L3 10-K/A 10 Oct 14 2013 FY Annual report (amended) Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 19, 2014	Jun. 28, 2013
Document And Entity Information [Abstract]	'	'	'
Document Type	'10-K/A	'	'
Amendment Flag	'true	'	'
Amendment Description	'We are filing this Amendment No. 1 (this “Amendment” or “Form 10-K/A”) to our Annual Report on Form 10-K for the fiscal year ended December 31, 2013 following the completion of the internal review of our Aerospace Systems segment, which is discussed in our document.	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'LLL	'	'
Entity Registrant Name	'L 3 COMMUNICATIONS HOLDINGS INC	'	'
Entity Central Index Key	'0001056239	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	85,847,821	'
Entity Public Float	'	'	$7.60

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$500	$349
Billed receivables, net of allowances of $26 in 2013 and $33 in 2012	991	968
Contracts in process	2,431	2,510
Inventories	359	358
Deferred income taxes	147	113
Other current assets	166	186
Total current assets	4,594	4,484
Property, plant and equipment, net	1,042	1,023
Goodwill	7,796	7,776
Identifiable intangible assets	285	314
Deferred debt issue costs	24	29
Other assets	247	174
Total assets	13,988	13,800
Current liabilities:	'	'
Accounts payable, trade	541	505
Accrued employment costs	545	555
Accrued expenses	458	469
Advance payments and billings in excess of costs incurred	576	621
Income taxes	31	21
Other current liabilities	383	392
Total current liabilities	2,534	2,563
Pension and postretirement benefits	727	1,360
Deferred income taxes	635	328
Other liabilities	406	393
Long-term debt	3,630	3,629
Total liabilities	7,932	8,273
Commitments and contingencies (see Note 20)	'	'
L-3 shareholders' equity:	'	'
L-3 Communications Holdings, Inc.'s common stock: $.01 par value; 300,000,000 shares authorized, 85,828,485 shares outstanding at December 31, 2013 and 90,433,743 shares outstanding at December 31, 2012 (L-3 Communications Corporation's common stock: $.01 par value, 100 shares authorized, issued and outstanding)	5,653	5,314
L-3 Communications Holdings, Inc.'s treasury stock (at cost), 66,118,406 shares at December 31, 2013 and 57,418,645 shares at December 31, 2012	-5,288	-4,488
Retained earnings	5,726	5,175
Accumulated other comprehensive loss	-110	-550
Total L-3 shareholders' equity	5,981	5,451
Noncontrolling interests	75	76
Total equity	6,056	5,527
Total liabilities and equity	$13,988	$13,800

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Allowances for billed receivables	$26	$33
Treasury stock (at cost), shares	66,118,406	57,418,645
L-3 Communications Holdings, Inc. [Member]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares outstanding	85,828,485	90,433,743
L-3 Communications Corporation [Member]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100	100
Common stock, shares issued	100	100
Common stock, shares outstanding	100	100

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	$7,189	$7,586	$7,549
Services	'	'	'	'	'	'	'	'	5,433	5,521	5,605
Total net sales	'	'	'	'	'	'	'	'	12,622	13,107	13,154
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-6,409	-6,782	-6,666
Services	'	'	'	'	'	'	'	'	-5,001	-5,017	-5,047
Total cost of sales	'	'	'	'	'	'	'	'	-11,410	-11,799	-11,713
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Interest expense	'	'	'	'	'	'	'	'	-177	-184	-204
Interest and other income, net	'	'	'	'	'	'	'	'	20	11	3
Debt retirement charge	'	'	'	'	'	'	'	'	'	-13	-35
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	1,055	1,122	1,162
Provision for income taxes	'	'	'	'	'	'	'	'	-295	-360	-296
Income from continuing operations	188	204	176	192	199	188	189	186	760	762	866
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	32	104
Net income	'	'	'	'	'	'	'	'	760	794	970
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-10	-12
Net income attributable to L-3	185	200	175	191	196	185	203	200	751	784	958
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	-2
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	$751	$784	$956
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.11	$1.94	$1.93	$1.88	$8.40	$7.85	$8.19
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.97
Basic earnings per share	$2.10	$2.23	$1.95	$2.12	$2.11	$1.93	$2.09	$2.02	$8.40	$8.14	$9.16
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.08	$1.91	$1.91	$1.86	$8.24	$7.74	$8.10
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.95
Diluted earnings per share	$2.04	$2.19	$1.92	$2.09	$2.08	$1.90	$2.06	$2	$8.24	$8.03	$9.05
Cash dividends paid per common share	'	'	'	'	'	'	'	'	$2.20	$2	$1.80
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	89.4	96.3	104.4
Diluted	'	'	'	'	'	'	'	'	91.1	97.6	105.6

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'		'		'
Net income	$760		$794		$970
Other comprehensive (loss) income :	'		'		'
Foreign currency translation adjustments	-25		34		-28
Unrealized (losses) gains on hedging instruments	-2	[1]	3	[1]	-10	[1]
Pension and postretirement benefit plans:	'		'		'
Amortization of net loss and prior service cost previously recognized	53	[2]	42	[2]	30	[2]
Net prior service (costs) credit arising during the period	-9	[3]	3	[3]	-1	[3]
Net gain (loss) arising during the period	423	[4]	-178	[4]	-189	[4]
Net change in pension and postretirement benefit plans	467		-133		-160
Total other comprehensive gain (loss)	440		-96		-198
Comprehensive income	1,200		698		772
Comprehensive income attributable to noncontrolling interests	-9		-10		-12
Comprehensive income attributable to L-3	$1,191		$688		$760
[1]	Net of income tax benefits of $3 million in 2013, income taxes of $2 million in 2012 and income tax benefits of $7 million in 2011
[2]	Net of income taxes of $30 million in 2013, $26 million in 2012 and $18 million in 2011
[3]	Net of income tax benefits of $5 million in 2013, income taxes of $2 million in 2012 and income tax benefits of $1 million in 2011
[4]	Net of income taxes of $243 million in 2013 and income tax benefits of $105 million in 2012 and $87 million in 2011

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'	'	'
Income tax benefits on unrealized (losses) gains on hedging instruments	($3)	$2	($7)
Income tax effect on amortization of net loss and prior service cost previously recognized	30	26	18
Income tax benefits on net prior service (costs) credit arising during the period	-5	2	-1
Income tax benefits on net gain (loss) arising during the period	$243	($105)	($87)

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
In Millions, except Share data, unless otherwise specified
Beginning Balance at Dec. 31, 2010	$6,862	$1	$4,800	($2,658)	$4,884	($256)	$91
Beginning Balance, Shares at Dec. 31, 2010	'	108,600,000	'	'	'	'	'
Net income	970	'	'	'	958	'	12
Other comprehensive gain (loss)	-198	'	'	'	'	-198	'
Distributions to noncontrolling interests	-11	'	'	'	'	'	-11
Cash dividends paid on common stock	-188	'	'	'	-188	'	'
Shares issued:	'	'	'	'	'	'	'
Employee savings plans	137	'	137	'	'	'	'
Employee savings plans, Shares	'	2,100,000	'	'	'	'	'
Exercise of stock options	18	'	18	'	'	'	'
Exercise of stock options, Shares	'	400,000	'	'	'	'	'
Employee stock purchase plan	46	'	46	'	'	'	'
Employee stock purchase plan, Shares	'	900,000	'	'	'	'	'
Stock-based compensation expense	64	'	64	'	'	'	'
Treasury stock purchased	-958	'	'	-958	'	'	'
Treasury stock purchased, Shares	'	-13,300,000	'	'	'	'	'
Other	-9	'	-2	'	-4	'	-3
Other, Shares	'	300,000	'	'	'	'	'
Ending Balance at Dec. 31, 2011	6,733	1	5,063	-3,616	5,650	-454	89
Ending Balance, Shares at Dec. 31, 2011	'	99,000,000	'	'	'	'	'
Net income	794	'	'	'	784	'	10
Other comprehensive gain (loss)	-96	'	'	'	'	-96	'
Distributions to noncontrolling interests	-10	'	'	'	'	'	-10
Cash dividends paid on common stock	-192	'	'	'	-192	'	'
Shares issued:	'	'	'	'	'	'	'
Employee savings plans	141	'	141	'	'	'	'
Employee savings plans, Shares	'	2,100,000	'	'	'	'	'
Exercise of stock options	19	'	19	'	'	'	'
Exercise of stock options, Shares	'	400,000	'	'	'	'	'
Employee stock purchase plan	39	'	39	'	'	'	'
Employee stock purchase plan, Shares	'	700,000	'	'	'	'	'
Stock-based compensation expense	60	'	60	'	'	'	'
Contribution received from the spin-off of Engility	335	'	'	'	335	'	'
Spin-off of Engility	-1,411	'	'	'	-1,398	'	-13
Treasury stock purchased	-872	'	'	-872	'	'	'
Treasury stock purchased, Shares	'	-12,100,000	'	'	'	'	'
Other	-13	'	-9	'	-4	'	'
Other, Shares	'	300,000	'	'	'	'	'
Ending Balance at Dec. 31, 2012	5,527	1	5,313	-4,488	5,175	-550	76
Ending Balance, Shares at Dec. 31, 2012	'	90,400,000	'	'	'	'	'
Net income	760	'	'	'	751	'	9
Other comprehensive gain (loss)	440	'	'	'	'	440	'
Distributions to noncontrolling interests	-10	'	'	'	'	'	-10
Cash dividends paid on common stock	-197	'	'	'	-197	'	'
Shares issued:	'	'	'	'	'	'	'
Employee savings plans	121	'	121	'	'	'	'
Employee savings plans, Shares	'	1,500,000	'	'	'	'	'
Exercise of stock options	128	'	128	'	'	'	'
Exercise of stock options, Shares	1,770,400	1,800,000	'	'	'	'	'
Employee stock purchase plan	36	'	36	'	'	'	'
Employee stock purchase plan, Shares	'	500,000	'	'	'	'	'
Stock-based compensation expense	59	'	59	'	'	'	'
Treasury stock purchased	-800	'	'	-800	'	'	'
Treasury stock purchased, Shares	'	-8,700,000	'	'	'	'	'
Other	-8	'	-5	'	-3	'	'
Other, Shares	'	300,000	'	'	'	'	'
Ending Balance at Dec. 31, 2013	$6,056	$1	$5,652	($5,288)	$5,726	($110)	$75
Ending Balance, Shares at Dec. 31, 2013	'	85,800,000	'	'	'	'	'

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash dividends paid on common stock, per share	$2.20	$2	$1.80
Retained Earnings [Member]	'	'	'
Cash dividends paid on common stock, per share	$2.20	$2	$1.80

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:	'	'	'
Net income	$760	$794	$970
Income from discontinued operations, net of tax	'	-32	-104
Income from continuing operations	760	762	866
Depreciation of property, plant and equipment	166	170	167
Amortization of intangibles and other assets	48	58	63
Deferred income tax provision	42	97	123
Stock-based employee compensation expense	59	59	57
Contributions to employee savings plans in L-3 Holdings' common stock	114	125	113
Amortization of pension and postretirement benefit plans net loss and prior service cost	83	68	48
Amortization of bond discounts and deferred debt issue costs (included in interest expense)	6	7	13
Goodwill impairment charge	'	'	43
Equity in losses of unconsolidated subsidiaries	'	3	12
Other non-cash items	2	9	11
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:	'	'	'
Billed receivables	-18	147	-13
Contracts in process	104	-67	-110
Inventories	2	-35	-14
Other assets	-88	8	-9
Accounts payable, trade	34	92	-35
Accrued employment costs	-5	-10	-23
Accrued expenses	-5	-100	68
Advance payments and billings in excess of costs incurred	-44	37	-39
Income taxes	31	-47	-16
Excess income tax benefits related to share-based payment arrangements	-4	-3	-2
Other current liabilities	-4	-46	-2
Pension and postretirement benefits	14	-64	-83
All other operating activities	-34	-39	-7
Net cash from operating activities from continuing operations	1,263	1,231	1,231
Investing activities:	'	'	'
Contribution received from the spin-off of Engility	'	335	'
Business acquisitions, net of cash acquired	-62	-348	-20
Proceeds from sale of a business	4	5	1
Capital expenditures	-209	-210	-187
Dispositions of property, plant and equipment	12	5	6
Cash from equity investees	'	20	'
Other investing activities	-6	-7	1
Net cash used in investing activities from continuing operations	-261	-200	-199
Financing activities:	'	'	'
Proceeds from sale of senior notes	'	'	1,143
Redemption of senior subordinated notes	'	-500	-1,150
Redemption of CODES	'	'	-11
Borrowings under revolving credit facility	1,893	596	625
Repayment of borrowings under revolving credit facility	-1,893	-596	-625
Common stock repurchased	-800	-872	-958
Dividends paid on L-3 Holdings' common stock	-199	-195	-188
Proceeds from exercise of stock options	128	19	22
Proceeds from employee stock purchase plan	36	39	46
Debt issue costs	'	-6	-11
Excess income tax benefits related to share-based payment arrangements	4	3	2
Other financing activities	-18	-15	-14
Net cash used in financing activities from continuing operations	-849	-1,527	-1,119
Effect of foreign currency exchange rate changes on cash and cash equivalents	-2	7	-4
Cash from (used in) discontinued operations:	'	'	'
Operating activities	'	75	253
Investing activities	'	'	-4
Financing activities	'	-1	-1
Cash from discontinued operations	'	74	248
Net (decrease) increase in cash and cash equivalents	151	-415	157
Cash and cash equivalents, beginning of the year	349	764	607
Cash and cash equivalents, end of the year	$500	$349	$764

