between the parties, the Tax Matters Agreement is not binding on the IRS. The Company has three existing real estate lease agreements, which include residual guarantee amounts, expiring on August 31, 2020 and are accounted for as operating leases. On or before the lease expiration date, the Company can exercise options under the lease agreements to renew the leases, purchase the properties for $45 million , or sell the properties on behalf of the lessor (the “Sale Option”). If the Company elects the Sale Option, the Company must pay the lessor a residual guarantee amount of $39 million for the properties, on or before the lease expiration date. In addition, at the time the properties are sold, the Company must pay the lessor a supplemental rent payment equal to the gross sales proceeds in excess of the residual guarantee, provided that such amount shall not exceed $6 million . For these real estate lease agreements, if the gross sales proceeds are less than the sum of the residual guarantee amount and the supplemental rent payment, the Company is required to pay a supplemental rent payment to the extent the reduction in the fair value of the properties is demonstrated by an independent appraisal to have been caused by the Company’s failure to properly maintain the properties. The aggregate residual guarantee amounts equal $39 million and are included in the future minimum payments under non-cancelable real estate operating lease payments relating to the expiration dates of such leases. Environmental Matters Management continually assesses the Company’s obligations with respect to applicable environmental protection laws, including those obligations assumed in connection with certain business acquisitions. While it is difficult to determine the timing and ultimate cost to be incurred by the Company in order to comply with these laws, based upon available internal and external assessments, with respect to those environmental loss contingencies of which management is aware, the Company believes that there are no environmental loss contingencies that, individually or in the aggregate, would be material to the Company’s consolidated results of operations. The Company accrues for these contingencies when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. 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 C&NS 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 December 31, 2018 , the Company did not record any amounts 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. To date, four lawsuits challenging the merger of L3 Technologies, Inc, and the Harris Corporation have been filed by purported L3 stockholders: (1) an individual action captioned Stein v. L3 Technologies, Inc., et al. , in the Southern District of New York, naming L3 and the members of L3’s board of directors; (2) a putative class action captioned Raul v. L3 Technologies, Inc., et al. , in the Southern District of New York, naming L3 and the members of L3’s board of directors; (3) a putative class action captioned Gross v. L3 Technologies, Inc., et al. , in the Southern District of New York, naming L3 and the members of L3’s board of directors; and (4) a putative class action captioned Kent v. L3 Technologies, Inc., et al. , in the District of Delaware, naming L3, the members of L3’s board of directors, Harris and Merger Sub. The lawsuits allege violations of Sections 14 and 20 of the Exchange Act in connection with disclosure related to the merger in this joint proxy statement/prospectus. Among other remedies, the lawsuits seek injunctive relief enjoining the merger, damages and costs. L3, Harris, Merger Sub and the L3 board of directors believe these lawsuits are without merit and intend to defend against them vigorously.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits The following table summarizes changes in the benefit obligations, the plan assets and funded status for all of the Company’s pension and postretirement benefit plans, as well as the aggregate balance sheet impact. Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 (in millions) Change in benefit obligation: Benefit obligation at the beginning of the year $ 4,228 $ 3,758 $ 165 $ 177 Service cost 103 97 2 2 Interest cost 143 142 5 5 Plan participants’ contributions 2 2 5 5 Amendments (13 ) — — — Actuarial (gain) loss (340 ) 391 (11 ) (13 ) Foreign currency exchange rate changes (27 ) 22 (2 ) 2 Curtailments and special termination benefits — 2 — — Benefits paid (159 ) (186 ) (14 ) (13 ) Benefit obligation at the end of the year $ 3,937 $ 4,228 $ 150 $ 165 Change in plan assets: Fair value of plan assets at the beginning of the year $ 3,047 $ 2,721 $ 67 $ 60 Actual return on plan assets (119 ) 391 (3 ) 8 Employer contributions 96 97 6 7 Plan participants’ contributions 2 2 5 5 Foreign currency exchange rate changes (27 ) 22 — — Benefits paid (159 ) (186 ) (14 ) (13 ) Fair value of plan assets at the end of the year $ 2,840 $ 3,047 $ 61 $ 67 Unfunded status at the end of the year $ (1,097 ) $ (1,181 ) $ (89 ) $ (98 ) Assets and (liabilities) recognized on the consolidated balance sheets consist of: Non-current assets $ 40 $ 48 $ — $ — Current liabilities (8 ) (6 ) (7 ) (8 ) Non-current liabilities (1,129 ) (1,223 ) (82 ) (90 ) $ (1,097 ) $ (1,181 ) $ (89 ) $ (98 ) The table below summarizes the net loss and prior service cost balances at December 31, in the accumulated other comprehensive loss account, before related tax effects, for all of the Company’s pension and postretirement benefit plans. Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 (in millions) Net loss (gain) $ 958 $ 1,035 $ (3 ) $ (3 ) Prior service (credit) cost (1 ) 10 (25 ) (27 ) Total amount recognized $ 957 $ 1,045 $ (28 ) $ (30 ) The aggregate accumulated benefit obligation (ABO) for all of the Company’s pension plans was $3,614 million at December 31, 2018 and $3,831 million at December 31, 2017 . The table below presents information for the pension plans with an ABO in excess of the fair value of plan assets at December 31, 2018 and 2017 . Pension Plans 2018 2017 (in millions) Projected benefit obligation $ 3,681 $ 3,875 Accumulated benefit obligation $ 3,367 $ 3,490 Fair value of plan assets $ 2,547 $ 2,651 The table below summarizes the weighted average assumptions used to determine the benefit obligations for the Company’s pension and postretirement plans disclosed at December 31, 2018 and 2017 . Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 Benefit obligations: Discount rate 4.43 % (1) 3.78 % (1) 4.28 % (2) 3.59 % (2) Rate of compensation increase 3.50 % (3) 3.50 % (3) __________________ (1) The weighted average discount rate assumptions used at December 31, 2018 and 2017 were comprised of separate assumptions determined by country of 4.48% and 3.81% for the U.S. based plans, respectively, and 3.88% and 3.39% for the Canadian based plans, respectively. (2) The weighted average discount rate assumptions used at December 31, 2018 and 2017 were comprised of separate assumptions determined by country of 4.34% and 3.63% for the U.S. based plans, respectively, and 3.81% and 3.33% for the Canadian based plans, respectively. (3) The weighted average rate of compensation increase assumptions were comprised of separate assumptions determined by country of 3.5% for both the U.S. based plans and Canadian based plans at December 31, 2018 and 2017 . The following table summarizes the components of net periodic benefit cost for the Company’s pension and postretirement benefit plans for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 (in millions) Components of net periodic benefit cost: Service cost (1) $ 103 $ 97 $ 94 $ 2 $ 2 $ 2 Interest cost 143 142 135 5 5 6 Expected return on plan assets (1) (223 ) (197 ) (186 ) (5 ) (4 ) (4 ) Amortization of prior service (credits) cost (2 ) 1 — (1 ) (1 ) (2 ) Amortization of net loss (gains) 74 61 52 (3 ) (2 ) (2 ) Curtailment loss and special termination benefits (2) 1 6 2 — — — Net periodic benefit cost $ 96 $ 110 $ 97 $ (2 ) $ — $ — __________________ (1) In connection with the adoption of ASU 2017-07, the Company reclassified pension plan administrative expenses amounting to $15 million and $14 million for the years ended December 31, 2017 and 2016, respectively, from the service cost component to the expected return on plan assets component of net periodic benefit cost. Including the aforementioned policy change in connection with the adoption of this standard, operating income increased by $11 million and $1 million for the years ended December 31, 2017 and 2016, respectively, with a corresponding decrease of Interest and other income, net. The Company’s percentage assumptions for expected long-term return on plan assets, which are disclosed further below, exclude expected plan administrative expenses. (2) During the year ended December 31, 2017, the curtailment loss and special termination benefits charge is primarily due to a pension curtailment charge in connection with the decision to discontinue future service accruals for substantially all salaried employee defined benefit plans effective January 1, 2019. The Company uses a spot rate approach in the measurement of the service and interest cost components of benefit cost for all of the Company's pension and postretirement benefit plans by applying specific spot rates along that yield curve to the relevant projected cash flows. The following table summarizes the other changes in plan assets and benefit obligations recognized in other comprehensive income for the Company’s pension and postretirement benefit plans for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 (in millions) Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): Net (gain) loss $ (3 ) $ 200 $ 179 $ (2 ) $ (17 ) $ (4 ) Prior service (cost) credit (13 ) (4 ) 15 — — (2 ) Amortization of net (loss) gain (74 ) (61 ) (52 ) 3 2 2 Amortization of prior service credit (cost) 2 (1 ) — 1 1 2 Total recognized in other comprehensive (loss) income (88 ) 134 142 2 (14 ) (2 ) Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 8 $ 244 $ 239 $ — $ (14 ) $ (2 ) The following table summarizes the amounts expected to be amortized from accumulated OCI and recognized as components of net periodic benefit costs during 2019 . Pension Plans Postretirement Benefit Plans Total (in millions) Net loss (gain) $ 44 $ (3 ) $ 41 Prior service credit (2 ) — (2 ) $ 42 $ (3 ) $ 39 The table below summarizes the weighted average assumptions used to determine the net periodic benefit cost for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 Discount rates: Benefit obligation 3.78 % (1) 4.40 % (1) 4.67 % (1) 3.59 % (4) 4.05 % (4) 4.22 % (4) Service cost 3.84 % 4.55 % 4.83 % 3.64 % 4.21 % 4.37 % Interest cost 3.45 % 3.84 % 3.95 % 3.07 % 3.26 % 3.26 % Expected long-term return on plan assets 7.92 % (2) 7.92 % (2) 7.92 % (2) 8.00 % 7.43 % 7.42 % Rate of compensation increase 3.50 % (3) 3.50 % (3) 3.50 % (3) __________________ (1) The weighted average discount rate assumptions used for the years ended December 31, 2018 , 2017 , and 2016 were comprised of separate assumptions determined by country of 3.81% , 4.45% and 4.73% for the U.S. based plans and 3.39% , 3.79% and 3.93% for the Canadian based plans, respectively. (2) The weighted average expected long-term return on plan assets assumptions used were comprised of separate assumptions determined by country of 8.00% for the years ended December 31, 2018 , 2017 and 2016 for the U.S. based plans and 7.25% for the Canadian based plans for the years ended December 31, 2018 , 2017 and 2016 . (3) The weighted average rate of compensation increase assumptions used for the years ended December 31, 2018 , 2017 and 2016 were comprised of separate assumptions determined by country of 3.50% for both the U.S and Canadian based plans. (4) The weighted average discount rate assumptions used for the years ended December 31, 2018 , 2017 and 2016 were comprised of separate assumptions determined by country of 3.63% , 4.11% and 4.28% for the U.S. based plans and 3.33% , 3.64% and 3.74% for the Canadian based plans, respectively. The expected long-term return on plan assets assumption represents the average rate that the Company expects to earn over the long-term on the assets of the Company’s benefit plans, including those from dividends, interest income and capital appreciation, net of investment management expenses. The Company utilizes a third-party consultant to assist in the development of the expected long-term return on plan assets, which is based on expectations regarding future long-term rates of return for the plans’ investment portfolio, with consideration given to the allocation of investments by asset class and historical rates of return for each individual asset class. The Company utilizes a building block methodology that utilizes historical and forward looking rates of return for each asset class and takes into account expected returns above inflation and risk premium. These long-term rates of return are then applied to the target portfolio allocations that are generally aligned with the actual asset allocations of the Company’s plans to develop the expected long-term rate of return. The annual increase in cost of benefits (health care cost trend rate) for the Company’s U.S. based plans covering retirees under 65 years of age is assumed to be an average of 6.75% in 2019 and is assumed to gradually decrease to a rate of 4.5% in 2028 and thereafter. The health care cost trend rate for the Company’s U.S. based plans covering retirees over 65 years of age is assumed to be an average of 7.75% in 2019 and is assumed to gradually decrease to a rate of 4.5% in 2032 and thereafter. The health care cost trend rate for the Company’s Canadian based plans is assumed to be an average of 7.0% in 2019 and is assumed to stay flat for four years and reduce to 5.0% for ten years thereafter. Health care cost trend assumptions are based on (1) observed or expected short term rates of increase for different types of health models based on actual claims experience and benchmarking, and (2) a reasonable estimate of an appropriate, sustainable level of health care cost trend in the future, weighting the factors that primarily influence trends, which are price inflation and cost leveraging benefit plan features. Assumed health care cost trend rates can have a significant effect on amounts reported for postretirement medical benefit plans. A one percentage point change in the assumed health care cost trend rates would have the following effects: 1 percentage point Increase Decrease (in millions) Effect on total service and interest cost $ — $ — Effect on postretirement benefit obligations $ 4 $ (4 ) Plan Assets. The Company’s Benefit Plan Committee (Committee) has the responsibility to formulate the investment policies and strategies for the plans’ assets. The Committee structures the investment of plan assets to achieve the following goals: (1) maximize the plans’ long-term rate of return on assets for an acceptable level of risk; and (2) limit the volatility of investment returns and consequent impact on the plans’ assets. In the pursuit of these goals, the Committee has formulated the following investment policies and objectives: (1) invest assets of the plans in a manner consistent with the fiduciary standards of the Employee Retirement Income Security Act of 1974 (ERISA); (2) preserve the plans’ assets; (3) maintain sufficient liquidity to fund benefit payments and pay plan expenses; (4) evaluate the performance of investment managers; and (5) achieve, on average, a minimum total rate of return equal to the established benchmarks for each asset category. The Committee retains a professional investment consultant to advise the Committee and help ensure that the above policies and strategies are met. The Committee does not actively manage the day to day operations and selection process of individual securities and investments, as it retains the professional services of qualified investment management organizations to fulfill those tasks. Qualified investment management organizations are evaluated on several criteria for selection, with a focus on the investment management organizations’ demonstrated capability to achieve results that will meet or exceed the investment objectives they have been assigned and conform to the policies established by the Committee. While the investment management organizations have investment discretion over the assets placed under their management, the Committee provides each investment manager with specific investment guidelines relevant to its asset class. The Committee has established the allowable range that the plans’ assets may be invested in for each major asset category. In addition, the Committee has established guidelines regarding diversification within asset categories to limit risk and exposure to a single or limited number of securities. The investments of the plans’ include a diversified portfolio of both equity and fixed income investments. Equity investments are further diversified across U.S. and non-U.S. stocks, small to large capitalization stocks, and growth and value stocks. Fixed income assets are diversified across U.S. and non-U.S. issuers, corporate and governmental issuers, and credit quality. The plan also invests in real estate through publicly traded real estate securities. Derivatives may be used only for hedging purposes or to create synthetic long positions. The plans are prohibited from directly owning commodities, unregistered securities, restricted stock, private placements, or interests in oil, gas, mineral exploration, or other development programs. Further, short selling or utilizing margin buying for investment purposes is prohibited. The table below presents the allowable range for each major category of the plans’ assets at December 31, 2018 and the Company’s pension plan and postretirement benefit plan weighted-average asset allocations at December 31, 2018 and 2017 , by asset category. U.S. Canada Asset Category Range 2018 2017 Range 2018 2017 Domestic equity (1) 30%-60% 47 % 47 % —% 13 % 15 % International equity (2) 10%-20% 10 11 — 52 47 Total equities 45%-75% 57 58 40%-80% 65 62 Fixed income securities 20%-40% 30 28 — 28 25 Other, primarily cash and cash equivalents 0%-15% 6 7 — 7 13 Total fixed income securities and cash and cash equivalents NA NA NA 20%-60% 35 38 Real estate securities 0%-15% 7 7 — — — Total 100 % 100 % 100 % 100 % __________________ (1) Domestic equities for Canadian plans refers to equities of Canadian companies. (2) International equities for Canadian plans includes equities of U.S. companies. NA - Not applicable. The Company’s Master Pension Trust Investment Policy does not provide an allocation percentage range to fixed income securities and cash and cash equivalents. The Committee regularly monitors the investment of the plans’ assets to ensure that the actual investment allocation remains within the established range. The Committee also regularly measures and monitors investment risk through ongoing performance reporting and investment manager reviews. Investment manager reviews include assessing the managers’ performance versus the appropriate benchmark index both in the short and long-term period, performance versus peers, and an examination of the risk the managers assumed in order to achieve rates of return. The table below presents the fair value of the Company’s pension plans’ assets by asset category segregated by level within the fair value hierarchy, as described below. U.S. Pension Plans’ Assets Canadian Pension Plans’ Assets Fair Value Measured At December 31, 2018 Fair Value Measured At December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 1,205 $ — $ — $ 1,205 $ 64 $ — $ — $ 64 International Equity 90 — — 90 95 — — 95 Fixed Income — Investment Grade (2) 313 160 — 473 — — — — Fixed Income — High Yield (3) — 271 — 271 — — — — Real Estate Investment Trusts (4) 185 — — 185 — — — — Other (5) — 146 — 146 4 16 — 20 Total assets at fair value $ 1,793 $ 577 $ — $ 2,370 $ 163 $ 16 $ — $ 179 Liabilities for unsettled trades, net (9 ) — Other investments measured at net asset value (6)(7) 176 124 Total $ 2,537 $ 303 U.S. Pension Plans’ Assets Canadian Pension Plans’ Assets Fair Value Measured At December 31, 2017 Fair Value Measured At December 31, 2017 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 1,297 $ — $ — $ 1,297 $ 71 $ — $ — $ 71 International Equity 87 — — 87 105 — — 105 Fixed Income — Investment Grade (2) 329 205 — 534 — — — — Fixed Income — High Yield (3) — 219 — 219 — — — — Real Estate Investment Trusts (4) 196 — — 196 — — — — Other (5) — 198 — 198 8 37 — 45 Total assets at fair value $ 1,909 $ 622 $ — $ 2,531 $ 184 $ 37 $ — $ 221 Liabilities for unsettled trades, net (30 ) — Other investments measured at net asset value (6)(7) 203 122 Total $ 2,704 $ 343 __________________ (1) Equity securities consist of investments in common stock of U.S. and international companies. The fair value of equity securities is based on quoted market prices available in active markets at the close of a trading day, primarily the New York Stock Exchange (NYSE), National Association of Securities Dealers Automated Quotations (NASDAQ), and various international exchanges. (2) Approximately 66% and 62% at December 31, 2018 and 2017 , respectively, of U.S. plan assets that are invested in the Fixed Income — Investment Grade asset category consist of a mutual fund offered by a registered investment company (the Fund) and fixed income securities. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. These investments are classified by the Company as a Level 1 measurement within the fair value hierarchy, as the mutual fund trades on an active market and daily, quoted prices are available. The remaining 34% and 38% at December 31, 2018 and 2017 , respectively, of U.S. plan assets are fixed income securities, primarily investment grade corporate bonds from various industries held directly by the plan. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs and are classified as Level 2. (3) Fixed Income — High Yield consists of investments in corporate high-yield bonds from various industries. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs. (4) Real Estate Investment Trusts (REITs) consist of securities that trade on the major exchanges and invest directly in real estate, either through properties or mortgages. (5) Other consists primarily of: (1) money market accounts, which invest primarily in short-term, high quality money market securities such as government obligations, commercial paper, time deposits and certificates of deposit, and are classified as Level 2, and (2) cash, which is classified as Level 1. (6) In accordance with ASU 2015-07, certain investments that are measured at fair value using the net asset value (NAV) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. (7) All of the U.S. plans other investments measured using NAV at December 31, 2018 and 2017 and approximately 30% and 31% at December 31, 2018 and 2017 , respectively, of the Canadian plans other investments measured using NAV consist of a regulated commingled equity trust fund, for which fair value is based on the NAV at the end of each month. The NAV is calculated by the fund manager based on the fair value of the fund’s holdings, primarily equity securities traded in active markets, determined as of the end of each month as a practical expedient to estimating fair value. This practical expedient is not used when it is determined to be probable that the fund will sell the investment for an amount different than the reported NAV. Withdrawals are permitted, with notice by the 20th day of each month, based on NAV. Approximately 70% and 69% at December 31, 2018 and 2017 , respectively, of the Canadian plans other investments measured using NAV are invested in regulated commingled bond funds (the “Bond Funds”). As these Bond Funds do not trade in an active market, the fair value is based on NAVs calculated by fund managers based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs as a practical expedient to estimating fair value and classified as Level 2. Withdrawals are permitted monthly, with notice between 0 and 3 days of the transaction date, based on NAV. The table below presents the fair value of the Company’s postretirement benefit plans’ assets by asset category segregated by level within the fair value hierarchy, as described below. Postretirement Benefit Plans’ Assets Fair Value Measured At December 31, 2018 Fair Value Measured At December 31, 2017 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 35 $ — $ — $ 35 $ 38 $ — $ — $ 38 International Equity 1 — — 1 2 — — 2 Fixed Income — Investment Grade (2) 9 2 — 11 10 3 — 13 Fixed Income — High Yield (3) — 4 — 4 — 3 — 3 Real Estate Investment Trusts (4) 3 — — 3 3 — — 3 Other (5) — 4 — 4 — 5 — 5 Total assets at fair value $ 48 $ 10 $ — $ 58 $ 53 $ 11 $ — $ 64 Other investments measured at net asset value (6)(7) 3 3 Total $ 61 $ 67 __________________ (1) Equity securities consist of investments in common stock of U.S. and international companies. The fair value of equity securities is based on quoted market prices available in active markets at the close of a trading day, primarily the NYSE, NASDAQ, and various international exchanges. (2) Approximately 82% and 77% at December 31, 2018 and 2017 , respectively, of the postretirement benefit plan assets that are invested in the Fixed Income — Investment Grade asset category consist of the Fund and fixed income securities. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. These investments are classified by the Company as a Level 1 measurement within the fair value hierarchy as the mutual fund trades on an active market and daily, quoted prices are available. The remaining 18% and 23% at December 31, 2018 and 2017 , respectively, of the postretirement benefit plan assets are fixed income securities, primarily investment grade corporate bonds from various industries held directly by the plan. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs and are classified as Level 2. (3) Fixed Income — High Yield consists of investments in corporate high-yield bonds from various industries. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs. (4) REITs consist of securities that trade on the major exchanges and invest directly, either through properties or mortgages. (5) Other consists primarily of money market accounts, which invest primarily in short-term, high quality money market securities such as government obligations, commercial paper, time deposits and certificates of deposit. (6) In accordance with ASU 2015-07, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. (7) All of the postretirement benefit plans other investments measured using NAV at December 31, 2018 and 2017 consist of a regulated commingled equity trust fund, which fair value is based on NAV at the end of each month. The NAV is calculated by the fund manager based on the fair value of the fund’s holdings, primarily equity securities traded in active markets, determined as of the end of each month as a practical expedient to estimating fair value. This practical expedient is not used when it is determined to be probable that the fund will sell the investment for an amount different than the reported NAV. Withdrawals are permitted, with notice by the 20th day of each month, based on NAV. Contributions. The funding policy for the Company’s pension and postretirement benefit plans is to contribute at least the minimum required by applicable laws and regulations or to directly make benefit payments where appropriate. The Company makes voluntary, additional contributions to the pension plans depending on a number of factors, including operating cash flow levels, alternative uses for excess cash and the plans’ funded status. At December 31, 2018 , all legal funding requirements had been met. For the year ending December 31, 2019 , the Company currently expects to contribute approximately $80 million to its pension plans, and approximately $8 million to its postretirement benefit plans. Estimated Future Benefit Payments. The following table presents expected pension and postretirement benefit payments and expected postretirement subsidies due to the Medicare Prescription Drug Improvement and Modernization Act of 2003, which reflect expected future service, as appropriate. Postretirement Benefits Pension Benefit Subsidy (in millions) 2019 $ 168 $ 12 $ — 2020 176 12 — 2021 184 12 — 2022 194 12 — 2023 201 12 — Years 2024 - 2028 1,150 53 1 Employee Savings Plans. Under its various employee savings plans, the Company matches the contributions of participating employees up to a designated level. The extent of the match, vesting terms and the form of the matching contributions vary among the plans. Under these plans, the Company’s matching contributions in L3’s common stock and cash were $118 million for 2018 , $115 million for 2017 and $118 million for 2016 . These matching contributions include amounts attributable to discontinued operations of $2 million for 2018 , $8 million for 2017 and $12 million for 2016 . Multiemployer Benefit Plans. Certain of the Company’s businesses participate in multiemployer defined benefit pension plans. The Company makes cash contributions to these plans under the terms of collective-bargaining agreements that cover its union employees based on a fixed rate per hour of service worked by the covered employees. The risks of participating in these multiemployer plans are different from single-employer plans in the following aspects: (1) assets contributed to the multiemployer plan by one employer may be used to provide benefits to employees of other participating employers, (2) if a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers and (3) if the Company chooses to stop participating in some of its multiemployer plans, the Company may be required to pay those plans an amount based on the underfunded status of the plan, referred to as a withdrawal liability. In connection with the sale of the Vertex Aerospace business, the Company no longer participates in the majority of its multiemployer plans. Under the Company's remaining multiemployer plans, cash contributed and expenses recorded for the year ended December 31, 2018 were less than $1 million .

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Year Ended December 31, 2018 2017 2016 (in millions) Interest paid $ 183 $ 165 $ 162 Income tax payments $ 108 $ 163 $ 120 Income tax refunds $ 7 $ 16 $ 8

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information and Disaggregation of Net Sales In the third quarter of 2018, the Company completed a realignment of its business segments to maximize growth and improve its integration and collaboration across the enterprise. As a result of the realignment, L3 has the following three reportable segments: (1) ISRS, (2) C&NS and (3) Electronic Systems. 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, gains or losses related to business divestitures, and certain other items that are excluded by management for purposes of evaluating the operating performance of the Company’s business segments. Certain Corporate and segment expenses of $15 million the year ended December 31, 2018 , $32 million for the year ended December 31, 2017 and $29 million for the year ended December 31, 2016 , that had previously been allocated to the Vertex Aerospace and NSS businesses were retained by the Company and were allocated to L3’s three reportable segments. The tables below present net sales, operating income, depreciation and amortization, capital expenditures and total assets by reportable segment. Year Ended December 31, 2018 2017 2016 (in millions) Net Sales Products ISRS $ 2,907 $ 2,540 $ 2,662 C&NS 2,307 2,424 2,238 Electronic Systems 2,007 1,814 1,617 Elimination of intercompany sales (56 ) (45 ) (64 ) Total products sales 7,165 6,733 6,453 Services ISRS $ 1,549 $ 1,463 $ 1,450 C&NS 787 717 678 Electronic Systems 789 695 653 Elimination of intercompany sales (46 ) (35 ) (24 ) Total services sales 3,079 2,840 2,757 Consolidated total $ 10,244 $ 9,573 $ 9,210 Operating income ISRS $ 448 $ 348 $ 362 C&NS 282 362 298 Electronic Systems 376 321 298 Segment total 1,106 1,031 958 Gain on sale of the Crestview & TCS businesses 42 — — Merger and acquisition related expenses (28 ) — — Consolidated total $ 1,120 $ 1,031 $ 958 Depreciation and amortization ISRS $ 92 $ 87 $ 80 C&NS 69 66 63 Electronic Systems 80 72 55 Consolidated total $ 241 $ 225 $ 198 Capital Expenditures ISRS $ 57 $ 74 $ 83 C&NS 50 76 51 Electronic Systems 108 52 66 Corporate 17 22 10 Consolidated total $ 232 $ 224 $ 210 Year Ended December 31, 2018 2017 2016 (in millions) Total Assets ISRS $ 4,720 $ 4,135 $ 4,117 C&NS 3,670 3,505 3,258 Electronic Systems 4,128 3,939 3,542 Corporate 1,000 709 467 Assets held for sale — 135 — Assets of discontinued operations — 306 481 Consolidated total $ 13,518 $ 12,729 $ 11,865 The table below presents property, plant and equipment, net by geographic area. Year Ended December 31, 2018 2017 (in millions) United States $ 973 $ 936 All other 196 174 Total $ 1,169 $ 1,110 The Company’s sales attributable to U.S. and international customers, based on location of the customer, are summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) U.S. $ 7,843 $ 7,344 $ 6,947 International: Canada 312 280 297 United Kingdom 309 335 331 Australia 219 268 254 China 156 167 67 Japan 145 125 81 Saudi Arabia 128 58 159 Turkey 113 61 61 Other 1,019 935 1,013 Total international 2,401 2,229 2,263 Consolidated $ 10,244 $ 9,573 $ 9,210 Net sales to principal customers are summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) U.S. Government agencies (1) $ 7,144 6,697 $ 6,399 Commercial 1,572 1,456 1,280 Foreign governments (1) 1,528 1,420 1,531 Consolidated $ 10,244 9,573 $ 9,210 __________________ (1) Includes sales for which the Company is the prime contractor as well as sales based on the ultimate end customer for which the Company is a subcontractor. Corporate assets not allocated to the reportable segments primarily include cash and cash equivalents, corporate office fixed assets, and deferred income tax assets. Disaggregation of Total Net Sales . The Company disaggregates its sales from contracts with customers by: (1) end customer, (2) contract type, (3) deliverable type and (4) revenue recognition method for each of its segments. 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 the year ended December 31, 2018 and indirect sales as a subcontractor or supplier represented the remaining 36% . The table below present total net sales disaggregated by end customer. Year Ended December 31, 2018 End Customer ISRS C&NS Electronic Systems Consolidated L3 (in millions) Total DoD $ 3,081 $ 2,291 $ 1,349 $ 6,721 Other U.S. Government 150 95 178 423 Total U.S. Government 3,231 2,386 1,527 7,144 Foreign governments (1) 1,006 327 195 1,528 Commercial — foreign 75 123 675 873 Commercial — domestic 129 223 347 699 Total $ 4,441 $ 3,059 $ 2,744 $ 10,244 __________________ (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 table below present total net sales disaggregated by contract type. Year Ended December 31, 2018 Contract Type ISRS C&NS Electronic Systems Consolidated L3 (in millions) Fixed-price (1) $ 2,839 $ 2,202 $ 2,317 $ 7,358 Cost-plus (2) 1,393 768 410 2,571 Time-and-material 209 89 17 315 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244 __________________ (1) Includes fixed-price incentive fee type contracts, which contributed approximately 1% to the Company's total net sales for the year ended December 31, 2018 . (2) Includes cost-plus award and incentive fee type contracts, which contributed approximately 4% to the Company's total net sales for the year ended December 31, 2018 . Sales by Deliverable Type: The table below present total net sales disaggregated by the type of deliverable, which is determined by the Company at the performance obligation level. Year Ended December 31, 2018 Sales by Deliverable Type ISRS C&NS Electronic Systems Consolidated L3 (in millions) Products $ 2,907 $ 2,299 $ 1,959 $ 7,165 Services 1,534 760 785 3,079 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244 Revenue Recognition Method: The table below present total net sales disaggregated based on the revenue recognition method applied. Year Ended December 31, 2018 Revenue Recognition Method ISRS C&NS Electronic Systems Consolidated L3 (in millions) Over time (cost-to-cost method) $ 3,352 $ 2,603 $ 1,649 $ 7,604 Point in time 866 359 705 1,930 Output method 74 23 343 440 Billing method 149 74 47 270 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244