Description_of_Business

Description of Business	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Description of Business	'
	1. Description of Business
	L-3 Communications Holdings, Inc. derives all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Communications). L-3 Communications Holdings, Inc. (L-3 Holdings and, together with its subsidiaries, referred to herein as L-3 or the Company) is a prime contractor in aerospace systems and national security solutions. L-3 is also a leading provider of a broad range of communication and electronic systems and products used on military 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), U.S. Department of State (DoS), allied international governments, and domestic and international commercial customers.
	In the first quarter of 2014, the Company completed a realignment of its segments to better align its organizational structure with customer priorities and increase operational efficiencies. As a result of the realignment, L-3’s structure consists of four segments: (1) Aerospace Systems, (2) Electronic Systems, (3) Communication Systems, and (4) National Security Solutions (NSS). The audited consolidated financial statements have been recast for this segment structure. Aerospace Systems delivers integrated solutions for the global Intelligence, Surveillance and Reconnaissance (ISR) market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Electronic Systems provides a broad range of components, products, subsystems, systems, and related services for military and commercial customers in several niche markets across several business areas. These business areas include precision engagement & training, power & propulsion systems, sensor systems, marine systems international, aviation products, warrior systems and security & detection. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. NSS provides cybersecurity solutions, high-performance computing, enterprise information technology (IT) services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and allied international governments. Financial information with respect to each of our segments is included in Note 23 to our audited consolidated financial statements.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2. Summary of Significant Accounting Policies
	Basis of Presentation: The accompanying financial statements comprise the consolidated financial statements of L-3 Holdings and L-3 Communications. L-3 Holdings’ only asset is its investment in the common stock of L-3 Communications, its wholly-owned subsidiary, and its only obligations are: (1) the 3% Convertible Contingent Debt Securities (CODES) due 2035, which were issued by L-3 Holdings on July 29, 2005, (2) its guarantee of borrowings under the Amended and Restated Revolving Credit Facility of L-3 Communications and (3) its guarantee of other contractual obligations of L-3 Communications and its subsidiaries. L-3 Holdings’ obligations relating to the CODES have been jointly, severally, fully and unconditionally guaranteed by L-3 Communications and certain of its wholly-owned domestic subsidiaries. Accordingly, such debt has been reflected as debt of L-3 Communications in its consolidated financial statements in accordance with the accounting standards for pushdown accounting. All issuances of and conversions into L-3 Holdings’ equity securities, including grants of stock options, restricted stock, restricted stock units and performance units by L-3 Holdings to employees and directors of L-3 Communications and its subsidiaries, have been reflected in the consolidated financial statements of L-3 Communications. As a result, the consolidated financial positions, results of operations and cash flows of L-3 Holdings and L-3 Communications are substantially the same. See Note 26 for additional information regarding the audited financial information of L-3 Communications and its subsidiaries.
	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 costs of sales during the reporting period. The most significant of these estimates and assumptions relate to contract revenue, profit and loss recognition, fair values of assets acquired and liabilities assumed in business combinations, 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 and environmental obligations, accrued product warranty costs, and the recoverability, 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 will differ from these estimates and could differ materially.
	The audited condensed consolidated balance sheet as of December 31, 2012 has been revised for the final purchase price allocation of the Link Simulation & Training U.K. Limited (Link U.K.) business acquisition. Link U.K is the commercial aircraft simulation business acquired from Thales Group effective August 6, 2012. During 2013, the Company completed the purchase price allocation, which was based on the final appraisals and valuations of the acquired assets and liabilities and estimated final closing date net working capital. The L-3 audited condensed consolidated balance sheet as of December 31, 2012 has been adjusted in accordance with the accounting standards for business combinations. See Note 5 for additional information regarding the final purchase price allocation for Link U.K. and resulting adjustments.
	Certain other reclassifications have been made to conform prior-year amounts to the current-year presentation.
	Principles of Consolidation: The consolidated financial statements of the Company include all wholly-owned and majority-owned subsidiaries. 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.
	Revenue Recognition: Substantially all of the Company’s sales are generated from written contractual (revenue) arrangements. The sales price for the Company’s revenue arrangements are either fixed-price, cost-plus or time-and-material type. Depending on the contractual scope of work, the Company utilizes either contract accounting standards or accounting standards for revenue arrangements with commercial customers to account for these contracts. Approximately 47% of the Company’s 2013 sales were accounted for under contract accounting standards, of which approximately 38% were fixed-price type contracts and approximately 9% were cost-plus type contracts. For contracts that are accounted for under contract accounting standards, sales and profits are recognized based on: (1) a Percentage-of-Completion (POC) method of accounting (fixed-price contracts), (2) allowable costs incurred plus the estimated profit on those costs (cost-plus contracts), or (3) direct labor hours expended multiplied by the contractual fixed rate per hour plus incurred costs for material (time-and-material contracts). Aggregate net changes in contract estimates increased operating income by $114 million, or 9%, for the year ended December 31, 2013, $72 million, or 6%, for the year ended December 31, 2012, and $73 million, or 5%, for the year ended December 31, 2011.
	Sales and profits on fixed-price type contracts covered by contract accounting standards are substantially recognized using POC methods of accounting. Sales and profits on fixed-price production contracts under which units are produced and delivered in a continuous or sequential process are recorded as units are delivered based on their contractual selling prices (the “units-of-delivery” method). Sales and profits on each fixed-price production contract under which units are not produced and delivered in a continuous or sequential process, or under which a relatively few number of units are produced, are recorded based on the ratio of actual cumulative costs incurred to the total estimated costs at completion of the contract, multiplied by the total estimated contract revenue, less cumulative sales recognized in prior periods (the “cost-to-cost” method). Under both POC methods of accounting, a single estimated total profit margin is used to recognize profit for each contract over its entire period of performance, which can exceed one year. Losses on contracts are recognized in the period in which they become evident. The impact of revisions of contract estimates, which may result from contract modifications, performance or other reasons, are recognized on a cumulative catch-up basis in the period in which the revisions are made.
	Sales and profits on cost-plus type contracts covered by contract accounting standards are recognized as allowable costs are incurred on the contract, at an amount equal to the allowable costs plus the estimated profit on those costs. The estimated profit on a cost-plus type contract is fixed or variable based on the contractual fee arrangement. Incentive and award fees are the primary variable fee contractual arrangements. Incentive and award fees on cost-plus type contracts are included as an element of total estimated contract revenues and are recorded as sales when a basis exists for the reasonable prediction of performance in relation to established contractual targets and the Company is able to make reasonably dependable estimates for them.
	Sales and profits on time-and-material type contracts are recognized on the basis of direct labor hours expended multiplied by the contractual fixed rate per hour, plus the actual costs of materials and other direct non-labor costs.
	Sales on arrangements for (1) fixed-price type contracts that require us to perform services that are not related to the production of tangible assets (Fixed-Price Service Contracts) and (2) certain commercial customers are recognized in accordance with accounting standards for revenue arrangements with commercial customers. Sales for the Company’s businesses whose customers are primarily commercial business enterprises are substantially all generated from single element revenue arrangements. Sales are recognized when there is persuasive evidence of an arrangement, delivery has occurred or services have been performed, the selling price to the buyer is fixed or determinable and collectability is reasonably assured. Sales for Fixed-Price Service Contracts that do not contain measurable units of work performed are generally recognized on a straight-line basis over the contractual service period, unless evidence suggests that the revenue is earned, or obligations fulfilled, in a different manner. Sales for Fixed-Price Service Contracts that contain measurable units of work performed are generally recognized when the units of work are completed. Sales and profit on cost-plus and time-and-material type contracts to perform services are recognized in the same manner as those within the scope of contract accounting standards, except for incentive and award fees. Cost-based incentive fees are recognized when they are realizable in the amount that would be due under the contractual termination provisions as if the contract was terminated. Performance based incentive fees and award fees are recorded as sales when awarded by the customer.
	For contracts with multiple deliverables, the Company applies the separation and allocation guidance under the accounting standard for revenue arrangements with multiple deliverables, unless all the deliverables are covered by contract accounting standards, in which case the Company applies the separation and allocation guidance under contract accounting standards. Revenue arrangements with multiple deliverables are evaluated to determine if the deliverables should be separated into more than one unit of accounting. The Company recognizes revenue for each unit of accounting based on the revenue recognition policies discussed above.
	Sales and profit in connection with contracts to provide services to the U.S. Government that contain collection risk because the contracts are incrementally funded and subject to the availability of funds appropriated, are deferred until a contract modification is obtained, indicating that adequate funds are available to the contract or task order.
	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 costs of sales 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 cost of sales as incurred.
	Customer-funded research and development costs are incurred pursuant to contracts (revenue arrangements) to perform research and development activities according to customer specifications. These costs are not accounted for as research and development expenses, and are also not indirect contract costs. Instead, these costs are direct contract costs and are expensed 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.
	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.
	The table below presents the changes in the Company’s accrued product warranty costs.
			Year Ended December 31,
			2013		2012
			(in millions)
	Accrued product warranty costs(1):
	Balance at January 1		$	99	$	94
	Acquisitions during this period			2		7
	Accruals for product warranties issued during the period			71		78
	Changes to accruals for product warranties existing before January 1			3		(3)
	Foreign currency translation adjustments			—		1
	Settlements made during the period			(76)		(78)
	Balance at December 31		$	99	$	99
		(1)	Warranty obligations incurred in connection with long-term production contracts that are accounted for under the POC cost-to-cost method are included within the contract estimates at completion and are excluded from the above amounts. 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.
	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 L-3 Holdings common stock instead of settling such obligations with cash payments, except for certain performance unit awards that are payable in cash.
	Compensation expense for all restricted stock unit and stock option awards is 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 L-3 Holdings 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. Compensation expense for performance units that are payable in cash is based on a binomial valuation technique (the Monte Carlo valuation model) adjusted for historical performance each reporting period and recognized on a straight-line basis over the requisite service period.
	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.
	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 on 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.
	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. 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 6, 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 general and administrative costs (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 commensurate with the profit margin that the Company earns on similar contracts.
	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 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 applying principally the straight-line method to the estimated useful lives of the related assets. Useful lives range substantially 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 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 valued at fair value.
	Goodwill: 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 or not that the fair value of a reporting unit is less than its carrying amount. L-3 did not utilize a qualitative assessment approach for the November 30, 2013 goodwill impairment test, as we chose instead to complete the quantitative two-step testing process for each reporting unit. The first step in the process is to identify 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 flows valuation approach. If a potential impairment is identified, the second step is to measure the impairment loss by comparing the implied fair value of goodwill with the carrying value of goodwill of the reporting unit. There were no impairment charges that resulted from the annual impairment assessment or change in circumstances during the years ended December 31, 2013 and 2012. The Company recorded a goodwill impairment charge of $43 million during the year ended December 31, 2011. See Note 8 for additional information on the goodwill impairment charge.
	Identifiable Intangible Assets: Identifiable intangible assets represent assets acquired as part of the Company’s business acquisitions and include customer contractual relationships, technology, 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 such estimates indicate that the duration of the Company’s customer contractual relationships has decreased compared to the estimates made as of the date the Company acquired these intangible assets, then the Company accelerates the amortization period for its customer contractual relationships over their remaining useful economic life.
	Derivative Financial Instruments: The Company’s derivative financial instruments include foreign currency forward contracts, which are entered into for risk management purposes, and an embedded derivative representing the contingent interest payment provision related to the CODES.
	The Company’s U.S. and foreign businesses enter into contracts with customers, subcontractors or vendors that are denominated in currencies other than their functional currencies. To protect the functional currency equivalent cash flows associated with certain of these contracts, the Company enters into foreign currency forward contracts. The Company’s activities involving foreign currency forward contracts are designed to hedge the changes in the functional currency equivalent cash flows due to movements in foreign exchange rates compared to the functional currency. The foreign currencies hedged are primarily the Canadian dollar, the U.S. dollar, the Euro 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.
	The embedded derivative related to the issuance of the CODES is recorded at fair value with changes reflected in the Consolidated Statements of Operations.
	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, 2013, 2012 and 2011 are 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 other comprehensive income (loss).
	Accounting Standards Issued and Not Yet Implemented: In July 2013, the FASB issued amendments to an accounting standard which requires an unrecognized tax benefit or portion of an unrecognized tax benefit to be presented as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward except when certain conditions exist. The amendments are effective for the Company for fiscal years beginning after December 15, 2013, including that year’s interim periods. The adoption of this standard will not impact the Company’s financial position, results of operations or cash flows.

Revisions_to_Previously_Issued

Revisions to Previously Issued Financial Statements	12 Months Ended
	Dec. 31, 2013
Accounting Changes and Error Corrections [Abstract]	'
Revisions to Previously Issued Financial Statements	'
	3. Revisions to Previously Issued Financial Statements
	The Company is revising its previously issued financial statements to update for: (1) accounting adjustments due to the internal review at its Aerospace Systems segment, (2) accounting related to a sales-type lease transaction for flight simulator systems within its Electronic Systems segment, and (3) previously identified immaterial errors already recognized in its financial statements but not recorded in the appropriate periods. The accounting errors related to the sales-type lease transaction and immaterial out of period amounts are not related to the internal review at its Aerospace Systems segment.
	Internal Review of Aerospace Systems Segment: The Company conducted an internal review related to instances of misconduct and accounting errors at its Aerospace Systems segment. This review was conducted with the assistance of outside legal and accounting advisors, and has been completed. As a result of the internal review, the Company identified and recorded aggregate pre-tax charges as follows: (1) $60 million for 2013, (2) $25 million for 2012, (3) $5 million for 2011, and (4) $4 million for periods prior to 2011.
	The adjustments related to the internal review only affected the Logistics Solutions and Platform Systems sectors of the Aerospace Systems segment. The cumulative aggregate adjustments attributable to the Logistics Solutions sector are approximately $82 million, and at the Platform Systems sector are approximately $12 million through 2013. The Logistics Solutions sector adjustments relate to: (1) losses of $54 million through 2013 with respect to the U.S. Army C-12 fixed-price maintenance and logistics support contract due to cost overruns inappropriately deferred, sales invoices inappropriately prepared, and the failure to timely and accurately perform contract estimates at completion and valuation assessments of inventories and receivables at the Army Sustainment Division, and (2) accounting errors of $28 million through 2013 in connection with the valuation of inventories and receivables, as well as the correction for certain accruals on other logistics support contracts. The Platform Systems sector adjustments are primarily due to: (1) losses of $2 million on two aircraft modification contracts and two contracts for rotary wing sub-assemblies and parts, and (2) write-offs of deferred costs of $10 million to design and test aerostructures for a new commercial aircraft.
	Sales-Type Lease Transaction: The Company routinely performs on-site accounting and internal control review procedures on a rotational basis. As part of a previously planned review of the Simulation & Training business in its Electronic Systems segment and unrelated to the internal review at its Aerospace Systems segment, the Company evaluated the accounting treatment related to a sales-type lease transaction with the U.S. Army for rotary wing flight simulator systems. The period of performance under this contract began in 2004 and ends in 2023. Based on the results of this evaluation, the Company has adjusted its previously issued financial statements to: (1) increase interest income accretion on the net investment related to this sales-type lease transaction by an estimated aggregate amount of approximately $5 million for 2013, $3 million for each of 2012 and 2011 and $12 million for periods prior to 2011, and (2) decrease sales by approximately $7 million for 2013 and decrease cost of sales by approximately $7 million for 2013 and $5 million for periods prior to 2011.
	Out of Period Amounts: The Company has identified various out of period amounts included in its previously issued financial statements that were deemed to be immaterial individually and in the aggregate. In prior periods, in accordance with Accounting Standards Codification (“ASC”) 650-10-S99 and S55 (formerly Staff Accounting Bulletins (“SAB”) No. 99 and No. 108), Accounting Changes and Error Corrections, the Company concluded that these errors were, individually, and in the aggregate, not material, quantitatively or qualitatively, to the financial statements in the period recorded or to the relevant prior periods. Accordingly, the Company recorded these errors in its financial statements in the period that the error was identified. The Company is, on a voluntary basis, revising its previously issued financial statements to correct for these errors already recognized in its financial statements but not recorded in the appropriate periods to reflect them in the appropriate period. These out of period amounts were not discovered as part of the internal review of the Aerospace Systems segment discussed above, but rather represent previously identified errors “resulting from mathematical mistakes, mistakes in application of generally accepted accounting principles, or oversight or misuse of facts that existed at the time the financial statements were prepared,” as defined in ASC 250-10-20 Accounting Changes and Error Corrections. The Company, therefore, is not treating these amounts as changes in estimates. These errors consist of: (1) increases in development and material costs related to Broadband Communication Systems that were recorded in the first quarter of 2013 but should have been recorded in the fourth quarter of 2012, (2) a sub-contractor subscription deposit that was recorded as sales and income in the fourth quarter of 2012 but should have been amortized to sales and income during 2013, (3) costs accrued in the fourth quarter of 2012 for goods or services received in the first quarter of 2013, (4) several unrecorded liabilities that were recorded in the first quarter of 2013 but should have been recorded in the fourth quarter of 2012, (5) a correction of accrued vacation that was recorded in the fourth quarter of 2013 but should have been recorded in the fourth quarter of 2012 and the first, second and third quarters of 2013, and (6) a warranty reserve reduction recorded in the third quarter of 2012 that should have been recorded in the fourth quarter of 2011.
	With respect to each of the immaterial out of period amounts included in the Company’s previously issued financial statements, the table below presents the: (1) nature of the adjustments, (2) applicable segment, (3) amount of increase (or decrease) to sales and operating income, (4) period recorded and (5) correct period.
					2013								2012								2011
	Nature of Adjustment		Applicable		Sales				Operating				Sales				Operating				Sales				Operating				Period	Correct
			Segment						Income								Income								Income				Recorded	Period
					($ in millions)
	Higher development and material costs for networked communications systems		Communication Systems		$	10			$	10			$	(10	)		$	(10	)		$	—			$	—			1Q 2013	4Q 2012
	Sub-contractor subscription deposit		Aerospace Systems			26				2				(26	)			(2	)			—				—			4Q 2012	1Q, 2Q,
																														3Q & Q4 2013
	Costs accruals for goods/services received		Aerospace Systems			5				1				(5	)			(1	)			—				—			4Q 2012	1Q 2013
	Unrecorded liabilities		Aerospace Systems			(2	)			—				2				—				—				—			1Q 2013	4Q 2012
	Accrued vacation		Aerospace Systems			—				1				—				(1	)			—				—			4Q 2013	4Q 2012,
																														1Q, 2Q & 3Q 2013
	Warranty reserve		Electronic Systems			—				—				3				(4	)			(3	)			4			3Q 2012	4Q 2011
	Total				$	39			$	14			$	(36	)		$	(18	)		$	(3	)		$	4
	The table below presents the impact of the matters discussed above on sales and pre-tax income for the years ended December 31, 2013, 2012 and 2011 and for the years ended prior to December 31, 2011.
			2013								2012								2011								Prior to 2011
			Sales				Pre-tax				Sales				Pre-tax				Sales				Pre-tax				Sales			Pre-tax
							Income								Income								Income							Income
			(in millions)
	Army C-12 Contract		$	(25)			$	(35)			$	(3)			$	(16)			$	(1)			$	(3)				—			—
	Other Logistics Support Contracts			(2)				(11)				(2)				(11)				—				(2)				(1)			(4)
	Logistics Solutions		$	(27)			$	(46)			$	(5)			$	(27)			$	(1)			$	(5)			$	(1)		$	(4)
	Platform Systems			(12)				(14)				3				2				—				—				—			—
	Total Internal Review of Aerospace Systems Segment		$	(39)			$	(60)			$	(2)			$	(25)			$	(1)			$	(5)			$	(1)		$	(4)
	Sales-Type Lease Transaction			(7)				5				—				3				—				3				—			17
	Out of Period Amounts			39				14				(36)				(18)				(3)				4				—			—
	Total Revisions		$	(7)			$	(41)			$	(38)			$	(40)			$	(4)			$	2			$	(1)		$	13
	In accordance with ASC 650-10-S99 and S55, the Company performed an analysis to determine if the impact of the amounts disclosed above were material to its previously issued financial statements. Based on that analysis, the Company believes that its previously issued financial statements are not materially misstated on either a quantitative or qualitative basis. However, as a result of completing the review, the Company believes that correcting these errors in the quarterly report on Form 10-Q for the second quarter of 2014 would, in the aggregate, cause a material misstatement to forecasted pre-tax income and net income for the fiscal year ending December 31, 2014. Accordingly, the Company is correcting these errors by revising its previously issued financial statements to record all the adjustments in the table above in the appropriate period.
	The tables below present the Company’s: (1) As Previously Reported, (2) Adjustments, and (3) As Currently Reported Condensed Consolidated Balance Sheets as of December 31, 2013 and 2012, Statements of Operations and Operating Activities for the Statement of Cash Flows, for the fiscal years ended December 31, 2013, 2012 and 2011. The Adjustments correct for: (1) the results of the Aerospace Systems internal review, (2) the accounting related to a sales-type lease transaction within the Company’s Electronic Systems segment and (3) immaterial out of period amounts previously recorded in the Company’s financial statements but not recorded in the appropriate period to reflect them in the appropriate period.
							Adjustments for:
			As				Aerospace				Sales-Type				Out of Period				As
			Previously				Systems				Lease				Amounts				Revised
			Reported				Segment				Transaction
							Internal
							Review
			(in millions)
	Condensed Consolidated Balance Sheet as of
	December 31, 2013:
	ASSETS
	Current Assets:
	Cash and cash equivalents		$	500			$	—			$	—			$	—			$	500
	Billed receivables, net of allowances of $26 in 2013			1,015				(24)				—				—				991
	Contracts in process			2,524				(67)				(26)				—				2,431
	Inventories			359				—				—				—				359
	Deferred income taxes			122				25				—				—				147
	Other current assets			129				9				28				—				166
	Total current assets			4,649				(57)				2				—				4,594
	Property, plant and equipment, net			1,039				3				—				—				1,042
	Goodwill			7,796				—				—				—				7,796
	Identifiable intangible assets			285				—				—				—				285
	Deferred debt issue costs			24				—				—				—				24
	Other assets			216				—				31				—				247
	Total assets		$	14,009			$	(54)			$	33			$	—			$	13,988
	LIABILITIES AND EQUITY
	Current Liabilities:
	Accounts payable, trade		$	541			$	—			$	—			$	—			$	541
	Accrued employment costs			543				2				—				—				545
Accrued expenses			455				3				—				—				458
Advance payments and billings in excess of costs incurred			570				1				5				—				576
Income taxes			31				—				—				—				31
Other current liabilities			383				—				—				—				383
Total current liabilities			2,523				6				5				—				2,534
Pension and postretirement benefits			727				—				—				—				727
Deferred income taxes			635				—				—				—				635
Other liabilities			396				—				10				—				406
Long-term debt			3,630				—				—				—				3,630
Total liabilities			7,911				6				15				—				7,932
Equity:
L-3 shareholders’ equity:
L-3 Communications Holdings, Inc.’s common stock			5,653				—				—				—				5,653
L-3 Communications Holdings, Inc.’s treasury stock at cost			(5,288)				—				—				—				(5,288)
Retained earnings			5,768				(60)				17				1				5,726
Accumulated other comprehensive loss			(110)				—				—				—				(110)
Total L-3 shareholders’ equity			6,023				(60)				17				1				5,981
Noncontrolling interests			75				—				—				—				75
Total equity			6,098				(60)				17				1				6,056
Total liabilities and equity		$	14,009			$	(54)			$	32			$	1			$	13,988
Condensed Consolidated Balance Sheet as of December 31, 2012:
ASSETS
Current Assets:
Cash and cash equivalents		$	349			$	—			$	—			$	—			$	349
Billed receivables, net of allowances of $33 in 2012			968				—				—				—				968
Contracts in process			2,597				(30)				(45)				(12)				2,510
Inventories			358				—				—				—				358
Deferred income taxes			95				12				—				6				113
Other current assets			138				—				45				3				186
Total current assets			4,505				(18)				—				(3)				4,484
Property, plant and equipment, net			1,016				1				—				6				1,023
Goodwill			7,776				—				—				—				7,776
Identifiable intangible assets			314				—				—				—				314
Deferred debt issue costs			29				—				—				—				29
Other assets			151				—				23				—				174
Total assets		$	13,791			$	(17)			$	23			$	3			$	13,800
LIABILITIES AND EQUITY
Current Liabilities:
Accounts payable, trade		$	494			$	—			$	—			$	11			$	505
Accrued employment costs			551				2				—				2				555
Accrued expenses			469				1				—				(1)				469
Advance payments and billings in excess of costs incurred			620				1				—				—				621
Income taxes			21				—				—				—				21
Other current liabilities			392				—				—				—				392
Total current liabilities			2,547				4				—				12				2,563
Pension and postretirement benefits			1,360				—				—				—				1,360
Deferred income taxes			328				—				—				—				328
Other liabilities			384				—				9				—				393
Long-term debt			3,629				—				—				—				3,629
Total liabilities			8,248				4				9				12				8,273
Equity:
L-3 shareholders’ equity:
L-3 Communications Holdings, Inc.’s common stock			5,314				—				—				—				5,314
L-3 Communications Holdings, Inc.’s treasury stock at cost			(4,488)				—				—				—				(4,488)
Retained earnings			5,191				(22)				14				(8)				5,175
Accumulated other comprehensive loss			(550)				—				—				—				(550)
Total L-3 shareholders’ equity			5,467				(22)				14				(8)				5,451
Noncontrolling interests			76				—				—				—				76
Total equity			5,543				(22)				14				(8)				5,527
Total liabilities and equity		$	13,791			$	(18)			$	23			$	4			$	13,800
Consolidated Statement of Operations for the year ended December 31, 2013:
Net sales:
Products		$	7,192			$	(11)			$	(7)			$	15			$	7,189
Services			5,437				(28)				—				24				5,433
Total net sales			12,629				(39)				(7)				39				12,622
Cost of sales:
Products			(6,409)				(3)				7				(4)				(6,409)
Services			(4,962)				(18)				—				(21)				(5,001)
Total cost of sales			(11,371)				(21)				7				(25)				(11,410)
Impairment charge			—				—				—				—				—
Operating income			1,258				(60)				—				14				1,212
Interest expense			(177)				—				—				—				(177)
Interest and other income, net			15				—				5				—				20
Debt retirement charge			—				—				—				—				—
Income from continuing operations before income taxes			1,096				(60)				5				14				1,055
Provision for income taxes			(309)				21				(2)				(5)				(295)
Income from continuing operations			787				(39)				3				9				760
Income from discontinued operations, net of income tax			—				—				—				—				—
Net income		$	787			$	(39)			$	3			$	9			$	760
Net income attributable to noncontrolling interests			(9)				—				—				—				(9)
Net income attributable to L-3		$	778			$	(39)			$	3			$	9			$	751
Net income allocable to participating securities			—				—				—				—				—
Net income allocable to L-3 Holdings’ common shareholders		$	778			$	(39)			$	3			$	9			$	751
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.70			$	(0.43)			$	0.03			$	0.10			$	8.40
Discontinued operations			—				—				—				—				—
Basic earnings per share		$	8.70			$	(0.43)			$	0.03			$	0.10			$	8.40
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.54			$	(0.43)			$	0.03			$	0.10			$	8.24
Discontinued operations			—				—				—				—				—
Diluted earnings per share		$	8.54			$	(0.43)			$	0.03			$	0.10			$	8.24
Cash dividends paid per common share		$	2.20			$	—			$	—			$	—			$	2.20
L-3 Holdings’ weighted average common shares outstanding:
Basic			89.4				—				—				—				89.4
Diluted			91.1				—				—				—				91.1
						Adjustments for:
		As				Aerospace				Sales-Type				Out of Period				As
		Previously				Systems				Lease				Amounts				Revised
		Reported				Segment				Transaction
						Internal
						Review
		(in millions, except per share data)
Consolidated Statement of Operations for the year ended December 31, 2012:
Net sales:
Products		$	7,535			$	64			$	—			$	(13)			$	7,586
Services			5,611				(66)				—				(24)				5,521
Total net sales			13,146				(2)				—				-37	(1)			13,107
Cost of sales:
Products			(6,724)				(57)				—				(1)				(6,782)
Services			(5,071)				34				—				20				(5,017)
Total cost of sales			(11,795)				(23)				—				19				(11,799)
Impairment charge			—				—				—				—				—
Operating income			1,351				(25)				—				(18)				1,308
Interest expense			(184)				—				—				—				(184)
Interest and other income, net			8				—				3				—				11
Debt retirement charge			(13)				—				—				—				(13)
Income from continuing operations before income taxes			1,162				(25)				3				(18)				1,122
Provision for income taxes			(374)				9				(1)				6				(360)
Income from continuing operations			788				(16)				2				(12)				762
Income from discontinued operations, net of income tax			32				—				—				—				32
Net income		$	820			$	(16)			$	2			$	(12)			$	794
Net income attributable to noncontrolling interests			(10)				—				—				—				(10)
Net income attributable to L-3		$	810			$	(16)			$	2			$	(12)			$	784
Net income allocable to participating securities			—				—				—				—				—
Net income allocable to L-3 Holdings’ common shareholders		$	810			$	(16)			$	2			$	(12)			$	784
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.12			$	(0.17)			$	0.02			$	(0.12)			$	7.85
Discontinued operations			0.29				—				—				—				0.29
Basic earnings per share		$	8.41			$	(0.17)			$	0.02			$	(0.12)			$	8.14
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.01			$	(0.17)			$	0.02			$	(0.12)			$	7.74
Discontinued operations			0.29				—				—				—				0.29
Diluted earnings per share		$	8.30			$	(0.17)			$	0.02			$	(0.12)			$	8.03
Cash dividends paid per common share		$	2.00			$	—			$	—			$	—			$	2.00
L-3 Holdings’ weighted average common shares outstanding:
Basic			96.3				—				—				—				96.3
Diluted			97.6				—				—				—				97.6
	(1)	Includes rounding of $1 million.
						Adjustments for:
		As				Aerospace				Sales-Type				Out of				As
		Previously				Systems				Lease				Period				Revised
		Reported				Segment				Transaction				Amounts
						Internal
						Review
		(in millions, except per share data)
Consolidated Statement of Operations for the year ended December 31, 2011:
Net sales:
Products		$	7,552			$	—			$	—			$	(3)			$	7,549
Services			5,606				(1)				—				—				5,605
Total net sales			13,158				(1)				—				(3)				13,154
Cost of sales:
Products			(6,673)				—				—				7				(6,666)
Services			(5,043)				(4)				—				—				(5,047)
Total cost of sales			(11,716)				(4)				—				7				(11,713)
Impairment charge			(43)				—				—				—				(43)
Operating income			1,399				(5)				—				4				1,398
Interest expense			(204)				—				—				—				(204)
Interest and other income, net			—				—				3				—				3
Debt retirement charge			(35)				—				—				—				(35)
Income from continuing operations before income taxes			1,160				(5)				3				4				1,162
Provision for income taxes			(296)				2				(1)				(1)				(296)
Income from continuing operations			864				(3)				2				3				866
Income from discontinued operations, net of income tax			104				—				—				—				104
Net income		$	968			$	(3)			$	2			$	3			$	970
Net income attributable to noncontrolling interests			(12)				—				—				—				(12)
Net income attributable to L-3		$	956			$	(3)			$	2			$	3			$	958
Net income allocable to participating securities			(2)				—				—				—				(2)
Net income allocable to L-3 Holdings’ common shareholders		$	954			$	(3)			$	2			$	3			$	956
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.17			$	(0.03)			$	0.02			$	0.03			$	8.19
Discontinued operations			0.97				—				—				—				0.97
Basic earnings per share		$	9.14			$	(0.03)			$	0.02			$	0.03			$	9.16
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.08			$	(0.03)			$	0.02			$	0.03			$	8.10
Discontinued operations			0.95				—				—				—				0.95
Diluted earnings per share		$	9.03			$	(0.03)			$	0.02			$	0.03			$	9.05
Cash dividends paid per common share		$	1.80			$	—			$	—			$	—			$	1.80
L-3 Holdings’ weighted average common shares outstanding:
Basic			104.4				—				—				—				104.4
Diluted			105.6				—				—				—				105.6
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2013:
Operating activities:
Net income		$	787			$	(27)			$	760
Income from discontinued operations, net of tax			—				—				—
Income from continuing operations			787				(27)				760
Depreciation of property, plant and equipment			166				—				166
Amortization of intangibles and other assets			48				—				48
Deferred income tax provision			48				(6)				42
Stock-based employee compensation expense			59				—				59
Contributions to employee savings plans in L-3 Holdings’ common stock			114				—				114
Amortization of pension and postretirement benefit plans net loss and prior service cost			83				—				83
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			6				—				6
Goodwill impairment charge			—				—				—
Equity in losses of unconsolidated subsidiaries			—				—				—
Other non-cash items			2				—				2
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			(42)				24				(18)
Contracts in process			94				10				104
Inventories			2				—				2
Other assets			(81)				(7)				(88)
Accounts payable, trade			45				(11)				34
Accrued employment costs			(5)				—				(5)
Accrued expenses			(6)				1				(5)
Advance payments and billings in excess of costs incurred			(50)				6				(44)
Income taxes			39				(8)				31
Excess income tax benefits related to share-based payment arrangements			(4)				—				(4)
Other current liabilities			(4)				—				(4)
Pension and postretirement benefits			14				—				14
All other operating activities			(52)				18				(34)
Net cash from operating activities from continuing operations		$	1,263			$	—			$	1,263
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2012:
Operating activities:
Net income		$	820			$	(26)			$	794
Income from discontinued operations, net of tax			(32)				—				(32)
Income from continuing operations			788				(26)				762
Depreciation of property, plant and equipment			170				—				170
Amortization of intangibles and other assets			58				—				58
Deferred income tax provision			112				(15)				97
Stock-based employee compensation expense			59				—				59
Contributions to employee savings plans in L-3 Holdings’ common stock			125				—				125
Amortization of pension and postretirement benefit plans net loss and prior service cost			68				—				68
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			7				—				7
Goodwill impairment charge			—				—				—
Equity in losses of unconsolidated subsidiaries			3				—				3
Other non-cash items			9				—				9
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			147				—				147
Contracts in process			(126)				59				(67)
Inventories			(35)				—				(35)
Other assets			11				(3)				8
Accounts payable, trade			81				11				92
Accrued employment costs			(13)				3				(10)
Accrued expenses			(100)				—				(100)
Advance payments and billings in excess of costs incurred			36				1				37
Income taxes			(48)				1				(47)
Excess income tax benefits related to share-based payment arrangements			(3)				—				(3)
Other current liabilities			(52)				6				(46)
Pension and postretirement benefits			(64)				—				(64)
All other operating activities			(2)				(37)				(39)
Net cash from operating activities from continuing operations		$	1,231			$	—			$	1,231
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2011:
Operating activities:
Net income		$	968			$	2			$	970
Income from discontinued operations, net of tax			(104)				—				(104)
Income from continuing operations			864				2				866
Depreciation of property, plant and equipment			167				—				167
Amortization of intangibles and other assets			63				—				63
Deferred income tax provision			124				(1)				123
Stock-based employee compensation expense			57				—				57
Contributions to employee savings plans in L-3 Holdings’ common stock			113				—				113
Amortization of pension and postretirement benefit plans net loss and prior service cost			48				—				48
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			13				—				13
Goodwill impairment charge			43				—				43
Equity in losses of unconsolidated subsidiaries			12				—				12
Other non-cash items			11				—				11
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			(13)				—				(13)
Contracts in process			(121)				11				(110)
Inventories			(14)				—				(14)
Other assets			(6)				(3)				(9)
Accounts payable, trade			(35)				—				(35)
Accrued employment costs			(23)				—				(23)
Accrued expenses			67				1				68
Advance payments and billings in excess of costs incurred			(39)				—				(39)
Income taxes			(18)				2				(16)
Excess income tax benefits related to share-based payment arrangements			(2)				—				(2)
Other current liabilities			4				(6)				(2)
Pension and postretirement benefits			(83)				—				(83)
All other operating activities			(1)				(6)				(7)
Net cash from operating activities from continuing operations		$	1,231			$	—			$	1,231

New_Accounting_Standards_Imple

New Accounting Standards Implemented	12 Months Ended
	Dec. 31, 2013
Accounting Changes and Error Corrections [Abstract]	'
New Accounting Standards Implemented	'
	4. New Accounting Standards Implemented
	Effective January 1, 2013, the Company adopted a new accounting standard issued by the Financial Accounting Standards Board (FASB), which adds new disclosure requirements for items reclassified out of accumulated other comprehensive income (loss) (AOCI). This standard requires entities to disclose additional information about reclassification adjustments, including: (1) changes in AOCI balances by component and (2) significant items reclassified out of AOCI. The adoption of this standard resulted in additional disclosures of items reclassified out of AOCI and did not impact the Company’s financial position, results of operations or cash flows. See Note 12 for these additional disclosures.