Severance and Restructuring Rel

Severance and Restructuring Related Costs	12 Months Ended
	Dec. 31, 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 severance and restructuring related costs of $26 million with respect to approximately 800 employees during the year ended December 31, 2018 , $101 million with respect to approximately 1,500 employees during the year ended December 31, 2017 and $17 million with respect to approximately 700 employees during the year ended December 31, 2016 . Severance and restructuring related costs are reported within operating costs and expenses on the consolidated statements of operations. Severance and restructuring related costs incurred by reportable segment are presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) ISRS (1)(2) $ 7 $ 38 $ 5 C&NS (3) 11 52 8 Electronic Systems (2) 8 11 4 Consolidated $ 26 $ 101 $ 17 __________________ (1) The severance and restructuring related costs incurred during the year ended December 31, 2017 include a $12 million loss on the sale of a building in Garland, Texas in the fourth quarter of 2017. (2) The severance and restructuring related costs incurred during the year ended December 31, 2017 include $1 million and $5 million of salaried employee pension plan curtailment losses for Electronic Systems and ISRS segments, respectively. See Note 20 for additional information. (3) The severance and restructuring related costs incurred during the year ended December 31, 2017 exclude a pre-tax gain of $42 million on the sale of the Company's property in San Carlos, California in the second quarter of 2017. The Company had severance and restructuring related liabilities of $14 million and $23 million included in other current liabilities on the Company’s balance sheets at December 31, 2018 and 2017 , respectively. The remaining liability balance at December 31, 2018 is expected to be paid in 2019 . The table below presents the change to the Company’s severance and restructuring related liability during the year ended December 31, 2018 . December 31, 2018 (in millions) Balance at beginning of period $ 23 Additional provisions 26 Cash payments (35 ) Balance at end of period $ 14

Unaudited Quarterly Financial D

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	. Unaudited Quarterly Financial Data Unaudited summarized financial data by quarter for the years ended December 31, 2018 and 2017 is presented in the tables below. The Company’s unaudited quarterly results of operations are affected, significantly in some periods, by the Company’s business acquisitions and divestitures. See Note 3 for additional information. First Second (1) Third (2) Fourth (3) (in millions, except per share data) 2018 Sales $ 2,371 $ 2,583 $ 2,519 $ 2,771 Operating income 251 321 272 276 Income from continuing operations 192 189 208 232 Net income 208 379 208 231 Net income attributable to L3 203 375 202 225 Basic EPS from continuing operations (4) 2.40 2.36 2.57 2.87 Basic EPS (4) 2.60 4.78 2.57 2.86 Diluted EPS from continuing operations (4) 2.34 2.33 2.54 2.83 Diluted EPS (4) 2.54 4.72 2.54 2.82 __________________ (1) Income from continuing operations includes debt retirement charges of $48 million ( $36 million after income taxes), or $0.45 per diluted share and a pre-tax gain of $48 million ( $25 million after income taxes), or $0.31 per diluted share, related to the divestiture of the Crestview Aerospace and TCS businesses. The Company recorded a pre-tax gain of $237 million ( $180 million after income taxes, or $2.27 per diluted share) related to the divestiture of the Vertex Aerospace business, which is reported in discontinued operations. (2) Income from continuing operations includes debt retirement charges of $21 million ( $16 million after income taxes), or $0.21 per diluted share, merger and acquisition related expenses of $5 million ( $4 million after income taxes), or $0.06 per diluted share and adjustments to divestiture gains of $4 million ( $4 million after income taxes), or $0.04 per diluted share, related to the sale of the Crestview Aerospace and TCS businesses. (3) Income from continuing operations includes merger and acquisition related expenses of $23 million ( $19 million after income taxes), or $0.24 per diluted share and adjustments to divestiture gains of $2 million ( $2 million after income taxes), or $0.03 per diluted share, related to the sale of the Crestview Aerospace and TCS businesses. (4) EPS in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Therefore, the sum of the four quarters’ EPS may not equal the full year computed EPS. First Second Third (1) Fourth (2) (in millions, except per share data) 2017 Sales $ 2,321 $ 2,385 $ 2,293 $ 2,574 Operating income 237 294 232 268 Income from continuing operations 157 195 146 271 Net income 168 207 25 293 Net income attributable to L3 164 202 22 289 Basic EPS from continuing operations (3) 1.97 2.44 1.83 3.42 Basic EPS (3) 2.11 2.59 0.28 3.70 Diluted EPS from continuing operations (3) 1.93 2.39 1.79 3.34 Diluted EPS (3) 2.07 2.54 0.28 3.62 __________________ (1) The Company recorded a goodwill impairment charge of $187 million or $1.67 per diluted share for the Vertex Aerospace reporting unit in 2017, which is reported in discontinued operations. (2) Provision for income taxes for the fourth quarter of 2017, includes estimated tax benefits of $79 million or $0.99 per diluted share, related to the enactment of the U.S. Tax Reform in December 2017. (3) EPS in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Therefore, the sum of the four quarters’ EPS may not equal the full year computed EPS.

Financial Information of L3 and

Financial Information of L3 and Its Subsidiaries	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Financial Information of L3 and Its Subsidiaries	Financial Information of L3 and Its Subsidiaries The debt of L3, including the senior notes and borrowings under amounts drawn against the Credit Facility, is guaranteed, on a joint and several, full and unconditional basis, by certain of its 100% owned domestic subsidiaries (the Guarantor Subsidiaries). See Note 10 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. In lieu of providing separate audited financial statements for the Guarantor Subsidiaries, the Company has included the accompanying condensed combining financial statements based on Rule 3-10 of SEC Regulation S-X. The Company does not believe that separate financial statements of the Guarantor Subsidiaries are material to users of the financial statements. The following 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 Non- Eliminations Consolidated (in millions) Condensed Combining Balance Sheets: At December 31, 2018: Current assets: Cash and cash equivalents $ 756 $ 21 $ 306 $ (17 ) $ 1,066 Billed receivables, net 291 341 287 — 919 Contract assets 562 833 195 — 1,590 Inventories 378 258 243 — 879 Prepaid expenses and other current assets 127 166 63 — 356 Total current assets 2,114 1,619 1,094 (17 ) 4,810 Goodwill 2,124 3,009 1,675 — 6,808 Other assets 690 765 445 — 1,900 Investment in and amounts due from consolidated subsidiaries 5,931 6,912 — (12,843 ) — Total assets $ 10,859 $ 12,305 $ 3,214 $ (12,860 ) $ 13,518 Current liabilities $ 821 $ 955 $ 688 $ (17 ) $ 2,447 Amounts due to consolidated subsidiaries — — 417 (417 ) — Other long-term liabilities 878 804 161 — 1,843 Long-term debt 3,321 — — — 3,321 Total liabilities 5,020 1,759 1,266 (434 ) 7,611 L3 shareholders’ equity 5,839 10,546 1,948 (12,494 ) 5,839 Noncontrolling interests — — — 68 68 Total equity 5,839 10,546 1,948 (12,426 ) 5,907 Total liabilities and equity $ 10,859 $ 12,305 $ 3,214 $ (12,860 ) $ 13,518 L3 Guarantor Non- Eliminations Consolidated (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 2,099 2,932 1,584 — 6,615 Other assets 658 687 321 — 1,666 Investment in and amounts due from consolidated subsidiaries 5,662 6,310 — (11,972 ) — Total assets $ 10,459 $ 11,471 $ 2,842 $ (12,043 ) $ 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 — — 391 (391 ) — Other long-term liabilities 1,009 729 131 — 1,869 Long-term debt 3,330 — — — 3,330 Total liabilities 5,376 1,578 1,086 (462 ) 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 $ 2,842 $ (12,043 ) $ 12,729 L3 Guarantor Non- Eliminations Consolidated (in millions) Condensed Combining Statements of Operations: For the year ended December 31, 2018: Total net sales $ 3,626 $ 5,259 $ 1,806 $ (447 ) $ 10,244 Total operating costs and expenses (3,180 ) (4,943 ) (1,462 ) 447 (9,138 ) Gain on sale of Crestview & TCS Businesses — 42 — — 42 Merger and acquisition related expenses (28 ) — — — (28 ) Operating income 418 358 344 — 1,120 Interest expense (163 ) — (1 ) — (164 ) Interest and other income, net 31 3 3 — 37 Debt retirement charges (69 ) — — — (69 ) Income from continuing operations before income taxes 217 361 346 — 924 Provision for income taxes (24 ) (40 ) (39 ) — (103 ) Equity in net income of consolidated subsidiaries 607 184 — (791 ) — Income from continuing operations 800 505 307 (791 ) 821 Income from discontinued operations, net of income tax 205 — — — 205 Net income 1,005 505 307 (791 ) 1,026 Net income attributable to noncontrolling interests — — — (21 ) (21 ) Net income attributable to L3 $ 1,005 $ 505 $ 307 $ (812 ) $ 1,005 Comprehensive income attributable to L3 $ 971 $ 427 $ 226 $ (653 ) $ 971 For the year ended December 31, 2017: Total net sales $ 3,520 $ 4,852 $ 1,581 $ (380 ) $ 9,573 Total operating costs and expenses (3,169 ) (4,446 ) (1,307 ) 380 (8,542 ) Operating income 351 406 274 — 1,031 Interest expense (168 ) — (1 ) — (169 ) Interest and other income (loss), net 6 (8 ) 11 — 9 Income from continuing operations before income taxes 189 398 284 — 871 Provision for income taxes (22 ) (47 ) (33 ) — (102 ) Equity in net income of consolidated subsidiaries 586 144 — (730 ) — Income from continuing operations 753 495 251 (730 ) 769 Loss from discontinued operations, net of income tax (76 ) — — — (76 ) Net income 677 495 251 (730 ) 693 Net income attributable to noncontrolling interests — — — (16 ) (16 ) Net income attributable to L3 $ 677 $ 495 $ 251 $ (746 ) $ 677 Comprehensive income attributable to L3 $ 712 $ 604 $ 378 $ (982 ) $ 712 For the year ended December 31, 2016: Total net sales $ 3,351 $ 4,842 $ 1,348 $ (331 ) $ 9,210 Total operating costs and expenses (3,064 ) (4,406 ) (1,113 ) 331 (8,252 ) Operating income 287 436 235 — 958 Interest expense (164 ) — — — (164 ) Interest and other income (loss), net 9 (3 ) 11 — 17 Debt retirement charges (7 ) — — — (7 ) Income from continuing operations before income taxes 125 433 246 — 804 Provision for income taxes (26 ) (92 ) (53 ) — (171 ) Equity in net income of consolidated subsidiaries 520 130 — (650 ) — Income from continuing operations 619 471 193 (650 ) 633 Income from discontinued operations, net of income tax 91 — — — 91 Net income 710 471 193 (650 ) 724 Net income attributable to noncontrolling interests — — — (14 ) (14 ) Net income attributable to L3 $ 710 $ 471 $ 193 $ (664 ) $ 710 Comprehensive income attributable to L3 $ 558 $ 409 $ 116 $ (525 ) $ 558 L3 Guarantor Non- Eliminations Consolidated (in millions) Condensed Combining Statements of Cash Flows: For the year ended December 31, 2018: Operating activities: Net cash from operating activities from continuing operations $ 555 $ 238 $ 256 $ (7 ) $ 1,042 Investing activities: Business acquisitions, net of cash acquired (193 ) — (176 ) — (369 ) Proceeds from sale of businesses, net of closing date cash balances 360 175 — — 535 Other investing activities (119 ) (90 ) (48 ) — (257 ) Net cash from (used in) investing activities from continuing operations 48 85 (224 ) — (91 ) Financing activities: Proceeds from sale of senior notes 1,798 — — — 1,798 Repurchases and redemptions of senior notes (1,865 ) — — — (1,865 ) Common stock repurchased (322 ) — — — (322 ) Dividends paid (254 ) — — — (254 ) Other financing activities 376 (318 ) 4 61 123 Net cash (used in) from financing activities from continuing operations (267 ) (318 ) 4 61 (520 ) Effect of foreign currency exchange rate changes on cash — — (15 ) — (15 ) Net decrease in cash and cash equivalents of discontinued operations (12 ) — — — (12 ) Net increase in cash 324 5 21 54 404 Cash and cash equivalents, beginning of the year 432 16 285 (71 ) 662 Cash and cash equivalents, end of the year $ 756 $ 21 $ 306 $ (17 ) $ 1,066 For the year ended December 31, 2017: Operating activities: Net cash from operating activities from continuing operations $ 374 $ 426 $ 263 $ (78 ) $ 985 Investing activities: Business acquisitions, net of cash acquired (316 ) — — — (316 ) Proceeds from sale of businesses, net of closing date cash balances 17 — 1 — 18 Other investing activities (92 ) (38 ) (25 ) — (155 ) Net cash used in investing activities from continuing operations (391 ) (38 ) (24 ) — (453 ) Financing activities: Common stock repurchased (180 ) — — — (180 ) Dividends paid (236 ) — — — (236 ) Other financing activities 490 (377 ) (177 ) 114 50 Net cash from (used in) financing activities from continuing operations 74 (377 ) (177 ) 114 (366 ) Effect of foreign currency exchange rate changes on cash — — 20 — 20 Net increase in cash and cash equivalents of discontinued operations 113 — — — 113 Net increase in cash 170 11 82 36 299 Cash and cash equivalents, beginning of the year 262 5 203 (107 ) 363 Cash and cash equivalents, end of the year $ 432 $ 16 $ 285 $ (71 ) $ 662 L3 Guarantor Non- Eliminations Consolidated (in millions) For the year ended December 31, 2016: Operating activities: Net cash from operating activities from continuing operations $ 440 $ 509 $ 259 $ (186 ) $ 1,022 Investing activities: Business acquisitions, net of cash acquired (388 ) — — — (388 ) Proceeds from sale of businesses, net of closing date cash balances 563 — (2 ) — 561 Other investing activities (63 ) (77 ) (43 ) — (183 ) Net cash from (used in) investing activities from continuing operations 112 (77 ) (45 ) — (10 ) Financing activities: Proceeds from sale of senior notes 547 — — — 547 Redemption of senior notes (856 ) — — — (856 ) Common stock repurchased (373 ) — — — (373 ) Dividends paid (220 ) — — — (220 ) Other financing activities 490 (427 ) (163 ) 146 46 Net cash used in financing activities from continuing operations (412 ) (427 ) (163 ) 146 (856 ) Effect of foreign currency exchange rate changes on cash — — (13 ) — (13 ) Net increase in cash and cash equivalents of discontinued operations 13 — — — 13 Net increase in cash 153 5 38 (40 ) 156 Cash and cash equivalents, beginning of the year 109 — 165 (67 ) 207 Cash and cash equivalents, end of the year $ 262 $ 5 $ 203 $ (107 ) $ 363

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 5, 2019, the Company sold its L3 Mobile Vision, Inc. (Mobile Vision) business, subject to working capital adjustments and certain indemnification liabilities. Mobile Vision had sales of $23 million and operating loss of $9 million for the year ended December 31, 2018.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation: 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 also 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 voting 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.
Accounting Estimates	Accounting Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (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 cost of sales during the reporting period. The most significant of these estimates and assumptions relate to sales, profit and loss recognition for 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 post-retirement 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 year ended December 31, 2018 and the Company’s balance sheet as of December 31, 2018 are presented under ASC 606, while the Company’s statement of operations for the years ended December 31, 2017 and 2016 and the Company’s balance sheet as of December 31, 2017 are presented under ASC 605, Revenue Recognition . 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 for 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 22 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 collectability 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 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 8 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 may be 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 in some cases result in liabilities to complete contracts in a loss position. Net sales recognized from the Company's performance obligations partially satisfied in prior periods were $264 million for the year ended December 31, 2018 and relate to revisions in contract estimates. The aggregate impact of net changes in contract estimates is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Operating income $ 213 $ 185 $ 149 Diluted earnings per share $ 2.03 $ 1.49 $ 1.23 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 year ended December 31, 2018 . % of Total Net Sales Over time (cost-to-cost method) 74 % Point in time 19 % Output method 4 % Billing method 3 % Total 100 % Remaining Performance Obligations: On December 31, 2018 , the Company had $11.6 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). The Company expects to recognize sales relating to existing performance obligations of approximately $7.3 billion in 2019 , $2.7 billion in 2020 , $0.7 billion in 2021 and $0.9 billion in the periods thereafter. Contract Assets and Contract Liabilities: Contract assets include unbilled contract receivables related to long-term contracts for which sales and profits are recognized primarily using cost-to-cost method of accounting and are classified as current. Unbilled contract receivables are reduced by amounts of unliquidated progress or performance-based payments. Under the terms of certain revenue arrangements (contracts) with the U.S. Government, the Company is entitled to receive progress payments as costs are incurred or performance-based payments upon the achievement of predetermined performance milestones. Unliquidated progress or performance-based payments arise from fixed-price type contracts with the U.S. Government that contain progress or performance-based payment clauses, and represent payments on invoices that have been collected in cash, but have not yet been liquidated. Progress payment invoices 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. Unliquidated progress or performance-based payments are liquidated as deliveries or other contract performance milestones are completed, at an amount equal to a percentage of the contract sales price for the items delivered or work performed, based on a contractual liquidation rate. Contract liabilities include advance payments, billings in excess of the revenue recognized and amounts received in excess of sales recognized on contracts (deferred revenue). Contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Advance payments and billings in excess of revenue recognized are classified as current, and deferred revenue as current or noncurrent based on the timing of expected revenue recognition. The noncurrent portion of deferred revenue is included in other liabilities in the Company's consolidated balance sheets. Contracts in Process: Contracts in Process include unbilled contract receivables and inventoried contract costs for which sales and profits are recognized primarily using a POC method of accounting under ASC 605. Unbilled Contract Receivables represent accumulated incurred costs and earned profits on contracts in process that have been recorded as sales, primarily using the cost-to-cost method, but have not been billed to customers. Inventoried Contract Costs primarily represent incurred costs on contracts using the units-of-delivery method of accounting and include direct costs and indirect costs, including overhead costs, and materials acquired for U.S. Government service contracts. As discussed in Note 5 , the Company’s inventoried contract costs for U.S. Government contracts, and contracts with prime contractors or subcontractors of the U.S. Government include allocated G&A, IRAD costs and B&P costs. Contracts in Process contain amounts relating to contracts and programs with long performance cycles, a portion of which may not be realized within one year. For contracts in a loss position, the unrecoverable costs expected to be incurred in future periods are recorded in Estimated Costs in Excess of Estimated Contract Value to Complete Contracts in Process in a Loss Position, which is a component of Other Current Liabilities. Under the terms of certain revenue arrangements (contracts) with the U.S. Government, the Company is entitled to receive progress payments as costs are incurred or milestone payments as work is performed. The U.S. Government has a security interest in the Unbilled Contract Receivables and Inventoried Contract Costs to which progress payments have been applied, and such progress payments are reflected as a reduction of the related amounts. Milestone payments that have been received in excess of contract costs incurred and related estimated profits are reported on the Company’s balance sheet as Advance Payments and Billings in Excess of Costs Incurred. The Company values its acquired contracts in process in connection with business acquisitions on the date of acquisition at contract value less the Company’s estimated costs to complete the contract and a reasonable profit allowance on the Company’s completion effort.
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.
Research and Development	Research and Development: Independent research and development (IRAD) costs sponsored by the Company and bid and proposal (B&P) costs relate to both U.S. Government contracts and those for international and commercial customers. The IRAD and B&P costs for certain of the Company’s businesses that are U.S. Government contractors are recoverable indirect contract costs that are allocated to U.S. Government contracts in accordance with U.S. Government procurement regulations, and are specifically excluded from research and development accounting standards. The Company includes the recoverable IRAD and B&P costs allocated to U.S. Government contracts in inventoried contract costs, and charges them to general and administrative expenses when the related contract sales are recognized as revenue. Research and development costs that are not recoverable on U.S. Government contracts are accounted for in accordance with research and development accounting standards and are expensed to general and administrative expenses as incurred. The total research and development expenses incurred were $326 million , $287 million and $258 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Customer-funded research and development costs are incurred pursuant to contracts (revenue arrangements) to perform research and development activities according to customer specifications. These direct contract costs and are charged to cost of sales when the corresponding revenue is recognized, which is generally as the research and development services are performed. Customer-funded research and development costs are substantially all incurred under cost-plus type contracts with the U.S. Government.
Contract Costs	Contract Costs: 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.
Product Warranties	Product Warranties: Product warranty costs are accrued when revenue is recognized for the covered products. Product warranty expense is recognized based on the terms of the product warranty and the related estimated costs. Accrued warranty costs are reduced as product warranty costs are incurred or as warranty periods expire.
Deferred Debt Issue Costs	Deferred Debt Issue Costs: Costs to issue debt are capitalized and deferred when incurred, and subsequently amortized to interest expense over the term of the related debt using the effective interest rate method. Deferred debt issuance costs, other than for line-of-credit arrangements, are presented in the Company’s consolidated balance sheets as a direct deduction from the carrying amount of the associated debt liability. Deferred debt issue costs for line-of-credit arrangements are presented in the Company’s consolidated balance sheets in other assets.
Pension Plan and Postretirement Benefit Plan Obligations	Pension Plan and Postretirement Benefit Plan Obligations: The Company maintains multiple pension plans, both contributory and non-contributory, covering employees at certain locations. Eligibility for participation in these plans varies and benefits are generally based on the participant’s compensation and/or years of service. The Company’s funding policy is generally to contribute in accordance with cost accounting standards that affect government contractors, subject to the Internal Revenue Code and regulations thereon. The Company also provides postretirement medical and life insurance benefits for retired employees and dependents at certain locations. Participants are eligible for these benefits when they retire from active service and meet the eligibility requirements for the Company’s pension plans. These benefits are funded primarily on a pay-as-you-go basis with the retiree generally paying a portion of the cost through contributions, deductibles and coinsurance provisions. In accordance with accounting standards for employee pension and postretirement benefits, the Company recognizes on a plan-by-plan basis the unfunded status of its pension and postretirement benefit plans in the consolidated financial statements and measures its pension and postretirement benefit plan assets and benefit obligations at December 31. The obligation for the Company’s pension plans and postretirement benefit plans and the related annual costs of employee benefits are calculated based on several long-term assumptions, including discount rates and expected mortality for employee benefit liabilities, and rates of return on plan assets, and expected annual rates for salary increases for employee participants in the case of pension plans, and expected annual increases in the costs of medical and other health care benefits in the case of postretirement benefit obligations. See Note 20 , Pension and Other Postretirement Benefits for additional information.
Stock-Based Compensation	Stock-Based Compensation: The Company follows the fair value based method of accounting for stock-based employee compensation, which requires the Company to expense all stock-based employee compensation. Stock-based employee compensation is primarily a non-cash expense because the Company settles these obligations by issuing shares of L3 common stock instead of settling such obligations with cash payments. Compensation expense for restricted stock unit and stock option awards is generally recognized on a straight-line basis over the requisite service period for the entire award based on the grant date fair value. All of the stock options granted to employees by the Company are non-qualified stock options under U.S. income tax regulations. Compensation expense for performance units payable in L3 common stock is based on the fair value of the units at the grant date (measurement date), adjusted each reporting period for progress towards the target award, and recognized on a straight-line basis over the requisite service period. Stock-based compensation expense is recognized net of estimated forfeitures.
Income Taxes	Income Taxes: The Company provides for income taxes using the liability method. Deferred income tax assets and liabilities reflect tax carryforwards and the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes, as determined under enacted tax laws and rates. The effect of changes in tax laws or rates is accounted for in the period of enactment. Valuation allowances for deferred tax assets are provided when it is more likely than not that the assets will not be realized, considering, when appropriate, tax planning strategies. Deferred income tax assets and liabilities are classified as noncurrent in the Company’s balance sheet. Income tax accounting standards prescribe: (1) a minimum recognition threshold that an income tax benefit arising from an uncertain income tax position taken, or expected to be taken, on an income tax return is required to meet before being recognized in the financial statements and (2) the measurement of the income tax benefits recognized from such positions. The Company’s accounting policy is to classify uncertain income tax positions that are not expected to be resolved in one year as non-current income tax liabilities and to classify potential interest and penalties on uncertain income tax positions as elements of the provision for income taxes in its financial statements.
Cash and Cash Equivalents	Cash and Cash Equivalents: Cash equivalents consist of highly liquid investments with an original maturity of three months or less at the time of purchase.
Inventories	Inventories: Inventories, other than Inventoried Contract Costs, are stated at cost (first-in, first-out or average cost), but not in excess of realizable value. A provision for excess, obsolete or inactive inventory is recorded based upon an analysis that considers current inventory levels, historical usage patterns and future sales expectations.
Property, Plant and Equipment	Property, Plant and Equipment: Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed by generally applying the straight-line method to the estimated useful lives of the related assets. Useful lives generally range from 10 to 40 years for buildings and improvements and three to 10 years for machinery, equipment, furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. When property, plant or equipment is retired or otherwise disposed of, the net book value of the asset is removed from the Company’s balance sheet and the net gain or loss is included in the determination of operating income. Property, plant and equipment acquired as part of a business acquisition is recorded at fair value.
Goodwill and Indefinite-lived Intangible Assets	Goodwill and Indefinite-lived Intangible Assets: The carrying value of goodwill and indefinite-lived identifiable intangible assets are not amortized, but are tested for impairment annually as of November 30 and, additionally on an interim basis, whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable. The accounting standards for goodwill allow for the assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company utilized a qualitative assessment approach for the November 30, 2018 goodwill impairment test for all of its identified reporting units. For each of the reporting units, the Company determined that it was not more likely than not that the fair values were less than their net book values. If the Company does not utilize a qualitative assessment approach, then the quantitative goodwill impairment test is utilized to identify potential impairments. The Company identifies any potential impairment by comparing the carrying value of a reporting unit to its fair value. The Company determines the fair value of its reporting units using a discounted cash flow valuation approach. If a potential impairment is identified, the Company will determine the amount of goodwill impairment by comparing the fair value of a reporting unit with its carrying amount. To the extent the carrying value of a reporting unit exceeds its fair value, a goodwill impairment charge is recognized. The annual impairment tests at November 30, 2018 and 2017 did not result in impairments to goodwill.
Identifiable Intangible Assets	Identifiable Intangible Assets: Identifiable intangible assets represent assets acquired as part of the Company’s business acquisitions and include customer contractual relationships, technology, in-process research and development (IPR&D), favorable leasehold interests and trade names. The initial measurement of these intangible assets is based on their fair values. Identifiable intangible assets are: (1) tested for impairment whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable and (2) amortized over their estimated useful lives as the economic benefits are consumed. The Company reviews and updates its estimates of the duration of its customer contractual relationships. If the Company’s current estimates indicate that the duration of its customer contractual relationships have decreased, then the Company adjusts the remaining amortization period for those customer contractual relationships to their remaining useful economic life.
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. 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 U.S. dollar, the Canadian dollar, the Euro, the United Arab Emirates dirham and the British pound. 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 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 accumulated other comprehensive income (loss) (accumulated OCI) 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.
Treasury Stock	Treasury Stock: The Company records treasury stock purchases at cost, which includes incremental direct transaction costs.
Translation of Foreign Currency and Foreign Currency Transactions	Translation of Foreign Currency and Foreign Currency Transactions: Transactions in foreign currencies are translated into the local (functional) currency of the respective business at the approximate prevailing rate at the time of the transaction. Foreign exchange transaction gains and losses in the years ended December 31, 2018 , 2017 and 2016 were not material to the Company’s results of operations. The operations of the Company’s foreign subsidiaries are translated from the local (functional) currencies into U.S. dollars using weighted average rates of exchange during each reporting period. The rates of exchange at each balance sheet date are used for translating the assets and liabilities of the Company’s foreign subsidiaries. Gains or losses resulting from these translation adjustments are included in the balance sheets as a component of accumulated OCI and are only recognized in income when a foreign subsidiary is divested.
New Accounting Pronouncements Implemented and Not Yet Implemented	Accounting Standards Issued and Not Yet Implemented: In February 2018, the Financial Accounting Standards Board (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's 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). The Company will measure and recognize its existing leases on the date of adoption based on the present value of the remaining minimum lease payments, as defined in existing guidance on accounting for leases. 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. The Company elected to use a modified retrospective approach for leases that exist or were entered into after the beginning of the earliest comparative period in the financial statements, with certain practical expedients available, and will recognize a cumulative-effect adjustment to the opening balance of retained earnings at January 1, 2019. The Company expects the standard to result in an increase of approximately $650 million to the Company's assets and liabilities for right-of-use assets and lease liabilities, but does not expect ASU 2016-02 to have an impact on its results of operations or cash flows. The Company does not expect the cumulative effect adjustment to the opening balance of retained earnings at January 1, 2019 to be material. See Note 19 for additional information about the Company’s leases, including the future minimum lease payments of the Company's operating leases at December 31, 2018. 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. New Accounting Standards Implemented: Effective January 1, 2018, the Company adopted 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, by $11 million for the year ended December 31, 2018 and increased operating income and decreased interest and other income, net, each by $11 million and $1 million for the years ended December 31, 2017 and 2016, respectively. The adoption of this standard did not impact pre-tax income for the years ended December 31, 2018, 2017 and 2016. 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 year ended December 31, 2018. In May 2014, the FASB issued ASU 2014-09 (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. 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 , the accounting standard in effect for periods ending prior to January 1, 2018. 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 to comply with ASC 606 presentation requirements. Specifically, 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 work in process 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.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Change in Accounting Estimate	The aggregate impact of net changes in contract estimates is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Operating income $ 213 $ 185 $ 149 Diluted earnings per share $ 2.03 $ 1.49 $ 1.23
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	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 table below presents the impact of the adoption of ASC 606 on the Company's statement of operations. Year Ended December 31, 2018 STATEMENT OF OPERATIONS Under ASC 605 Effect of ASC 606 As Reported Under ASC 606 (in millions) Net Sales: Products $ 7,004 $ 161 $ 7,165 Services 3,101 (22 ) 3,079 Total 10,105 139 10,244 Operating costs and expenses: Cost of sales — Products $ (5,235 ) $ (110 ) $ (5,345 ) Cost of sales — Services (2,193 ) 1 (2,192 ) General and administrative expenses (1,598 ) (3 ) (1,601 ) Gain on sale of the Crestview & TCS Businesses 41 1 42 Merger and acquisition related expenses (28 ) — (28 ) Operating income 1,092 28 1,120 Income from continuing operations before income taxes 896 28 924 Provision for income taxes (96 ) (7 ) (103 ) Income from continuing operations 800 21 821 Income from discontinued operations, net of income taxes 214 (9 ) 205 Net income 1,014 12 1,026 Net income attributable to L3 $ 993 $ 12 $ 1,005 Basic earnings per share attributable to common shareholders: Continuing operations $ 9.92 $ 0.27 $ 10.19 Discontinued operations 2.73 (0.12 ) 2.61 Basic earnings per share $ 12.65 $ 0.15 $ 12.80 Diluted earnings per share attributable to common shareholders: Continuing operations $ 9.79 $ 0.26 $ 10.05 Discontinued operations 2.69 (0.11 ) 2.58 Diluted earnings per share $ 12.48 $ 0.15 $ 12.63 The following table quantifies the impact of adopting ASC 606 on segment net sales and segment operating income. Effect of ASC 606 Year Ended December 31, 2018 Sales Operating Income (in millions) ISRS $ 21 $ 1 C&NS 68 12 Electronic Systems 50 14 Segment totals $ 139 $ 27 The table below presents the impact of the adoption of ASC 606 on the Company's balance sheet. December 31, 2018 BALANCE SHEET Under Effect of As Reported Under ASC 606 (in millions) Assets Current assets: Contract assets $ — $ 1,590 $ 1,590 Contracts in process 2,127 (2,127 ) — Inventories 393 486 879 Prepaid expenses and other current assets 340 16 356 Total current assets 4,845 (35 ) 4,810 Other assets 295 46 341 Total assets $ 13,507 $ 11 $ 13,518 Liabilities Current liabilities: Accrued expenses $ 275 $ (24 ) $ 251 Contract liabilities — 669 669 Advance payments and billings in excess of costs incurred 604 (604 ) — Income taxes payable 53 (4 ) 49 Other current liabilities 364 (76 ) 288 Total current liabilities 2,486 (39 ) 2,447 Deferred income taxes 185 11 196 Other liabilities 422 14 436 Total liabilities 7,625 (14 ) 7,611 Shareholders' Equity Retained earnings 7,399 25 7,424 Total equity $ 5,882 $ 25 $ 5,907 The aggregate impact of net changes in contract estimates is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Operating income $ 213 $ 185 $ 149 Diluted earnings per share $ 2.03 $ 1.49 $ 1.23
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 year ended December 31, 2018 . % of Total Net Sales Over time (cost-to-cost method) 74 % Point in time 19 % Output method 4 % Billing method 3 % Total 100 %
Changes in Company's Accrued Product Warranty Costs	The table below presents the changes in the Company’s accrued product warranty costs. Year Ended December 31, 2018 2017 (in millions) Accrued product warranty costs (1) : Balance at January 1 $ 99 $ 109 Acquisitions during the period — 3 Accruals for product warranties issued during the period 44 52 Changes to accruals for product warranties existing before January 1 1 — Settlements made during the period (55 ) (66 ) Foreign currency translation adjustments (1 ) 1 Balance at December 31 $ 88 $ 99 __________________ (1) The balances above include both the current and non-current amounts.