Acquisitions_and_Divestures

Acquisitions and Divestures	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Acquisitions and Divestures	'
	5. Acquisitions and Divestures
	Business Acquisitions
	All business acquisitions are included in the Company’s results of operations from their respective acquisition dates.
	2013 Business Acquisition
	On December 19, 2013, the Company acquired Mustang Technology Group, L.P. (Mustang) business for an aggregate purchase price of $54 million, which was financed with cash on hand. The purchase price is subject to adjustment based on closing date net working capital. Mustang develops and manufactures radar-based sensors and systems used in precision-guided weapons, electronic warfare, unmanned systems and other military applications. Based on the preliminary purchase price allocations, the aggregate goodwill recognized for this business was $44 million, most of which is expected to be deductible for income tax purposes. The goodwill was assigned to the Electronic Systems reportable segment. The final purchase price allocation is expected to be completed in the second quarter of 2014 and will be based on final purchase price, final appraisals and other analysis of fair values of acquired assets and liabilities. The Company does not expect differences between the preliminary and final purchase price allocations to have a material impact on its results of operations or financial position.
	2012 Business Acquisitions
	During the year ended December 31, 2012, in separate transactions, the Company acquired three businesses for an aggregate purchase price of $349 million, which were financed with cash on hand. Based on the final purchase price allocations, the aggregate goodwill recognized for these businesses was $278 million, of which $182 million is expected to be deductible for income tax purposes. The goodwill was assigned to the Electronic Systems reportable segment. A description of each business acquisition made by the Company during the year ended December 31, 2012 is listed below:
		•		On February 6, 2012, the Company acquired the Kollmorgen Electro-Optical business (named L-3 KEO). L-3 KEO develops and manufactures specialized equipment, including submarine photonics systems and periscopes, ship fire control systems, visual landing aids and ground electro-optical and sensor-cueing systems for the U.S. military and allied international governments.
		•		On April 13, 2012, the Company acquired the assets and liabilities of MAVCO, Inc. (MAVCO). MAVCO is an audio, video, lighting and broadcast systems integrations business primarily for cruise lines.
		•		On August 6, 2012, the Company acquired the commercial aircraft simulation business from Thales Group (named Link Simulation & Training U.K. Limited (Link U.K.)). Link U.K. is a leading manufacturer of flight simulation systems for the commercial aviation market.
	The purchase prices and purchase price allocations for L-3 KEO and MAVCO were finalized as of June 28, 2013 and December 31, 2012, respectively, with no significant changes from the preliminary amounts. The Link U.K. purchase price allocation was finalized as of September 27, 2013 based on the results of the final appraisals and valuations of the assets and liabilities acquired and estimated final closing date net working capital. The final purchase price allocations resulted in certain adjustments to the preliminary valuations, the most significant of which included an increase to goodwill of $32 million, which included $4 million for foreign currency translation adjustments, an increase to other liabilities of $17 million, and a decrease of $16 million to contracts in process. The purchase price for Link U.K. was finalized in the fourth quarter of 2013 and resulted in a $6 million final net working capital adjustment that had been previously accrued. As discussed in Note 2, the audited condensed consolidated balance sheet as of December 31, 2012 has been revised for these adjustments in accordance with accounting standards for business combinations.
	2011 Business Acquisitions
	During the year ended December 31, 2011, in separate transactions, the Company acquired two businesses for an aggregate purchase price of $18 million, which were financed with cash on hand. Based on final purchase price allocations, the aggregate goodwill recognized for these businesses was $19 million, of which $14 million is expected to be deductible for income tax purposes. The goodwill was assigned to the reportable segments listed below:
	Segment		December 31,
			2013
			(in millions)
	Electronic Systems		$	10
	Communication Systems			9
	Total		$	19
	A description of each business acquisition made by the Company during the year ended December 31, 2011 is listed below:
		•		On July 1, 2011, the Company acquired the communications and engineering business of ComHouse Wireless L.P. (ComHouse). The acquired business provides L-3 with cellular wave form modulation technology that can be used to counter improvised explosive devices.
		•		On October 28, 2011, the Company acquired the cargo radiation screening business of Detector Networks International LLC (DNI). The purchase price for DNI is subject to additional, contingent consideration not to exceed $10 million and is based on DNI’s post-acquisition financial performance through December 31, 2014. The Company recorded a $7 million liability on the acquisition date for the fair value of the contingent consideration, which was reduced by $2 million in 2012 and $5 million in 2013 due to lower than expected financial performance.
	The purchase prices for ComHouse and DNI are final and the purchase price allocations for these acquisitions were completed with no significant changes from the preliminary amounts.
	Business Divestitures
	2012 Spin-off of Engility
	The Company completed the spin-off of its subsidiary, Engility Holdings, Inc. (Engility), on July 17, 2012. In connection with the spin-off, Engility made a cash distribution of $335 million to L-3. A portion of the proceeds were used to redeem $250 million of the 6 3⁄8% Senior Subordinated Notes due 2015 (6 3⁄8% 2015 Notes) on July 26, 2012. There was no gain or loss recognized by L-3 as a result of the spin-off transaction.
	Prior to the completion of the spin-off, L-3 and Engility entered into a Distribution Agreement dated July 16, 2012 and several other agreements that govern certain aspects of L-3’s relationship with Engility. These agreements generally provide that each party is responsible for its respective assets, liabilities and obligations, including employee benefits, insurance and tax-related assets and liabilities, following the spin-off, whether accrued or contingent. The agreements also described certain services that L-3 provided to Engility that were substantially completed by December 31, 2013.
	L-3 incurred transaction expenses in connection with the spin-off of $19 million ($14 million after income taxes) for the year ended December 31, 2012 and $9 million ($7 million after income taxes) for the year ended December 31, 2011, which have been included in discontinued operations. In addition, L-3 allocated interest expense for debt not directly attributable or related to L-3’s other operations of $14 million and $31 million to discontinued operations for the years ended December 31, 2012 and 2011, respectively. Interest expense was allocated in accordance with the accounting standards for discontinued operations and was based on the ratio of Engility net assets to the sum of: (1) total L-3 consolidated net assets and (2) L-3 consolidated total debt.
	Engility’s statement of operations data, which has been classified as discontinued operations, is provided in the table below.
			January 1		Year Ended
			to July 17,		December 31,
			2012		2011
			(in millions)
	Product and service revenues		$	911	$	2,011
	Operating income from discontinued operations before income taxes			68		199
	Interest expense allocated to discontinued operations			(14)		(31)
	Income from discontinued operations before income taxes		$	54	$	168
	Income tax expense			(22)		(64)
	Income from discontinued operations, net of income taxes		$	32	$	104
	Net income from discontinued operations attributable to noncontrolling interests			(4)		(3)
	Net income from discontinued operations attributable to L-3		$	28	$	101
	2011 Business Divestiture
	On February 22, 2011, the Company divested the MOI business of Microdyne Corporation (Microdyne), which was within the Electronic Systems segment. The divestiture resulted in a pre-tax loss of $2 million. Microdyne’s annual revenues (approximately $8 million), operating results and net assets were not material for any period presented and, therefore, this divestiture is not reported as a discontinued operation. The net proceeds from the sale are included in investing activities on the Consolidated Statement of Cash Flows.
	Unaudited Pro Forma Statements of Operations Data
	The following unaudited pro forma Statements of Operations data presents the combined results of the Company and its business acquisitions completed during the years ended December 31, 2013, 2012 and 2011, assuming that the business acquisitions completed during 2013, 2012 and 2011 had occurred on January 1, 2011.
			Year Ended December 31,
			2013		2012		2011
			(in millions, except per share data)
	Pro forma net sales		$	12,657	$	13,239	$	13,498
	Pro forma income from continuing operations		$	760	$	764	$	883
	Pro forma net income attributable to L-3		$	751	$	786	$	975
	Pro forma diluted earnings per share from continuing operations		$	8.24	$	7.76	$	8.26
	Pro forma diluted earnings per share		$	8.24	$	8.05	$	9.21
	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.

Contracts_in_Process

Contracts in Process	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Contracts in Process	'
	6. 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. In connection with contracts in process assumed by the Company in its business acquisitions, the underlying contractual customer relationships are separately recognized as identifiable intangible assets at the date of acquisition, and are discussed and presented in Note 8.
		December 31,
		2013		2012
		(in millions)
	Unbilled contract receivables, gross	$	2,502	$	2,802
	Unliquidated progress payments		(1,035)		(1,256)
	Unbilled contract receivables, net		1,467		1,546
	Inventoried contract costs, gross		1,044		1,091
	Unliquidated progress payments		(80)		(127)
	Inventoried contract costs, net		964		964
	Total contracts in process	$	2,431	$	2,510
	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 and time-and-material 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. The Company believes that approximately 98% of the unbilled contract receivables at December 31, 2013 will be billed and collected within one year.
	Unliquidated Progress Payments. Unliquidated progress payments arise from fixed-price type contracts with the U.S. Government that contain progress payment clauses, and represent progress 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 75% to 80% of incurred costs. Unliquidated progress 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. Therefore, 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 cost of sales by the Company’s U.S. Government contractor businesses for the periods presented.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Amounts included in inventoried contract costs at beginning of the year	$	110	$	91	$	97
	IRAD and B&P costs incurred		296		336		327
	Other G&A costs incurred		893		891		843
	Total contract costs incurred		1,189		1,227		1,170
	Amounts charged to cost of sales		(1,161)		(1,208)		(1,176)
	Amounts included in inventoried contract costs at end of the year	$	138	$	110	$	91
	The table below presents a summary of selling, general and administrative expenses and research and development expenses for the Company’s commercial businesses, which are expensed as incurred and included in cost of sales on the Consolidated Statements of Operations.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Selling, general and administrative expenses	$	293	$	306	$	300
	Research and development expenses		74		88		73
	Total	$	367	$	394	$	373

Inventories

Inventories	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
Inventories	'
	7. Inventories
	Inventories at Lower of Cost or Market. The table below presents the components of inventories at the lower of cost (first-in, first-out or average cost) or realizable value.
		December 31,
		2013		2012
		(in millions)
	Raw materials, components and sub-assemblies	$	160	$	166
	Work in process		125		121
	Finished goods		74		71
	Total	$	359	$	358

Goodwill_and_Identifiable_Inta

Goodwill and Identifiable Intangible Assets	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Identifiable Intangible Assets	'
	8. 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). 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, 2013, the Company had approximately 48,000 employees, and the substantial majority of the sales generated by the Company’s businesses are 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.
			Aerospace				Electronic				Communication				NSS				Consolidated
			Systems				Systems				Systems								Total
			(in millions)
	Balance at December 31, 2011		$	1,764			$	3,750			$	992			$	966			$	7,472
	Business acquisitions			—				278				—				—				278
	Foreign currency translation(1)			6				18				—				2				26
	Balance at December 31, 2012		$	1,770			$	4,046			$	992			$	968			$	7,776
	Business acquisition			—				44				—				—				44
	Business disposition			—				(2)				—				—				(2)
	Foreign currency translation(1)			(19)				(3)				—				—				(22)
	Balance at December 31, 2013		$	1,751			$	4,085			$	992			$	968			$	7,796
		(1)	The changes in goodwill from foreign currency translation adjustments are due to fluctuations in the U.S. dollar and foreign currency exchange rates. The decreases in goodwill presented in Electronic Systems and Aerospace Systems segments during 2013 were primarily due to the strengthening of the U.S. dollar against the Canadian dollar and Australian dollar, partially offset by the weakening of the U.S. dollar against the Euro and British pound. Conversely, the increases in goodwill presented in the Electronic Systems, Aerospace Systems and NSS segments during 2012 were due to the weakening of the U.S dollar against the Euro, Canadian dollar and the British pound.
	The $44 million increase to goodwill for the year ended December 31, 2013 was due to the Mustang business acquisition. The $278 million increase to goodwill for the year ended December 31, 2012 was due to three business acquisitions completed during the year.
	As discussed in Note 2, the carrying value of goodwill is tested for impairment annually as of November 30 and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable, on an interim basis using a two step process.
	The first step of the November 30, 2013 and November 30, 2012 annual impairment tests did not indicate any impairments. The November 30, 2011 annual impairment test did identify an impairment at the Marine Services business, which is now part of the Marine & Power Systems business included in the Electronic Systems segment. The Company performed the second step of the impairment test in accordance with the accounting standards for goodwill to measure the impairment loss and determined that the implied goodwill was $43 million lower than the carrying amount. Accordingly, the Company recorded a non-cash impairment charge of $43 million ($42 million after income taxes, or $0.40 per diluted share) for the impairment of goodwill. The Company’s accumulated goodwill impairment losses were $58 million at December 31, 2013 and 2012, of which $43 million and $15 million were recorded in the Electronic Systems and Communication Systems segments, respectively.
	Identifiable Intangible Assets. The most significant identifiable intangible asset that is separately recognized for the Company’s business acquisitions is customer contractual relationships. All of the Company’s customer relationships are established through written customer contracts (revenue arrangements). The fair value for customer contractual relationships is determined, as of the date of acquisition, based on estimates and judgments regarding expectations for the estimated future after-tax earnings and cash flows (including cash flows for working capital) arising from the follow-on sales on contract (revenue arrangement) renewals expected from the customer contractual relationships over their estimated lives, including the probability of expected future contract renewals and sales, less a contributory assets charge, all of which is discounted to present value.
	Information on the Company’s identifiable intangible assets that are subject to amortization is presented in the table below.
			December 31, 2013														December 31, 2012
			Weighted		Gross				Accumulated				Net				Gross				Accumulated		Net
			Average		Carrying				Amortization				Carrying				Carrying				Amortization		Carrying
			Amortization		Amount								Amount				Amount						Amount
			Period
			(in years)						(in millions)
	Customer contractual relationships		19		$	466			$	253			$	213			$	460			$	225	$	235
	Technology		11			168				108				60				164				98		66
	Other		17			27				15				12				27				14		13
	Total		17		$	661			$	376			$	285			$	651			$	337	$	314
	Amortization expense recorded by the Company for its identifiable intangible assets is presented in the table below.
			Year Ended December 31,
			2013				2012				2011
			(in millions)
	Amortization expense		$	39			$	47			$	54
	Based on gross carrying amounts at December 31, 2013, the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2014 through 2018 is presented in the table below.
			Year Ending December 31,
			2014				2015				2016				2017				2018
			(in millions)
	Estimated amortization expense		$	43			$	40			$	33			$	31			$	25

Other_Current_Liabilities_and_

Other Current Liabilities and Other Liabilities	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Other Current Liabilities and Other Liabilities	'
	9. Other Current Liabilities and Other Liabilities
	The table below presents the components of other current liabilities.
		December 31,
		2013		2012
		(in millions)
	Other Current Liabilities:
	Accruals for pending and threatened litigation (see Note 20)	$	6	$	7
	Estimated costs in excess of estimated contract value to complete contracts in process in a loss position		78		96
	Accrued product warranty costs		75		76
	Accrued interest		52		53
	Deferred revenues		35		35
	Estimated contingent purchase price payable for acquired businesses		—		4
	Other		137		121
	Total other current liabilities	$	383	$	392
	The table below presents the components of other liabilities.
		December 31,
		2013		2012
		(in millions)
	Other Liabilities:
	Non-current income taxes payable (see Note 18)	$	177	$	146
	Accrued workers’ compensation		46		57
	Deferred compensation		45		43
	Accrued product warranty costs		24		23
	Notes payable and capital lease obligations		15		24
	Estimated contingent purchase price payable for acquired businesses		—		5
	Other		99		95
	Total other liabilities	$	406	$	393

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	10. Property, Plant and Equipment
	The table below presents the components of Property, Plant and Equipment.
		December 31,
		2013		2012
		(in millions)
	Land	$	62	$	63
	Buildings and improvements		415		407
	Machinery, equipment, furniture and fixtures		1,643		1,532
	Leasehold improvements		328		322
	Gross property, plant and equipment		2,448		2,324
	Accumulated depreciation and amortization		(1,406)		(1,301)
	Property, plant and equipment, net	$	1,042	$	1,023

Debt

Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt	'
	11. Debt
	The components of long-term debt and a reconciliation to the carrying amount of long-term debt are presented in the table below.
			December 31,
			2013				2012
			(in millions)
	L-3 Communications:
	Borrowings under Amended and Restated Revolving Credit Facility(1)		$	—			$	—
	3.95% Senior Notes due 2016			500				500
	5.20% Senior Notes due 2019			1,000				1,000
	4.75% Senior Notes due 2020			800				800
	4.95% Senior Notes due 2021			650				650
	Subtotal			2,950				2,950
	L-3 Holdings:
	3% Convertible Contingent Debt Securities due 2035			689				689
	Principal amount of long-term debt			3,639				3,639
	Unamortized discounts			(9)				(10)
	Carrying amount of long-term debt		$	3,630			$	3,629
		(1)	During 2013, L-3 Communications’ aggregate borrowings and repayments under the Amended and Restated Revolving Credit Facility were $1,893 million. L-3 Communications had the availability of substantially all of its $1 billion Amended and Restated Revolving Credit Facility at December 31, 2013 and 2012.
	L-3 Communications Amended and Restated Revolving Credit Facility
	On February 3, 2012, L-3 Communications amended and restated its $1 billion Revolving Credit Facility, which extended the expiration date to February 3, 2017. The terms of the Amended and Restated Revolving Credit Facility are substantially consistent with the terms of this facility prior to its amendment and restatement except that: (1) provisions that previously limited the ability of L-3 Communications to pay dividends, repurchase L-3 Holdings’ common stock and make other distributions with respect to any capital stock were eliminated, (2) a provision that previously limited the ability of L-3 Communications to make investments in L-3 Holdings was made less restrictive and (3) the cost of borrowings, loan commitment fees and letter of credit fees were reduced. In addition, the Amended and Restated Revolving Credit Facility provides for uncommitted incremental revolving facilities and additional term loan facilities in an aggregate principal amount of up to $500 million. Borrowings under the Amended and Restated Revolving Credit Facility bear interest, at L-3 Communications’ option, at either (1) the “base rate” equal to the highest of (a) 0.50% per annum above the latest federal funds rate, (b) the Bank of America “prime rate” (as defined in the Amended and Restated Revolving Credit Facility), and (c) 1.00% per annum above a “Eurodollar Rate” (as defined in the Amended and Restated Revolving Credit Facility), plus a spread ranging from 0.25% to 1.00% per annum, or (2) a “Eurodollar Rate” (as defined in the Amended and Restated Revolving Credit Facility) plus a spread ranging from 1.25% to 2.00% per annum. L-3 Communications pays: (1) commitment fees calculated on the daily amounts of the available unused commitments at a rate ranging from 0.15% to 0.325% per annum, (2) letter of credit fees ranging from 0.675% to 1.20% per annum for commercial and performance letters of credit and (3) letter of credit fees ranging from 1.25% to 2.00% for financial letters of credit. The interest rate spread and the commitment fee rate, in all cases, depend on L-3 Communications’ debt rating at the time of determination. The debt rating is based on the credit ratings as determined by Standard & Poor’s Rating Services, Moody’s Investors Service, Inc. and Fitch Ratings of L-3 Communications’ non-credit enhanced senior, unsecured long-term debt.
	L-3 Communications Senior Notes
	The Senior Notes are unsecured senior obligations of L-3 Communications. The terms of each outstanding Senior Note are presented in the table below.
	Note		Date of Issuance		Amount				Discount(1)				Net				Effective		Redemption
					Issued								Cash				Interest		at Treasury
													Proceeds				Rate		Rate(2)(3)
					(in millions)
	3.95% Senior Notes due November 15, 2016		November 22, 2011		$	500			$	4			$	491				4.11%		50 bps
	5.20% Senior Notes due October 15, 2019		2-Oct-09		$	1,000			$	4			$	987				5.25%		30 bps
	4.75% Senior Notes due July 15, 2020		21-May-10		$	800			$	3			$	790				4.79%		25 bps
	4.95% Senior Notes due February 15, 2021		7-Feb-11		$	650			$	4			$	639				5.02%		25 bps
		(1)	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 may be redeemed at any time prior to their maturity at the option of L-3 Communications, in whole or in part, at a redemption price equal to the greater of (1) 100% of the principal amount, or (2) 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 Senior Indentures), plus the spread indicated in the table above.
		(3)	Upon the occurrence of a change in control (as defined in the Senior Indentures), each holder of the notes will have the right to require L-3 Communications 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.
	Information on the Senior Subordinated Notes redeemed by the Company during the years ended December 31, 2012 and 2011 is presented in the table below.
	Note		Redemption Date				Principal				Debt				Redemption Price
							Amount				Retirement				% of Principal
							Redeemed				Charge
							(in millions)
	6 3⁄8% Senior Subordinated Notes due October 15, 2015			15-Oct-12			$	250			$	5				101.06%
	6 3⁄8% Senior Subordinated Notes due October 15, 2015(1)			26-Jul-12			$	250			$	8				102.13%
	6 3⁄8% Senior Subordinated Notes due October 15, 2015			December 22, 2011			$	500			$	17				102.13%
	5 7⁄8% Senior Subordinated Notes due January 15, 2015			9-Mar-11			$	650			$	18				101.96%
	(1)	In connection with the spin-off, Engility made a cash distribution of $335 million to L-3, a portion of which was used to redeem $250 million of the 6 3⁄8% 2015 Notes.
	L-3 Holdings
	In 2005, L-3 Holdings sold $700 million of 3% Convertible Contingent Debt Securities (CODES) due August 1, 2035. Interest is payable semi-annually on February 1 and August 1 of each year. On February 2, 2011, L-3 Holdings repurchased approximately $11 million of the CODES as a result of the exercise by the holders of their contractual right to require L-3 Holdings to repurchase their CODES. Holders of the remaining CODES may require L-3 Holdings to repurchase the CODES, in whole or in part, on February 1, 2016, February 1, 2021, February 1, 2026 and February 1, 2031 at a cash repurchase price equal to 100% of the principal amount of the CODES (plus accrued and unpaid interest, including contingent interest and additional interest, if any). In addition, holders of the CODES may require L-3 Holdings to repurchase the CODES at a repurchase price equal to 100% of the principal amount of the CODES (plus accrued and unpaid interest, including contingent interest and additional interest, if any) if a “fundamental change” (as such term is defined in the indenture governing the CODES) occurs prior to maturity of the CODES. At December 31, 2013 and 2012, the remaining $689 million principal amount of CODES was classified as long-term debt.
	In accordance with the provisions of the accounting standard for convertible debt, the Company separately accounts for the liability and equity (conversion option) components of the CODES in a manner that reflects the Company’s non-convertible debt borrowing rate. Through February 1, 2011, the effective interest rate of the CODES was 6.33% and interest expense related to both the contractual coupon interest and amortization of the discount on the liability components. The Company amortized the discount on the liability component of the CODES through February 1, 2011 which was the first date that the holders of the CODES had a contractual right to require L-3 Holdings to repurchase the CODES. Interest expense for the CODES after February 1, 2011 relates only to the contractual coupon interest. Interest expense recognized was $21 million for both years ended December 31, 2013 and 2012, and $23 million for the year ended December 31, 2011, a portion of which was allocated to discontinued operations in 2012 and 2011 as a result of the spin-off of Engility. The carrying amount of the equity components (conversion feature) of the CODES was $64 million at December 31, 2013 and 2012.
	The CODES are convertible into cash and shares of L-3 Holdings’ common stock based on a current conversion rate of 11.0813 shares of L-3 Holdings common stock per one thousand dollars in principal amount of the CODES (equivalent to a conversion price of $90.24 per share) only under the following circumstances: (1) prior to August 1, 2033, on any date during any fiscal quarter (and only during such fiscal quarter) beginning after September 30, 2005, if the closing sales price of the common stock of L-3 Holdings is more than 120% of the then current conversion price (currently $108.29) for at least 20 trading days in the 30 consecutive trading-day period ending on the last trading day of the previous fiscal quarter; (2) on or after August, 1, 2033, at all times on or after any date on which the closing sale price of the common stock of L-3 Holdings is more than 120% of the then current conversion price (currently $108.29); (3) if we distribute to all holders of our common stock, rights or warrants (other than pursuant to a rights plan) entitling them to purchase, for a period of 45 calendar days or less, shares of L-3 Holdings’ common stock at a price less than the average closing sales price for the ten trading days preceding the declaration date for such distribution; (4) if we distribute to all holders of our common stock, cash and other assets, debt securities or rights to purchase L-3 Holdings’ securities (other than pursuant to a rights plan), which distribution has a per share value exceeding 10% of the closing sale price of L-3 Holdings common stock on the trading day preceding the declaration date for such distribution; (5) during the five consecutive business-day period following any five consecutive trading-day period in which the average trading price of the CODES was less than 98% of the average of the closing sale price of L-3 Holdings common stock during such five trading day period multiplied by the then current conversion rate; (6) during a specified period if the CODES have been called for redemption; or (7) during a specified period if a “fundamental change” occurs. The conversion rate is subject to adjustments in certain circumstances set forth in the indenture governing the CODES. For the year ended December 31, 2013, the conversion feature of the CODES was dilutive to earnings per share (EPS) (see Note 17).
	Upon conversion of the CODES, the settlement amount will be computed as follows: (1) if L-3 Holdings elects to satisfy the entire conversion obligation in cash, L-3 Holdings will deliver to the holder for each one thousand dollars in principal amount of the CODES converted cash in an amount equal to the conversion value; or (2) if L-3 Holdings elects to satisfy the conversion obligation in a combination of cash and common stock, L-3 Holdings will deliver to the holder for each one thousand dollars in principal amount of the CODES converted (x) cash in an amount equal to (i) the fixed dollar amount per one thousand dollars in principal amount of the CODES of the conversion obligation to be satisfied in cash specified in the notice regarding L-3 Holdings’ chosen method of settlement or, if lower, the conversion value, or (ii) the percentage of the conversion obligation to be satisfied in cash specified in the notice regarding L-3 Holdings chosen method of settlement multiplied by the conversion value, as the case may be (the “cash amount”); provided that in either case the cash amount shall in no event be less than the lesser of (a) the principal amount of the CODES converted and (b) the conversion value; and (y) a number of shares of common stock of L-3 Holdings for each of the 20 trading days in the conversion period equal to 1/20th of (i) the conversion rate then in effect minus (ii) the quotient of the cash amount divided by the closing price of common stock of L-3 Holdings for that day (plus cash in lieu of fractional shares, if applicable).
	The CODES are senior unsecured obligations of L-3 Holdings and rank equal in right of payment with all existing and future senior indebtedness and senior to all future senior subordinated indebtedness of L-3 Holdings. The CODES are jointly and severally guaranteed on a senior subordinated basis by the existing and future domestic subsidiaries of L-3 Holdings that guarantee any other indebtedness of L-3 Holdings or any of its domestic subsidiaries.
	The CODES are subject to redemption at the option of L-3 Holdings, in whole or in part, at a cash redemption price (plus accrued and unpaid interest, including contingent interest and additional interest, if any) equal to 100% of the principal amount of the CODES.
	Holders of the CODES have a right to receive contingent interest payments, which will be paid on the CODES during any six-month period commencing February 1, 2011 in which the trading price of the CODES for each of the five trading days ending on the second trading day preceding the first day of the applicable six-month interest period equals or exceeds 120% of the principal amount of the CODES. The contingent interest payable per one thousand dollars in principal amount of CODES will equal 0.25% of the average trading price of one thousand dollars in principal amount of CODES during the five trading days ending on the second trading day preceding the first day of the applicable six-month interest period. The contingent interest payment provision has been accounted for as an embedded derivative. The amount assigned to the embedded derivative is adjusted periodically through other income (expense) for changes in its fair value, if any. The change in the fair value of the embedded derivative related to the CODES was $0 for the years ended December 31, 2013, 2012 and 2011.
	Guarantees
	L-3 Communications
	The borrowings under the Amended and Restated Revolving Credit Facility are fully and unconditionally guaranteed by L-3 Holdings and by substantially all of the material 100% owned domestic subsidiaries of L-3 Communications on an unsecured senior basis. The payment of principal and premium, if any, and interest on the Senior Notes is fully and unconditionally guaranteed, on an unsecured senior basis, jointly and severally, by L-3 Communications’ material 100% owned domestic subsidiaries that guarantee any of its other indebtedness.
	L-3 Holdings
	The payment of principal and premium, if any, and interest on the CODES is fully and unconditionally guaranteed, on an unsecured senior subordinated basis, jointly and severally, by L-3 Communications and its 100% owned domestic subsidiaries that guarantee any of its other liabilities.
	Subordination
	The guarantees of the Amended and Restated Revolving Credit Facility and the Senior Notes rank senior to the guarantees of the CODES and rank pari passu with each other.
	Covenants
	Financial and other restrictive covenants. The Amended and Restated Revolving Credit Facility contains financial and other restrictive covenants that limit, among other things, the ability of the subsidiaries of L-3 Communications to borrow additional funds, and the ability of L-3 Communications and its subsidiaries to incur liens, make investments, merge or consolidate or dispose of assets. The Company’s Amended and Restated Revolving Credit Facility contains covenants that require that (1) the Company’s consolidated leverage ratio be less than or equal to 4.0 to 1.0; (2) the Company’s consolidated interest coverage ratio be greater than or equal to 3.0 to 1.0; and (3) the Company’s consolidated senior leverage ratio be less than or equal to 3.5 to 1.0, in each case, as of the end of any fiscal quarter. 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. As of December 31, 2013, the Company was in compliance with its financial and other restrictive covenants.
	The Senior Indentures contain covenants customary for investment grade notes, including covenants that restrict the ability of L-3 Communications 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 L-3 Communications and its subsidiaries to enter into certain sale and leaseback transactions (as defined in the Senior Indentures).
	Cross default provisions. The Amended and Restated Revolving 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 L-3 Holdings, L-3 Communications or its subsidiaries, so long as the aggregate amount of such indebtedness, swap contracts or guarantees is at least $50 million and such defaults (other than payment defaults and defaults that have resulted in acceleration) have not been cured within 10 days. The CODES indenture contains cross acceleration provisions that are triggered when holders of the indebtedness of L-3 Holdings or any of its subsidiaries (or the payment of which is guaranteed by such entities) accelerate at least $50 million in aggregate principal amount of those obligations. The Senior Notes indenture contains a cross acceleration provision that is triggered when a default or acceleration occurs under any indenture or instrument of L-3 Communications or its subsidiaries or the payment of which is guaranteed by L-3 Communications or its subsidiaries in an aggregate amount of at least $100 million.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive (Loss) Income	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Accumulated Other Comprehensive (Loss) Income	'
	12. Accumulated Other Comprehensive (Loss) Income
	The changes in the accumulated other comprehensive (loss) income (AOCI) balances, net of related tax effects are presented in the table below.
			Foreign		Unrealized		Unrecognized		Total
			currency		gains		(losses) gains and		accumulated
			translation		(losses)		prior service		other
					on hedging		cost, net		comprehensive
					instruments				loss
			(in millions)
	Balance at December 31, 2010		$	161	$	10	$	(427)	$	(256)
	Period change			(28)		(10)		(160)		(198)
	Balance at December 31, 2011		$	133	$	—	$	(587)	$	(454)
	Period change			34		3		(133)		(96)
	Balance at December 31, 2012		$	167	$	3	$	(720)	$	(550)
	Period change			(25)		(2)		467		440
	Balance at December 31, 2013		$	142	$	1	$	(253)	$	(110)
	The amounts reclassified from AOCI are presented in the table below.
			Foreign		Unrealized		Unrecognized		Total
			currency		gains		(losses) and		accumulated
			translation		(losses) on		prior service		other
					hedging		cost, net		comprehensive
					instruments				(loss) income
			(in millions)
	Balance at December 31, 2012		$	167	$	3	$	(720)	$	(550)
	Other comprehensive (loss) income before reclassifications, net of tax			(25)		(1)		414		388
	Amounts reclassified from other comprehensive (loss) income, net of tax			—		(1)		53		52
	Net current period other comprehensive (loss) income			(25)		(2)		467		440
	Balance at December 31, 2013		$	142	$	1	$	(253)	$	(110)
	Further details regarding the amounts reclassified from AOCI are presented in the table below.
			Amount Reclassified from
			Accumulated
			Other Comprehensive
			(Loss) Income
	Details About Accumulated Other		Year ended December 31,		Affected Line Item in the
	Comprehensive (Loss) Income Components		2013		Audited Consolidated
					Statement of Operations
			(millions)
	Loss on hedging instruments		$	(1)	Cost of sales-products
				(1)	Income from continuing operations before income taxes
				—	Provision for income taxes
			$	(1)	Income from continuing operations
	Amortization of defined benefit pension items:
	Net loss		$	83	(a)
				83	Income from continuing operations before income taxes
				(30)	Provision for income taxes
			$	53	Income from continuing operations
	Total reclassification for the period		$	52	Income from continuing operations
		(a)	Amounts related to pension and postretirement benefit plans were reclassified from AOCI and recorded as a component of net periodic benefit cost (see Note 21 for additional information).

Equity

Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Equity	'
	13. Equity
	The $1.5 billion share repurchase program authorized on April 26, 2011 by L-3 Holdings’ Board of Directors expired on April 30, 2013. On February 5, 2013, L-3 Holdings’ Board of Directors approved a new share repurchase program that authorizes L-3 Holdings to repurchase up to an additional $1.5 billion of its common stock through June 30, 2015. Repurchases of L-3 Holdings’ common stock under the February 5, 2013 share repurchase program are made at management’s discretion in accordance with applicable U.S. Federal securities laws in the open market or otherwise. The timing and actual number of shares to be repurchased in the future will depend on a variety of factors, including the Company’s financial position, earnings, legal requirements, other investment opportunities (including acquisitions), market conditions and other factors. L-3 Holdings repurchased 8.7 million shares of its common stock at an average price of $91.95 per share for an aggregate amount of $800 million from January 1, 2013 through December 31, 2013. Approximately 2.1 million of the share repurchases, for an aggregate amount of $168 million, were repurchased pursuant to the April 26, 2011 share repurchase program. The remaining share repurchases were made pursuant to the share repurchase program authorized on February 5, 2013. All share repurchases of L-3 Holdings’ common stock have been recorded as treasury shares.
	From January 1, 2014 through February 19, 2014, L-3 Holdings repurchased 928,040 shares of its common stock at an average price of $107.52 per share for an aggregate amount of approximately $100 million. The remaining dollar value of authorization under our February 5, 2013 share repurchase program at February 19, 2014 is $768 million.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	14. Fair Value Measurements
	L-3 applies the accounting standards for fair value measurements to all of the Company’s assets and liabilities that are measured and recorded at fair value. 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,
			2013						2012
	Description		Level 1(1)		Level 2(2)		Level 3(3)		Level 1(1)		Level 2(2)		Level 3(3)
			(in millions)
	Assets
	Cash equivalents		$	299	$	—	$	—	$	284	$	—	$	—
	Derivatives (foreign currency forward contracts)			—		6		—		—		8		—
	Total assets		$	299	$	6	$	—	$	284	$	8	$	—
	Liabilities
	Derivatives (foreign currency forward contracts)		$	—	$	5	$	—	$	—	$	3	$	—
		(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 Company has no Level 3 assets or liabilities.