Acquisitions, Divestitures an_2

Acquisitions, Divestitures and Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales and Income Before Income Taxes for Kigre, G-Air, Doss Aviation, Adaptive Methods, Open Water Power, OceanServer and ETD Business	Net sales and income before income taxes for ASV Global, C.K. Industrial Engineers, Azimuth Security, Linchpin Labs, Applied Defense Solutions and Latitude Engineering, included in L3’s consolidated statement of operations for the year ended December 31, 2018 , are presented in the table below. Year Ended (in millions) Net sales $ 46 Loss before income taxes (1) $ (7 ) __________________ (1) Includes intangible amortization of $7 million and IRAD expense of $1 million .
Unaudited Pro Forma Statements of Operations Data	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. Year Ended December 31, 2018 2017 (in millions, except per share data) Pro forma net sales $ 10,324 $ 9,741 Pro forma income from continuing operations attributable to L3 $ 805 $ 756 Pro forma net income attributable to L3 $ 1,010 $ 680 Pro forma diluted earnings per share from continuing operations $ 10.11 $ 9.50 Pro forma diluted earnings per share $ 12.69 $ 8.54
Components of Pre-tax (Loss) Gain Recognized, Proceeds Received and Net Sales Included in Continuing Operations From Business Divestitures	The table below presents pre-tax (loss) gain recognized, the proceeds received and net sales included in continuing operations from these divestitures. Year Ended December 31, 2017 Pre-Tax Proceeds 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
Net Sales and Income Before Income Taxes for Aviation Jet Services, Coleman, the Display Product Line, MSI, BSI, the Tinsley Product Line and Klein	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. Year Ended December 31, 2017 2016 (in millions) Net sales $ 10 $ 59 Income before income taxes $ 2 $ 8
Discontinued Operations, 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	The table below presents Crestview & TCS Businesses’ results of operations, which is included in continuing operations. Year Ended December 31, 2018 2017 2016 (in millions) Net sales $ 64 $ 119 $ 166 Gain on sale of businesses $ 42 $ — $ — Income from continuing operations before income taxes $ 45 $ (2 ) $ 12
Major Classes of Assets and Liabilities Included as Discontinued Operations/Held For Sale	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
Vertex Aerospace and NSS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Major Classes of Assets and Liabilities Included as Discontinued Operations/Held For Sale	The table below presents the statements of operations data for Vertex Aerospace and NSS. 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 their net assets to the sum of: (1) total L3 consolidated net assets and (2) L3 consolidated total debt. Year Ended December 31, 2018 2017 2016 (in millions) Net sales $ 597 $ 1,429 $ 1,402 Operating costs and expenses (1) (561 ) (1,531 ) (1,357 ) Operating income (loss) from discontinued operations 36 (102 ) 45 Interest expense allocated to discontinued operations (1 ) (2 ) (5 ) Gain on sale of businesses 234 — 64 Income (loss) from discontinued operations before income taxes 269 (104 ) 104 Income tax (expense) benefit (64 ) 28 (13 ) Income (loss) from discontinued operations, net of income taxes $ 205 $ (76 ) $ 91 __________________ (1) Due to a decline in estimated fair value, the Company recorded a goodwill impairment charge of $187 million during 2017 related to Vertex Ae
Vertex Aerospace [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Major Classes of Assets and Liabilities Included as Discontinued Operations/Held For Sale	The major classes of assets and liabilities 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 were not expected to be used to pay down long-term debt. As discussed above, since the sale of NSS was completed on February 1, 2016, the balances below exclude NSS. 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

Contract Assets and Contract _2

Contract Assets and Contract Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability	The table below presents the components of net contract assets. December 31, January 1, (in millions) Contract assets $ 1,590 $ 1,349 Contract liabilities — current (669 ) (565 ) Contract liabilities — non-current (31 ) (28 ) Net contract assets $ 890 $ 756
Components of Contract Assets	The components of contract assets are presented in the table below. December 31, January 1, (in millions) Unbilled contract receivables, gross $ 2,716 $ 2,232 Unliquidated progress payments and advances (1,126 ) (883 ) Total contract assets $ 1,590 $ 1,349

Contracts in Process (Tables)

Contracts in Process (Tables)	12 Months Ended
	Dec. 31, 2018
Contractors [Abstract]
Components of Contracts in Process	The components of contracts in process are presented in the table below. The unbilled contract receivables, inventoried contract costs and unliquidated progress payments principally relate to contracts with the U.S. Government and prime contractors or subcontractors of the U.S. Government. 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 periods presented. Year Ended December 31, 2017 2016 (in millions) Amounts included in inventoried contract costs at beginning of the year $ 173 $ 137 Contract costs incurred: IRAD and B&P 333 304 Other G&A 842 749 Total 1,175 1,053 Amounts charged to operating costs and expenses (1,179 ) (1,017 ) Amounts included in inventoried contract costs at end of the year $ 169 $ 173

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Inventories at Lower of Cost or Realizable Value	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 5 for additional information. In accordance with ASC 606, all work in process relating to goods that customers do not currently control are classified within inventories on the Company's consolidated balance sheet at December 31, 2018 , without regard to whether the goods are standard or customized. December 31, 2018 2017 (in millions) Raw materials, components and sub-assemblies $ 351 $ 184 Work in process 330 98 Finished goods 198 107 Total $ 879 $ 389

Goodwill and Identifiable Int_2

Goodwill and Identifiable Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 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. ISRS C&NS Electronic Consolidated (in millions) December 31, 2016 Goodwill $ 2,512 $ 1,883 $ 2,083 $ 6,478 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) 2,466 1,868 2,040 6,374 Business acquisitions (1) 8 73 131 212 Business divestitures (2) — — (12 ) (12 ) Foreign currency translation adjustments 26 21 46 93 Assets held for sale (3) (42 ) — (10 ) (52 ) December 31, 2017 Goodwill 2,504 1,977 2,238 6,719 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) 2,458 1,962 2,195 6,615 Business acquisitions (1) 158 56 33 247 Foreign currency translation adjustments (20 ) (11 ) (23 ) (54 ) December 31, 2018 Goodwill 2,634 2,022 2,248 6,904 Accumulated impairment losses (46 ) (15 ) (43 ) (104 ) $ 2,596 $ 2,007 $ 2,205 $ 6,808 __________________ (1) For the year ended December 31, 2018 , business acquisitions for the ISRS segment included the acquisitions of the Azimuth Security and Linchpin Labs and Applied Defense Solutions businesses and the purchase price allocation adjustments for the Kigre business acquisition. Business acquisitions for the C&NS segment included the acquisitions of the ASV Global business and purchase price allocation adjustments for the Adaptive Methods business acquisition. Business acquisitions for the Electronic Systems segment included the acquisitions of the Latitude Engineering and C.K. Industrial Engineers businesses and purchase price allocation adjustments for the G-Air and Doss Aviation business acquisitions. For the year ended December 31, 2017 , business acquisitions for the ISRS segment included primarily the Kigre business acquisition. Business acquisitions for the C&NS segment included primarily the Adaptive Methods, Open Water Power, and OceanServer business acquisitions. Business acquisitions for the Electronic Systems segment included the acquisitions of the ETD, Doss Aviation and G-Air businesses and purchase price allocation adjustments for the MacH and Aerosim business acquisitions. (2) The decrease for the Electronic Systems segment was due to the divestitures of Coleman and Aviation Jet Services during the quarterly period ended March 31, 2017. (3) The Crestview & TCS businesses from the Company’s ISRS segment were classified as held for sale as of December 31, 2017.
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. December 31, 2018 December 31, 2017 Weighted Average Gross Accumulated Net Gross Accumulated Net (in years) (in millions) Customer contractual relationships 16 $ 468 $ 288 $ 180 $ 393 $ 257 $ 136 Technology 9 245 132 113 189 114 75 Other 9 49 18 31 29 14 15 Total subject to amortization 762 438 324 611 385 226 IPR&D indefinite 66 — 66 66 — 66 Total $ 828 $ 438 $ 390 $ 677 $ 385 $ 292
Amortization Expense	The table below presents amortization expense recorded by the Company for its identifiable intangible assets. Year Ended December 31, 2018 2017 2016 (in millions) Amortization expense $ 49 $ 43 $ 33
Estimated Amortization Expense	Based on gross carrying amounts at December 31, 2018 , the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2019 through 2023 is presented in the table below. Year Ending December 31, 2019 2020 2021 2022 2023 (in millions) Estimated amortization expense $ 51 $ 47 $ 42 $ 37 $ 28

Other Current Liabilities and_2

Other Current Liabilities and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	The table below presents the components of other current liabilities. December 31, 2018 2017 (in millions) Other Current Liabilities: Accrued product warranty costs $ 66 $ 69 Estimated costs in excess of estimated contract value to complete contracts in process in a loss position 40 63 Accrued interest 18 43 Estimated contingent purchase price payable for acquired businesses (see Note 13) 10 11 Deferred revenues — 38 Other 154 143 Total other current liabilities $ 288 $ 367
Other Liabilities	The table below presents the components of other liabilities. December 31, 2018 2017 (in millions) Other Liabilities: Non-current income taxes payable (see Note 17) $ 161 $ 164 Deferred compensation 53 49 Notes payable and capital lease obligations 40 16 Contract liabilities (see Note 4) 31 — Accrued product warranty costs 22 30 Accrued workers’ compensation 20 23 Estimated contingent purchase price payable for acquired businesses (see Note 13) 10 20 Deferred revenues — 19 Other 99 77 Total other liabilities $ 436 $ 398

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The table below presents the components of property, plant and equipment. December 31, 2018 2017 (in millions) Land $ 34 $ 34 Buildings and improvements 428 404 Machinery, equipment, furniture and fixtures 2,081 1,959 Leasehold improvements 407 376 Gross property, plant and equipment 2,950 2,773 Accumulated depreciation and amortization (1,781 ) (1,663 ) Property, plant and equipment, net $ 1,169 $ 1,110

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 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 long-term debt is presented in the table below. December 31, 2018 2017 (in millions) Borrowings under Revolving Credit Facility (1) $ — $ — 5.20% Senior Notes due 2019 — 1,000 4.75% Senior Notes due 2020 — 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 3,350 3,350 Unamortized discounts (7 ) (7 ) Deferred debt issue costs (22 ) (13 ) Carrying amount of long-term debt $ 3,321 $ 3,330 __________________ (1) During 2018 , L3's aggregate borrowings and repayments under the Credit Facility were $501 million . L3 had the full availability of its $1 billion Credit Facility at December 31, 2018 and December 31, 2017
Information Regarding Outstanding Senior Subordinated Notes	The senior notes are unsecured senior obligations of L3. The terms of each outstanding senior note are presented in the table below. Note Date of Issuance Amount Issued Discount (1) Net Cash Proceeds Effective Interest Rate Redemption at Treasury Rate (2)(3) (dollars in millions) 4.95% Senior Notes due February 15, 2021 February 7, 2011 $ 650 $ 4 $ 639 5.02 % 25 bps 3.85% Senior Notes due June 15, 2023 (4) June 6, 2018 $ 800 $ 2 $ 792 3.89 % 20 bps 3.95% Senior Notes due May 28, 2024 (5) May 28, 2014 $ 650 $ 3 $ 641 4.02 % 20 bps 3.85% Senior Notes due December 15, 2026 December 5, 2016 $ 550 $ 3 $ 542 3.91 % 25 bps 4.40% Senior Notes due June 15, 2028 (4) 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 senior notes maturing in 2023 may be redeemed at any time prior to May 15, 2023 (one month prior to maturity) and the senior notes maturing in 2021, 2024, 2026 and 2028 may be redeemed at any time prior to November 15, 2020, February 28, 2024, September 15, 2026 and March 15, 2028, respectively, (three months prior to their 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 senior notes maturing in 2021, 2023, 2024, 2026 and 2028 are redeemed at any time on or after November 15, 2020, May 15, 2023, February 28, 2024, September 15, 2026 and March 15, 2028, respectively, the redemption price would be equal to 100% of the principal amount. (3) Upon the occurrence of a change in control (as defined in the indentures governing the senior notes) along with a “change of control triggering event” (generally described as the applicable series of senior notes ceasing to be rated investment grade, 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. (4) 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. (5) On December 22, 2015, the Company repurchased $300 million of the 3.95% Senior Notes
Repurchases, Redemptions and Maturities of Senior Notes	of Senior Notes The repurchases, redemptions and maturities of senior notes are presented in the table below. Note Settlement Type Date Settled Aggregate Amount Premium Cash Payments Interest Total Cash Payments Debt Charge (dollars in millions) 5.20% Senior Notes due 2019 (1) Redemption July 6, 2018 $ 317 103.048 % $ 327 $ 4 $ 331 $ 10 4.75% Senior Notes due 2020 (1) Redemption July 6, 2018 $ 265 103.818 % $ 275 $ 6 $ 281 $ 11 5.20% Senior Notes due 2019 (2) Tender Offer June 6, 2018 $ 683 103.282 % $ 705 $ 5 $ 710 $ 24 4.75% Senior Notes due 2020 (2) Tender Offer June 6, 2018 $ 535 104.092 % $ 557 $ 10 $ 567 $ 24 1.50% Senior Notes due 2017 Redemption December 30, 2016 $ 350 100.323 % $ 351 $ 1 $ 352 $ 2 3.95% Senior Notes due 2016 Maturity November 15, 2016 $ 200 100.000 % $ 200 $ — $ 200 $ — 3.95% Senior Notes due 2016 Redemption May 20, 2016 $ 300 101.475 % $ 305 $ — $ 305 $ 5 __________________ (1) The debt retirement charge includes $1 million which represents the non-cash retirement of associated unamortized debt issue costs and discounts. (2) Cash payments exclude $1 million of tender offer fees. 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 co

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive (Loss) Income (AOCI) (Tables)	12 Months Ended
	Dec. 31, 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 Unrealized Unrecognized Total (in millions) Balance at December 31, 2015 $ (101 ) $ (8 ) $ (465 ) $ (574 ) Other comprehensive (loss) income before reclassifications, net of tax (77 ) 3 (119 ) (193 ) Amounts reclassified from AOCI, net of tax — 11 30 41 Net current period other comprehensive (loss) income (77 ) 14 (89 ) (152 ) Balance at December 31, 2016 $ (178 ) $ 6 $ (554 ) $ (726 ) Other comprehensive income (loss) before reclassifications, net of tax 124 7 (137 ) (6 ) Amounts reclassified from AOCI, net of tax — (4 ) 45 41 Net current period other comprehensive income (loss) 124 3 (92 ) 35 Balance at December 31, 2017 $ (54 ) $ 9 $ (646 ) $ (691 ) Other comprehensive loss before reclassifications, net of tax (82 ) (17 ) 14 (85 ) Amounts reclassified from AOCI, net of tax — (2 ) 53 51 Net current period other comprehensive (loss) income (82 ) (19 ) 67 (34 ) Balance at December 31, 2018 $ (136 ) $ (10 ) $ (579 ) $ (725 )
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 Year Ended December 31, Details About AOCI Components 2018 2017 2016 (in millions) Gain (loss) on hedging instruments $ 3 $ 5 $ (13 ) Cost of sales-products 3 5 (13 ) Income from continuing operations before income taxes (1 ) (1 ) 2 Provision for income taxes $ 2 $ 4 $ (11 ) Income from continuing operations Amortization of defined benefit pension and postretirement items: Net loss (b) $ (68 ) $ (59 ) $ (48 ) Income from continuing operations before income taxes 15 14 18 Provision for income taxes $ (53 ) $ (45 ) $ (30 ) Income from continuing operations Total reclassification for the period $ (51 ) $ (41 ) $ (41 ) Income from continuing operations __________________ (a) Amounts in parentheses indicate charges to the 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).

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 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. December 31, 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 $ 660 $ — $ — $ 310 $ — $ — Derivatives (foreign currency forward contracts) — 1 — — 11 — Total assets $ 660 $ 1 $ — $ 310 $ 11 $ — Liabilities Derivatives (foreign currency forward contracts) $ — $ 17 $ — $ — $ 1 $ — Contingent consideration — — 20 — — 31 Total liabilities $ — $ 17 $ 20 $ — $ 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 year ended December 31, 2018 . December 31, 2018 (in millions) Balance at beginning of period $ 31 Acquisitions and investments 11 Cash payments (7 ) Changes in fair value of contingent consideration, net (15 ) Balance at end of period $ 20

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 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. December 31, 2018 December 31, 2017 Carrying Estimated Carrying Estimated (in millions) Senior notes (1) $ 3,321 $ 3,355 $ 3,330 $ 3,502 Foreign currency forward contracts (2) $ (16 ) $ (16 ) $ 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 15 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2018 . Currency Notional Amounts (in millions) U.S. dollar $ 204 Canadian dollar 123 Euro 67 United Arab Emirates dirham 12 British pound 9 Total $ 415
Location of Company's Derivative Instruments Recorded at Fair Value on the Consolidated Balance Sheets	The table below presents the location of the Company’s derivative instruments recorded at fair value on the consolidated balance sheets. December 31, 2018 December 31, 2017 Other Other Other Other Other Other Other Other (in millions) Derivatives designated as hedging instruments: Foreign currency forward contracts (1) $ 1 $ — $ 13 $ 4 $ 11 $ — $ 1 $ — Total derivative instruments $ 1 $ — $ 13 $ 4 $ 11 $ — $ 1 $ — __________________ (1) See Note 13 for a description of the fair value hierarchy related to the Company's foreign currency forward contracts.

L3's Earnings Per Share (Tables

L3's Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 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. Year Ended December 31, 2018 2017 2016 (in millions, except per share data) Reconciliation of net income: Net income $ 1,026 $ 693 $ 724 Net income from continuing operations attributable to noncontrolling interests (21 ) (16 ) (14 ) Net income attributable to L3’s common shareholders $ 1,005 $ 677 $ 710 Earnings (loss) attributable to L3’s common shareholders: Continuing operations $ 800 $ 753 $ 619 Discontinued operations, net of income tax 205 (76 ) 91 Net income attributable to L3’s common shareholders $ 1,005 $ 677 $ 710 Earnings per share attributable to L3’s common shareholders: Basic: Weighted average common shares outstanding 78.5 78.0 77.4 Basic earnings (loss) per share: Continuing operations $ 10.19 $ 9.65 $ 7.99 Discontinued operations, net of income tax 2.61 (0.97 ) 1.18 Net income $ 12.80 $ 8.68 $ 9.17 Diluted: Common and potential common shares: Weighted average common shares outstanding 78.5 78.0 77.4 Effect of dilutive securities 1.1 1.6 1.4 Common and potential common shares 79.6 79.6 78.8 Diluted earnings (loss) per share: Continuing operations $ 10.05 $ 9.46 $ 7.86 Discontinued operations, net of income tax 2.58 (0.95 ) 1.15 Net income $ 12.63 $ 8.51 $ 9.01

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income from Continuing Operations Before Income Taxes	Income from continuing operations before income taxes is summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Domestic $ 630 $ 649 $ 608 Foreign 294 222 196 Income from continuing operations before income taxes $ 924 $ 871 $ 804
Components of Current and Deferred Portions of Provision for Income Taxes on Continuing Operations	The components of the Company’s current and deferred portions of the provision for income taxes on continuing operations are presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Current income tax provision: Federal $ 30 $ 44 $ 88 State and local 18 10 8 Foreign 62 56 48 Subtotal 110 110 144 Deferred income tax provision/(benefit): Federal (7 ) (16 ) 25 State and local — 6 2 Foreign — 2 — Subtotal (7 ) (8 ) 27 Total provision for income taxes $ 103 $ 102 $ 171
Reconciliation of Statutory Federal Income Tax Rate to Effective Income Tax Rate on Continuing Operations	A reconciliation of the statutory federal income tax rate to the effective income tax rate on continuing operations of the Company is presented in the table below. Year Ended December 31, 2018 2017 2016 Statutory federal income tax rate 21.0 % 35.0 % 35.0 % State and local income taxes, net of federal income tax benefit 2.6 2.0 2.0 Foreign income taxes (0.9 ) (6.7 ) (3.0 ) Manufacturing benefits — (1.4 ) (2.2 ) Research and experimentation and other tax credits (5.2 ) (4.1 ) (4.6 ) Resolution of tax contingencies (3.8 ) (0.4 ) (3.1 ) Tax deductible dividends (0.5 ) (0.9 ) (1.0 ) Equity compensation - excess income tax benefits (4.0 ) (2.3 ) (2.1 ) Mergers, acquisitions and divestitures 1.3 — — Tax reform (0.1 ) (9.1 ) — Other, net 0.7 (0.4 ) 0.3 Effective income tax rate on continuing operations 11.1 % 11.7 % 21.3 %
Components of Net Deferred Tax Assets and Liabilities	The significant components of the Company’s net deferred tax assets and liabilities are presented in the table below. December 31, 2018 2017 (in millions) Deferred tax assets: Inventoried costs $ 47 $ 44 Compensation and benefits 90 94 Pension and postretirement benefits 271 281 Loss carryforwards 13 12 Tax credit carryforwards 4 5 Other 67 57 Deferred tax assets 492 493 Less: valuation allowance (14 ) (10 ) Deferred tax assets, net of valuation allowance 478 483 Deferred tax liabilities: Goodwill and other intangible assets $ (549 ) $ (514 ) Income recognition on contracts in process (18 ) (24 ) Property, plant and equipment (66 ) (59 ) Other (36 ) (41 ) Deferred tax liabilities (669 ) (638 ) Total deferred tax liabilities, net of valuation allowance $ (191 ) $ (155 )
Classification of Deferred Tax Assets and Liabilities	The classification of the Company’s deferred tax assets and liabilities are presented in the table below. December 31, 2018 2017 (in millions) Non-current deferred tax assets $ 5 $ 3 Non-current deferred tax liabilities (196 ) (158 ) Total net deferred tax liabilities $ (191 ) $ (155 )
Summary of Loss and Tax Credit Carryforwards	The following table presents the Company’s loss and tax credit carryforwards at December 31, 2018 on a tax-return basis. The Company has established a valuation allowance as indicated in those instances in which it does not believe that it is more likely than not it will generate sufficient taxable income, of the appropriate character and in the applicable subsidiary, to utilize the carryforwards. Year Ended December 31, 2018 Carryforwards Valuation Allowances Gross Tax Gross Tax Expiration (in millions) Federal net operating loss carryforwards $ 23 $ 5 $ (5 ) $ (1 ) 2026-2034 Foreign net operating loss carryforwards 18 4 (10 ) (3 ) Indefinite State net operating loss carryforwards 291 4 (131 ) (3 ) 2019-2038 Total loss carryforwards $ 13 $ (7 ) State tax credit carryforwards 5 4 (4 ) (3 ) 2019-2033 Total tax credit carryforwards $ 4 $ (3 )
Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Interest and Penalties	At December 31, 2018 , the total amount of unrecognized tax benefits was $183 million , $150 million of which would reduce the effective income tax rate, if recognized. A reconciliation of the change in unrecognized income tax benefits, excluding potential interest and penalties, is presented in the table below. 2018 2017 2016 (in millions) Balance at January 1 $ 178 $ 110 $ 124 Additions for tax positions related to the current year 13 14 16 Additions for tax positions related to prior years 37 66 2 Reductions for tax positions related to prior years (20 ) (4 ) (24 ) Reductions for tax positions related to settlements with taxing authorities (7 ) — (1 ) Reduction for tax positions related to prior years as a result of a lapse of statute of limitations (18 ) (8 ) (7 ) Balance at December 31 $ 183 $ 178 $ 110

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense by Form of Award	The Company’s stock-based compensation expense by form of award, including stock-based compensation recorded in discontinued operations related to Vertex Aerospace and NSS, is presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) Stock options $ 7 $ 7 $ 10 Restricted stock units 43 43 35 Performance units 10 7 4 Total before income taxes 60 57 49 Income taxes (13 ) (12 ) (18 ) Total after income taxes 47 45 31 Less: Stock-based compensation recorded in discontinued operations, net of income taxes — 1 1 Stock-based compensation recorded in continuing operations, net of income taxes $ 47 $ 44 $ 30
Company's Stock Option Activity and Changes	The table below presents a summary of the Company’s stock option activity at December 31, 2018 and changes during the year then ended. Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in thousands) (in years) (in millions) Number of shares under option: Outstanding at January 1, 2018 2,698.9 $ 113.67 5.7 $ 227 Options granted 221.9 208.92 Options exercised (1,533.4 ) 97.49 Options forfeited (175.7 ) 147.37 Outstanding at December 31, 2018 1,211.7 $ 146.70 6.4 $ 42 Vested and expected to vest at December 31, 2018 (1) 1,205.6 $ 146.48 6.4 $ 42 Exercisable at December 31, 2018 666.1 $ 119.03 4.7 $ 37 __________________ (1) Represents outstanding options reduced by expected forfeitures for options not fully vested.
Weighted Average Assumptions in Valuation Model	The weighted average assumptions used in the valuation model are presented in the table below. 2018 Grants 2017 Grants 2016 Grants Expected holding period (in years) 5.2 5.2 5.0 Expected volatility 19.8 % 19.9 % 21.3 % Expected dividend yield 1.8 % 2.0 % 2.8 % Risk-free interest rate 2.7 % 2.0 % 1.1 %
Company's Nonvested Restricted Stock Unit Awards and Changes	The table below presents a summary of the Company’s nonvested restricted stock unit awards at December 31, 2018 and changes during the year then ended. Number of Shares Weighted Average Grant Date Fair Value (in thousands) Nonvested balance at January 1, 2018 902.7 $ 137.12 Granted 317.9 205.73 Vested (320.7 ) 137.00 Forfeited (86.2 ) 142.21 Nonvested balance at December 31, 2018 813.7 $ 163.44
Company's Performance Unit Awards Based on Expected Performance	The table below presents a summary of the Company’s performance unit awards based on expected performance at December 31, 2018 and changes during the year then ended. Payable in Shares (EPS) Number of Weighted Average (in thousands) Outstanding at January 1, 2018 132.1 $ 135.99 Granted 22.1 209.91 Increase due to expected performance 25.3 38.96 Vested (57.5 ) 116.20 Forfeited (27.0 ) 133.41 Outstanding at December 31, 2018 95.0 $ 140.14