Financial_Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2013
Investments, All Other Investments [Abstract]	'
Financial Instruments	'
	15. Financial Instruments
	At December 31, 2013 and 2012, the Company’s financial instruments consisted primarily of cash and cash equivalents, billed receivables, trade accounts payable, Senior Notes, CODES 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, 2013				December 31, 2012
			Carrying		Estimated		Carrying		Estimated
			Amount		Fair Value		Amount		Fair Value
			(in millions)
	Senior Notes(1)		$	2,941	$	3,121	$	2,940	$	3,301
	CODES(1)		$	689	$	830	$	689	$	697
	Foreign currency forward contracts(2)		$	1	$	1	$	5	$	5
		(1)	The Company measures the fair value of its Senior Notes and CODES 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 16 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	16. 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 as of December 31, 2013.
	Currency		Notional Amount
			(in millions)
	Canadian dollar		$	137
	U.S. dollar			98
	Euro			66
	British pound			18
	Other			2
	Total		$	321
	At December 31, 2013, the Company’s foreign currency forward contracts had maturities through 2018.
	The table below presents the fair values and the location of the Company’s derivative instruments in the consolidated balance sheets.
			December 31, 2013								December 31, 2012
			Other		Other		Other		Other		Other		Other		Other		Other
			Current		Assets		Current		Liabilities		Current		Assets		Current		Liabilities
			Assets				Liabilities				Assets				Liabilities
			(in millions)
	Derivatives designated as hedging instruments:
	Foreign currency forward contracts(1)		$	5	$	1	$	3	$	2	$	4	$	4	$	2	$	1
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts(1)			—		—		—		—		—		—		—		—
	Embedded derivative related to the CODES			—		—		—		—		—		—		—		—
	Total derivative instruments		$	5	$	1	$	3	$	2	$	4	$	4	$	2	$	1
		(1)	See Note 14 for a description of the fair value hierarchy related to the Company’s foreign currency forward contracts.
	The effect of gains or losses from foreign currency forward contracts was not material to the consolidated statements of operations for the years ended December 31, 2013 and 2012. At December 31, 2013, the estimated net amount of existing losses that are expected to be reclassified into income within the next 12 months is $1 million.

L3_Holdings_Earnings_Per_Share

L-3 Holdings' Earnings Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
L-3 Holdings' Earnings Per Share	'
	17. L-3 Holdings’ Earnings Per Share
	A reconciliation of basic and diluted EPS is presented in the table below.
			Year Ended December 31,
			2013		2012		2011
			(in millions, except per share data)
	Reconciliation of net income:
	Net income		$	760	$	794	$	970
	Net income from continuing operations attributable to noncontrolling interests			-9		-6		-9
	Net income from discontinued operations attributable to noncontrolling interests			—		-4		-3
	Net income allocable to participating securities			—		—		-2
	Net income allocable to L-3 Holdings common shareholders		$	751	$	784	$	956
	Earnings allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	751	$	756	$	855
	Discontinued operations, net of income tax			—		28		101
	Net income allocable to L-3 Holdings common shareholders		$	751	$	784	$	956
	Earnings per share allocable to L-3 Holdings’ common shareholders:
	Basic:
	Weighted average common shares outstanding			89.4		96.3		104.4
	Basic earnings per share allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	8.40	$	7.85	$	8.19
	Discontinued operations, net of income tax			—		0.29		0.97
	Basic earnings per share		$	8.40	$	8.14	$	9.16
	Diluted:
	Common and potential common shares:
	Weighted average common shares outstanding			89.4		96.3		104.4
	Assumed exercise of stock options			3.9		1.9		2.0
	Unvested restricted stock awards			1.8		2.0		1.8
	Employee stock purchase plan contributions			0.2		0.3		0.2
	Performance unit awards			0.1		0.1		0.1
	Assumed purchase of common shares for treasury			-4.5		-3		-2.9
	Assumed conversion of the CODES(1)			0.2		—		—
	Common and potential common shares			91.1		97.6		105.6
	Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	8.24	$	7.74	$	8.10
	Discontinued operations, net of income tax			—		0.29		0.95
	Diluted earnings per share		$	8.24	$	8.03	$	9.05
		(1)	L-3 Holdings’ CODES had no impact on diluted EPS for the years ended December 31, 2012 and 2011 because the average market price of L-3 Holdings’ common stock during these periods was less than the price at which the CODES would have been convertible into L-3 Holdings’ common stock. As of December 31, 2013, 2012 and 2011, the conversion prices were $90.24, $91.21 and $96.48, respectively.
	The computation of diluted EPS excluded shares for stock options and employee stock purchase plan contributions of 0.9 million and 3.2 million for the years ended December 31, 2013 and 2012, as they were anti-dilutive. In addition, shares for stock options of 3.2 million for the year ended December 31, 2011, were anti-dilutive and excluded from diluted EPS.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	18. Income Taxes
	Income from continuing operations before income taxes is summarized in the table below.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Domestic	$	858	$	892	$	895
	Foreign		197		230		267
	Income from continuing operations before income taxes	$	1,055	$	1,122	$	1,162
	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,
		2013		2012		2011
		(in millions)
	Current income tax provision:
	Federal	$	181	$	198	$	78
	State and local		34		21		26
	Foreign		38		44		69
	Subtotal		253		263		173
	Deferred income tax provision:
	Federal		35		80		95
	State and local		—		8		15
	Foreign		7		9		13
	Subtotal		42		97		123
	Total provision for income taxes	$	295	$	360	$	296
	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,
		2013		2012		2011
	Statutory federal income tax rate		35.0%		35.0%	35.0%
	State and local income taxes, net of federal income tax benefit		2.1		1.7	2.3
	Foreign income taxes		(1.6)		(2.0)	(2.6)
	Manufacturing benefits		(1.9)		(1.8)	(1.5)
	Research and experimentation and other tax credits		(3.6)		(0.5)	(1.1)
	Resolution of tax contingencies		(1.0)		(0.9)	(7.7)
	Goodwill impairment		—		—	1.2
	Other, net		(1.0)		0.6	(0.1)
	Effective income tax rate on continuing operations		28.0%		32.1%	25.5%
	The significant components of the Company’s net deferred tax assets and liabilities are presented in the table below.
		December 31,
		2013		2012
		(in millions)
	Deferred tax assets:
	Inventoried costs	$	72	$	33
	Compensation and benefits		164		114
	Pension and postretirement benefits		207		444
	Loss carryforwards		24		20
	Tax credit carryforwards		7		9
	Other		75		48
	Gross deferred tax assets		549		668
	Less: valuation allowance		(22)		(19)
	Net deferred tax assets		527		649
	Deferred tax liabilities:
	Goodwill and other intangible assets	$	726	$	657
	Income recognition on contracts in process		58		56
	Property, plant and equipment		85		71
	Long-term debt-CODES		81		73
	Other		65		7
	Gross deferred tax liabilities		1,015		864
	Total net deferred tax liabilities	$	(488)	$	(215)
	The classification of the Company’s deferred tax assets and liabilities are presented in the table below.
		December 31,
		2013		2012
		(in millions)
	Current deferred tax assets	$	147	$	113
	Non-current deferred tax liabilities		(635)		(328)
Total net deferred tax liabilities	$	(488)	$	(215)
At December 31, 2013, the Company had approximately $26 million of capital loss carryforwards that will expire, if unused, beginning in 2016. The realizability of the $9 million resulting deferred tax asset depends on the Company generating a like amount of capital gains before the losses expire. The Company does not believe that it is more likely than not that it will generate sufficient capital gains during this time period, and has therefore established a full valuation allowance against the capital loss carryforward. The Company also has $6 million of Federal net operating loss carryforwards that expire, if unused, between 2026 and 2030 and are subject to limitations based upon the future taxable income of certain subsidiaries, and $34 million of foreign net operating losses that can be carried forward indefinitely. The Company has established a valuation allowance against the resulting $10 million deferred tax asset because it does not believe that it is more likely than not that the subsidiaries with the net operating losses will generate sufficient taxable income to utilize the losses. In addition, the Company had $124 million of state net operating losses that will expire, if unused, between 2016 and 2033 and $10 million of tax credit carryforwards related to state and foreign research and experimentation credits and investment tax credits that will expire, if unused, beginning in 2014. The Company believes that it will generate sufficient taxable income, of the appropriate character, to utilize $72 million of the state net operating losses and substantially all of the state and foreign credit carryforwards before they expire.
As of December 31, 2013, the total amount of unrecognized tax benefits was $169 million, $102 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.
	2013		2012		2011
	(in millions)
Balance at January 1	$	138	$	150	$	201
Additions for tax positions related to the current year		18		8		10
Additions for tax positions related to prior years		41		9		33
Reductions for tax positions related to prior years		-8		-13		-13
Reductions for tax positions related to settlements with taxing authorities		—		-1		-5
Reduction for tax positions related to prior years as a result of a lapse of statute of limitations		-20		-15		-76
Balance at December 31	$	169	$	138	$	150
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. The statutes of limitations for the Company’s U.S. Federal income tax returns for the years ended December 31, 2010 through 2012 are open as of December 31, 2013. The U.S. Internal Revenue Service (IRS) commenced audits of the Company’s U.S. Federal income tax returns for 2011 and 2010. The Company cannot predict the outcome of the audits at this time. As of December 31, 2013, the Company anticipates that unrecognized tax benefits will decrease by approximately $18 million over the next 12 months due to the potential resolution of unrecognized tax benefits involving several jurisdictions and tax periods. The actual amount could vary significantly depending on the ultimate timing and nature of any settlements.
During the years ended December 31, 2013 and 2012, the statutes of limitations for several of the Company’s tax returns, including its 2009 and 2008 U.S. Federal income tax returns, respectively, as well as certain foreign tax returns expired. As a result, the Company reduced its income tax provision by $10 million in both years ended December 31, 2013 and 2012 for the reversal of previously accrued amounts.
During the year ended December 31, 2011, the Company reached an agreement with the IRS relating to the audit of the Company’s 2006 and 2007 U.S. Federal income tax returns. The Company also reached agreement on several state and foreign audits. As a result of these agreements, the Company reversed previously accrued income tax expense of $12 million, including interest and penalties. In addition, the statutes of limitations for the 2006 and 2007 U.S. Federal income tax returns and certain foreign and state tax returns expired in 2011. As a result, the Company reversed $81 million of previously accrued income tax expense, which included interest and penalties.
As of December 31, 2013 and 2012, current and non-current income taxes payable include accrued potential interest of $11 million ($7 million after income taxes) and $11 million ($6 million after income taxes), respectively, and potential penalties of $8 million and $7 million, respectively. With respect to the interest related items, the Company’s income tax expense included a benefit of $2 million and $6 million for the years ended December 31, 2012 and 2011, respectively.
At December 31, 2013, the Company has not provided deferred U.S. income taxes and foreign withholding taxes for $325 million of undistributed earnings by its non-U.S. subsidiaries as such earnings are intended to be reinvested indefinitely. Quantification of additional taxes that may be payable on distribution is not practicable.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	19. 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, 2013, 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 L-3 Holdings’ restricted stock units, performance units and options to purchase L-3 Holdings’ common stock.
	On April 30, 2013, the stockholders of L-3 Holdings approved an amendment to the 2008 LTPP. The principal purpose of the amendment was to increase the number of shares authorized for issuance under the 2008 Plan by 6.5 million shares. In addition, the plan was amended to: (1) include all future equity issuances to non-employee directors under the 2008 LTPP instead of through the L-3 Communications Holdings, Inc. 2008 Directors Stock Incentive Plan (2008 DSIP), a separate equity plan previously used solely for non-employee directors, (2) include revised limits on the amount of annual equity grants to employees and include new limits on the amount of annual equity grants to non-employee directors, and (3) modify the way that shares issued under full value awards (that is, awards other than stock options or stock appreciations rights) granted under the 2008 LTPP are counted for purposes of calculating the number of authorized shares that have been issued, as further described below.
	The amendment to the 2008 LTPP increased the number of shares authorized for issuance under the 2008 LTPP to approximately 19.2 million shares. Under the 2008 LTPP, each share of L-3 Holdings’ common stock issued under a full value award granted on or after February 26, 2013 is counted as 3.69 shares for purposes of this share limit. Each share issued under full value awards granted between March 1, 2010 and February 25, 2013 is counted as 2.6 shares for purposes of the share limit. At December 31, 2013, 7.9 million shares of L-3 Holdings’ common stock remained available for future awards under the 2008 LTPP.
	The Company’s stock-based compensation by form of award, including stock-based compensation recorded in discontinued operations as a result of the spin-off of Engility, is presented in the table below.
			Year Ended December 31,
			2013		2012		2011
			(in millions)
	Stock options		$	10	$	10	$	11
	Restricted stock units			41		46		48
	Performance units			7		8		5
	Total before income taxes			58		64		64
	Income taxes			-22		-24		-24
	Total after income taxes			36		40		40
	Less: Stock based compensation recorded in discontinued operations, net of income taxes			—		1		4
	Stock based compensation recorded in continuing operations, net of income taxes		$	36	$	39	$	36
	Engility Spin-off Adjustments. As a result of the spin-off of Engility, effective July 17, 2012, all outstanding stock-based compensation awards related to Engility employees were assumed by Engility. Also in connection with the spin-off, the share amounts for all remaining L-3 outstanding stock options, restricted stock units and performance units, and the strike price for stock options were adjusted to maintain the aggregate intrinsic value at the Engility spin-off date of all grants outstanding on that date, pursuant to the terms of the stock-based compensation plans under which they were issued. Taking into account the change in the value of the Company’s common stock as a result of the distribution of the Engility shares to the Company’s shareholders, the conversion ratio for the remaining stock options, restricted stock units and performance units was 1.043678. For stock options, the net effect of these adjustments was an increase to the stock options outstanding due to the limited number of stock options assumed by Engility for the Engility employees. For restricted stock units, the net effect of these adjustments was a decrease in restricted stock units outstanding as the number of shares assumed by Engility for the Engility employees exceeded the impact of the adjustment for restricted stock units held by L-3 employees. The Engility spin-off adjustments are reflected in the January 1, 2013 share amounts in the stock option, restricted stock unit award and performance award tables below.
	Stock Options. The exercise price of stock options granted under the 2008 LTPP may not be less than the fair market value of L-3 Holdings’ common stock on the date of grant. Options expire after 10 years from the date of grant and vest ratably over a three year period on the annual anniversary of the date of grant. 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 as of December 31, 2013 and changes during the year then ended.
			Number of		Weighted		Weighted		Aggregate
			Options		Average		Average		Intrinsic
					Exercise		Remaining		Value
					Price		Contractual
							Term
			(in thousands)				(in years)		(in millions)
	Number of shares under option:
	Outstanding at January 1, 2013			4,989.9	$	76.57		5.8	$	23
	Options granted			741.7		77.00
	Options exercised			(1,770.4)		73.24
	Options forfeited			(78.3)		89.93
	Outstanding at December 31, 2013			3,882.9	$	77.90		6.2	$	112
	Vested and expected to vest at December 31, 2013(1)			3,865.9	$	77.91		6.2	$	112
	Exercisable at December 31, 2013			2,420.9	$	80.44		4.9	$	64