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Payments under Non-Cancelable Operating Leases	The following table presents future minimum payments under non-cancelable operating leases with initial or remaining terms in excess of one year at December 31, 2018 . Real Estate Equipment Total (in millions) 2019 $ 111 $ 4 $ 115 2020 132 2 134 2021 81 1 82 2022 73 — 73 2023 65 — 65 Thereafter 506 — 506 Total minimum payments required 968 7 975 Sublease rentals under non-cancelable leases (7 ) — (7 ) Net minimum payments required $ 961 $ 7 $ 968

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Changes in Benefit Obligations, Plan Assets and Funded Status and Aggregate Balance Sheet Impact	The following table summarizes changes in the benefit obligations, the plan assets and funded status for all of the Company’s pension and postretirement benefit plans, as well as the aggregate balance sheet impact. Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 (in millions) Change in benefit obligation: Benefit obligation at the beginning of the year $ 4,228 $ 3,758 $ 165 $ 177 Service cost 103 97 2 2 Interest cost 143 142 5 5 Plan participants’ contributions 2 2 5 5 Amendments (13 ) — — — Actuarial (gain) loss (340 ) 391 (11 ) (13 ) Foreign currency exchange rate changes (27 ) 22 (2 ) 2 Curtailments and special termination benefits — 2 — — Benefits paid (159 ) (186 ) (14 ) (13 ) Benefit obligation at the end of the year $ 3,937 $ 4,228 $ 150 $ 165 Change in plan assets: Fair value of plan assets at the beginning of the year $ 3,047 $ 2,721 $ 67 $ 60 Actual return on plan assets (119 ) 391 (3 ) 8 Employer contributions 96 97 6 7 Plan participants’ contributions 2 2 5 5 Foreign currency exchange rate changes (27 ) 22 — — Benefits paid (159 ) (186 ) (14 ) (13 ) Fair value of plan assets at the end of the year $ 2,840 $ 3,047 $ 61 $ 67 Unfunded status at the end of the year $ (1,097 ) $ (1,181 ) $ (89 ) $ (98 ) Assets and (liabilities) recognized on the consolidated balance sheets consist of: Non-current assets $ 40 $ 48 $ — $ — Current liabilities (8 ) (6 ) (7 ) (8 ) Non-current liabilities (1,129 ) (1,223 ) (82 ) (90 ) $ (1,097 ) $ (1,181 ) $ (89 ) $ (98 )
Net Loss and Prior Service Cost Balances in Accumulated Other Comprehensive Loss Account	The table below summarizes the net loss and prior service cost balances at December 31, in the accumulated other comprehensive loss account, before related tax effects, for all of the Company’s pension and postretirement benefit plans. Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 (in millions) Net loss (gain) $ 958 $ 1,035 $ (3 ) $ (3 ) Prior service (credit) cost (1 ) 10 (25 ) (27 ) Total amount recognized $ 957 $ 1,045 $ (28 ) $ (30 )
Pension Plans with an Accumulated Benefit Obligation in Excess of Fair Value of Plan Assets	The table below presents information for the pension plans with an ABO in excess of the fair value of plan assets at December 31, 2018 and 2017 . Pension Plans 2018 2017 (in millions) Projected benefit obligation $ 3,681 $ 3,875 Accumulated benefit obligation $ 3,367 $ 3,490 Fair value of plan assets $ 2,547 $ 2,651
Weighted Average Assumptions Used to Determine Benefit Obligations	The table below summarizes the weighted average assumptions used to determine the benefit obligations for the Company’s pension and postretirement plans disclosed at December 31, 2018 and 2017 . Pension Plans Postretirement Benefit Plans 2018 2017 2018 2017 Benefit obligations: Discount rate 4.43 % (1) 3.78 % (1) 4.28 % (2) 3.59 % (2) Rate of compensation increase 3.50 % (3) 3.50 % (3) __________________ (1) The weighted average discount rate assumptions used at December 31, 2018 and 2017 were comprised of separate assumptions determined by country of 4.48% and 3.81% for the U.S. based plans, respectively, and 3.88% and 3.39% for the Canadian based plans, respectively. (2) The weighted average discount rate assumptions used at December 31, 2018 and 2017 were comprised of separate assumptions determined by country of 4.34% and 3.63% for the U.S. based plans, respectively, and 3.81% and 3.33% for the Canadian based plans, respectively. (3) The weighted average rate of compensation increase assumptions were comprised of separate assumptions determined by country of 3.5% for both the U.S. based plans and Canadian based plans at December 31, 2018 and 2017 .
Components of Net Periodic Benefit Cost	The following table summarizes the components of net periodic benefit cost for the Company’s pension and postretirement benefit plans for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 (in millions) Components of net periodic benefit cost: Service cost (1) $ 103 $ 97 $ 94 $ 2 $ 2 $ 2 Interest cost 143 142 135 5 5 6 Expected return on plan assets (1) (223 ) (197 ) (186 ) (5 ) (4 ) (4 ) Amortization of prior service (credits) cost (2 ) 1 — (1 ) (1 ) (2 ) Amortization of net loss (gains) 74 61 52 (3 ) (2 ) (2 ) Curtailment loss and special termination benefits (2) 1 6 2 — — — Net periodic benefit cost $ 96 $ 110 $ 97 $ (2 ) $ — $ — __________________ (1) In connection with the adoption of ASU 2017-07, the Company reclassified pension plan administrative expenses amounting to $15 million and $14 million for the years ended December 31, 2017 and 2016, respectively, from the service cost component to the expected return on plan assets component of net periodic benefit cost. Including the aforementioned policy change in connection with the adoption of this standard, operating income increased by $11 million and $1 million for the years ended December 31, 2017 and 2016, respectively, with a corresponding decrease of Interest and other income, net. The Company’s percentage assumptions for expected long-term return on plan assets, which are disclosed further below, exclude expected plan administrative expenses. (2) During the year ended December 31, 2017, the curtailment loss and special termination benefits charge is primarily due to a pension curtailment charge in connection with the decision to discontinue future service accruals for substantially all salaried employee defined benefit plans effective January 1, 2019.
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss)	The following table summarizes the other changes in plan assets and benefit obligations recognized in other comprehensive income for the Company’s pension and postretirement benefit plans for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 (in millions) Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): Net (gain) loss $ (3 ) $ 200 $ 179 $ (2 ) $ (17 ) $ (4 ) Prior service (cost) credit (13 ) (4 ) 15 — — (2 ) Amortization of net (loss) gain (74 ) (61 ) (52 ) 3 2 2 Amortization of prior service credit (cost) 2 (1 ) — 1 1 2 Total recognized in other comprehensive (loss) income (88 ) 134 142 2 (14 ) (2 ) Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 8 $ 244 $ 239 $ — $ (14 ) $ (2 )
Amounts Expected to be Amortized from Accumulated OCI and Recognized as Components of Net Periodic Benefit Costs	The following table summarizes the amounts expected to be amortized from accumulated OCI and recognized as components of net periodic benefit costs during 2019 . Pension Plans Postretirement Benefit Plans Total (in millions) Net loss (gain) $ 44 $ (3 ) $ 41 Prior service credit (2 ) — (2 ) $ 42 $ (3 ) $ 39
Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost	The table below summarizes the weighted average assumptions used to determine the net periodic benefit cost for the years ended December 31, 2018 , 2017 and 2016 . Pension Plans Postretirement Benefit Plans 2018 2017 2016 2018 2017 2016 Discount rates: Benefit obligation 3.78 % (1) 4.40 % (1) 4.67 % (1) 3.59 % (4) 4.05 % (4) 4.22 % (4) Service cost 3.84 % 4.55 % 4.83 % 3.64 % 4.21 % 4.37 % Interest cost 3.45 % 3.84 % 3.95 % 3.07 % 3.26 % 3.26 % Expected long-term return on plan assets 7.92 % (2) 7.92 % (2) 7.92 % (2) 8.00 % 7.43 % 7.42 % Rate of compensation increase 3.50 % (3) 3.50 % (3) 3.50 % (3) __________________ (1) The weighted average discount rate assumptions used for the years ended December 31, 2018 , 2017 , and 2016 were comprised of separate assumptions determined by country of 3.81% , 4.45% and 4.73% for the U.S. based plans and 3.39% , 3.79% and 3.93% for the Canadian based plans, respectively. (2) The weighted average expected long-term return on plan assets assumptions used were comprised of separate assumptions determined by country of 8.00% for the years ended December 31, 2018 , 2017 and 2016 for the U.S. based plans and 7.25% for the Canadian based plans for the years ended December 31, 2018 , 2017 and 2016 . (3) The weighted average rate of compensation increase assumptions used for the years ended December 31, 2018 , 2017 and 2016 were comprised of separate assumptions determined by country of 3.50% for both the U.S and Canadian based plans. (4) The weighted average discount rate assumptions used for the years ended December 31, 2018 , 2017 and 2016 were comprised of separate assumptions determined by country of 3.63% , 4.11% and 4.28% for the U.S. based plans and 3.33% , 3.64% and 3.74% for the Canadian based plans, respectively.
Effect of One Percentage Point Change in Assumed Health Care Cost Trend Rates	A one percentage point change in the assumed health care cost trend rates would have the following effects: 1 percentage point Increase Decrease (in millions) Effect on total service and interest cost $ — $ — Effect on postretirement benefit obligations $ 4 $ (4 )
Allowable Range for Each Major Category of the Plans' Assets and Weighted-Average Asset Allocations by Asset Category	The table below presents the allowable range for each major category of the plans’ assets at December 31, 2018 and the Company’s pension plan and postretirement benefit plan weighted-average asset allocations at December 31, 2018 and 2017 , by asset category. U.S. Canada Asset Category Range 2018 2017 Range 2018 2017 Domestic equity (1) 30%-60% 47 % 47 % —% 13 % 15 % International equity (2) 10%-20% 10 11 — 52 47 Total equities 45%-75% 57 58 40%-80% 65 62 Fixed income securities 20%-40% 30 28 — 28 25 Other, primarily cash and cash equivalents 0%-15% 6 7 — 7 13 Total fixed income securities and cash and cash equivalents NA NA NA 20%-60% 35 38 Real estate securities 0%-15% 7 7 — — — Total 100 % 100 % 100 % 100 % __________________ (1) Domestic equities for Canadian plans refers to equities of Canadian companies. (2) International equities for Canadian plans includes equities of U.S. companies. NA - Not applicable. The Company’s Master Pension Trust Investment Policy does not provide an allocation percentage range to fixed income securities and cash and cash equivalents.
Fair Value of the Company's Pension Plans' and Postretirement Benefit Plans' Assets	The table below presents the fair value of the Company’s postretirement benefit plans’ assets by asset category segregated by level within the fair value hierarchy, as described below. Postretirement Benefit Plans’ Assets Fair Value Measured At December 31, 2018 Fair Value Measured At December 31, 2017 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 35 $ — $ — $ 35 $ 38 $ — $ — $ 38 International Equity 1 — — 1 2 — — 2 Fixed Income — Investment Grade (2) 9 2 — 11 10 3 — 13 Fixed Income — High Yield (3) — 4 — 4 — 3 — 3 Real Estate Investment Trusts (4) 3 — — 3 3 — — 3 Other (5) — 4 — 4 — 5 — 5 Total assets at fair value $ 48 $ 10 $ — $ 58 $ 53 $ 11 $ — $ 64 Other investments measured at net asset value (6)(7) 3 3 Total $ 61 $ 67 __________________ (1) Equity securities consist of investments in common stock of U.S. and international companies. The fair value of equity securities is based on quoted market prices available in active markets at the close of a trading day, primarily the NYSE, NASDAQ, and various international exchanges. (2) Approximately 82% and 77% at December 31, 2018 and 2017 , respectively, of the postretirement benefit plan assets that are invested in the Fixed Income — Investment Grade asset category consist of the Fund and fixed income securities. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. These investments are classified by the Company as a Level 1 measurement within the fair value hierarchy as the mutual fund trades on an active market and daily, quoted prices are available. The remaining 18% and 23% at December 31, 2018 and 2017 , respectively, of the postretirement benefit plan assets are fixed income securities, primarily investment grade corporate bonds from various industries held directly by the plan. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs and are classified as Level 2. (3) Fixed Income — High Yield consists of investments in corporate high-yield bonds from various industries. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs. (4) REITs consist of securities that trade on the major exchanges and invest directly, either through properties or mortgages. (5) Other consists primarily of money market accounts, which invest primarily in short-term, high quality money market securities such as government obligations, commercial paper, time deposits and certificates of deposit. (6) In accordance with ASU 2015-07, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. (7) All of the postretirement benefit plans other investments measured using NAV at December 31, 2018 and 2017 consist of a regulated commingled equity trust fund, which fair value is based on NAV at the end of each month. The NAV is calculated by the fund manager based on the fair value of the fund’s holdings, primarily equity securities traded in active markets, determined as of the end of each month as a practical expedient to estimating fair value. This practical expedient is not used when it is determined to be probable that the fund will sell the investment for an amount different than the reported NAV. Withdrawals are permitted, with notice by the 20th day of each month, based on NAV. The table below presents the fair value of the Company’s pension plans’ assets by asset category segregated by level within the fair value hierarchy, as described below. U.S. Pension Plans’ Assets Canadian Pension Plans’ Assets Fair Value Measured At December 31, 2018 Fair Value Measured At December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 1,205 $ — $ — $ 1,205 $ 64 $ — $ — $ 64 International Equity 90 — — 90 95 — — 95 Fixed Income — Investment Grade (2) 313 160 — 473 — — — — Fixed Income — High Yield (3) — 271 — 271 — — — — Real Estate Investment Trusts (4) 185 — — 185 — — — — Other (5) — 146 — 146 4 16 — 20 Total assets at fair value $ 1,793 $ 577 $ — $ 2,370 $ 163 $ 16 $ — $ 179 Liabilities for unsettled trades, net (9 ) — Other investments measured at net asset value (6)(7) 176 124 Total $ 2,537 $ 303 U.S. Pension Plans’ Assets Canadian Pension Plans’ Assets Fair Value Measured At December 31, 2017 Fair Value Measured At December 31, 2017 Asset Category Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in millions) Equity securities (1) : U.S. Equity $ 1,297 $ — $ — $ 1,297 $ 71 $ — $ — $ 71 International Equity 87 — — 87 105 — — 105 Fixed Income — Investment Grade (2) 329 205 — 534 — — — — Fixed Income — High Yield (3) — 219 — 219 — — — — Real Estate Investment Trusts (4) 196 — — 196 — — — — Other (5) — 198 — 198 8 37 — 45 Total assets at fair value $ 1,909 $ 622 $ — $ 2,531 $ 184 $ 37 $ — $ 221 Liabilities for unsettled trades, net (30 ) — Other investments measured at net asset value (6)(7) 203 122 Total $ 2,704 $ 343 __________________ (1) Equity securities consist of investments in common stock of U.S. and international companies. The fair value of equity securities is based on quoted market prices available in active markets at the close of a trading day, primarily the New York Stock Exchange (NYSE), National Association of Securities Dealers Automated Quotations (NASDAQ), and various international exchanges. (2) Approximately 66% and 62% at December 31, 2018 and 2017 , respectively, of U.S. plan assets that are invested in the Fixed Income — Investment Grade asset category consist of a mutual fund offered by a registered investment company (the Fund) and fixed income securities. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. These investments are classified by the Company as a Level 1 measurement within the fair value hierarchy, as the mutual fund trades on an active market and daily, quoted prices are available. The remaining 34% and 38% at December 31, 2018 and 2017 , respectively, of U.S. plan assets are fixed income securities, primarily investment grade corporate bonds from various industries held directly by the plan. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs and are classified as Level 2. (3) Fixed Income — High Yield consists of investments in corporate high-yield bonds from various industries. The fair values of these investments are based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs. (4) Real Estate Investment Trusts (REITs) consist of securities that trade on the major exchanges and invest directly in real estate, either through properties or mortgages. (5) Other consists primarily of: (1) money market accounts, which invest primarily in short-term, high quality money market securities such as government obligations, commercial paper, time deposits and certificates of deposit, and are classified as Level 2, and (2) cash, which is classified as Level 1. (6) In accordance with ASU 2015-07, certain investments that are measured at fair value using the net asset value (NAV) per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. (7) All of the U.S. plans other investments measured using NAV at December 31, 2018 and 2017 and approximately 30% and 31% at December 31, 2018 and 2017 , respectively, of the Canadian plans other investments measured using NAV consist of a regulated commingled equity trust fund, for which fair value is based on the NAV at the end of each month. The NAV is calculated by the fund manager based on the fair value of the fund’s holdings, primarily equity securities traded in active markets, determined as of the end of each month as a practical expedient to estimating fair value. This practical expedient is not used when it is determined to be probable that the fund will sell the investment for an amount different than the reported NAV. Withdrawals are permitted, with notice by the 20th day of each month, based on NAV. Approximately 70% and 69% at December 31, 2018 and 2017 , respectively, of the Canadian plans other investments measured using NAV are invested in regulated commingled bond funds (the “Bond Funds”). As these Bond Funds do not trade in an active market, the fair value is based on NAVs calculated by fund managers based on yields currently available on comparable bonds of issuers with similar credit ratings, quoted prices of similar bonds in an active market, or cash flows based on observable inputs as a practical expedient to estimating fair value and classified as Level 2. Withdrawals are permitted monthly, with notice between 0 and 3 days of the transaction date, based on NAV.
Estimated Future Benefit Payments	The following table presents expected pension and postretirement benefit payments and expected postretirement subsidies due to the Medicare Prescription Drug Improvement and Modernization Act of 2003, which reflect expected future service, as appropriate. Postretirement Benefits Pension Benefit Subsidy (in millions) 2019 $ 168 $ 12 $ — 2020 176 12 — 2021 184 12 — 2022 194 12 — 2023 201 12 — Years 2024 - 2028 1,150 53 1

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Year Ended December 31, 2018 2017 2016 (in millions) Interest paid $ 183 $ 165 $ 162 Income tax payments $ 108 $ 163 $ 120 Income tax refunds $ 7 $ 16 $ 8

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Summary of Segment Information	The tables below present net sales, operating income, depreciation and amortization, capital expenditures and total assets by reportable segment. Year Ended December 31, 2018 2017 2016 (in millions) Net Sales Products ISRS $ 2,907 $ 2,540 $ 2,662 C&NS 2,307 2,424 2,238 Electronic Systems 2,007 1,814 1,617 Elimination of intercompany sales (56 ) (45 ) (64 ) Total products sales 7,165 6,733 6,453 Services ISRS $ 1,549 $ 1,463 $ 1,450 C&NS 787 717 678 Electronic Systems 789 695 653 Elimination of intercompany sales (46 ) (35 ) (24 ) Total services sales 3,079 2,840 2,757 Consolidated total $ 10,244 $ 9,573 $ 9,210 Operating income ISRS $ 448 $ 348 $ 362 C&NS 282 362 298 Electronic Systems 376 321 298 Segment total 1,106 1,031 958 Gain on sale of the Crestview & TCS businesses 42 — — Merger and acquisition related expenses (28 ) — — Consolidated total $ 1,120 $ 1,031 $ 958 Depreciation and amortization ISRS $ 92 $ 87 $ 80 C&NS 69 66 63 Electronic Systems 80 72 55 Consolidated total $ 241 $ 225 $ 198 Capital Expenditures ISRS $ 57 $ 74 $ 83 C&NS 50 76 51 Electronic Systems 108 52 66 Corporate 17 22 10 Consolidated total $ 232 $ 224 $ 210 Year Ended December 31, 2018 2017 2016 (in millions) Total Assets ISRS $ 4,720 $ 4,135 $ 4,117 C&NS 3,670 3,505 3,258 Electronic Systems 4,128 3,939 3,542 Corporate 1,000 709 467 Assets held for sale — 135 — Assets of discontinued operations — 306 481 Consolidated total $ 13,518 $ 12,729 $ 11,865
Property, Plant and Equipment by Geographic Area	The table below presents property, plant and equipment, net by geographic area. Year Ended December 31, 2018 2017 (in millions) United States $ 973 $ 936 All other 196 174 Total $ 1,169 $ 1,110
Company's Sales Attributable to U.S. Customers and International Customers	The Company’s sales attributable to U.S. and international customers, based on location of the customer, are summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) U.S. $ 7,843 $ 7,344 $ 6,947 International: Canada 312 280 297 United Kingdom 309 335 331 Australia 219 268 254 China 156 167 67 Japan 145 125 81 Saudi Arabia 128 58 159 Turkey 113 61 61 Other 1,019 935 1,013 Total international 2,401 2,229 2,263 Consolidated $ 10,244 $ 9,573 $ 9,210
Net Sales to Principal Customers	Net sales to principal customers are summarized in the table below. Year Ended December 31, 2018 2017 2016 (in millions) U.S. Government agencies (1) $ 7,144 6,697 $ 6,399 Commercial 1,572 1,456 1,280 Foreign governments (1) 1,528 1,420 1,531 Consolidated $ 10,244 9,573 $ 9,210 __________________ (1) Includes sales for which the Company is the prime contractor as well as sales based on the ultimate end customer for which the Company is a subcontractor.
Revenue by End Customer [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The table below present total net sales disaggregated by end customer. Year Ended December 31, 2018 End Customer ISRS C&NS Electronic Systems Consolidated L3 (in millions) Total DoD $ 3,081 $ 2,291 $ 1,349 $ 6,721 Other U.S. Government 150 95 178 423 Total U.S. Government 3,231 2,386 1,527 7,144 Foreign governments (1) 1,006 327 195 1,528 Commercial — foreign 75 123 675 873 Commercial — domestic 129 223 347 699 Total $ 4,441 $ 3,059 $ 2,744 $ 10,244 __________________ (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 table below present total net sales disaggregated by contract type. Year Ended December 31, 2018 Contract Type ISRS C&NS Electronic Systems Consolidated L3 (in millions) Fixed-price (1) $ 2,839 $ 2,202 $ 2,317 $ 7,358 Cost-plus (2) 1,393 768 410 2,571 Time-and-material 209 89 17 315 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244 __________________ (1) Includes fixed-price incentive fee type contracts, which contributed approximately 1% to the Company's total net sales for the year ended December 31, 2018 . (2) Includes cost-plus award and incentive fee type contracts, which contributed approximately 4% to the Company's total net sales for the year ended December 31, 2018 .
Revenue by Deliverable Type [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The table below present total net sales disaggregated by the type of deliverable, which is determined by the Company at the performance obligation level. Year Ended December 31, 2018 Sales by Deliverable Type ISRS C&NS Electronic Systems Consolidated L3 (in millions) Products $ 2,907 $ 2,299 $ 1,959 $ 7,165 Services 1,534 760 785 3,079 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244
Revenue by Revenue Recognition Method [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The table below present total net sales disaggregated based on the revenue recognition method applied. Year Ended December 31, 2018 Revenue Recognition Method ISRS C&NS Electronic Systems Consolidated L3 (in millions) Over time (cost-to-cost method) $ 3,352 $ 2,603 $ 1,649 $ 7,604 Point in time 866 359 705 1,930 Output method 74 23 343 440 Billing method 149 74 47 270 Total sales $ 4,441 $ 3,059 $ 2,744 $ 10,244

Severance and Restructuring R_2

Severance and Restructuring Related Costs (Tables)	12 Months Ended
	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Severance and Restructuring Costs Incurred by Reportable Segment	Severance and restructuring related costs are reported within operating costs and expenses on the consolidated statements of operations. Severance and restructuring related costs incurred by reportable segment are presented in the table below. Year Ended December 31, 2018 2017 2016 (in millions) ISRS (1)(2) $ 7 $ 38 $ 5 C&NS (3) 11 52 8 Electronic Systems (2) 8 11 4 Consolidated $ 26 $ 101 $ 17 __________________ (1) The severance and restructuring related costs incurred during the year ended December 31, 2017 include a $12 million loss on the sale of a building in Garland, Texas in the fourth quarter of 2017. (2) The severance and restructuring related costs incurred during the year ended December 31, 2017 include $1 million and $5 million of salaried employee pension plan curtailment losses for Electronic Systems and ISRS segments, respectively. See Note 20 for additional information. (3) The severance and restructuring related costs incurred during the year ended December 31, 2017 exclude a pre-tax gain of $42 million on the sale of the Company's property in San Carlos, California in the second quarter of 2017. The Company had severance and restructuring related liabilities of $14 million and $23 million included in other current liabilities on the Company’s balance sheets at December 31, 2018 and 2017 , respectively. The remaining liability balance at December 31, 2018 is expected to be paid in 2019 . The table below presents the change to the Company’s severance and restructuring related liability during the year ended December 31, 2018 . December 31, 2018 (in millions) Balance at beginning of period $ 23 Additional provisions 26 Cash payments (35 ) Balance at end of period $ 14

Unaudited Quarterly Financial_2

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	Unaudited summarized financial data by quarter for the years ended December 31, 2018 and 2017 is presented in the tables below. The Company’s unaudited quarterly results of operations are affected, significantly in some periods, by the Company’s business acquisitions and divestitures. See Note 3 for additional information. First Second (1) Third (2) Fourth (3) (in millions, except per share data) 2018 Sales $ 2,371 $ 2,583 $ 2,519 $ 2,771 Operating income 251 321 272 276 Income from continuing operations 192 189 208 232 Net income 208 379 208 231 Net income attributable to L3 203 375 202 225 Basic EPS from continuing operations (4) 2.40 2.36 2.57 2.87 Basic EPS (4) 2.60 4.78 2.57 2.86 Diluted EPS from continuing operations (4) 2.34 2.33 2.54 2.83 Diluted EPS (4) 2.54 4.72 2.54 2.82 __________________ (1) Income from continuing operations includes debt retirement charges of $48 million ( $36 million after income taxes), or $0.45 per diluted share and a pre-tax gain of $48 million ( $25 million after income taxes), or $0.31 per diluted share, related to the divestiture of the Crestview Aerospace and TCS businesses. The Company recorded a pre-tax gain of $237 million ( $180 million after income taxes, or $2.27 per diluted share) related to the divestiture of the Vertex Aerospace business, which is reported in discontinued operations. (2) Income from continuing operations includes debt retirement charges of $21 million ( $16 million after income taxes), or $0.21 per diluted share, merger and acquisition related expenses of $5 million ( $4 million after income taxes), or $0.06 per diluted share and adjustments to divestiture gains of $4 million ( $4 million after income taxes), or $0.04 per diluted share, related to the sale of the Crestview Aerospace and TCS businesses. (3) Income from continuing operations includes merger and acquisition related expenses of $23 million ( $19 million after income taxes), or $0.24 per diluted share and adjustments to divestiture gains of $2 million ( $2 million after income taxes), or $0.03 per diluted share, related to the sale of the Crestview Aerospace and TCS businesses. (4) EPS in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Therefore, the sum of the four quarters’ EPS may not equal the full year computed EPS. First Second Third (1) Fourth (2) (in millions, except per share data) 2017 Sales $ 2,321 $ 2,385 $ 2,293 $ 2,574 Operating income 237 294 232 268 Income from continuing operations 157 195 146 271 Net income 168 207 25 293 Net income attributable to L3 164 202 22 289 Basic EPS from continuing operations (3) 1.97 2.44 1.83 3.42 Basic EPS (3) 2.11 2.59 0.28 3.70 Diluted EPS from continuing operations (3) 1.93 2.39 1.79 3.34 Diluted EPS (3) 2.07 2.54 0.28 3.62 __________________ (1) The Company recorded a goodwill impairment charge of $187 million or $1.67 per diluted share for the Vertex Aerospace reporting unit in 2017, which is reported in discontinued operations. (2) Provision for income taxes for the fourth quarter of 2017, includes estimated tax benefits of $79 million or $0.99 per diluted share, related to the enactment of the U.S. Tax Reform in December 2017. (3) EPS in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Therefore, the sum of the four quarters’ EPS may not equal the full year computed EPS.

Financial Information of L3 a_2

Financial Information of L3 and Its Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Combining Balance Sheets	The following 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 Non- Eliminations Consolidated (in millions) Condensed Combining Balance Sheets: At December 31, 2018: Current assets: Cash and cash equivalents $ 756 $ 21 $ 306 $ (17 ) $ 1,066 Billed receivables, net 291 341 287 — 919 Contract assets 562 833 195 — 1,590 Inventories 378 258 243 — 879 Prepaid expenses and other current assets 127 166 63 — 356 Total current assets 2,114 1,619 1,094 (17 ) 4,810 Goodwill 2,124 3,009 1,675 — 6,808 Other assets 690 765 445 — 1,900 Investment in and amounts due from consolidated subsidiaries 5,931 6,912 — (12,843 ) — Total assets $ 10,859 $ 12,305 $ 3,214 $ (12,860 ) $ 13,518 Current liabilities $ 821 $ 955 $ 688 $ (17 ) $ 2,447 Amounts due to consolidated subsidiaries — — 417 (417 ) — Other long-term liabilities 878 804 161 — 1,843 Long-term debt 3,321 — — — 3,321 Total liabilities 5,020 1,759 1,266 (434 ) 7,611 L3 shareholders’ equity 5,839 10,546 1,948 (12,494 ) 5,839 Noncontrolling interests — — — 68 68 Total equity 5,839 10,546 1,948 (12,426 ) 5,907 Total liabilities and equity $ 10,859 $ 12,305 $ 3,214 $ (12,860 ) $ 13,518 L3 Guarantor Non- Eliminations Consolidated (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 2,099 2,932 1,584 — 6,615 Other assets 658 687 321 — 1,666 Investment in and amounts due from consolidated subsidiaries 5,662 6,310 — (11,972 ) — Total assets $ 10,459 $ 11,471 $ 2,842 $ (12,043 ) $ 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 — — 391 (391 ) — Other long-term liabilities 1,009 729 131 — 1,869 Long-term debt 3,330 — — — 3,330 Total liabilities 5,376 1,578 1,086 (462 ) 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 $ 2,842 $ (12,043 ) $ 12,729
Condensed Combining Statements of Operations	L3 Guarantor Non- Eliminations Consolidated (in millions) Condensed Combining Statements of Operations: For the year ended December 31, 2018: Total net sales $ 3,626 $ 5,259 $ 1,806 $ (447 ) $ 10,244 Total operating costs and expenses (3,180 ) (4,943 ) (1,462 ) 447 (9,138 ) Gain on sale of Crestview & TCS Businesses — 42 — — 42 Merger and acquisition related expenses (28 ) — — — (28 ) Operating income 418 358 344 — 1,120 Interest expense (163 ) — (1 ) — (164 ) Interest and other income, net 31 3 3 — 37 Debt retirement charges (69 ) — — — (69 ) Income from continuing operations before income taxes 217 361 346 — 924 Provision for income taxes (24 ) (40 ) (39 ) — (103 ) Equity in net income of consolidated subsidiaries 607 184 — (791 ) — Income from continuing operations 800 505 307 (791 ) 821 Income from discontinued operations, net of income tax 205 — — — 205 Net income 1,005 505 307 (791 ) 1,026 Net income attributable to noncontrolling interests — — — (21 ) (21 ) Net income attributable to L3 $ 1,005 $ 505 $ 307 $ (812 ) $ 1,005 Comprehensive income attributable to L3 $ 971 $ 427 $ 226 $ (653 ) $ 971 For the year ended December 31, 2017: Total net sales $ 3,520 $ 4,852 $ 1,581 $ (380 ) $ 9,573 Total operating costs and expenses (3,169 ) (4,446 ) (1,307 ) 380 (8,542 ) Operating income 351 406 274 — 1,031 Interest expense (168 ) — (1 ) — (169 ) Interest and other income (loss), net 6 (8 ) 11 — 9 Income from continuing operations before income taxes 189 398 284 — 871 Provision for income taxes (22 ) (47 ) (33 ) — (102 ) Equity in net income of consolidated subsidiaries 586 144 — (730 ) — Income from continuing operations 753 495 251 (730 ) 769 Loss from discontinued operations, net of income tax (76 ) — — — (76 ) Net income 677 495 251 (730 ) 693 Net income attributable to noncontrolling interests — — — (16 ) (16 ) Net income attributable to L3 $ 677 $ 495 $ 251 $ (746 ) $ 677 Comprehensive income attributable to L3 $ 712 $ 604 $ 378 $ (982 ) $ 712 For the year ended December 31, 2016: Total net sales $ 3,351 $ 4,842 $ 1,348 $ (331 ) $ 9,210 Total operating costs and expenses (3,064 ) (4,406 ) (1,113 ) 331 (8,252 ) Operating income 287 436 235 — 958 Interest expense (164 ) — — — (164 ) Interest and other income (loss), net 9 (3 ) 11 — 17 Debt retirement charges (7 ) — — — (7 ) Income from continuing operations before income taxes 125 433 246 — 804 Provision for income taxes (26 ) (92 ) (53 ) — (171 ) Equity in net income of consolidated subsidiaries 520 130 — (650 ) — Income from continuing operations 619 471 193 (650 ) 633 Income from discontinued operations, net of income tax 91 — — — 91 Net income 710 471 193 (650 ) 724 Net income attributable to noncontrolling interests — — — (14 ) (14 ) Net income attributable to L3 $ 710 $ 471 $ 193 $ (664 ) $ 710 Comprehensive income attributable to L3 $ 558 $ 409 $ 116 $ (525 ) $ 558
Condensed Combining Statements of Cash Flows	L3 Guarantor Non- Eliminations Consolidated (in millions) Condensed Combining Statements of Cash Flows: For the year ended December 31, 2018: Operating activities: Net cash from operating activities from continuing operations $ 555 $ 238 $ 256 $ (7 ) $ 1,042 Investing activities: Business acquisitions, net of cash acquired (193 ) — (176 ) — (369 ) Proceeds from sale of businesses, net of closing date cash balances 360 175 — — 535 Other investing activities (119 ) (90 ) (48 ) — (257 ) Net cash from (used in) investing activities from continuing operations 48 85 (224 ) — (91 ) Financing activities: Proceeds from sale of senior notes 1,798 — — — 1,798 Repurchases and redemptions of senior notes (1,865 ) — — — (1,865 ) Common stock repurchased (322 ) — — — (322 ) Dividends paid (254 ) — — — (254 ) Other financing activities 376 (318 ) 4 61 123 Net cash (used in) from financing activities from continuing operations (267 ) (318 ) 4 61 (520 ) Effect of foreign currency exchange rate changes on cash — — (15 ) — (15 ) Net decrease in cash and cash equivalents of discontinued operations (12 ) — — — (12 ) Net increase in cash 324 5 21 54 404 Cash and cash equivalents, beginning of the year 432 16 285 (71 ) 662 Cash and cash equivalents, end of the year $ 756 $ 21 $ 306 $ (17 ) $ 1,066 For the year ended December 31, 2017: Operating activities: Net cash from operating activities from continuing operations $ 374 $ 426 $ 263 $ (78 ) $ 985 Investing activities: Business acquisitions, net of cash acquired (316 ) — — — (316 ) Proceeds from sale of businesses, net of closing date cash balances 17 — 1 — 18 Other investing activities (92 ) (38 ) (25 ) — (155 ) Net cash used in investing activities from continuing operations (391 ) (38 ) (24 ) — (453 ) Financing activities: Common stock repurchased (180 ) — — — (180 ) Dividends paid (236 ) — — — (236 ) Other financing activities 490 (377 ) (177 ) 114 50 Net cash from (used in) financing activities from continuing operations 74 (377 ) (177 ) 114 (366 ) Effect of foreign currency exchange rate changes on cash — — 20 — 20 Net increase in cash and cash equivalents of discontinued operations 113 — — — 113 Net increase in cash 170 11 82 36 299 Cash and cash equivalents, beginning of the year 262 5 203 (107 ) 363 Cash and cash equivalents, end of the year $ 432 $ 16 $ 285 $ (71 ) $ 662 L3 Guarantor Non- Eliminations Consolidated (in millions) For the year ended December 31, 2016: Operating activities: Net cash from operating activities from continuing operations $ 440 $ 509 $ 259 $ (186 ) $ 1,022 Investing activities: Business acquisitions, net of cash acquired (388 ) — — — (388 ) Proceeds from sale of businesses, net of closing date cash balances 563 — (2 ) — 561 Other investing activities (63 ) (77 ) (43 ) — (183 ) Net cash from (used in) investing activities from continuing operations 112 (77 ) (45 ) — (10 ) Financing activities: Proceeds from sale of senior notes 547 — — — 547 Redemption of senior notes (856 ) — — — (856 ) Common stock repurchased (373 ) — — — (373 ) Dividends paid (220 ) — — — (220 ) Other financing activities 490 (427 ) (163 ) 146 46 Net cash used in financing activities from continuing operations (412 ) (427 ) (163 ) 146 (856 ) Effect of foreign currency exchange rate changes on cash — — (13 ) — (13 ) Net increase in cash and cash equivalents of discontinued operations 13 — — — 13 Net increase in cash 153 5 38 (40 ) 156 Cash and cash equivalents, beginning of the year 109 — 165 (67 ) 207 Cash and cash equivalents, end of the year $ 262 $ 5 $ 203 $ (107 ) $ 363

Description of Business (Detail

Description of Business (Details) $ in Millions	Jun. 29, 2018USD ($)	Dec. 31, 2018USD ($)	Sep. 28, 2018USD ($)	Jun. 29, 2018USD ($)	Mar. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 29, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)Segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Oct. 14, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | Segment										3
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of the Crestview Aerospace and TCS businesses										$ 42	$ 0	$ 0
Net sales		$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	10,244	9,573	9,210
Merged Entity, Ownership Percentage													46.00%
Vertex Aerospace [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of business, sale price	$ 540			540
Gain on sale of the Crestview Aerospace and TCS businesses				237
Gain on sale of businesses, after tax				180
Gain from discontinued operations, before tax	234
Gain from discontinued operations, after tax	177
Net sales										600	1,400	1,300
Crestview Aerospace and TCS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of the Crestview Aerospace and TCS businesses	42	2	4	48						42	0	0
Gain on sale of businesses, after tax	$ 19	$ 2	$ 4	$ 25
Net sales										$ 64	$ 119	$ 166
Harris Corporation [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Merger, Shares Received, Ratio													1.30
Harris Corporation [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Merged Entity, Ownership Percentage													54.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Summary of Significant Accounting Policies [Line Items]
Research and development expense	$ 326	$ 287	$ 258
Percentage of incurred costs billed	80.00%
Cumulative Effect of New Accounting Principle in Period of Adoption		13
Revenue Recognition [Abstract]
Percentage of fixed-price type contracts	80.00%
Performance-based Billings as Percent of Contract Price, Maximum	90.00%
Accounting Estimates [Abstract]
Performance obligations partially satisfied in prior periods	$ 264
Increase in operating income due to changes in contract estimates	$ 213	$ 185	$ 149
Increase in operating income due to changes in contract estimates, diluted (in dollars per share)	$ 2.03	$ 1.49	$ 1.23
Revenue from Contract with Customer [Abstract]
Over time (cost-to-cost method) (percent)	74.00%
Point in time (percent)	19.00%
Output method (percent)	4.00%
Billing method (percent)	3.00%
Total (percent)	100.00%
Accrued product warranty costs [Roll Forward]:
Balance at January 1	$ 99	$ 109
Acquisitions during this period	0	3
Accruals for product warranties issued during the period	44	52
Changes to accruals for product warranties existing before January 1	1	0
Settlements made during the period	(55)	(66)
Foreign currency translation adjustments	(1)	1
Balance at December 31	$ 88	99	$ 109
Minimum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	10 years
Minimum [Member] | Machinery, Equipment, Furniture and Fixtures [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	3 years
Maximum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	40 years
Maximum [Member] | Machinery, Equipment, Furniture and Fixtures [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	10 years
Accounting Standards Update 2017-07 [Member]
Summary of Significant Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle, effect of change on operating income	$ 11	11	1
New Accounting pronouncement or change in accounting principle, effect of change on interest and other income, net	$ (11)	(11)	$ (1)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Summary of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		13
Sales Revenue, Net [Member] | Accounting Standards Update 2014-09 [Member]
Summary of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 380
Subsequent Event [Member] | Accounting Standards Update 2016-02 [Member]
Summary of Significant Accounting Policies [Line Items]
Right-of-use asset				$ 650
Lease liability				$ 650

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Remaining Performance Obligations (Details) $ in Billions	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 11.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Accounting Policies [Abstract]
Revenue, Remaining Performance Obligation, Amount	7.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Accounting Policies [Abstract]
Revenue, Remaining Performance Obligation, Amount	2.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Accounting Policies [Abstract]
Revenue, Remaining Performance Obligation, Amount	0.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Accounting Policies [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 0.9

Summary of Significant Accoun_6

Summary of Significant Accounting Policies Balance sheet Items (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract assets	$ 1,590	$ 1,349	$ 0
Contracts in process	0	0	1,933
Inventories	879	926	389
Prepaid Expense and Other Assets	356	317
Assets Held-for-sale, Not Part of Disposal Group, Current	0	138	135	$ 0
Assets of discontinued operations	0	285	306	481
Assets, Current	4,810	4,400	4,448
Other assets	341	313	264
Total Assets	13,518	12,730	12,729	11,865
Accrued expenses	251	204	217
Contract liabilities	669	565	0
Advance payments and billings in excess of costs incurred	0	0	509
Income taxes payable	49		19
Other current liabilities	288	318	367
Liabilities held for sale	0	16	17
Liabilities of discontinued operations	0	203	226
Liabilities, Current	2,447	2,349	2,379
Deferred income taxes	196	162	158
Other liabilities	436	412	398
Liabilities	7,611	7,566	7,578
Retained earnings	7,424	6,672	6,659
Total equity	5,907	5,164	5,151	$ 4,624	$ 4,429
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract assets	1,590	1,349
Contracts in process	(2,127)	(1,933)
Inventories	486	537
Prepaid Expense and Other Assets	16	17
Assets Held-for-sale, Not Part of Disposal Group, Current		3
Assets of discontinued operations		(21)
Assets, Current	(35)	(48)
Other assets	46	49
Total Assets	11	1
Accrued expenses	(24)	(13)
Contract liabilities	669	565
Advance payments and billings in excess of costs incurred	(604)	(509)
Income taxes payable	(4)
Other current liabilities	(76)	(49)
Liabilities held for sale		(1)
Liabilities of discontinued operations		(23)
Liabilities, Current	(39)	(30)
Deferred income taxes	11	4
Other liabilities	14	14
Liabilities	(14)	(12)
Retained earnings	25	13
Total equity	25	$ 13
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract assets	0		0
Contracts in process	2,127		1,933
Inventories	393		389
Prepaid Expense and Other Assets	340		300
Assets Held-for-sale, Not Part of Disposal Group, Current			135
Assets of discontinued operations			306
Assets, Current	4,845		4,448
Other assets	295		264
Total Assets	13,507		12,729
Accrued expenses	275		217
Contract liabilities	0		0
Advance payments and billings in excess of costs incurred	604		509
Income taxes payable	53
Other current liabilities	364		367
Liabilities held for sale			17
Liabilities of discontinued operations			226
Liabilities, Current	2,486		2,379
Deferred income taxes	185		158
Other liabilities	422		398
Liabilities	7,625		7,578
Retained earnings	7,399		6,659
Total equity	$ 5,882		$ 5,151

Summary of Significant Accoun_7

Summary of Significant Accounting Policies Statement of operations items (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Cost of sales									(9,138)	(8,542)	(8,252)
General and administrative expenses									(1,601)	(1,520)	(1,287)
Gain on sale of the Crestview Aerospace and TCS businesses									42	0	0
Merger and acquisition related expenses									(28)	0	0
Operating Income (Loss)	276	272	321	251	268	232	294	237	1,120	1,031	958
Income from continuing operations before income taxes									924	871	804
Provision for income taxes									(103)	(102)	(171)
Income from continuing operations	232	208	189	192	271	146	195	157	821	769	633
Income (loss) from discontinued operations, net of income taxes									205	(76)	91
Net (loss) income	231	208	379	208	293	25	207	168	1,026	693	724
Net income attributable to L3	$ 225	$ 202	$ 375	$ 203	$ 289	$ 22	$ 202	$ 164	$ 1,005	$ 677	$ 710
Continuing operations (in dollars per share)	$ 2.87	$ 2.57	$ 2.36	$ 2.40	$ 3.42	$ 1.83	$ 2.44	$ 1.97	$ 10.19	$ 9.65	$ 7.99
Discontinued operations (in dollars per share)									2.61	(0.97)	1.18
Basic EPS (in dollars per share)	2.86	2.57	4.78	2.60	3.70	0.28	2.59	2.11	12.80	8.68	9.17
Continuing operations (in dollars per share)	2.83	2.54	2.33	2.34	3.34	1.79	2.39	1.93	10.05	9.46	7.86
Discontinued operations (in dollars per share)									2.58	(0.95)	1.15
Earnings Per Share, Diluted	$ 2.82	$ 2.54	$ 4.72	$ 2.54	$ 3.62	$ 0.28	$ 2.54	$ 2.07	$ 12.63	$ 8.51	$ 9.01
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									$ 10,105
General and administrative expenses									(1,598)
Gain on sale of the Crestview Aerospace and TCS businesses									41
Merger and acquisition related expenses									(28)
Operating Income (Loss)									1,092
Income from continuing operations before income taxes									896
Provision for income taxes									(96)
Income from continuing operations									800
Income (loss) from discontinued operations, net of income taxes									214
Net (loss) income									1,014
Net income attributable to L3									$ 993
Continuing operations (in dollars per share)									$ 9.92
Discontinued operations (in dollars per share)									2.73
Basic EPS (in dollars per share)									12.65
Continuing operations (in dollars per share)									9.79
Discontinued operations (in dollars per share)									2.69
Earnings Per Share, Diluted									$ 12.48
Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									$ 7,165	$ 6,733	$ 6,453
Cost of sales									(5,345)	(4,967)	(4,879)
Product [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									7,004
Cost of sales									(5,235)
Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									3,079	2,840	2,757
Cost of sales									(2,192)	(2,055)	(2,086)
Service [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									3,101
Cost of sales									(2,193)
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									139
General and administrative expenses									(3)
Gain on sale of the Crestview Aerospace and TCS businesses									1
Merger and acquisition related expenses									0
Operating Income (Loss)									28
Income from continuing operations before income taxes									28
Provision for income taxes									(7)
Income from continuing operations									21
Income (loss) from discontinued operations, net of income taxes									(9)
Net (loss) income									12
Net income attributable to L3									$ 12
Continuing operations (in dollars per share)									$ 0.27
Discontinued operations (in dollars per share)									(0.12)
Basic EPS (in dollars per share)									0.15
Continuing operations (in dollars per share)									0.26
Discontinued operations (in dollars per share)									(0.11)
Earnings Per Share, Diluted									$ 0.15
Accounting Standards Update 2014-09 [Member] | Product [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									$ 161
Cost of sales									(110)
Accounting Standards Update 2014-09 [Member] | Service [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									(22)
Cost of sales									1
ISR Systems [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									4,441
ISR Systems [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,907
ISR Systems [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									1,534
ISR Systems [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									21
Operating Income (Loss)									1
C&NS [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									3,059
C&NS [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,299
C&NS [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									760
C&NS [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									68
Operating Income (Loss)									12
Electronic Systems [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,744
Electronic Systems [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									1,959
Electronic Systems [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									785
Electronic Systems [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									50
Operating Income (Loss)									14
Operating Segments [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Income (Loss)									1,106	1,031	958
Operating Segments [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									139
Operating Income (Loss)									27
Operating Segments [Member] | ISR Systems [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Income (Loss)									448	348	362
Operating Segments [Member] | ISR Systems [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,907	2,540	2,662
Operating Segments [Member] | ISR Systems [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									1,549	1,463	1,450
Operating Segments [Member] | C&NS [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Income (Loss)									282	362	298
Operating Segments [Member] | C&NS [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,307	2,424	2,238
Operating Segments [Member] | C&NS [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									787	717	678
Operating Segments [Member] | Electronic Systems [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Income (Loss)									376	321	298
Operating Segments [Member] | Electronic Systems [Member] | Product [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									2,007	1,814	1,617
Operating Segments [Member] | Electronic Systems [Member] | Service [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales									$ 789	$ 695	$ 653

Acquisitions, Divestitures an_3

Acquisitions, Divestitures and Discontinued Operations, Business Acquisitions (Details) £ in Millions, $ in Millions

Sep. 20, 2018USD ($)

Sep. 18, 2018USD ($)

Sep. 18, 2018GBP (£)

Aug. 31, 2018USD ($)shares

Aug. 31, 2018AUD ($)shares

Jun. 29, 2018USD ($)

Jun. 28, 2018USD ($)

Dec. 18, 2017USD ($)

Oct. 27, 2017USD ($)

Sep. 08, 2017USD ($)

May 19, 2017USD ($)

Jan. 05, 2017USD ($)

Nov. 22, 2016USD ($)

Nov. 22, 2016GBP (£)

Sep. 30, 2016USD ($)

Jan. 22, 2016USD ($)

Dec. 31, 2018USD ($)

Sep. 28, 2018USD ($)

Jun. 29, 2018USD ($)

Mar. 30, 2018USD ($)

Dec. 31, 2017USD ($)

Sep. 29, 2017USD ($)

Jun. 30, 2017USD ($)

Mar. 31, 2017USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Aug. 31, 2018AUD ($)

Feb. 16, 2018USD ($)

Sep. 12, 2017USD ($)

Mar. 17, 2017USD ($)

Nov. 22, 2016GBP (£)

Business Acquisition [Line Items]

Gain on sale of the Crestview Aerospace and TCS businesses

$ 42,000,000

$ 0

$ 0

Goodwill recognized

$ 6,808,000,000

$ 6,615,000,000

6,808,000,000

6,615,000,000

6,374,000,000

Fair value of liability, contingent consideration

20,000,000

31,000,000

20,000,000

31,000,000

Net sales

2,771,000,000

$ 2,519,000,000

$ 2,583,000,000

$ 2,371,000,000

2,574,000,000

$ 2,293,000,000

$ 2,385,000,000

$ 2,321,000,000

10,244,000,000

9,573,000,000

9,210,000,000

Loss before income taxes

924,000,000

871,000,000

804,000,000

Amortization expense

$ 49,000,000

43,000,000

33,000,000

Technology [Member]

Business Acquisition [Line Items]

Finite lived intangible assets, weighted average amortization period

9 years

Customer Relationships [Member]

Business Acquisition [Line Items]

Finite lived intangible assets, weighted average amortization period

16 years

2018 Business Acquisitions [Member]

Business Acquisition [Line Items]

Net sales

$ 46,000,000

Loss before income taxes

(7,000,000)

Amortization expense

7,000,000

IRAD expense

1,000,000

ASV Global LLC [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 94,000,000

Cash acquired from acquisition

1,000,000

C.K. Industrial Engineers Limited [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 24,000,000

£ 18

Cash acquired from acquisition

5,000,000

£ 4

Goodwill recognized

$ 13,000,000

Azimuth Security and Linchpin Labs [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 185,000,000

$ 249

Cash acquired from acquisition

15,000,000

$ 21

Fair value of liability, contingent consideration

$ 31,000,000

$ 43

Contingent consideration (shares) | shares

161,087

161,087

Increase to equity for fair value of contingent consideration

$ 6,000,000

Applied Defense Solutions [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 53,000,000

Cash acquired from acquisition

$ 1,000,000

Goodwill recognized

40,000,000

40,000,000

L3 Latitude Engineering [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 15,000,000

Fair value of liability, contingent consideration

20,000,000

Increase to equity for fair value of contingent consideration

6,000,000

Kigre, Inc [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 13,000,000

Goodwill recognized

9,000,000

Goodwill deductible for income tax purposes

$ 0

Escola De Aviacao Aerocondor, S.A [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 13,000,000

Goodwill recognized

12,000,000

Goodwill deductible for income tax purposes

$ 0

Doss Aviation, Inc. [Member]

Business Acquisition [Line Items]

Goodwill recognized

$ 37,000,000

Goodwill deductible for income tax purposes

$ 13,000,000

Adaptive Methods, Inc. [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 33,000,000

Goodwill recognized

28,000,000

Goodwill deductible for income tax purposes

$ 28,000,000

Open Water Power, Inc. [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 17,000,000

Goodwill recognized

25,000,000

Goodwill deductible for income tax purposes

0

Fair value of liability, contingent consideration

14,000,000

Open Water Power, Inc. [Member] | IPR&D [Member]

Business Acquisition [Line Items]

Identifiable intangible assets

$ 65,000,000

OceanServer Technology, Inc. [Member]

Business Acquisition [Line Items]

Goodwill recognized

$ 19,000,000

Goodwill deductible for income tax purposes

$ 19,000,000

Explosive Trace Detection Business of Implant Sciences [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 118,000,000

Goodwill recognized

80,000,000

Goodwill deductible for income tax purposes

$ 80,000,000

$ 0

MacDonald Humfrey (Automation) Limited [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

327,000,000

£ 263

Goodwill recognized

255,000,000

£ 204

Identifiable intangible assets

$ 56,000,000

45

Finite lived intangible assets, weighted average amortization period

10 years

10 years

Fair value of liability, contingent consideration

$ 26,000,000

21

Contingent consideration

38,000,000

30

MacDonald Humfrey (Automation) Limited [Member] | Technology [Member]

Business Acquisition [Line Items]

Identifiable intangible assets

12,000,000

10

MacDonald Humfrey (Automation) Limited [Member] | Customer Relationships [Member]

Business Acquisition [Line Items]

Identifiable intangible assets

36,000,000

29

MacDonald Humfrey (Automation) Limited [Member] | Trade Name [Member]

Business Acquisition [Line Items]

Identifiable intangible assets

$ 8,000,000

£ 6

Micreo Limited And Aerosim Technologies Inc [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 86,000,000

Goodwill recognized

59,000,000

Goodwill deductible for income tax purposes

$ 6,000,000

Advanced Technical Materials Incorporation [Member]

Business Acquisition [Line Items]

Purchase price of acquisition

$ 27,000,000

Goodwill recognized

20,000,000

Goodwill deductible for income tax purposes

$ 20,000,000

C&NS [Member]

Business Acquisition [Line Items]

Goodwill recognized

2,007,000,000

1,962,000,000

2,007,000,000

1,962,000,000

1,868,000,000

Net sales

3,059,000,000

C&NS [Member] | ASV Global LLC [Member]

Business Acquisition [Line Items]

Goodwill recognized

54,000,000

Goodwill deductible for income tax purposes

16,000,000

C&NS [Member] | ASV Global LLC [Member] | Technology [Member]

Business Acquisition [Line Items]

Identifiable intangible assets

$ 30,000,000

ISR Systems [Member]

Business Acquisition [Line Items]

Goodwill recognized

2,596,000,000

2,458,000,000

2,596,000,000

2,458,000,000

2,466,000,000

Net sales

4,441,000,000

ISR Systems [Member] | Azimuth Security and Linchpin Labs [Member]

Business Acquisition [Line Items]

Goodwill recognized

117,000,000

Goodwill deductible for income tax purposes

20,000,000

Identifiable intangible assets

$ 90,000,000

ISR Systems [Member] | Azimuth Security and Linchpin Labs [Member] | Technology [Member]

Business Acquisition [Line Items]

Finite lived intangible assets, weighted average amortization period

4 years

4 years

ISR Systems [Member] | Azimuth Security and Linchpin Labs [Member] | Customer Relationships [Member]

Business Acquisition [Line Items]

Finite lived intangible assets, weighted average amortization period

20 years

20 years

Electronic Systems [Member]

Business Acquisition [Line Items]

Goodwill recognized

$ 2,205,000,000

$ 2,195,000,000

2,205,000,000

$ 2,195,000,000

$ 2,040,000,000

Net sales

$ 2,744,000,000

Electronic Systems [Member] | L3 Latitude Engineering [Member]

Business Acquisition [Line Items]

Goodwill recognized

15,000,000

Post-acquisition Performance through December 2021 [Member] | L3 Latitude Engineering [Member]

Business Acquisition [Line Items]

Fair value of liability, contingent consideration

15,000,000

Post-acquisition Milestone Achievements through December 2020 [Member] | L3 Latitude Engineering [Member]

Business Acquisition [Line Items]

Fair value of liability, contingent consideration

$ 5,000,000

Peak Nano Optics, LLC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]

Business Acquisition [Line Items]

Goodwill recognized

$ 11,000,000

Ownership interest (percent)

25.00%

Equity method investments

$ 20,000,000

Peak Nano Optics, LLC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | IPR&D [Member]

Business Acquisition [Line Items]

Intangible assets acquired

$ 13,000,000

Acquisitions, Divestitures an_4

Acquisitions, Divestitures and Discontinued Operations, Unaudited Pro Forma Statements of Operations Data (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Pro forma net sales	$ 10,324	$ 9,741
Pro forma income from continuing operations attributable to L3	805	756
Pro forma net income attributable to L3	$ 1,010	$ 680
Pro forma diluted earnings per share from continuing operations (in dollars per share)	$ 10.11	$ 9.50
Pro forma diluted earnings per share (in dollars per share)	$ 12.69	$ 8.54

Acquisitions, Divestitures an_5

Acquisitions, Divestitures and Discontinued Operations, Business Divestitures (Details) € in Millions, $ in Millions	Jun. 29, 2018USD ($)	Dec. 31, 2018USD ($)	Sep. 28, 2018USD ($)	Jun. 29, 2018USD ($)	Mar. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 29, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Mar. 01, 2017USD ($)	Mar. 01, 2017EUR (€)	Feb. 24, 2017USD ($)	Feb. 23, 2017USD ($)
Business Divestiture [Abstract]
Net sales		$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Gain on sale of businesses										42	0	0
Income from continuing operations before income taxes										924	871	804
Income (Loss) from Continuing Operations [Member]
Business Divestiture [Abstract]
Gain on sale of businesses											(4)
Proceeds received											25
Net sales											10
Discontinued Operations [Member]
Business Divestiture [Abstract]
Net sales											10	59
Income from continuing operations before income taxes											2	8
Crestview Aerospace and TCS [Member]
Business Divestiture [Abstract]
Net sales										64	119	166
Gain on sale of businesses	$ 42	$ 2	$ 4	$ 48						42	0	0
Income from continuing operations before income taxes										$ 45	(2)	$ 12
Aviation Jet Services Divestiture [Member]
Business Divestiture [Abstract]
Gain on sale of businesses											(5)
Proceeds received											1
Net sales											1
Sale of business, sale price													$ 1	€ 1
Coleman Divestiture [Member]
Business Divestiture [Abstract]
Gain on sale of businesses											(3)
Proceeds received											17
Net sales											9
Sale of business, sale price															$ 15
Display Product Line Divestiture [Member]
Business Divestiture [Abstract]
Gain on sale of businesses											4
Proceeds received											7
Net sales											$ 0
Sale of business, sale price																$ 7