		(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 was $12.09, $11.32, and $15.54 for the years ended December 31, 2013, 2012 and 2011, respectively. The aggregate intrinsic value, disclosed in the table above, represents the difference between L-3 Holdings’ 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 L-3 Holdings’ stock price at the time of exercise and the related exercise price, was $32 million, $7 million and $8 million for the years ended December 31, 2013, 2012 and 2011, respectively. At December 31, 2013, unrecognized compensation costs related to stock options were $10 million ($6 million after income taxes), which are expected to be recognized over a weighted average remaining period of 1.1 years.
	The actual income tax benefit realized related to compensation deductions arising from the exercise of stock options by the Company’s employees totaled $10 million, $2 million and $3 million for the years ended December 31, 2013, 2012 and 2011, 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 L-3 Holdings’ 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 L-3 Holdings’ historical share price volatility matching the expected holding period.
		•		Expected Dividend Yield. Expected dividend yield is based on L-3 Holdings’ 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.
			2013		2012		2011
			Grants		Grants		Grants
	Expected holding period (in years)			5.6		5.4		5.2
	Expected volatility			26.4%		27.0%		26.4%
	Expected dividend yield			3.6%		3.6%		2.8%
	Risk-free interest rate			1.0%		1.0%		2.2%
	Restricted Stock Units. The Company awards restricted stock units that automatically convert into shares of L-3 Holdings’ 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). These awards are subject to forfeiture until certain restrictions have lapsed, including a three year cliff vesting period for employees and a one year cliff vesting period for directors, in each case starting on the date of grant. The weighted average grant date fair value of the restricted stock units awarded was $77.12, $70.42 and $80.17 for the years ended December 31, 2013, 2012 and 2011, respectively. The grant date fair value of the restricted stock unit awards is based on L-3 Holdings’ 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. Retirement eligible employees are those employees that have attained the age of 65 and have 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).
	The table below presents a summary of the Company’s nonvested restricted stock unit awards as of December 31, 2013 and changes during the year then ended.
			Number of		Weighted
			Shares		Average
					Grant Date
					Fair Value
			(in thousands)
	Nonvested balance at January 1, 2013			1,729.7	$	75.64
	Granted			606.4		77.12
	Vested			(476.4)		85.81
	Forfeited			(85.9)		73.60
	Nonvested balance at December 31, 2013			1,773.8	$	73.51
	As of December 31, 2013, total unrecognized compensation costs related to nonvested restricted stock unit awards were $48 million ($30 million after income taxes) and are expected to be recognized over a weighted average remaining period of 1.2 years. The total fair value of restricted stock unit awards vested during the years ended December 31, 2013, 2012 and 2011 as of their vesting dates was $37 million, $44 million and $35 million, respectively.
	Performance Units. The Company awards performance units, with each unit having a value at the time of grant equal to a share of L-3 Holdings’ 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 L-3 Holdings’ common stock, or are paid in cash based on the closing price of L-3 Holdings’ 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 of L-3 Holdings.
	During the years ended December 31, 2013, 2012, and 2011, the Company awarded performance units with a weighted average grant date fair value per unit of $77.00, $70.43 and $95.50, respectively. Of these units, (1) all the units granted in 2013 and 2012 and half of the units granted in 2011 have performance conditions based on L-3’s diluted earnings per share (the EPS Element) and (2) half of the units granted in 2011 have performance conditions based on L-3’s total stockholder return relative to a peer group of companies (the TSR Element). The Company did not award any performance units related to the TSR Element in 2013 and 2012. The performance periods for the units 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 based on the EPS Element are payable in shares of L-3 Holdings’ common stock, while units based on the TSR Element are payable in cash. As of December 31, 2013, total unrecognized compensation costs related to the performance units were $6 million ($4 million after income taxes) and are expected to be recognized over a weighted average remaining period of 1.4 years.
The table below presents a summary of the Company’s performance unit awards based on expected performance as of December 31, 2013 and changes during the year then ended.
		Payable in Cash (TSR)				Payable in Shares (EPS)
		Number of		Weighted Average		Number of		Weighted Average
		Units		Grant Date		Units		Grant Date
				Fair Value				Fair Value
		(in thousands)				(in thousands)
Outstanding at January 1, 2013			59.3	$	106.20		125.6	$	71.86
Granted			—		—		61.7		77.00
(Decrease) increase due to expected performance			(33.1)		106.20		59.9		69.04
Vested			(25.3)		106.20		(67.9)		76.82
Forfeited			(0.9)		106.20		(3.8)		69.56
Outstanding at December 31, 2013			—	$	—		175.5	$	70.84
The performance period for the units awarded in 2011 ended on December 31, 2013. Based on the EPS Element and TSR Element achieved during the performance period, a total of 93,251 performance units having a fair market value of $10.0 million as of their vesting date were earned by the participants on December 31, 2013.
Performance Units Fair Value Assumptions. The TSR Element is initially measured at fair value and subsequently remeasured each reporting period using a Monte Carlo valuation model that incorporates current assumptions, including L-3 Holdings’ stock price and the variables described below.
	•		Expected Volatility. Expected volatility is based on L-3 Holdings’ historical share price volatility matching the remaining measurement period.
	•		Expected Dividend Yield. Expected dividend yield is based on L-3 Holdings’ anticipated dividend payments and historical pattern of dividend increases over the remaining measurement period.
	•		Risk-Free Interest Rate. Risk-free interest rates for the performance units are based on U.S. Treasuries for a maturity matching the remaining measurement period.
Changes in assumptions can materially impact the estimated fair value of the TSR Element from period to period. The weighted average assumptions used in the valuation model as of December 31, 2013 for the 2011 TSR Element are presented in the table below.
		2011
		Grants
Expected volatility			10.2%
Expected dividend yield			2.2%
Risk-free interest rate			0.02%
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 L-3 Holdings’ 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.
As of December 31, 2013, 4.6 million shares were available for future issuance under the 2009 ESPP (i.e., excluding the effect of shares issued in January 2014 as described below). In July 2013, the Company issued 0.2 million shares under the 2009 ESPP at an average price of $81.71 per share, which covered employee contributions for the six months ended June 30, 2013. In January 2014, the Company issued 0.2 million shares under the 2009 ESPP at an average price of $101.55 per share, which covered employee contributions for the six months ended December 31, 2013. The 5% discount is not recognized as compensation expense in accordance with the accounting standard for share-based compensation expense.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	20. Commitments and Contingencies
	Non-Cancelable Operating Leases
	The Company leases certain facilities and equipment under agreements expiring at various dates through 2037. 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, 2013.
		Real Estate		Equipment		Total
				(in millions)
	2014	$	145	$	9	$	154
	2015		88		5		93
	2016		72		3		75
	2017		65		1		66
	2018		53		1		54
	Thereafter		110		—		110
	Total minimum payments required		533		19		552
	Less: Sublease rentals under non-cancelable leases		4		—		4
	Net minimum payments required	$	529	$	19	$	548
	Rent expense was $141 million for 2013, $145 million for 2012, and $140 million for 2011. Sublease rental income was $6 million for 2013 and $5 million for both 2012 and 2011.
	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 $634 million and $504 million at December 31, 2013 and 2012, respectively. The letters of credit reduced the availability under the Amended and Restated Revolving Credit Facility by less than $1 million at December 31, 2013 and 2012, respectively. 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, L-3 entered into a Distribution Agreement and several other agreements that govern certain aspects of L-3’s relationship with Engility, including employee matters, tax matters, transition services, and the future supplier/customer relationship between L-3 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 L-3 to the U.S. Internal Revenue Service (IRS) for the consolidated U.S. Federal income taxes of L-3’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 L-3 and Engility will each bear responsibility, and L-3 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 L-3 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 two existing real estate lease agreements, which include residual guarantee amounts, expiring on August 31, 2015 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 both properties for $28 million, or sell both 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 $23 million for both properties, on or before the lease expiration date. In addition, at the time both 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 $5 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 $23 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.
	The Company has a contract to provide and operate a full-service training facility for the U.S. Air Force (USAF), including simulator systems adjacent to a USAF base in Oklahoma. The Company acted as the construction agent on behalf of the third-party owner-lessors for procurement and construction for the simulator systems, which were completed and delivered in August 2002. The Company, as lessee, entered into operating lease agreements for a term of 15 years for the simulator systems with the owner-lessors. At the end of the lease term, the Company may elect to purchase the simulator systems at fair market value, which can be no less than $7 million and no greater than $21 million. If the Company does not elect to purchase the simulator systems on the date of expiration (during the first quarter of 2018), the Company shall pay to the lessor, as additional rent, $7 million and return the simulator systems to the lessors.
	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 U.S. Government and international government customers. 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. 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. International government contracts generally include comparable provisions relating to terminations for convenience and default, as well as other procurement clauses relevant to the international government.
	Litigation Matters
	The Company is also subject to litigation, proceedings, claims or assessments and various contingent liabilities incidental to its businesses, including those 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. The estimated amounts of liabilities recorded for pending and threatened litigation are disclosed in Note 9. Amounts recoverable from insurance contracts or third parties are recorded as assets when deemed probable. At December 31, 2013, 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 quarterly and adjusts 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 one or more of the following matters, unless otherwise stated below, the Company believes that it is not probable that a loss has been incurred in any of these matters. With respect to the litigation matters 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. Accordingly, our current judgment as to the likelihood of our loss (or our current estimate as to the potential range of loss, if applicable) with respect to any particular litigation matter may turn out to be wrong. Therefore, it is possible that the financial position, results of operations or cash flows of the Company could be materially adversely affected in any particular period by the unfavorable resolution of one or more of these or other contingencies.
	Kalitta Air. On January 31, 1997, a predecessor of Kalitta Air filed a lawsuit in the U.S. District Court for the Northern District of California (the trial court) asserting, among other things, negligence and negligent misrepresentation against Central Texas Airborne Systems, Inc. (CTAS), a predecessor to L-3 Integrated Systems (L-3 IS), in connection with work performed by a predecessor to CTAS to convert two Boeing 747 aircraft from passenger configuration to cargo freighters. CTAS’ insurance carrier has accepted defense of this matter and has retained counsel, subject to a reservation of rights by the insurer to dispute its obligations under the applicable insurance policies in the event a judgment is ultimately rendered against CTAS. The work at issue in the lawsuit was performed using Supplemental Type Certificates (STCs) issued in 1988 by the Federal Aviation Administration (FAA). In 1996, following completion of the work, the FAA issued an airworthiness directive with respect to the STCs that effectively grounded the aircraft. Following two jury trials (in which Kalitta Air did not prevail) and related appeals to the U.S. Court of Appeals for the Ninth Circuit (the Court of Appeals), a third jury trial for this matter began on October 31, 2011, during which Kalitta Air sought damages of approximately $235 million plus an unspecified amount of pre-judgment interest that, in other contexts, has been claimed by Kalitta Air to exceed $240 million. Following the completion of the third trial on November 30, 2011, the jury rendered a verdict in favor of CTAS, finding no negligence on the part of CTAS. The trial court entered a judgment upon the verdict on March 20, 2012. Kalitta Air filed an appeal of the judgment with the Court of Appeals on July 23, 2012. The Court of Appeals ruled against Kalitta Air and affirmed the trial court’s judgment on November 25, 2013. Kalitta Air subsequently filed a motion for a rehearing of its appeal, which was denied by the Court of Appeals on January 8, 2014.
	Bashkirian Airways. On July 1, 2004, lawsuits were filed on behalf of the estates of 31 Russian children in the state courts of Washington, Arizona, California, Florida, New York and New Jersey against Honeywell, Honeywell TCAS, Thales USA, Thales France, the Company and Aviation Communications & Surveillance Systems (ACSS), which is a joint venture of L-3 and Thales. The suits relate to the crash over southern Germany of a Bashkirian Airways Tupelov TU 154M aircraft and a DHL Boeing 757 cargo aircraft. On-board the Tupelov aircraft were 9 crew members and 60 passengers, including 45 children. The Boeing aircraft carried a crew of two. Both aircraft were equipped with Honeywell/ACSS Model 2000, Change 7 Traffic Collision and Avoidance Systems (TCAS). Sensing the other aircraft, the on-board DHL TCAS instructed the DHL pilot to descend, and the Tupelov on-board TCAS instructed the Tupelov pilot to climb. However, the Swiss air traffic controller ordered the Tupelov pilot to descend. The Tupelov pilot disregarded the on-board TCAS and put the Tupelov aircraft into a descent striking the DHL aircraft in midair at approximately 35,000 feet. All crew and passengers of both planes were lost. Investigations by the National Transportation Safety Board after the crash revealed that both TCAS units were performing as designed. The suits allege negligence and strict product liability based upon the design of the units and the training provided to resolve conflicting commands and seek approximately $315 million in damages, including $150 million in punitive damages. The Company’s insurers have accepted defense of this matter and have retained counsel. The matters were consolidated in the U.S. District Court for the District of New Jersey, which then dismissed the actions on the basis of forum non conveniens. Plaintiffs representing 30 of the estates re-filed their complaint against ACSS on April 23, 2007 with the Barcelona Court’s Registry in Spain. On March 9, 2010, the court ruled in favor of the plaintiffs and entered judgment against ACSS in the amount of approximately $6.7 million, all of which represented compensatory damages. Both ACSS and the plaintiffs appealed the judgment. In May 2012, the appellate court ruled in favor of the plaintiffs and entered judgment against ACSS in the amount of $48 million. ACSS filed an appeal of the judgment with the Supreme Court of Spain on September 28, 2012. On July 1, 2013, the Supreme Court agreed to consider the appeal, and the parties are awaiting the Supreme Court’s decision. The Company believes that the ruling and the damages awarded are inconsistent with the law and evidence presented, and accordingly, that it is not probable that the Company has incurred a loss with respect to this matter. As of the date of this filing, 18 out of the 30 plaintiffs have released their claims against ACSS in consideration for payments made by the Company’s insurance carriers.