Acquisitions, Divestitures an_6

Acquisitions, Divestitures and Discontinued Operations, Assets Held for Sale (Details) - USD ($) $ in Millions	Jun. 29, 2018	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales		$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Assets [Abstract]
Total assets classified as held for sale						135					135
Liabilities [Abstract]
Gain on sale of the Crestview Aerospace and TCS businesses										42	0	0
Income from continuing operations before income taxes										924	871	804
Crestview Aerospace and TCS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales										64	119	166
Liabilities [Abstract]
Gain on sale of the Crestview Aerospace and TCS businesses	$ 42	$ 2	$ 4	$ 48						42	0	0
Income from continuing operations before income taxes										$ 45	(2)	$ 12
Crestview Aerospace and TCS [Member] | Discontinued Operations, Held-for-sale [Member]
Assets [Abstract]
Billed receivables						14					14
Contracts in process						33					33
Total current assets						47					47
Property, plant and equipment, net						34					34
Goodwill						52					52
Identifiable intangible assets						2					2
Total assets classified as held for sale						135					135
Liabilities [Abstract]
Accounts payable, trade						3					3
Accrued employment costs						2					2
Accrued expenses						3					3
Other current liabilities						5					5
Total current liabilities						13					13
Deferred income taxes						4					4
Liabilities held for sale						$ 17					$ 17

Acquisitions, Divestitures an_7

Acquisitions, Divestitures and Discontinued Operations, Discontinued Operations (Details) - USD ($) $ in Millions	Jun. 29, 2018	Feb. 01, 2016	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of businesses											$ 42	$ 0	$ 0
Net sales			$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	10,244	9,573	9,210
Discontinued Operations [Abstract]
(Loss) income from discontinued operations net of income taxes											205	(76)	91
Liabilities [Abstract]
Current liabilities			0				226				0	226		$ 203
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales												10	59
Vertex Aerospace [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of business, sale price	$ 540				540
Gain on sale of businesses					237
Gain on sale of businesses, after tax					180
Gain from discontinued operations, before tax	234
Gain from discontinued operations, after tax	177
Net sales											600	1,400	1,300
Discontinued Operations [Abstract]
Goodwill impairment charges								$ 187				187
Vertex Aerospace [Member] | Discontinued Operations [Member]
Assets [Abstract]
Current assets							284					284
Property, plant and equipment, net							13					13
Other intangible assets							7					7
Other assets							2					2
Total assets of discontinued operations							306					306
Liabilities [Abstract]
Accounts payable, trade							63					63
Other current liabilities							131					131
Other current liabilities							194					194
Long-term liabilities							32					32
Current liabilities							$ 226					226
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	42		2	4	48						42	0	0
Gain on sale of businesses, after tax	$ 19		$ 2	$ 4	$ 25
Net sales											64	119	166
NSS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of discontinued operations		$ 547
NSS [Member] | Discontinued Operations [Member] | CACI International Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of discontinued operations		$ 547
Vertex Aerospace and NSS [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of businesses											234	0	64
Discontinued Operations [Abstract]
Net sales											597	1,429	1,402
Operating costs and expenses (1)											(561)	(1,531)	(1,357)
Operating (loss) income from discontinued operations											36	(102)	45
Interest expense allocated to discontinued operations											(1)	(2)	(5)
(Loss) income from discontinued operations before income taxes											269	(104)	104
Income tax benefit (expense)											(64)	28	(13)
(Loss) income from discontinued operations net of income taxes											$ 205	$ (76)	$ 91

Contract Assets and Contract _3

Contract Assets and Contract Liabilities Components of Net Contract Assets (Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract assets	$ 1,590	$ 1,349	$ 0
Contract liabilities — current	(669)	(565)	0
Contract liabilities — non-current	(31)	(28)	$ 0
Contract with Customer, Asset, Net	890	$ 756
Increase (Decrease) in Contract with Customer, Assets	241
Increase in contract liabilities	107
Contract with Customer, Liability, Revenue Recognized	$ 457

Contract Assets and Contract _4

Contract Assets and Contract Liabilities Components of Contract Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Unbilled contract receivables, gross	$ 2,716	$ 2,232	$ 1,874
Unliquidated Progress Payments For Unbilled Contract Receivables	(1,126)	(883)	(761)
Contract with Customer, Asset, Net, Current	$ 1,590	$ 1,349	$ 0

Contracts in Process (Details)

Contracts in Process (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Jan. 01, 2018
Contracts Receivable [Abstract]
Unbilled contract receivables, gross	$ 1,874		$ 2,716	$ 2,232
Unliquidated progress payments	(761)		(1,126)	(883)
Unbilled contract receivables, net	1,113
Inventoried contract costs, gross	891
Unliquidated progress payments	(71)
Inventoried contract costs, net	820
Contracts in process	1,933		$ 0	$ 0
Summary Of Inventory For Long Term Contracts Or Programs [Roll Forward]
Amounts included in inventoried contract costs at beginning of the year	173	$ 137
Contract costs incurred [Abstract]:
IRAD and B&P	333	304
Other G&A	842	749
Total	1,175	1,053
Amounts charged to cost of sales	(1,179)	(1,017)
Amounts included in inventoried contract costs at end of the year	$ 169	$ 173

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials, components and sub-assemblies	$ 351		$ 184
Work in process	330		98
Finished goods	198		107
Total	879	$ 926	$ 389
General and Administrative Costs in Inventory, Amount Remaining	31
General and Administrative Costs in Inventory, Amount Incurred	1,181
General and Administrative Costs in Inventory, Amount Charged to Expense	$ 1,221

Goodwill and Identifiable Int_3

Goodwill and Identifiable Intangible Assets, Allocated by Reportable Segment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)Employee	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Goodwill [Line Items]
Approximate number of employees | Employee	31,000
Goodwill [Roll Forward]
Goodwill	$ 6,904	$ 6,719	$ 6,478
Accumulated impairment losses	(104)	(104)	(104)
Balance, Beginning	6,615	6,374
Business acquisitions	247	212
Business divestitures		(12)
Foreign currency translation adjustments	(54)	93
Assets held for sale		(52)
Balance, Ending	6,808	6,615
ISR Systems [Member]
Goodwill [Roll Forward]
Goodwill	2,634	2,504	2,512
Accumulated impairment losses	(46)	(46)	(46)
Balance, Beginning	2,458	2,466
Business acquisitions	158	8
Business divestitures		0
Foreign currency translation adjustments	(20)	26
Assets held for sale		(42)
Balance, Ending	2,596	2,458
C&NS [Member]
Goodwill [Roll Forward]
Goodwill	2,022	1,977	1,883
Accumulated impairment losses	(15)	(15)	(15)
Balance, Beginning	1,962	1,868
Business acquisitions	56	73
Business divestitures		0
Foreign currency translation adjustments	(11)	21
Assets held for sale		0
Balance, Ending	2,007	1,962
Electronic Systems [Member]
Goodwill [Roll Forward]
Goodwill	2,248	2,238	2,083
Accumulated impairment losses	(43)	(43)	$ (43)
Balance, Beginning	2,195	2,040
Business acquisitions	33	131
Business divestitures		(12)
Foreign currency translation adjustments	(23)	46
Assets held for sale		(10)
Balance, Ending	$ 2,205	$ 2,195

Goodwill and Identifiable Int_4

Goodwill and Identifiable Intangible Assets, Identifiable Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite-lived intangible assets, gross carrying amount	$ 762	$ 611
Finite-lived intangible assets, accumulated amortization	438	385
Net carrying amount	324	226
Amortization expense	49	43	$ 33
Estimated Amortization Expense for Identifiable Intangible Assets [Abstract]
Estimated amortization expense, 2019	51
Estimated amortization expense, 2020	47
Estimated amortization expense, 2021	42
Estimated amortization expense, 2022	37
Estimated amortization expense, 2023	28
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	828	677
Intangible assets, net carrying amount	390	292
IPR&D [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 66	66
Customer Contractual Relationships [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period	16 years
Finite-lived intangible assets, gross carrying amount	$ 468	393
Finite-lived intangible assets, accumulated amortization	288	257
Net carrying amount	$ 180	136
Technology [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period	9 years
Finite-lived intangible assets, gross carrying amount	$ 245	189
Finite-lived intangible assets, accumulated amortization	132	114
Net carrying amount	$ 113	75
Other [Member]
Finite-Lived Intangible Assets Subject to Amortization [Abstract]
Finite lived intangible assets, weighted average amortization period	9 years
Finite-lived intangible assets, gross carrying amount	$ 49	29
Finite-lived intangible assets, accumulated amortization	18	14
Net carrying amount	$ 31	$ 15

Other Current Liabilities and_3

Other Current Liabilities and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Current Liabilities [Abstract]
Accrued product warranty costs	$ 66		$ 69
Estimated costs in excess of estimated contract value to complete contracts in process in a loss position	40		63
Accrued interest	18		43
Estimated contingent purchase price payable for acquired businesses (see Note 3)	10		11
Deferred revenues	0		38
Other	154		143
Total other current liabilities	288	$ 318	367
Other Liabilities [Abstract]
Non-current income taxes payable (see Note 17)	161		164
Deferred compensation	53		49
Notes payable and capital lease obligations	40		16
Contract liabilities (see Note 4)	31	28	0
Accrued product warranty costs	22		30
Accrued workers' compensation	20		23
Estimated contingent purchase price payable for acquired businesses (see Note 3)	10		20
Deferred revenues	0		19
Other	99		77
Total other liabilities	$ 436	$ 412	$ 398

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Land	$ 34	$ 34
Buildings and improvements	428	404
Machinery, equipment, furniture and fixtures	2,081	1,959
Leasehold improvements	407	376
Gross property, plant and equipment	2,950	2,773
Accumulated depreciation and amortization	(1,781)	(1,663)
Property, plant and equipment, net	$ 1,169	$ 1,110

Debt, Components of Debt and Re

Debt, Components of Debt and Reconciliation to Carrying Amount of Current and Long-Term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2016	Dec. 22, 2015
Components of Debt [Abstract]
Repayments under the credit facility	$ 501,000,000	$ 1,328,000,000	$ 819,000,000
Proceeds under the credit facility	501,000,000	1,328,000,000	$ 819,000,000
Available borrowings under credit facility	1,000,000,000
4.95% Senior Notes due 2021 [Member]
Components of Debt [Abstract]
Unamortized discounts	(4,000,000)
3.85% Senior Notes due 2023 [Member]
Components of Debt [Abstract]
Unamortized discounts	(2,000,000)
3.95% Senior Notes due 2024 [Member]
Components of Debt [Abstract]
Unamortized discounts	(3,000,000)
Interest rate on senior notes					3.95%
3.85% Senior Notes due 2026 [Member]
Components of Debt [Abstract]
Unamortized discounts	(3,000,000)
4.40% Senior Notes due 2028 [Member]
Components of Debt [Abstract]
Unamortized discounts	$ (1,000,000)
Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Revolving credit facility expiration period	5 years
Total aggregate borrowings under revolving credit facility				$ 1,000,000,000
Revolving credit facility expiration date	Oct. 31, 2021
Uncommitted incremental revolving facilities and additional term loan facilities				$ 600,000,000
Revolving Credit Facility [Member] | Federal Funds Rate [Member] | Minimum [Member]
Line of Credit Facility [Abstract]
Applicable spread on base rate	0.125%
Revolving Credit Facility [Member] | Federal Funds Rate [Member] | Maximum [Member]
Line of Credit Facility [Abstract]
Applicable spread on base rate	1.00%
Revolving Credit Facility [Member] | Eurodollar [Member] | Minimum [Member]
Line of Credit Facility [Abstract]
Applicable spread on base rate	1.125%
Revolving Credit Facility [Member] | Eurodollar [Member] | Maximum [Member]
Line of Credit Facility [Abstract]
Applicable spread on base rate	2.00%
L3 Technologies [Member]
Components of Debt [Abstract]
Borrowings under Revolving Credit Facility	$ 0	0
Principal amount of long-term debt	3,350,000,000	3,350,000,000
Unamortized discounts	(7,000,000)	(7,000,000)
Deferred debt issue costs	(22,000,000)	(13,000,000)
Carrying amount of long-term debt	$ 3,321,000,000	3,330,000,000
L3 Technologies [Member] | 5.20% Senior Notes due 2019 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	5.20%
Debt instrument maturity period	2,019
L3 Technologies [Member] | 4.75% Senior Notes due 2020 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	4.75%
Debt instrument maturity period	2,020
L3 Technologies [Member] | 4.95% Senior Notes due 2021 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	4.95%
Debt instrument maturity period	2,021
L3 Technologies [Member] | 3.85% Senior Notes due 2023 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	3.85%
Debt instrument maturity period	2,023
L3 Technologies [Member] | 3.95% Senior Notes due 2024 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	3.95%
Debt instrument maturity period	2,024
L3 Technologies [Member] | 3.85% Senior Notes due 2026 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	3.85%
Debt instrument maturity period	2,026
L3 Technologies [Member] | 4.40% Senior Notes due 2028 [Member]
Components of Debt [Abstract]
Interest rate on senior notes	4.40%
Debt instrument maturity period	2,028
L3 Technologies [Member] | Revolving Credit Facility [Member]
Components of Debt [Abstract]
Repayments under the credit facility	$ (501,000,000)
Proceeds under the credit facility	501,000,000
Available borrowings under credit facility	1,000,000,000	1,000,000,000
Senior Notes [Member] | L3 Technologies [Member] | 5.20% Senior Notes due 2019 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	0	1,000,000,000
Senior Notes [Member] | L3 Technologies [Member] | 4.75% Senior Notes due 2020 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	0	800,000,000
Senior Notes [Member] | L3 Technologies [Member] | 4.95% Senior Notes due 2021 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	650,000,000	650,000,000
Senior Notes [Member] | L3 Technologies [Member] | 3.85% Senior Notes due 2023 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	800,000,000	0
Senior Notes [Member] | L3 Technologies [Member] | 3.95% Senior Notes due 2024 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	350,000,000	350,000,000
Senior Notes [Member] | L3 Technologies [Member] | 3.85% Senior Notes due 2026 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	550,000,000	550,000,000
Senior Notes [Member] | L3 Technologies [Member] | 4.40% Senior Notes due 2028 [Member]
Components of Debt [Abstract]
Principal amount of long-term debt	$ 1,000,000,000	$ 0

Debt, Outstanding Senior Subord

Debt, Outstanding Senior Subordinated Notes (Details) - USD ($)	Jul. 06, 2018	Jun. 06, 2018	Dec. 30, 2016	Nov. 15, 2016	May 20, 2016	Dec. 22, 2015	Sep. 28, 2018	Jun. 29, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instruments [Abstract]
Senior Notes due									Nov. 15, 2016
Senior Notes Redemption [Abstract]
Tender date									Jun. 6, 2018
Maturity date									Nov. 15, 2016
Interest paid									$ 183,000,000	$ 165,000,000	$ 162,000,000
Total cash payments, maturity									1,865,000,000	0	856,000,000
Debt retirement charge							$ 21,000,000	$ 48,000,000	$ (69,000,000)	0	$ (7,000,000)
4.95% Senior Notes due 2021 [Member]
Debt Instruments [Abstract]
Date of Issuance									Feb. 7, 2011
Amount Issued									$ 650,000,000
Discount									4,000,000
Net Cash Proceeds									$ 639,000,000
Effective Interest Rate									5.02%
Redemption at Treasury Rate									0.25%
3.85% Senior Notes due 2023 [Member]
Debt Instruments [Abstract]
Date of Issuance									Jun. 6, 2018
Amount Issued									$ 800,000,000
Discount									2,000,000
Net Cash Proceeds									$ 792,000,000
Effective Interest Rate									3.89%
Redemption at Treasury Rate									0.20%
3.95% Senior Notes due 2024 [Member]
Debt Instruments [Abstract]
Date of Issuance									May 28, 2014
Amount Issued									$ 650,000,000
Discount									3,000,000
Net Cash Proceeds									$ 641,000,000
Effective Interest Rate									4.02%
Redemption at Treasury Rate									0.20%
Interest rate on senior notes						3.95%
Senior Notes Redemption [Abstract]
Cash payments, tender offer						$ 300,000,000
3.85% Senior Notes due 2026 [Member]
Debt Instruments [Abstract]
Date of Issuance									Dec. 5, 2016
Amount Issued									$ 550,000,000
Discount									3,000,000
Net Cash Proceeds									$ 542,000,000
Effective Interest Rate									3.91%
Redemption at Treasury Rate									0.25%
4.40% Senior Notes due 2028 [Member]
Debt Instruments [Abstract]
Date of Issuance									Jun. 6, 2018
Amount Issued									$ 1,000,000,000
Discount									1,000,000
Net Cash Proceeds									$ 990,000,000
Effective Interest Rate									4.41%
Redemption at Treasury Rate									0.25%
5.20% Senior Notes due 2019 [Member]
Debt Instruments [Abstract]
Redemption price, premium (percent)	103.048%
Debt Instrument, Aggregate Principal Included in Tender Offer		$ 1,000,000,000
Senior Notes Redemption [Abstract]
Redemption Date									Jul. 6, 2018
Redemption amount	$ 317,000,000
Redemption price, premium (percent)	103.048%
Cash payments, redemption	$ 327,000,000
Interest paid	4,000,000
Total cash payments, redemption	331,000,000
Debt retirement charge	$ 10,000,000
4.75% Senior Notes due 2020 [Member]
Debt Instruments [Abstract]
Redemption price, premium (percent)	103.818%
Debt Instrument, Aggregate Principal Included in Tender Offer		800,000,000
Senior Notes Redemption [Abstract]
Redemption Date									Jul. 6, 2018
Redemption amount	$ 265,000,000
Redemption price, premium (percent)	103.818%
Cash payments, redemption	$ 275,000,000
Interest paid	6,000,000
Total cash payments, redemption	281,000,000
Debt retirement charge	11,000,000
5.20% Senior Notes due 2019, Tender Offer [Member]
Senior Notes Redemption [Abstract]
Tender amount		$ 683,000,000
Tender offer price, premium (percent)		103.282%
Cash payments, tender offer		$ 705,000,000
Interest paid		5,000,000
Total cash payments, tender offer		710,000,000
Debt retirement charge		24,000,000
4.75% Senior Notes due 2020, Tender Offer [Member]
Senior Notes Redemption [Abstract]
Tender amount		$ 535,000,000
Tender offer price, premium (percent)		104.092%
Cash payments, tender offer		$ 557,000,000
Interest paid		10,000,000
Total cash payments, tender offer		567,000,000
Debt retirement charge		24,000,000
1.50% Senior Notes due 2017 [Member]
Debt Instruments [Abstract]
Redemption price, premium (percent)			100.323%
Senior Notes Redemption [Abstract]
Redemption Date									Dec. 30, 2016
Redemption amount			$ 350,000,000
Redemption price, premium (percent)			100.323%
Cash payments, redemption			$ 351,000,000
Interest paid			1,000,000
Total cash payments, redemption			352,000,000
Debt retirement charge			2,000,000
3.95% Senior Notes due 2016 [Member]
Debt Instruments [Abstract]
Redemption price, premium (percent)					101.475%
Senior Notes Redemption [Abstract]
Redemption Date									May 20, 2016
Redemption amount					$ 300,000,000
Maturity amount			$ 200,000,000
Redemption price, premium (percent)					101.475%
Maturity price, premium (percent)				100.00%
Cash payments, redemption					$ 305,000,000
Cash payments, maturity				$ 200,000,000
Interest paid				0	0
Total cash payments, redemption					305,000,000
Total cash payments, maturity				200,000,000
Debt retirement charge				$ 0	$ 5,000,000
Notes due 2023 and 2028 [Member]
Debt Instruments [Abstract]
Proceeds from Issuance of Debt		1,782,000,000
Redemption of Senior Notes [Member]
Senior Notes Redemption [Abstract]
Non-cash retirement of unamortized debt issue costs and discounts	$ 1,000,000
Notes Settled under Tender Offers [Member]
Senior Notes Redemption [Abstract]
Non-cash retirement of unamortized debt issue costs and discounts		3,000,000
Tender offer fees		$ 1,000,000
L3 Technologies [Member]
Debt Instruments [Abstract]
Discount									$ 7,000,000	7,000,000
Redemption price, premium (percent)									101.00%
Senior Notes Redemption [Abstract]
Maturity amount									$ 3,350,000,000	$ 3,350,000,000
Redemption price, premium (percent)									101.00%
L3 Technologies [Member] | Minimum [Member]
Debt Instruments [Abstract]
Redemption price, premium (percent)									100.00%
Senior Notes Redemption [Abstract]
Redemption price, premium (percent)									100.00%
L3 Technologies [Member] | 4.95% Senior Notes due 2021 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									4.95%
L3 Technologies [Member] | 3.85% Senior Notes due 2023 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									3.85%
L3 Technologies [Member] | 3.95% Senior Notes due 2024 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									3.95%
L3 Technologies [Member] | 3.85% Senior Notes due 2026 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									3.85%
L3 Technologies [Member] | 4.40% Senior Notes due 2028 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									4.40%
L3 Technologies [Member] | 5.20% Senior Notes due 2019 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									5.20%
L3 Technologies [Member] | 4.75% Senior Notes due 2020 [Member]
Debt Instruments [Abstract]
Interest rate on senior notes									4.75%

Debt, Guarantees and Covenants

Debt, Guarantees and Covenants (Details) - L3 Technologies [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Ownership percentage	100.00%
Minimum consolidated interest coverage ratio under revolving credit facility covenants	300.00%
Minimum consolidated senior leverage ratio under revolving credit facility covenants	375.00%
Maximum consolidated senior leverage ratio under revolving credit facility covenants	400.00%
Minimum aggregate amount of indebtedness, swap contracts or guarantees to trigger cross default provisions	$ 75
Maximum days to cure defaults triggering cross default provisions	10 days
Minimum aggregate amount of senior notes accelerated to trigger cross default provisions	$ 100

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive (Loss) Income (AOCI), Summary of AOCI Balances Including Amounts Reclassified from AOCI into Net Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	$ 5,083
Other comprehensive (loss) income before reclassifications, net of tax	(85)	$ (6)	$ (193)
Amounts reclassified from AOCI, net of tax	51	41	41
Net current period other comprehensive (loss) income	(34)	35	(152)
Ending Balance	5,839	5,083
Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(691)	(726)	(574)
Ending Balance	(725)	(691)	(726)
Foreign Currency Translation Adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(54)	(178)	(101)
Other comprehensive (loss) income before reclassifications, net of tax	(82)	124	(77)
Amounts reclassified from AOCI, net of tax	0	0	0
Net current period other comprehensive (loss) income	(82)	124	(77)
Ending Balance	(136)	(54)	(178)
Unrealized (Losses) Gains on Hedging Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	9	6	(8)
Other comprehensive (loss) income before reclassifications, net of tax	(17)	7	3
Amounts reclassified from AOCI, net of tax	(2)	(4)	11
Net current period other comprehensive (loss) income	(19)	3	14
Ending Balance	(10)	9	6
Unrecognized (Losses) Gains and Prior Service Cost, Net [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(646)	(554)	(465)
Other comprehensive (loss) income before reclassifications, net of tax	14	(137)	(119)
Amounts reclassified from AOCI, net of tax	53	45	30
Net current period other comprehensive (loss) income	67	(92)	(89)
Ending Balance	$ (579)	$ (646)	$ (554)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive (Loss) Income (AOCI), Summary of Amounts Reclassified from AOCI into Net Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales									$ (9,138)	$ (8,542)	$ (8,252)
Income from continuing operations before income taxes									924	871	804
Provision for income taxes									(103)	(102)	(171)
Income from continuing operations	$ 232	$ 208	$ 189	$ 192	$ 271	$ 146	$ 195	$ 157	821	769	633
Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations									(51)	(41)	(41)
Losses on Hedging Instruments [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales									3	5	(13)
Income from continuing operations before income taxes									3	5	(13)
Provision for income taxes									(1)	(1)	2
Income from continuing operations									2	4	(11)
Amortization of Defined Benefit Pension Items [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes									(68)	(59)	(48)
Provision for income taxes									15	14	18
Income from continuing operations									$ (53)	$ (45)	$ (30)

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Millions	Feb. 19, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 08, 2017
Class of Stock [Line Items]
Aggregate amount of repurchased shares		$ 322,000,000	$ 180,000,000	$ 373,000,000
Cash dividends declared per common share (in dollars per share)		$ 3.2	$ 3	$ 2.8
Cash dividends		$ 254,000,000	$ 236,000,000	$ 220,000,000
Previously accrued dividends for employee-held stock awards		1,000,000
Subsequent Event [Member]
Class of Stock [Line Items]
Cash dividends declared per common share (in dollars per share)	$ 0.85
Dividend declared date	Feb. 12, 2019
Dividend paid date	Mar. 15, 2019
Dividend paid, record date	Mar. 1, 2019
Treasury Stock [Member]
Class of Stock [Line Items]
Aggregate amount of repurchased shares		$ 322,000,000	$ 180,000,000	$ 373,000,000
Share Repurchase Program December 4, 2014 [Member] | Treasury Stock [Member]
Class of Stock [Line Items]
Number of common shares repurchased (in shares)		1.6
Average price per share of repurchased shares (in dollars per share)		$ 196.64
Aggregate amount of repurchased shares		$ 322,000,000
Share Repurchase Program May 8, 2017 [Member]
Class of Stock [Line Items]
Amount of shares authorized to be repurchased					$ 1,500,000,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Liabilities [Abstract]
Contingent consideration	$ 31	$ 20	$ 31
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	31
Acquisitions and investments	11
Cash payments	(7)
Changes in fair value of contingent consideration, net	(15)
Balance at end of period	20
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets [Abstract]
Cash equivalents		660	310
Derivatives (foreign currency forward contracts)		0	0
Total assets		660	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
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets [Abstract]
Cash equivalents		0	0
Derivatives (foreign currency forward contracts)		1	11
Total assets		1	11
Liabilities [Abstract]
Derivatives (foreign currency forward contracts)		17	1
Contingent consideration	0	0	0
Total liabilities		17	1
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	0
Balance at end of period	0
Fair Value, Measurements, 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	20	31
Total liabilities		$ 20	$ 31
Business Combination, Contingent Consideration, Liability [Abstract]
Balance at beginning of period	31
Balance at end of period	$ 20

Financial Instruments (Details)

Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	$ 3,321	$ 3,330
Foreign currency forward contracts	(16)	10
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes	3,355	3,502
Foreign currency forward contracts	$ (16)	$ 10

Derivative Financial Instrume_3

Derivative Financial Instruments, Outstanding Forward Contracts By Currency (Details) - Foreign Currency Forward Contracts [Member] $ in Millions	Dec. 31, 2018USD ($)
Derivative [Line Items]
Notional amount	$ 415
U.S. Dollar [Member]
Derivative [Line Items]
Notional amount	204
Canadian Dollar [Member]
Derivative [Line Items]
Notional amount	123
Euro [Member]
Derivative [Line Items]
Notional amount	67
United Arab Emirates, Dirhams
Derivative [Line Items]
Notional amount	12
British Pound [Member]
Derivative [Line Items]
Notional amount	$ 9

Derivative Financial Instrume_4

Derivative Financial Instruments, Fair Value on Consolidated Balance Sheet (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Realized pre-tax gain (loss) on forward contract	$ 3	$ 5	$ (13)
Estimated net amount of existing gains expected to be reclassified into income within the next 12 months	10
Other Current Assets [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets	1	11
Other Current Assets [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, assets	1	11
Other Assets [Member] | Designated as Hedging Instruments [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 Current Liabilities [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities	13	1
Other Current Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities	13	1
Other Liabilities [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities	4	0
Other Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total derivative instruments, liabilities	$ 4	$ 0

L3's Earnings Per Share, Reconc

L3's Earnings Per Share, Reconciliation of Basic and Diluted Earnings Per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of net income (loss) [Abstract]
Net income	$ 231	$ 208	$ 379	$ 208	$ 293	$ 25	$ 207	$ 168	$ 1,026	$ 693	$ 724
Net income from continuing operations attributable to noncontrolling interests									(21)	(16)	(14)
Net income attributable to L3	225	202	375	203	289	22	202	164	1,005	677	710
Earnings (loss) attributable to L3's common shareholders: [Abstract]
Continuing operations									800	753	619
Discontinued operations, net of income tax									205	(76)	91
Net income attributable to L3	$ 225	$ 202	$ 375	$ 203	$ 289	$ 22	$ 202	$ 164	$ 1,005	$ 677	$ 710
Basic [Abstract]
Weighted average common shares outstanding (in shares)									78.5	78	77.4
Basic earnings (loss) per share attributable to common shareholders:
Continuing operations (in dollars per share)	$ 2.87	$ 2.57	$ 2.36	$ 2.40	$ 3.42	$ 1.83	$ 2.44	$ 1.97	$ 10.19	$ 9.65	$ 7.99
Discontinued operations, net of income tax (in dollars per share)									2.61	(0.97)	1.18
Basic earnings (loss) per share (in dollars per share)	2.86	2.57	4.78	2.60	3.70	0.28	2.59	2.11	$ 12.80	$ 8.68	$ 9.17
Common and potential common shares [Abstract]
Weighted average common shares outstanding (in shares)									78.5	78	77.4
Effect of dilutive securities									1.1	1.6	1.4
Common and potential common shares (in shares)									79.6	79.6	78.8
Diluted earnings (loss) per share attributable to common shareholders:
Continuing operations (in dollars per share)	2.83	2.54	2.33	2.34	3.34	1.79	2.39	1.93	$ 10.05	$ 9.46	$ 7.86
Discontinued operations, net of income tax (in dollars per share)									2.58	(0.95)	1.15
Diluted earnings (loss) per share (in dollars per share)	$ 2.82	$ 2.54	$ 4.72	$ 2.54	$ 3.62	$ 0.28	$ 2.54	$ 2.07	$ 12.63	$ 8.51	$ 9.01

L3's Earnings Per Share (Detail

L3's Earnings Per Share (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Shares excluded from computation of diluted earnings per share (in shares)	0.3	0.3	0.4

Income Taxes, Income from Conti

Income Taxes, Income from Continuing Operations Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Estimated tax benefit amount	$ 1	$ 79
Cumulative tax benefit amount	80
Benefit amount from remeasurement of deferred tax assets	98
Estimated toll charge	18
Domestic	630	649	$ 608
Foreign	294	222	196
Income from continuing operations before income taxes	$ 924	$ 871	$ 804

Income Taxes, Components of Cur

Income Taxes, Components of Current and Deferred Portions of Provision for Income Taxes on Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current income tax provision [Abstract]
Federal	$ 30	$ 44	$ 88
State and local	18	10	8
Foreign	62	56	48
Subtotal	110	110	144
Deferred income tax provision/(benefit) [Abstract]
Federal	(7)	(16)	25
State and local	0	6	2
Foreign	0	2	0
Subtotal	(7)	(8)	27
Total provision for income taxes	$ 103	$ 102	$ 171

Income Taxes, Reconciliation of

Income Taxes, Reconciliation of Statutory Federal Income Tax Rate to Effective Income Tax Rate on Continuing Operations (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	21.00%	35.00%	35.00%
State and local income taxes, net of federal income tax benefit	2.60%	2.00%	2.00%
Foreign income taxes	(0.90%)	(6.70%)	(3.00%)
Manufacturing benefits	(0.00%)	(1.40%)	(2.20%)
Research and experimentation and other tax credits	(5.20%)	(4.10%)	(4.60%)
Resolution of tax contingencies	(3.80%)	(0.40%)	(3.10%)
Tax deductible dividends	(0.50%)	(0.90%)	(1.00%)
Equity compensation - excess income tax benefits	(4.00%)	(2.30%)	(2.10%)
Goodwill impairment	1.30%	0.00%	0.00%
Tax Reform	(0.10%)	(9.10%)	0.00%
Other, net	0.70%	(0.40%)	0.30%
Effective income tax rate on continuing operations	11.10%	11.70%	21.30%

Income Taxes, Components of Net

Income Taxes, Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets [Abstract]
Inventoried costs	$ 47	$ 44
Compensation and benefits	90	94
Pension and postretirement benefits	271	281
Loss carryforwards	13	12
Tax credit carryforwards	4	5
Other	67	57
Deferred tax assets	492	493
Less: valuation allowance	(14)	(10)
Deferred tax assets, net of valuation allowance	478	483
Deferred tax liabilities [Abstract]
Goodwill and other intangible assets	(549)	(514)
Income recognition on contracts in process	(18)	(24)
Property, plant and equipment	(66)	(59)
Other	(36)	(41)
Deferred tax liabilities	(669)	(638)
Total deferred tax liabilities, net of valuation allowance	$ (191)	$ (155)

Income Taxes, Classification of

Income Taxes, Classification of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Non-current deferred tax assets	$ 5		$ 3
Non-current deferred tax liabilities	(196)	$ (162)	(158)
Total deferred tax liabilities, net of valuation allowance	$ (191)		$ (155)

Income Taxes, Summary of Loss a

Income Taxes, Summary of Loss and Tax Credit Carryforwards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Tax Effected	$ 13	$ 12
Capital loss carryforwards, Valuation Allowance, Tax Effected	(14)	(10)
Total loss carryforwards, Tax Effected	13
Tax credit carryforwards, Tax Effected	4	$ 5
Total loss carryforwards, Valuation Allowance Tax Effected	(7)
Tax credit carryforwards, Valuation Allowances Tax Effected	(3)
Federal [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Gross	23
Capital loss carryforwards, Tax Effected	5
Capital loss carryforwards, Valuation Allowance, Gross	(5)
Capital loss carryforwards, Valuation Allowance, Tax Effected	$ (1)
Federal [Member] | Minimum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration Period	2,026
Federal [Member] | Maximum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration Period	2,036
Foreign [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Gross	$ 18
Capital loss carryforwards, Tax Effected	4
Capital loss carryforwards, Valuation Allowance, Gross	(10)
Capital loss carryforwards, Valuation Allowance, Tax Effected	(3)
State [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Gross	291
Capital loss carryforwards, Tax Effected	4
Capital loss carryforwards, Valuation Allowance, Gross	(131)
Capital loss carryforwards, Valuation Allowance, Tax Effected	(3)
Tax credit carryforwards, Tax Effected	4
Tax credit carryforwards, Gross	5
Tax credit carryforwards, Valuation Allowances Gross	(4)
Tax credit carryforwards, Valuation Allowances Tax Effected	$ (3)
State [Member] | Minimum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration Period	2,019
Tax credit carryforwards, Expiration Periods	2,019
State [Member] | Maximum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration Period	2,038
Tax credit carryforwards, Expiration Periods	2,033

Income Taxes, Reconciliation _2

Income Taxes, Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Interest and Penalties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 178	$ 110	$ 124	$ 183
Unrecognized tax benefits that would reduce the effective income tax rate				$ 150
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	178	110	124
Additions for tax positions related to the current year	13	14	16
Additions for tax positions related to prior years	37	66	2
Reductions for tax positions related to prior years	(20)	(4)	(24)
Reductions for tax positions related to settlements with taxing authorities	(7)	0	(1)
Reduction for tax positions related to prior years as a result of a lapse of statute of limitations	(18)	(8)	(7)
Balance at December 31	$ 183	$ 178	$ 110

Income Taxes, Income Tax Return

Income Taxes, Income Tax Returns (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Anticipated decrease in unrecognized tax benefits over the next 12 months	$ 27
Reversal of previously accrued income tax expense, including interest and penalties	35	$ 4	$ 25
Accrued potential interest included within current and non-current income taxes payable	15
Accrued potential interest included within current and non-current income taxes payable after income taxes	11
Potential penalties	9	8
Benefit (Expense) Related Items Included in Income Taxes Expenses	2	$ 5
Undistributed earnings of non-U.S. Companies	$ 1,000

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock-Based Compensation Plans (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 03, 2016	Feb. 23, 2016	Feb. 22, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of L-3 Holdings common stock available to be awarded (in shares)					4,260	3,690
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Stock based compensation	$ 60	$ 57	$ 49
Income taxes	(13)	(12)	(18)
Total after income taxes	47	45	31
Less: Stock-based compensation recorded in discontinued operations, net of income taxes	0	1	1
Stock-based compensation recorded in continuing operations, net of income taxes	47	44	30
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Stock based compensation	7	7	10
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Stock based compensation	43	43	35
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Stock based compensation	$ 10	$ 7	$ 4
2008 Long Term Performance Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of additional shares authorized for issuance under the amendment (in shares)				6,800
Number of shares authorized for issuance under the amendment (in shares)				26,000
Maximum number of shares of L-3 Holdings common stock may be issued pursuant to "full value" awards under the amendment (in shares)	7,000

Stock-Based Compensation, Sto_2

Stock-Based Compensation, Stock Options (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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)	$ 37.72	$ 28.35	$ 15.90
Intrinsic value of stock options exercised	$ 165	$ 44	$ 34
Unrecognized compensation costs related to stock awards	8
Unrecognized compensation costs related to equity awards after income taxes	$ 7
Weighted average remaining period for recognition of unrecognized costs related to equity awards	1 year 6 months 1 day
Actual income tax benefit realized related to compensation deductions arising from the exercise of stock options	$ 40	$ 16	$ 12
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning Balance, Outstanding (in shares)	2,698,900
Options granted (in shares)	221,900
Options exercised (in shares)	(1,533,400)
Options forfeited (in shares)	(175,700)
Ending Balance, Outstanding (in shares)	1,211,700	2,698,900
Vested and expected to vest (in shares)	1,205,600
Exercisable (in shares)	666,100
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning Balance, Outstanding (in dollars per share)	$ 113.67
Options granted (in dollars per share)	208.92
Options exercised (in dollars per share)	97.49
Options forfeited (in dollars per share)	147.37
Ending Balance, Outstanding (in dollars per share)	146.70	$ 113.67
Vested and expected to vest (in dollars per share)	146.48
Exercisable (in dollars per share)	$ 119.03
Weighted Average Remaining Contractual Term [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 4 months 24 days	5 years 8 months 12 days
Vested and expected to vest	6 years 4 months 24 days
Exercisable	4 years 8 months 12 days
Aggregate Intrinsic Value [Abstract]
Beginning Balance, Outstanding	$ 227
Ending Balance, Outstanding	42	$ 227
Vested and expected to Vest	42
Exercisable	$ 37
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected holding period	5 years 2 months 12 days	5 years 2 months 12 days	5 years
Expected volatility	19.80%	19.90%	21.30%
Expected dividend yield	1.80%	2.00%	2.80%
Risk-free interest rate	2.70%	2.00%	1.10%

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Units (Details) - Restricted Stock [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Weighted average grant date fair value (in dollars per share)	$ 205.73	$ 169.23	$ 116.72
Length of service after grant date	1 year
Retirement eligibility, employee age	60 years
Service period, minimum	5 years
Retirement eligibility, employee age with no service requirement	65 years
Unrecognized compensation costs related to stock awards	$ 46
Unrecognized compensation costs related to equity awards after income taxes	$ 36
Weighted average remaining period for recognition of unrecognized costs related to equity awards	1 year 4 months 24 days
Fair value of restricted stock unit awards vested	$ 67	$ 53	$ 57
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning Balance, Nonvested (in shares)	902,700
Granted (in shares)	317,900
Vested (in shares)	(320,700)
Forfeited (in shares)	(86,200)
Ending Balance, Nonvested (in shares)	813,700	902,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning Balance, Nonvested (in dollars per share)	$ 137.12
Granted (in dollars per share)	205.73	$ 169.23	$ 116.72
Vested (in dollars per share)	137
Forfeited (in dollars per share)	142.21
Ending Balance, Nonvested (in dollars per share)	$ 163.44	$ 137.12
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 Units [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 209.91	$ 168.80	$ 116.20
Length of service after grant date	3 years	3 years	3 years
Unrecognized compensation costs related to stock awards	$ 10
Unrecognized compensation costs related to equity awards after income taxes	$ 10
Weighted average remaining period for recognition of unrecognized costs related to equity awards	1 year 6 months 1 day
Total performance units earned (in shares)	57,508
Fair market value performance units earned as of their vesting date	$ 11
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning Balance, Nonvested (in shares)	132,100
Granted (in shares)	22,100
Increase due to expected performance (in shares)	25,300
Vested (in shares)	(57,500)
Forfeited (in shares)	(27,000)
Ending Balance, Nonvested (in shares)	95,000	132,100
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning Balance, Nonvested (in dollars per share)	$ 135.99
Granted (in dollars per share)	209.91	$ 168.80	$ 116.20
Increase due to expected performance (in dollars per share)	38.96
Vested (in dollars per share)	116.20
Forfeited (in dollars per share)	133.41
Ending Balance, Nonvested (in dollars per share)	$ 140.14	$ 135.99
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range	200.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range	0.00%

Stock-Based Compensation, Emplo

Stock-Based Compensation, Employee Stock Purchase Plan (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2019	Jul. 31, 2018	Dec. 31, 2018	May 03, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee discount on the purchase of common stock			5.00%
2008 Long Term Performance Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance under the amendment (in shares)				26
2009 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair market value for offering period			95.00%
Offering period to purchase shares			6 months
Share purchases funded through payroll deductions, value			$ 21,250
Issued shares under the ESPP (in shares)		0.1
Average price of issued shares under the ESPP (in dollars per share)		$ 192.96
Number of shares authorized for issuance under the amendment (in shares)			3.3
2009 Employee Stock Purchase Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share purchases funded through payroll deductions, percentage			10.00%
2009 Employee Stock Purchase Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued shares under the ESPP (in shares)	0.1
Average price of issued shares under the ESPP (in dollars per share)	$ 162.91

Commitments and Contingencies,

Commitments and Contingencies, Non-Cancelable Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,019	$ 115
2,020	134
2,021	82
2,022	73
2,023	65
Thereafter	506
Total minimum payments required	975
Sublease rentals under non-cancelable leases	(7)
Net minimum payments required	968
Rent expense, net of sublease income	105	$ 103	$ 97
Sublease rental income	2	$ 1	$ 2
Real Estate [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,019	111
2,020	132
2,021	81
2,022	73
2,023	65
Thereafter	506
Total minimum payments required	968
Sublease rentals under non-cancelable leases	(7)
Net minimum payments required	961
Equipment [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,019	4
2,020	2
2,021	1
2,022	0
2,023	0
Thereafter	0
Total minimum payments required	7
Sublease rentals under non-cancelable leases	0
Net minimum payments required	$ 7

Commitments and Contingencies_2

Commitments and Contingencies, Letters of Credit and Guarantees (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)lease_agreement	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Total outstanding letters of credit	$ 410	$ 416
Available borrowings under Credit Facility	$ 1,000
Number of existing real estate lease agreements | lease_agreement	3
Real estate lease agreements, expiry date	Aug. 31, 2020
Purchase price of property on or before expiration date	$ 45
Residual guarantee amount	39
Maximum amount of supplemental rent payment	6
Aggregate residual guarantee amount	$ 39

Commitments and Contingencies_3

Commitments and Contingencies, Litigation Matters (Details) - HVC Alkmaar [Member] € in Millions	Jul. 23, 2014EUR (€)
Property Damages [Member]
Loss Contingencies [Line Items]
Claims for estimated damages	€ 11
Business Interruption [Member]
Loss Contingencies [Line Items]
Claims for estimated damages	€ 35

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits, Changes in Benefit Obligations, Plan Assets and Funded Status and Aggregate Balance Sheet Impact (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets and (liabilities) recognized on the consolidated balance sheets consist of [Abstract]
Non-current liabilities	$ (1,211)	$ (1,313)
Pension Plans [Member]
Change in benefit obligation [Abstract]
Benefit obligation at the beginning of the year	4,228	3,758
Service cost	103	97	$ 94
Interest cost	143	142	135
Plan participants' contributions	2	2
Amendments	(13)	0
Actuarial loss (gain)	(340)	391
Foreign currency exchange rate changes	(27)	22
Curtailments and special termination benefits	0	2
Benefits paid	(159)	(186)
Benefit obligation at the end of the year	3,937	4,228	3,758
Change in plan assets [Abstract]
Fair value of plan assets at the beginning of the year	3,047	2,721
Actual return on plan assets	(119)	391
Employer contributions	96	97
Plan participants' contributions	2	2
Foreign currency exchange rate changes	(27)	22
Benefits paid	(159)	(186)
Fair value of plan assets at the end of the year	2,840	3,047	2,721
Unfunded status at the end of the year	(1,097)	(1,181)
Assets and (liabilities) recognized on the consolidated balance sheets consist of [Abstract]
Non-current assets	40	48
Current liabilities	(8)	(6)
Non-current liabilities	(1,129)	(1,223)
Total	(1,097)	(1,181)
Postretirement Benefit Plans [Member]
Change in benefit obligation [Abstract]
Benefit obligation at the beginning of the year	165	177
Service cost	2	2	2
Interest cost	5	5	6
Plan participants' contributions	5	5
Amendments	0	0
Actuarial loss (gain)	(11)	(13)
Foreign currency exchange rate changes	(2)	2
Curtailments and special termination benefits	0	0
Benefits paid	(14)	(13)
Benefit obligation at the end of the year	150	165	177
Change in plan assets [Abstract]
Fair value of plan assets at the beginning of the year	67	60
Actual return on plan assets	(3)	8
Employer contributions	6	7
Plan participants' contributions	5	5
Foreign currency exchange rate changes	0	0
Benefits paid	(14)	(13)
Fair value of plan assets at the end of the year	61	67	$ 60
Unfunded status at the end of the year	(89)	(98)
Assets and (liabilities) recognized on the consolidated balance sheets consist of [Abstract]
Non-current assets	0	0
Current liabilities	(7)	(8)
Non-current liabilities	(82)	(90)
Total	$ (89)	$ (98)

Pension and Other Postretirem_4

Pension and Other Postretirement Benefits, Net Loss and Prior Service Cost Balances in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	$ 958	$ 1,035
Prior service cost (credit)	(1)	10
Total amount recognized	957	1,045
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(3)	(3)
Prior service cost (credit)	(25)	(27)
Total amount recognized	$ (28)	$ (30)

Pension and Other Postretirem_5

Pension and Other Postretirement Benefits, Aggregate Accumulated Benefit Obligation in Excess of Fair Value (Details) - Pension Plans [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Aggregate accumulated benefit obligation (ABO)	$ 3,614	$ 3,831
Projected benefit obligation	3,681	3,875
Accumulated benefit obligation	3,367	3,490
Fair value of plan assets	$ 2,547	$ 2,651

Pension and Other Postretirem_6

Pension and Other Postretirement Benefits, Weighted Average Assumptions Used to Determine Benefit Obligations (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plans [Member]
Benefit obligations [Abstract]
Discount rate	4.43%	3.78%
Rate of compensation increase	3.50%	3.50%
Pension Plans [Member] | U.S. [Member]
Benefit obligations [Abstract]
Rate of compensation increase	3.50%	3.50%
Assumptions used to determine net periodic benefit cost, weighted average discount rate	4.48%	3.81%
Pension Plans [Member] | Canada [Member]
Benefit obligations [Abstract]
Rate of compensation increase	3.50%	3.50%
Assumptions used to determine net periodic benefit cost, weighted average discount rate	3.88%	3.39%
Postretirement Benefit Plans [Member]
Benefit obligations [Abstract]
Discount rate	4.28%	3.59%
Postretirement Benefit Plans [Member] | U.S. [Member]
Benefit obligations [Abstract]
Assumptions used to determine net periodic benefit cost, weighted average discount rate	4.34%	3.63%
Postretirement Benefit Plans [Member] | Canada [Member]
Benefit obligations [Abstract]
Assumptions used to determine net periodic benefit cost, weighted average discount rate	3.81%	3.33%

Pension and Other Postretirem_7

Pension and Other Postretirement Benefits, Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 103	$ 97	$ 94
Interest cost	143	142	135
Expected return on plan assets	(223)	(197)	(186)
Amortization of prior service cost (credits)	(2)	1	0
Amortization of net loss (gains)	74	61	52
Curtailment loss and special termination benefits	1	6	2
Net periodic benefit cost	96	110	97
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	2	2	2
Interest cost	5	5	6
Expected return on plan assets	(5)	(4)	(4)
Amortization of prior service cost (credits)	(1)	(1)	(2)
Amortization of net loss (gains)	(3)	(2)	(2)
Curtailment loss and special termination benefits	0	0	0
Net periodic benefit cost	(2)	0	0
Accounting Standards Update 2017-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
New accounting pronouncement or change in accounting principle, effect of change on operating income	$ 11	11	1
Accounting Standards Update 2017-07 [Member] | Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost		$ 15	$ 14

Pension and Other Postretirem_8

Pension and Other Postretirement Benefits, Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	$ 41
Prior service credit	(2)
Total amount expected to be amortized	39
Pension Plans [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	(3)	$ 200	$ 179
Prior service (cost) credit	(13)	(4)	15
Amortization of net (loss) gain	(74)	(61)	(52)
Amortization of prior service (cost) credit	2	(1)	0
Total recognized in other comprehensive income (loss)	(88)	134	142
Total recognized in net periodic benefit cost and other comprehensive income (loss)	8	244	239
Net loss (gain)	44
Prior service credit	(2)
Total amount expected to be amortized	42
Postretirement Benefit Plans [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	(2)	(17)	(4)
Prior service (cost) credit	0	0	(2)
Amortization of net (loss) gain	3	2	2
Amortization of prior service (cost) credit	1	1	2
Total recognized in other comprehensive income (loss)	2	(14)	(2)
Total recognized in net periodic benefit cost and other comprehensive income (loss)	0	$ (14)	$ (2)
Net loss (gain)	(3)
Prior service credit	0
Total amount expected to be amortized	$ (3)

Pension and Other Postretirem_9

Pension and Other Postretirement Benefits, Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Effect of one percentage point increase on total service and interest cost	$ 0
Effect of one percentage point decrease on total service and interest cost	0
Effect of one percentage point increase on postretirement benefit obligations	4
Effect of one percentage point decrease on postretirement benefit obligations	$ (4)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.78%	4.40%	4.67%
Service cost	3.84%	4.55%	4.83%
Interest cost	3.45%	3.84%	3.95%
Expected long-term return on plan assets	7.92%	7.92%	7.92%
Rate of compensation increase	3.50%	3.50%	3.50%
Pension Plans [Member] | U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.81%	4.45%	4.73%
Expected long-term return on plan assets	8.00%	8.00%	8.00%
Rate of compensation increase	3.50%	3.50%	3.50%
Health care cost trend rate, covering retirees under 65 years of age next fiscal year	6.75%
Health care cost trend rate, covering retirees over 65 years of age next fiscal year	7.75%
Pension Plans [Member] | U.S. [Member] | 2028 and Thereafter [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate, covering retirees under 65 years of age	4.50%
Pension Plans [Member] | U.S. [Member] | 2032 and Thereafter [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate, covering retirees over 65 years of age	4.50%
Pension Plans [Member] | Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.39%	3.79%	3.93%
Expected long-term return on plan assets	7.25%	7.25%	7.25%
Rate of compensation increase	3.50%	3.50%	3.50%
Health care cost trend rate next fiscal year	7.00%
Pension Plans [Member] | Canada [Member] | 2028 and Thereafter [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate	5.00%
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.59%	4.05%	4.22%
Service cost	3.64%	4.21%	4.37%
Interest cost	3.07%	3.26%	3.26%
Expected long-term return on plan assets	8.00%	7.43%	7.42%
Postretirement Benefit Plans [Member] | U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.63%	4.11%	4.28%
Postretirement Benefit Plans [Member] | Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	3.33%	3.64%	3.74%

Pension and Other Postretire_10

Pension and Other Postretirement Benefits, Weighted Average Asset Allocations by Asset Category (Details) - Pension and Postemployment Retirement Benefit Plans [Member]	Dec. 31, 2018	Dec. 31, 2017
U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	100.00%	100.00%
U.S. [Member] | Total Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	57.00%	58.00%
U.S. [Member] | Total Equities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	45.00%
U.S. [Member] | Total Equities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	75.00%
U.S. [Member] | Domestic Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	47.00%	47.00%
U.S. [Member] | Domestic Equity [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	30.00%
U.S. [Member] | Domestic Equity [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	60.00%
U.S. [Member] | International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	10.00%	11.00%
U.S. [Member] | International Equity [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	10.00%
U.S. [Member] | International Equity [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	20.00%
U.S. [Member] | Total Fixed Income Securities and Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)
Weighted-average asset allocations
U.S. [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	30.00%	28.00%
U.S. [Member] | Fixed Income Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	20.00%
U.S. [Member] | Fixed Income Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	40.00%
U.S. [Member] | Other, Primarily Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	6.00%	7.00%
U.S. [Member] | Other, Primarily Cash and Cash Equivalents [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	0.00%
U.S. [Member] | Other, Primarily Cash and Cash Equivalents [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	15.00%
U.S. [Member] | Real Estate Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	7.00%	7.00%
U.S. [Member] | Real Estate Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	0.00%
U.S. [Member] | Real Estate Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	15.00%
Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	100.00%	100.00%
Canada [Member] | Total Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	65.00%	62.00%
Canada [Member] | Total Equities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	40.00%
Canada [Member] | Total Equities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	80.00%
Canada [Member] | Domestic Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	13.00%	15.00%
Canada [Member] | International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	52.00%	47.00%
Canada [Member] | Total Fixed Income Securities and Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	35.00%	38.00%
Canada [Member] | Total Fixed Income Securities and Cash and Cash Equivalents [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	20.00%
Canada [Member] | Total Fixed Income Securities and Cash and Cash Equivalents [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations (percent)	60.00%
Canada [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	28.00%	25.00%
Canada [Member] | Other, Primarily Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	7.00%	13.00%
Canada [Member] | Real Estate Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	0.00%	0.00%

Pension and Other Postretire_11

Pension and Other Postretirement Benefits, Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Equity securities [Abstract]
Fair value of company's plan assets	$ 2,840	$ 3,047	$ 2,721
Pension Plans [Member] | U.S. [Member]
Equity securities [Abstract]
Liabilities for unsettled trades, net	(9)	(30)
Fair value of company's plan assets	$ 2,537	$ 2,704
Percentage of mutual fund in total investment in fixed income - investment grade securities	66.00%	62.00%
Percentage of pooled bond funds in total investment in fixed income - investment grade securities	34.00%	38.00%
Pension Plans [Member] | U.S. [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	$ 1,793	$ 1,909
Pension Plans [Member] | U.S. [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	577	622
Pension Plans [Member] | U.S. [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | U.S. Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	1,205	1,297
Pension Plans [Member] | U.S. [Member] | U.S. Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	1,205	1,297
Pension Plans [Member] | U.S. [Member] | U.S. Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | U.S. Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | International Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	90	87
Pension Plans [Member] | U.S. [Member] | International Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	90	87
Pension Plans [Member] | U.S. [Member] | International Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | International Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Fixed Income - Investment Grade [Member]
Equity securities [Abstract]
Fair value of company's plan assets	473	534
Pension Plans [Member] | U.S. [Member] | Fixed Income - Investment Grade [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	313	329
Pension Plans [Member] | U.S. [Member] | Fixed Income - Investment Grade [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	160	205
Pension Plans [Member] | U.S. [Member] | Fixed Income - Investment Grade [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Fixed Income - High Yield [Member]
Equity securities [Abstract]
Fair value of company's plan assets	271	219
Pension Plans [Member] | U.S. [Member] | Fixed Income - High Yield [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Fixed Income - High Yield [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	271	219
Pension Plans [Member] | U.S. [Member] | Fixed Income - High Yield [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Real Estate Investment Trusts [Member]
Equity securities [Abstract]
Fair value of company's plan assets	185	196
Pension Plans [Member] | U.S. [Member] | Real Estate Investment Trusts [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	185	196
Pension Plans [Member] | U.S. [Member] | Real Estate Investment Trusts [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Real Estate Investment Trusts [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Other [Member]
Equity securities [Abstract]
Fair value of company's plan assets	146	198
Pension Plans [Member] | U.S. [Member] | Other [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Other [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	146	198
Pension Plans [Member] | U.S. [Member] | Other [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | U.S. [Member] | Total Assets at Fair Value [Member]
Equity securities [Abstract]
Fair value of company's plan assets	2,370	2,531
Pension Plans [Member] | U.S. [Member] | Other Investments Measured at Net Asset Value [Member]
Equity securities [Abstract]
Fair value of company's plan assets	176	203
Pension Plans [Member] | Canada [Member]
Equity securities [Abstract]
Liabilities for unsettled trades, net	0	0
Fair value of company's plan assets	$ 303	$ 343
Percentage of mutual fund investment in equity trust funds	30.00%	31.00%
Percentage of pooled bond fund investment in equity trust funds	70.00%	69.00%
Pension Plans [Member] | Canada [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	$ 163	$ 184
Pension Plans [Member] | Canada [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	16	37
Pension Plans [Member] | Canada [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | U.S. Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	64	71
Pension Plans [Member] | Canada [Member] | U.S. Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	64	71
Pension Plans [Member] | Canada [Member] | U.S. Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | U.S. Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | International Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	95	105
Pension Plans [Member] | Canada [Member] | International Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	95	105
Pension Plans [Member] | Canada [Member] | International Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | International Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - Investment Grade [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - Investment Grade [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - Investment Grade [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - Investment Grade [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - High Yield [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - High Yield [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - High Yield [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Fixed Income - High Yield [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Real Estate Investment Trusts [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Real Estate Investment Trusts [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Real Estate Investment Trusts [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Real Estate Investment Trusts [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Other [Member]
Equity securities [Abstract]
Fair value of company's plan assets	20	45
Pension Plans [Member] | Canada [Member] | Other [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	4	8
Pension Plans [Member] | Canada [Member] | Other [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	16	37
Pension Plans [Member] | Canada [Member] | Other [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Pension Plans [Member] | Canada [Member] | Total Assets at Fair Value [Member]
Equity securities [Abstract]
Fair value of company's plan assets	179	221
Pension Plans [Member] | Canada [Member] | Other Investments Measured at Net Asset Value [Member]
Equity securities [Abstract]
Fair value of company's plan assets	$ 124	$ 122
Minimum [Member]
Equity securities [Abstract]
Notice Required Prior to Withdrawal from Bond Funds	0 days
Maximum [Member]
Equity securities [Abstract]
Notice Required Prior to Withdrawal from Bond Funds	3 days

Pension and Other Postretire_12

Pension and Other Postretirement Benefits, Fair Value of Postretirement Benefit Plans Assets (Details) - Postretirement Benefit Plans [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity securities [Abstract]
Fair value of company's plan assets	$ 61	$ 67	$ 60
Percentage of mutual fund in total investment in fixed income - investment grade securities	82.00%	77.00%
Percentage of pooled bond funds in total investment in fixed income - investment grade securities	18.00%	23.00%
Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	$ 48	$ 53
Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	10	11
Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
U.S. Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	35	38
U.S. Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	35	38
U.S. Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
U.S. Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
International Equity [Member]
Equity securities [Abstract]
Fair value of company's plan assets	1	2
International Equity [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	1	2
International Equity [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
International Equity [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Fixed Income - Investment Grade [Member]
Equity securities [Abstract]
Fair value of company's plan assets	11	13
Fixed Income - Investment Grade [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	9	10
Fixed Income - Investment Grade [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	2	3
Fixed Income - Investment Grade [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Fixed Income - High Yield [Member]
Equity securities [Abstract]
Fair value of company's plan assets	4	3
Fixed Income - High Yield [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Fixed Income - High Yield [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	4	3
Fixed Income - High Yield [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Real Estate Investment Trusts [Member]
Equity securities [Abstract]
Fair value of company's plan assets	3	3
Real Estate Investment Trusts [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	3	3
Real Estate Investment Trusts [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Real Estate Investment Trusts [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Other [Member]
Equity securities [Abstract]
Fair value of company's plan assets	4	5
Other [Member] | Level 1 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Other [Member] | Level 2 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	4	5
Other [Member] | Level 3 [Member]
Equity securities [Abstract]
Fair value of company's plan assets	0	0
Total Assets at Fair Value [Member]
Equity securities [Abstract]
Fair value of company's plan assets	58	64
Other Investments Measured at Net Asset Value [Member]
Equity securities [Abstract]
Liabilities for unsettled trades, net	$ 3	$ 3

Pension and Other Postretire_13

Pension and Other Postretirement Benefits, Contributions (Details) $ in Millions	Dec. 31, 2018USD ($)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contributions to plans in 2018	$ 80
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contributions to plans in 2018	$ 8

Pension and Other Postretire_14

Pension and Other Postretirement Benefits, Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2018USD ($)
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,019	$ 168
2,020	176
2,021	184
2,022	194
2,023	201
Years 2024-2028	1,150
Postretirement Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,019	12
2,020	12
2,021	12
2,022	12
2,023	12
Years 2024-2028	53
Subsidy Receipts, 2019	0
Subsidy Receipts, 2020	0
Subsidy Receipts, 2021	0
Subsidy Receipts, 2022	0
Subsidy Receipts, 2023	0
Subsidy Receipts, Years 2024-2028	$ 1

Pension and Other Postretire_15

Pension and Other Postretirement Benefits, Employee Savings Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Cash contributed to multiemployer plans (less than)	$ 1
Expenses of multiemployer plans (less than)	1
Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's matching contributions in L-3 Holdings' common stock and cash	118	$ 115	$ 118
Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's matching contributions in L-3 Holdings' common stock and cash	$ 2	$ 8	$ 12

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 183	$ 165	$ 162
Income tax payments	108	163	120
Income tax refunds	$ 7	$ 16	$ 8

Segment Information, Products a

Segment Information, Products and Services (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018USD ($)	Sep. 28, 2018USD ($)	Jun. 29, 2018USD ($)	Mar. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 29, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)Segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Jan. 01, 2018USD ($)
Segment Reporting [Abstract]
Corporate expenses									$ 15	$ 32	$ 29
Number of reportable segments | Segment									3
Segment Reporting Information [Line Items]
Total net sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	9,573	9,210
Segment Reporting Information, Operating Income (Loss) [Abstract]
Operating income	276	$ 272	$ 321	$ 251	268	$ 232	$ 294	$ 237	1,120	1,031	958
Gain on sale of the Crestview Aerospace and TCS businesses									42	0	0
Merger and acquisition related expenses									(28)	0	0
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization									241	225	198
Capital Expenditures [Abstract]
Capital Expenditures									232	224	210
Total Assets [Abstract]
Total Assets	13,518				12,729				13,518	12,729	11,865	$ 12,730
Assets held for sale	0				135				0	135	0	138
Assets of discontinued operations	0				306				0	306	481	$ 285
ISR Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									4,441
C&NS [Member]
Segment Reporting Information [Line Items]
Total net sales									3,059
Electronic Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									2,744
Operating Segments [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Operating income									1,106	1,031	958
Operating Segments [Member] | ISR Systems [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Operating income									448	348	362
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization									92	87	80
Capital Expenditures [Abstract]
Capital Expenditures									57	74	83
Total Assets [Abstract]
Total Assets	4,720				4,135				4,720	4,135	4,117
Operating Segments [Member] | C&NS [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Operating income									282	362	298
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization									69	66	63
Capital Expenditures [Abstract]
Capital Expenditures									50	76	51
Total Assets [Abstract]
Total Assets	3,670				3,505				3,670	3,505	3,258
Operating Segments [Member] | Electronic Systems [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Operating income									376	321	298
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization									80	72	55
Capital Expenditures [Abstract]
Capital Expenditures									108	52	66
Total Assets [Abstract]
Total Assets	4,128				3,939				4,128	3,939	3,542
Corporate [Member]
Capital Expenditures [Abstract]
Capital Expenditures									17	22	10
Total Assets [Abstract]
Total Assets	$ 1,000				$ 709				1,000	709	467
Product [Member]
Segment Reporting Information [Line Items]
Total net sales									7,165	6,733	6,453
Product [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									2,907
Product [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Total net sales									2,299
Product [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									1,959
Product [Member] | Operating Segments [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									2,907	2,540	2,662
Product [Member] | Operating Segments [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Total net sales									2,307	2,424	2,238
Product [Member] | Operating Segments [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									2,007	1,814	1,617
Product [Member] | Elimination of Intercompany Sales [Member]
Segment Reporting Information [Line Items]
Total net sales									(56)	(45)	(64)
Service [Member]
Segment Reporting Information [Line Items]
Total net sales									3,079	2,840	2,757
Service [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									1,534
Service [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Total net sales									760
Service [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									785
Service [Member] | Operating Segments [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									1,549	1,463	1,450
Service [Member] | Operating Segments [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Total net sales									787	717	678
Service [Member] | Operating Segments [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Total net sales									789	695	653
Service [Member] | Elimination of Intercompany Sales [Member]
Segment Reporting Information [Line Items]
Total net sales									$ (46)	$ (35)	$ (24)

Segment Information, Sales by T

Segment Information, Sales by Type (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Direct Sales to End Customer as Percent of Consolidated Sales									64.00%
Indirect Sales as Subcontractor or Supplier as Percent of Consolidated Sales									36.00%
Fixed Price Incentive Fee Type Contracts as Percent of Net Sales									1.00%
Cost-plus and Incentive Fee Type Contracts as Percent of Net Sales									4.00%
Cost Input Method [Member]
Segment Reporting Information [Line Items]
Net sales									$ 7,604
Transferred at Point in Time [Member]
Segment Reporting Information [Line Items]
Net sales									1,930
Output Method [Member]
Segment Reporting Information [Line Items]
Net sales									440
Billing Method [Member]
Segment Reporting Information [Line Items]
Net sales									270
ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									4,441
ISR Systems [Member] | Cost Input Method [Member]
Segment Reporting Information [Line Items]
Net sales									3,352
ISR Systems [Member] | Transferred at Point in Time [Member]
Segment Reporting Information [Line Items]
Net sales									866
ISR Systems [Member] | Output Method [Member]
Segment Reporting Information [Line Items]
Net sales									74
ISR Systems [Member] | Billing Method [Member]
Segment Reporting Information [Line Items]
Net sales									149
C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									3,059
C&NS [Member] | Cost Input Method [Member]
Segment Reporting Information [Line Items]
Net sales									2,603
C&NS [Member] | Transferred at Point in Time [Member]
Segment Reporting Information [Line Items]
Net sales									359
C&NS [Member] | Output Method [Member]
Segment Reporting Information [Line Items]
Net sales									23
C&NS [Member] | Billing Method [Member]
Segment Reporting Information [Line Items]
Net sales									74
Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									2,744
Electronic Systems [Member] | Cost Input Method [Member]
Segment Reporting Information [Line Items]
Net sales									1,649
Electronic Systems [Member] | Transferred at Point in Time [Member]
Segment Reporting Information [Line Items]
Net sales									705
Electronic Systems [Member] | Output Method [Member]
Segment Reporting Information [Line Items]
Net sales									343
Electronic Systems [Member] | Billing Method [Member]
Segment Reporting Information [Line Items]
Net sales									47
Department of Defense [Member]
Segment Reporting Information [Line Items]
Net sales									6,721
Department of Defense [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									3,081
Department of Defense [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									2,291
Department of Defense [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,349
Other U.S. Government [Member]
Segment Reporting Information [Line Items]
Net sales									423
Other U.S. Government [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									150
Other U.S. Government [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									95
Other U.S. Government [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									178
Total U. S. Government [Member]
Segment Reporting Information [Line Items]
Net sales									7,144
Total U. S. Government [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									3,231
Total U. S. Government [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									2,386
Total U. S. Government [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,527
Foreign Government Debt [Member]
Segment Reporting Information [Line Items]
Net sales									1,528
Foreign Government Debt [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,006
Foreign Government Debt [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									327
Foreign Government Debt [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									195
Commercial - Foreign [Member]
Segment Reporting Information [Line Items]
Net sales									873
Commercial - Foreign [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									75
Commercial - Foreign [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									123
Commercial - Foreign [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									675
Commercial - Domestic [Member]
Segment Reporting Information [Line Items]
Net sales									699
Commercial - Domestic [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									129
Commercial - Domestic [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									223
Commercial - Domestic [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									347
Fixed-price Contract [Member]
Segment Reporting Information [Line Items]
Net sales									7,358
Fixed-price Contract [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									2,839
Fixed-price Contract [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									2,202
Fixed-price Contract [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									2,317
Cost-plus Contract [Member]
Segment Reporting Information [Line Items]
Net sales									2,571
Cost-plus Contract [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,393
Cost-plus Contract [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									768
Cost-plus Contract [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									410
Time-and-materials Contract [Member]
Segment Reporting Information [Line Items]
Net sales									315
Time-and-materials Contract [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									209
Time-and-materials Contract [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									89
Time-and-materials Contract [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									17
Product [Member]
Segment Reporting Information [Line Items]
Net sales									7,165	6,733	6,453
Product [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									2,907
Product [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									2,299
Product [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,959
Service [Member]
Segment Reporting Information [Line Items]
Net sales									3,079	$ 2,840	$ 2,757
Service [Member] | ISR Systems [Member]
Segment Reporting Information [Line Items]
Net sales									1,534
Service [Member] | C&NS [Member]
Segment Reporting Information [Line Items]
Net sales									760
Service [Member] | Electronic Systems [Member]
Segment Reporting Information [Line Items]
Net sales									$ 785

Segment Information, Geographic

Segment Information, Geographic Location (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Property, plant and equipment, net	1,169				1,110				1,169	1,110
U.S. Government Agencies [Member]
Segment Reporting Information [Line Items]
Net sales									7,144	6,697	6,399
Commercial [Member]
Segment Reporting Information [Line Items]
Net sales									1,572	1,456	1,280
Foreign Governments [Member]
Segment Reporting Information [Line Items]
Net sales									1,528	1,420	1,531
Reportable Geographical Components [Member] | U.S. [Member]
Segment Reporting Information [Line Items]
Net sales									7,843	7,344	6,947
Property, plant and equipment, net	973				936				973	936
Reportable Geographical Components [Member] | Total International [Member]
Segment Reporting Information [Line Items]
Net sales									2,401	2,229	2,263
Reportable Geographical Components [Member] | Canada [Member]
Segment Reporting Information [Line Items]
Net sales									312	280	297
Reportable Geographical Components [Member] | United Kingdom [Member]
Segment Reporting Information [Line Items]
Net sales									309	335	331
Reportable Geographical Components [Member] | Australia [Member]
Segment Reporting Information [Line Items]
Net sales									219	268	254
Reportable Geographical Components [Member] | China [Member]
Segment Reporting Information [Line Items]
Net sales									156	167	67
Reportable Geographical Components [Member] | Japan [Member]
Segment Reporting Information [Line Items]
Net sales									145	125	81
Reportable Geographical Components [Member] | Saudi Arabia [Member]
Segment Reporting Information [Line Items]
Net sales									128	58	159
Reportable Geographical Components [Member] | Turkey [Member]
Segment Reporting Information [Line Items]
Net sales									113	61	61
Reportable Geographical Components [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									1,019	935	$ 1,013
Property, plant and equipment, net	$ 196				$ 174				$ 196	$ 174

Severance and Restructuring R_3

Severance and Restructuring Related Costs (Details) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 29, 2018USD ($)	Dec. 31, 2017USD ($)		Dec. 31, 2018USD ($)Employee	Dec. 31, 2017USD ($)Employee	Dec. 31, 2016USD ($)Employee
Restructuring Cost and Reserve [Line Items]
Number of employees of restructuring costs | Employee				800	1,500	700
Gain (loss) on sale of property	$ 42	$ (12)	[1]
Restructuring Reserve [Roll Forward]
Balance at beginning of period				$ 23
Additional provisions				26	$ 101	$ 17
Cash payments				(35)
Balance at end of period		$ 23		14	23
ISR Systems [Member]
Restructuring Cost and Reserve [Line Items]
Curtailment loss				5
Restructuring Reserve [Roll Forward]
Additional provisions				7	38	5
C&NS [Member]
Restructuring Reserve [Roll Forward]
Additional provisions				11	52	8
Electronic Systems [Member]
Restructuring Cost and Reserve [Line Items]
Curtailment loss				1
Restructuring Reserve [Roll Forward]
Additional provisions				8	11	4
Consolidated Entities [Member]
Restructuring Reserve [Roll Forward]
Additional provisions				$ 26	$ 101	$ 17
[1]	The severance and restructuring related costs incurred during the year ended December 31, 2017 include a $12 million loss on the sale of a building in Garland, Texas in the fourth quarter of 2017.

Unaudited Quarterly Financial_3

Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 29, 2018	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Line Items]
Sales		$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Operating income		276	272	321	251	268	232	294	237	1,120	1,031	958
Income from continuing operations		232	208	189	192	271	146	195	157	821	769	633
Net income		231	208	379	208	293	25	207	168	1,026	693	724
Net income attributable to L3		$ 225	$ 202	$ 375	$ 203	$ 289	$ 22	$ 202	$ 164	$ 1,005	$ 677	$ 710
Basic EPS from continuing operations (in dollars per share)		$ 2.87	$ 2.57	$ 2.36	$ 2.40	$ 3.42	$ 1.83	$ 2.44	$ 1.97	$ 10.19	$ 9.65	$ 7.99
Basic EPS (in dollars per share)		2.86	2.57	4.78	2.60	3.70	0.28	2.59	2.11	12.80	8.68	9.17
Diluted EPS from continuing operations (in dollars per share)		2.83	2.54	2.33	2.34	3.34	1.79	2.39	1.93	10.05	9.46	7.86
Earnings Per Share, Diluted		$ 2.82	$ 2.54	$ 4.72	$ 2.54	$ 3.62	0.28	$ 2.54	$ 2.07	$ 12.63	$ 8.51	$ 9.01
Debt retirement charge			$ 21	$ 48						$ (69)	$ 0	$ (7)
Debt retirement charge, after tax			16	$ 36
Gain on sale of businesses										42	0	0
Acquisition and merger related costs		$ 23	5
Acquisition and merger related costs, after tax		$ 19	$ 4
Estimated tax benefit amount						$ 79
Earnings per share, diluted (in dollars per share)						$ 0.99
Crestview Aerospace and TCS [Member]
Quarterly Financial Data [Line Items]
Sales										64	119	166
Earnings Per Share, Diluted		$ 0.03	$ 0.04	$ 0.31
Gain on sale of businesses	$ 42	$ 2	$ 4	$ 48						42	0	0
Gain on sale of businesses, after tax	$ 19	$ 2	$ 4	$ 25
Vertex Aerospace [Member]
Quarterly Financial Data [Line Items]
Sales										$ 600	1,400	$ 1,300
Earnings Per Share, Diluted				$ 2.27			$ 1.67
Gain on sale of businesses				$ 237
Gain on sale of businesses, after tax				$ 180
Goodwill impairment charges							$ 187				$ 187
Debt Retirement Charges [Member]
Quarterly Financial Data [Line Items]
Earnings Per Share, Diluted			$ 0.21	$ 0.45
Merger and Acquisition Related Costs [Member]
Quarterly Financial Data [Line Items]
Earnings Per Share, Diluted		$ 0.24	$ 0.06

Financial Information of L3 a_3

Financial Information of L3 and Its Subsidiaries, Condensed Combining Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 1,066		$ 662	$ 363	$ 207
Billed receivables, net	919		723
Contract assets	1,590	$ 1,349	0
Contracts in process	0	0	1,933
Inventories	879	926	389
Prepaid expenses and other current assets	356		300
Prepaid expenses and other current assets			689
Assets held for sale			135
Assets of discontinued operations	0	285	306	481
Total current assets	4,810	4,400	4,448
Goodwill	6,808		6,615	6,374
Other assets	1,900		1,666
Investment in and amounts due from consolidated subsidiaries	0		0
Total assets	13,518	12,730	12,729	11,865
Current liabilities	2,447		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	1,843		1,869
Long-term debt	3,321		3,330
Total liabilities	7,611	7,566	7,578
L3 shareholders' equity	5,839		5,083
Noncontrolling interests	68		68
Total equity	5,907	$ 5,164	5,151	4,624	4,429
Total liabilities and equity	13,518		12,729
Parent Company [Member]
Current assets:
Cash and cash equivalents	756		432	262	109
Billed receivables, net	291		266
Contract assets	562
Contracts in process			706
Inventories	378
Prepaid expenses and other current assets	127
Prepaid expenses and other current assets			330
Assets held for sale			0
Assets of discontinued operations			306
Total current assets	2,114		2,040
Goodwill	2,124		2,099
Other assets	690		658
Investment in and amounts due from consolidated subsidiaries	5,931		5,662
Total assets	10,859		10,459
Current liabilities	821		811
Liabilities held for sale			0
Liabilities of discontinued operations			226
Amounts due to consolidated subsidiaries	0		0
Other long-term liabilities	878		1,009
Long-term debt	3,321		3,330
Total liabilities	5,020		5,376
L3 shareholders' equity	5,839		5,083
Noncontrolling interests	0		0
Total equity	5,839		5,083
Total liabilities and equity	10,859		10,459
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	21		16	5	0
Billed receivables, net	341		244
Contract assets	833
Contracts in process			912
Inventories	258
Prepaid expenses and other current assets	166
Prepaid expenses and other current assets			235
Assets held for sale			135
Assets of discontinued operations			0
Total current assets	1,619		1,542
Goodwill	3,009		2,932
Other assets	765		687
Investment in and amounts due from consolidated subsidiaries	6,912		6,310
Total assets	12,305		11,471
Current liabilities	955		832
Liabilities held for sale			17
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	0		0
Other long-term liabilities	804		729
Long-term debt	0		0
Total liabilities	1,759		1,578
L3 shareholders' equity	10,546		9,893
Noncontrolling interests	0		0
Total equity	10,546		9,893
Total liabilities and equity	12,305		11,471
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	306		285	203	165
Billed receivables, net	287		213
Contract assets	195
Contracts in process			315
Inventories	243
Prepaid expenses and other current assets	63
Prepaid expenses and other current assets			124
Assets held for sale			0
Assets of discontinued operations			0
Total current assets	1,094		937
Goodwill	1,675		1,584
Other assets	445		321
Investment in and amounts due from consolidated subsidiaries	0		0
Total assets	3,214		2,842
Current liabilities	688		564
Liabilities held for sale			0
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	417		391
Other long-term liabilities	161		131
Long-term debt	0		0
Total liabilities	1,266		1,086
L3 shareholders' equity	1,948		1,756
Noncontrolling interests	0		0
Total equity	1,948		1,756
Total liabilities and equity	3,214		2,842
Eliminations [Member]
Current assets:
Cash and cash equivalents	(17)		(71)	$ (107)	$ (67)
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	(17)		(71)
Goodwill	0		0
Other assets	0		0
Investment in and amounts due from consolidated subsidiaries	(12,843)		(11,972)
Total assets	(12,860)		(12,043)
Current liabilities	(17)		(71)
Liabilities held for sale			0
Liabilities of discontinued operations			0
Amounts due to consolidated subsidiaries	(417)		(391)
Other long-term liabilities	0		0
Long-term debt	0		0
Total liabilities	(434)		(462)
L3 shareholders' equity	(12,494)		(11,649)
Noncontrolling interests	68		68
Total equity	(12,426)		(11,581)
Total liabilities and equity	$ (12,860)		$ (12,043)

Financial Information of L3 a_4

Financial Information of L3 and Its Subsidiaries, Condensed Combining Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Total net sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Total cost of sales									(9,138)	(8,542)	(8,252)
Gain on sale of the Crestview Aerospace and TCS businesses									42	0	0
Merger and acquisition related expenses									(28)	0	0
Operating Income (Loss)	276	272	321	251	268	232	294	237	1,120	1,031	958
Interest expense									(164)	(169)	(164)
Interest and other income, net									37	9	17
Debt retirement charges		21	48						(69)	0	(7)
Income from continuing operations before income taxes									924	871	804
Provision for income taxes									(103)	(102)	(171)
Equity in net income (loss) of consolidated subsidiaries									0	0	0
Income from continuing operations	232	208	189	192	271	146	195	157	821	769	633
(Loss) income from discontinued operations, net of income taxes									205	(76)	91
Net (loss) income	231	208	379	208	293	25	207	168	1,026	693	724
Net income attributable to noncontrolling interests									(21)	(16)	(14)
Net income attributable to L3	$ 225	$ 202	$ 375	$ 203	$ 289	$ 22	$ 202	$ 164	1,005	677	710
Comprehensive (loss) income attributable to L3									971	712	558
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales									3,626	3,520	3,351
Total cost of sales									(3,180)	(3,169)	(3,064)
Gain on sale of the Crestview Aerospace and TCS businesses									0
Merger and acquisition related expenses									(28)
Operating Income (Loss)									418	351	287
Interest expense									(163)	(168)	(164)
Interest and other income, net									31	6	9
Debt retirement charges									(69)		(7)
Income from continuing operations before income taxes									217	189	125
Provision for income taxes									(24)	(22)	(26)
Equity in net income (loss) of consolidated subsidiaries									607	586	520
Income from continuing operations									800	753	619
(Loss) income from discontinued operations, net of income taxes									205	(76)	91
Net (loss) income									1,005	677	710
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to L3									1,005	677	710
Comprehensive (loss) income attributable to L3									971	712	558
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales									5,259	4,852	4,842
Total cost of sales									(4,943)	(4,446)	(4,406)
Gain on sale of the Crestview Aerospace and TCS businesses									42
Merger and acquisition related expenses									0
Operating Income (Loss)									358	406	436
Interest expense									0	0	0
Interest and other income, net									3	(8)	(3)
Debt retirement charges									0		0
Income from continuing operations before income taxes									361	398	433
Provision for income taxes									(40)	(47)	(92)
Equity in net income (loss) of consolidated subsidiaries									184	144	130
Income from continuing operations									505	495	471
(Loss) income from discontinued operations, net of income taxes									0	0	0
Net (loss) income									505	495	471
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to L3									505	495	471
Comprehensive (loss) income attributable to L3									427	604	409
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales									1,806	1,581	1,348
Total cost of sales									(1,462)	(1,307)	(1,113)
Gain on sale of the Crestview Aerospace and TCS businesses									0
Merger and acquisition related expenses									0
Operating Income (Loss)									344	274	235
Interest expense									(1)	(1)	0
Interest and other income, net									3	11	11
Debt retirement charges									0		0
Income from continuing operations before income taxes									346	284	246
Provision for income taxes									(39)	(33)	(53)
Equity in net income (loss) of consolidated subsidiaries									0	0	0
Income from continuing operations									307	251	193
(Loss) income from discontinued operations, net of income taxes									0	0	0
Net (loss) income									307	251	193
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to L3									307	251	193
Comprehensive (loss) income attributable to L3									226	378	116
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Total net sales									(447)	(380)	(331)
Total cost of sales									447	380	331
Gain on sale of the Crestview Aerospace and TCS businesses									0
Merger and acquisition related expenses									0
Operating Income (Loss)									0	0	0
Interest expense									0	0	0
Interest and other income, net									0	0	0
Debt retirement charges									0		0
Income from continuing operations before income taxes									0	0	0
Provision for income taxes									0	0	0
Equity in net income (loss) of consolidated subsidiaries									(791)	(730)	(650)
Income from continuing operations									(791)	(730)	(650)
(Loss) income from discontinued operations, net of income taxes									0	0	0
Net (loss) income									(791)	(730)	(650)
Net income attributable to noncontrolling interests									(21)	(16)	(14)
Net income attributable to L3									(812)	(746)	(664)
Comprehensive (loss) income attributable to L3									$ (653)	$ (982)	$ (525)

Financial Information of L3 a_5

Financial Information of L3 and Its Subsidiaries, Condensed Combining Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net cash from operating activities from continuing operations	$ 1,042	$ 985	$ 1,022
Investing activities:
Business acquisitions, net of cash acquired	(369)	(316)	(388)
Proceeds from sale of business, net of closing date cash balances	535	18	561
Other investing activities	(257)	(155)	(183)
Net cash used in investing activities from continuing operations	(91)	(453)	(10)
Financing activities:
Proceeds from sale of senior notes	1,798	0	547
Redemption of senior notes	(1,865)	0	(856)
Common stock repurchased	(322)	(180)	(373)
Dividends paid on L3's common stock	(254)	(236)	(220)
Other financing activities	123	50	46
Net cash used in financing activities from continuing operations	(520)	(366)	(856)
Effect of foreign currency exchange rate changes on cash	(15)	20	(13)
Net increase in cash and cash equivalents of discontinued operations	(12)	113	13
Net (decrease) increase in cash	404	299	156
Cash and cash equivalents, beginning of the year	662	363	207
Cash and cash equivalents, end of the year	1,066	662	363
Parent Company [Member]
Operating activities:
Net cash from operating activities from continuing operations	555	374	440
Investing activities:
Business acquisitions, net of cash acquired	(193)	(316)	(388)
Proceeds from sale of business, net of closing date cash balances	360	17	563
Other investing activities	(119)	(92)	(63)
Net cash used in investing activities from continuing operations	48	(391)	112
Financing activities:
Proceeds from sale of senior notes	1,798		547
Redemption of senior notes	(1,865)		(856)
Common stock repurchased	(322)	(180)	(373)
Dividends paid on L3's common stock	(254)	(236)	(220)
Other financing activities	376	490	490
Net cash used in financing activities from continuing operations	(267)	74	(412)
Effect of foreign currency exchange rate changes on cash	0	0	0
Net increase in cash and cash equivalents of discontinued operations	(12)	113	13
Net (decrease) increase in cash	324	170	153
Cash and cash equivalents, beginning of the year	432	262	109
Cash and cash equivalents, end of the year	756	432	262
Guarantor Subsidiaries [Member]
Operating activities:
Net cash from operating activities from continuing operations	238	426	509
Investing activities:
Business acquisitions, net of cash acquired	0	0	0
Proceeds from sale of business, net of closing date cash balances	175	0	0
Other investing activities	(90)	(38)	(77)
Net cash used in investing activities from continuing operations	85	(38)	(77)
Financing activities:
Proceeds from sale of senior notes	0		0
Redemption of senior notes	0		0
Common stock repurchased	0	0	0
Dividends paid on L3's common stock	0	0	0
Other financing activities	(318)	(377)	(427)
Net cash used in financing activities from continuing operations	(318)	(377)	(427)
Effect of foreign currency exchange rate changes on cash	0	0	0
Net increase in cash and cash equivalents of discontinued operations	0	0	0
Net (decrease) increase in cash	5	11	5
Cash and cash equivalents, beginning of the year	16	5	0
Cash and cash equivalents, end of the year	21	16	5
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash from operating activities from continuing operations	256	263	259
Investing activities:
Business acquisitions, net of cash acquired	(176)	0	0
Proceeds from sale of business, net of closing date cash balances	0	1	(2)
Other investing activities	(48)	(25)	(43)
Net cash used in investing activities from continuing operations	(224)	(24)	(45)
Financing activities:
Proceeds from sale of senior notes	0		0
Redemption of senior notes	0		0
Common stock repurchased	0	0	0
Dividends paid on L3's common stock	0	0	0
Other financing activities	4	(177)	(163)
Net cash used in financing activities from continuing operations	4	(177)	(163)
Effect of foreign currency exchange rate changes on cash	(15)	20	(13)
Net increase in cash and cash equivalents of discontinued operations	0	0	0
Net (decrease) increase in cash	21	82	38
Cash and cash equivalents, beginning of the year	285	203	165
Cash and cash equivalents, end of the year	306	285	203
Eliminations [Member]
Operating activities:
Net cash from operating activities from continuing operations	(7)	(78)	(186)
Investing activities:
Business acquisitions, net of cash acquired	0	0	0
Proceeds from sale of business, net of closing date cash balances	0	0	0
Other investing activities	0	0	0
Net cash used in investing activities from continuing operations	0	0	0
Financing activities:
Proceeds from sale of senior notes	0		0
Redemption of senior notes	0		0
Common stock repurchased	0	0	0
Dividends paid on L3's common stock	0	0	0
Other financing activities	61	114	146
Net cash used in financing activities from continuing operations	61	114	146
Effect of foreign currency exchange rate changes on cash	0	0	0
Net increase in cash and cash equivalents of discontinued operations	0	0	0
Net (decrease) increase in cash	54	36	(40)
Cash and cash equivalents, beginning of the year	(71)	(107)	(67)
Cash and cash equivalents, end of the year	$ (17)	$ (71)	$ (107)

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Sales	$ 2,771	$ 2,519	$ 2,583	$ 2,371	$ 2,574	$ 2,293	$ 2,385	$ 2,321	$ 10,244	$ 9,573	$ 9,210
Operating Income (Loss)	$ 276	$ 272	$ 321	$ 251	$ 268	$ 232	$ 294	$ 237	1,120	$ 1,031	$ 958
Mobile Vision [Member]
Subsequent Event [Line Items]
Sales									23
Operating Income (Loss)									$ (9)