Pensions_and_Other_Employee_Be

Pensions and Other Employee Benefits	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Pensions and Other Employee Benefits	'
	21. Pensions and Other Employee Benefits
	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. Plan assets are invested primarily in listed stocks, mutual funds, corporate bonds, U.S. Government obligations and U.S. Government agency obligations.
	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 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 as of December 31.
	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
			2013		2012		2013		2012
			(in millions)
	Change in benefit obligation:
	Benefit obligation at the beginning of the year		$	3,222	$	2,679	$	218	$	216
	Service cost			126		113		4		4
	Interest cost			132		134		7		10
	Plan participants’ contributions			2		2		4		4
	Amendments			14		—		—		(5)
	Obligation assumed in connection with a business acquisition(1)			—		29		—		3
	Actuarial (gain) loss			(402)		358		(23)		(2)
	Foreign currency exchange rate changes			(21)		8		(3)		1
	Curtailments, settlements and special termination benefits			3		3		—		1
	Benefits paid			(103)		(104)		(13)		(14)
	Benefit obligation at the end of the year		$	2,973	$	3,222	$	194	$	218
	Change in plan assets:
	Fair value of plan assets at the beginning of the year		$	2,026	$	1,712	$	47	$	42
	Actual return on plan assets			394		215		9		4
	Assets acquired in connection with a business acquisition(1)			—		29		—		—
	Employer contributions			105		173		8		11
	Plan participants’ contributions			2		2		4		4
	Foreign currency exchange rate changes			(21)		6		—		—
	Transfers(2)			—		(7)		—		—
	Benefits paid			(103)		(104)		(13)		(14)
	Fair value of plan assets at the end of the year		$	2,403	$	2,026	$	55	$	47
	Unfunded status at the end of the year		$	(570)	$	(1,196)	$	(139)	$	(171)
	Assets and (liabilities) recognized in the consolidated balance sheets consist of:
	Non-current assets		$	35	$	9	$	—	$	—
	Current liabilities			(8)		(7)		(9)		(9)
	Non-current liabilities			(597)		(1,198)		(130)		(162)
			$	(570)	$	(1,196)	$	(139)	$	(171)
		(1)	Represents pension and postretirement plan obligations and pension plan assets assumed/acquired during 2012 as part of the L-3 KEO business acquisition.
		(2)	Represents assets related to various supplemental executive retirement plans that had previously been classified as pension plan assets; however, such assets are not held by the plans and are now classified as other assets.
	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
			2013		2012		2013		2012
			(in millions)
	Net loss (gain)		$	425	$	1,146	$	(9)	$	21
	Prior service cost (credit)			1		(12)		(8)		(10)
	Total amount recognized		$	426	$	1,134	$	(17)	$	11
	The aggregate accumulated benefit obligation (ABO) for all of the Company’s pension plans was $2,657 million at December 31, 2013 and $2,783 million at December 31, 2012. The table below presents information for the pension plans with an ABO in excess of the fair value of plan assets at December 31, 2013 and 2012.
			Pension Plans
			2013		2012
			(in millions)
	Projected benefit obligation		$	2,408	$	3,177
	Accumulated benefit obligation			2,115		2,743
	Fair value of plan assets			1,815		1,975
	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, 2013 and 2012.
			Pension Plans				Postretirement
							Benefit Plans
			2013		2012		2013		2012
	Benefit obligations:
	Discount rate			5.03%(1)		4.15%(1)		4.43%(2)		3.37%(2)
	Rate of compensation increase			3.50%(3)		3.56%(3)		3.50%(3)		3.59%(3)
		(1)	The weighted average discount rate assumptions used at December 31, 2013 and 2012 were comprised of separate assumptions determined by country of 5.1% and 4.2% for the U.S. based plans, 4.7% and 3.9% for the Canadian based plans and 3.5% and 3.4% for the German based plans.
		(2)	The weighted average discount rate assumptions used at December 31, 2013 and 2012 were comprised of separate assumptions determined by country of 4.4% and 3.3% for the U.S. based plans and 4.6% and 3.7% for the Canadian based plans.
	(3)	The weighted average rate of compensation increase assumptions were comprised of separate assumptions determined by country of 3.5% for the U.S. based plans at both December 31, 2013 and 2012 and 3.5% and 4.0% for the Canadian based plans at December 31, 2013 and 2012.
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, 2013, 2012 and 2011.
		Pension Plans						Postretirement
								Benefit Plans
		2013		2012		2011		2013				2012				2011
		(in millions)
Components of net periodic benefit cost:
Service cost		$	126	$	113	$	106	$	4			$	4			$	5
Interest cost			132		134		128		7				10				10
Expected return on plan assets			(164)		(145)		(139)		(4)				(3)				(2)
Amortization of prior service cost (credits)			1		1		1		(3)				(3)				(3)
Amortization of net loss			83		69		49		2				1				1
Curtailment or settlement loss			3		7		—		—				1				—
Net periodic benefit cost		$	181	$	179	$	145	$	6			$	10			$	11
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, 2013, 2012 and 2011.
		Pension Plans						Postretirement
								Benefit Plans
		2013		2012		2011		2013				2012				2011
		(in millions)
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net (gain) loss		$	(637)	$	287	$	266	$	(29)			$	(3)			$	10
Prior service cost (credit)			14		(1)		2		—				(5)				—
Amortization of net loss			(83)		(69)		(49)		(2)				(1)				(1)
Amortization of prior service (cost) credit			(1)		(1)		(1)		3				3				3
Total recognized in other comprehensive income			(707)		216		218		(28)				(6)				12
Total recognized in net periodic benefit cost and other comprehensive income		$	(526)	$	395	$	363	$	(22)			$	4			$	23
The following table summarizes the amounts expected to be amortized from accumulated other comprehensive income (loss) and recognized as components of net periodic benefit costs during 2014.
		Pension		Postretirement		Total
		Plans		Benefit Plans
				(in millions)
Net loss (gain)		$	17	$	(1)	$	16
Prior service cost (credit)			2		(2)		—
		$	19	$	(3)	$	16
The table below summarizes the weighted average assumptions used to determine the net periodic benefit cost for the years ended December 31, 2013, 2012 and 2011.
		Pension Plans						Postretirement
								Benefit Plans
		2013		2012		2011		2013				2012				2011
Discount rate			4.15%(1)		5.02%(1)		5.57%(1)		3.37%(4)				4.71%(4)				5.40%(4)
Expected long-term return on plan assets			8.13%(2)		8.15%(2)		8.57%(2)		7.64%				7.64%				6.20%
Rate of compensation increase			3.50%(3)		4.06%(3)		4.50%(3)		3.50%				4.09%				4.50%
	(1)	The weighted average discount rate assumptions used for the years ended December 31, 2013, 2012, and 2011 were comprised of separate assumptions determined by country of 4.2%, 5.1% and 5.6% for the U.S. based plans, 3.9%, 4.4% and 5.4% for the Canadian based plans and 3.4%, 5.1%, and 5.4% for the German 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 8.25% for the U.S. based plans for the year ended December 31, 2013, 2012 and 2011 and 7.25% for the year ended December 31, 2013 and 7.5% for the years ended December 31, 2012 and 2011 for the Canadian based plans.
	(3)	The weighted average rate of compensation increase assumptions used for the year ended December 31, 2013 were comprised of separate assumptions determined by country of 3.5% for both the U.S and Canadian based plans. The rate of compensation increase assumptions were 4.0% for the U.S based plans and 4.5% for the Canadian based plans for the year ended December 31, 2012. The rate of compensation increase assumptions were 4.5% for both the U.S. and Canadian based plans for the year ended December 31, 2011.
	(4)	The weighted average discount rate assumptions used for the years ended December 31, 2013, 2012 and 2011 were comprised of separate assumptions determined by country of 3.3%, 4.8% and 5.4% for the U.S. based plans and 3.7%, 4.3% and 5.4% 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. 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 our plans to develop the expected long-term rate of return.
The annual increase in cost of benefits (health care cost trend rate) is assumed to be an average of 8.0% in 2014 and is assumed to gradually decrease to a rate of 5.0% in 2020 and 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 factors that influence trend primarily price inflation and cost leveraging benefit plan features. Assumed health care cost trend rates 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		$	1	$	—
Effect on postretirement benefit obligations			9		(7)
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 interest 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, 2013 as well as the Company’s pension plan and postretirement benefit plan weighted-average asset allocations at December 31, 2013 and 2012, by asset category.
		U.S.						Canada
Asset Category		2013 and 2012		2013		2012		2013 Range		2013				2012 Range				2012
		Range
Domestic equity(1)			30%-60%		54%		51%	10%-25%			20%				15%-30%				19%
International equity(2)			10%-20%		11		10	30%-60%			49				20%-50%				46
Fixed income securities			20%-40%		22		29	20%-60%			28				25%-55%				32
Real estate securities			0%-15%		6		8	—			—				—				—
Other, primarily cash and cash equivalents			0%-15%		7		2	0%-15%			3				0%-15%				3
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.
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 at December 31, 2013 and 2012, 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										Fair Value Measured at
		December 31, 2013										December 31, 2013
Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
		(in millions)
Equity securities(1):
U.S. Equity		$	1,141	$	—	$	—	$	1,141			$	54			$	18			$	—			$	72
International Equity			79		146		—		225				117				18				—				135
Fixed Income — Investment Grade(2)			216		135		—		351				—				82				—				82
Fixed Income — High Yield(3)			—		118		—		118				—				—				—				—
Real Estate Investment Trusts(4)			118		—		—		118				—				—				—				—
Other(5)			—		150		—		150				6				5				—				11
Total		$	1,554	$	549	$	—	$	2,103			$	177			$	123			$	—			$	300
		Fair Value Measured at										Fair Value Measured at
		December 31, 2012										December 31, 2012
Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
		(in millions)
Equity securities(1):
U.S. Equity		$	893	$	—	$	—	$	893			$	43			$	13			$	—			$	56
International Equity			67		117		—		184				98				21				—				119
Fixed Income — Investment Grade(2)			194		197		—		391				—				88				—				88
Fixed Income — High Yield(3)			—		105		—		105				—				—				—				—
Real Estate Investment Trusts(4)			138		—		—		138				—				—				—				—
Other(5)			—		42		—		42				3				7				—				10
Total		$	1,292	$	461	$	—	$	1,753			$	144			$	129			$	—			$	273
	(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. The Level 2 investment balance is derived from a regulated commingled equity trust fund, which fair value is based on the net asset value (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. Withdrawals are permitted monthly based on NAV.
	(2)	Approximately 62% in 2013 and 50% in 2012 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”). The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. This Fund is 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 38% of U.S. plan assets in 2013 are primarily investment grade corporate bonds from various industries held directly by the Company. 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. The remaining 50% of U.S. plan assets in 2012 and all of the Canadian plan assets for both 2013 and 2012 are invested in regulated commingled equity trust 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 and classified as Level 2. Withdrawals are permitted monthly based on NAV.
	(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) cash equivalents maintained in commingled trust funds, 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.
The table below presents the fair value of the Company’s postretirement benefit plans’ assets at December 31, 2013 and 2012, by asset category segregated by level within the fair value hierarchy, as described below.
		Postretirement Benefit Plans’ Assets
		Fair Value Measured at										Fair Value Measured at
		December 31, 2013										December 31, 2012
Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
		(in millions)
Equity securities(1):
U.S. Equity		$	23	$	—	$	—	$	23			$	27			$	—			$	—			$	27
International Equity			1		2		—		3				1				1				—				2
Fixed Income — Investment Grade(2)			21		2		—		23				11				3				—				14
Fixed Income — High Yield(3)			—		2		—		2				—				1				—				1
Real Estate Investment Trusts(4)			2		—		—		2				2				—				—				2
Other(5)			—		2		—		2				—				1				—				1
Total		$	47	$	8	$	—	$	55			$	41			$	6			$	—			$	47
	(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. The Level 2 investment balance is derived from 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. Withdrawals are permitted monthly based on NAV.
	(2)	Approximately 91% in 2013 and 79% in 2012 of the postretirement benefit plan assets that are invested in the Fixed Income — Investment Grade asset category consist of a mutual fund offered by the Fund. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. This Fund is 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 9% of postretirement benefit plan assets in 2013 are primarily investment grade corporate bonds from various industries held directly by the Company. 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. The remaining 21% in 2012 of the postretirement benefit plan assets are invested in the Bond Fund. As the Bond Fund does not trade in an active market, the fair value is based on NAV’s calculated by the fund manager 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 classified as Level 2. Withdrawals are permitted monthly based on NAV.
	(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 in real estate, either through properties or mortgages.
	(5)	Other consists primarily of cash equivalents maintained in commingled trust funds, 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.
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, 2013, all legal funding requirements had been met. For the year ending December 31, 2014, the Company currently expects to contribute between approximately $97 million and $108 million to its pension plans, and approximately $10 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.
		Pension		Postretirement
		Benefits		Benefits
				Benefit		Subsidy
				Payments		Receipts
		(in millions)
2014		$	116		13		—
2015			125		13		—
2016			134		14		—
2017			146		14		—
2018			152		15		—
Years 2019-2023			925		77		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 L-3 Holdings’ common stock and cash attributable to continuing operations were $120 million for 2013, $126 million for 2012 and $113 million for 2011. The Company’s matching contributions in L-3 Holdings’ common stock and cash attributable to discontinued operations were $8 million for 2012 and $24 million for 2011.
Multi-employer Benefit Plans. Certain of the Company’s businesses participate in multi-employer 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 multi-employer plans are different from single-employer plans in the following aspects: (1) assets contributed to the multi-employer 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 multi-employer 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.
Under these plans, the Company contributed cash and recorded expenses for each of its individually significant plans and all of its other plans in aggregate as noted in the table below.
Pension Fund		EIN/Pension		Pension				FIP/RP(2)		Contributions by												Surcharge				Expiration
		Plan Number		Protection Act				Status Pending/		L-3 Communications												Imposed				Date of
				Zone				Implemented																		Collective-
				Status(1)																						Bargaining
				2013		2012				2013				2012				2011								Agreement
										(in millions)
IAM National Pension Fund			51-6031295/002		Green		Green	No		$	21(3)			$	20(4)			$	19(4)				No			2/14/2014 to
																										1/29/2016(5)
Other Pension Funds(6)											—				—				—
							Total contributions			$	21			$	20			$	19
	(1)	A zone status rating of green indicates the plan is at least 80% funded. The funding status of the IAM National Pension Fund was impacted by a market value investment loss for the plan year ended December 31, 2008, which amortization was extended over five years.
	(2)	Funding improvement plan or rehabilitation plan.
	(3)	At the date the audited financial statements for the Company were issued, Form 5500 for the plan year ending December 31, 2013 was not available.
	(4)	Represents 6% of total plan contributions for both years ended December 31, 2012 and 2011 based on Form 5500.
	(5)	The Company is a party to multiple bargaining agreements for multiple projects that require contributions into the IAM National Pension Fund. The most significant of these agreements, expiring April 27, 2014, cover multiple programs in the Company’s Aerospace Systems reportable segment and represent 72% of 2013 contributions.
	(6)	Consists of three pension funds in which the Company’s contributions are individually, and in the aggregate, insignificant.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
	22. Supplemental Cash Flow Information
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Interest paid on outstanding debt	$	171	$	198	$	238
	Income tax payments		245		332		273
	Income tax refunds		23		22		18

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Information	'
	23. Segment Information
	The Company has four reportable segments, which are described in Note 1. The Company evaluates the performance of its operating segments and reportable segments based on their sales and operating income. All corporate expenses are allocated to the Company’s operating segments using an allocation methodology prescribed by U.S. Government regulations for government contractors. Accordingly, all costs and expenses, except for the goodwill impairment charge in 2011 (which was not included in the Company’s segment performance measures), are included in the Company’s measure of segment profitability. Certain Corporate expenses of $10 million and $26 million for the years ended December 31, 2012 and 2011, respectively, that had previously been allocated to the Engility businesses were retained by the Company and were allocated to L-3’s four 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,
			2013		2012		2011
			(in millions)
	Net Sales
	Products
	Aerospace Systems		$	1,827	$	1,755	$	1,579
	Electronic Systems			3,661		3,754		3,862
	Communication Systems			1,755		2,083		2,042
	NSS			71		98		153
	Elimination of intercompany sales			(125)		(104)		(87)
	Total products sales			7,189		7,586		7,549
	Services
	Aerospace Systems			2,730		2,844		2,857
	Electronic Systems			1,054		1,011		928
	Communication Systems			471		445		428
	NSS			1,228		1,292		1,465
	Elimination of intercompany sales			(50)		(71)		(73)
	Total services sales			5,433		5,521		5,605
	Consolidated total		$	12,622	$	13,107	$	13,154
	Operating Income
	Aerospace Systems		$	426	$	437	$	451
	Electronic Systems			533		569		624
	Communication Systems			168		223		265
	NSS			85		79		101
	Segment Total		$	1,212	$	1,308	$	1,441
	Impairment charge(1)			—		—		(43)
	Consolidated total		$	1,212	$	1,308	$	1,398
	Depreciation and amortization
	Aerospace Systems		$	38	$	46	$	44
	Electronic Systems			117		121		124
	Communication Systems			48		47		43
	NSS			11		14		19
	Consolidated total		$	214	$	228	$	230
	Capital Expenditures
	Aerospace Systems		$	54	$	42	$	42
	Electronic Systems			71		77		79
	Communication Systems			59		84		60
	NSS			5		5		5
	Corporate			20		2		1
	Consolidated total		$	209	$	210	$	187
	Total Assets
	Aerospace Systems		$	3,087	$	3,074	$	3,125
	Electronic Systems			6,928		6,792		6,607
	Communication Systems			2,130		2,179		1,783
	NSS			1,247		1,228		1,317
	Corporate			596		527		959
	Assets of discontinued operations			—		—		1,729
	Consolidated total		$	13,988	$	13,800	$	15,520
		(1)	Represents a non-cash goodwill impairment charge recorded in the fourth quarter of 2011 due to a decline in the estimated fair value of a reporting unit within the Electronic Systems segment.
	Corporate assets not allocated to the reportable segments primarily include cash and cash equivalents, corporate office fixed assets, deferred income tax assets and liabilities and deferred debt issue costs. In addition, substantially all of the Company’s assets are located in North America.
	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,
			2013		2012		2011
			(in millions)
	U.S.		$	9,808	$	10,658	$	11,067
	International:
	United Kingdom			449		360		310
	Canada			357		314		328
	Germany			272		263		243
	Australia			218		222		118
	South Korea			178		125		93
Saudi Arabia			132		76		41
Italy			107		116		98
Other			1,101		973		856
Total international			2,814		2,449		2,087
Consolidated		$	12,622	$	13,107	$	13,154
Net sales to principal customers are summarized in the table below.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
U.S. Government agencies(1)		$	9,186	$	9,986	$	10,438
Commercial			1,689		1,658		1,524
Allied international governments(1)			1,747		1,463		1,192
Consolidated		$	12,622	$	13,107	$	13,154
	(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.

Employee_Severance_and_Termina

Employee Severance and Termination Costs	12 Months Ended
	Dec. 31, 2013
Restructuring and Related Activities [Abstract]	'
Employee Severance and Termination Costs	'
	24. Employee Severance and Termination Costs
	Consistent with the Company’s strategy to continuously improve its cost structure and right-size its businesses, especially in view of sequestration and other DoD budget restrictions, L-3 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 and due to the impact of sequestration at certain affected business units, the Company recorded employee severance and other termination costs of $29 million with respect to approximately 2,000 employees during the year ended December 31, 2013, $23 million with respect to approximately 1,600 employees during the year ended December 31, 2012 and $20 million with respect to approximately 1,200 employees for the year ended December 31, 2011. Employee severance and other termination costs are reported within cost of sales on the consolidated statement of operations. The remaining balance to be paid in connection with these initiatives was $11 million at December 31, 2013 and $9 million at December 31, 2012. Employee severance and other termination costs incurred by reportable segment for the years ended December 31, 2013, 2012 and 2011 are presented in the table below.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Aerospace Systems	$	2	$	1	$	3
	Electronic Systems		16		13		12
	Communication Systems		11		8		4
	NSS		—		1		1
	Consolidated	$	29	$	23	$	20

Unaudited_Quarterly_Financial_

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Unaudited Quarterly Financial Data	'
	25. Unaudited Quarterly Financial Data
	Unaudited summarized financial data by quarter for the years ended December 31, 2013 and 2012 is presented in the table below. The Company’s unaudited quarterly results of operations are affected, significantly in some periods, by our business acquisitions. See Note 5.
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter
			(in millions, except per share data)
	2013
	Sales		$	3,197	$	3,189	$	3,002	$	3,234
	Operating income			310		290		306		306
	Income from continuing operations			192		176		204		188
	Net income attributable to L-3			191		175		200		185
	Basic EPS(1) (2)			2.12		1.95		2.23		2.10
	Diluted EPS(1) (2)			2.09		1.92		2.19		2.04
	2012
	Sales		$	3,160	$	3,143	$	3,284	$	3,520
	Operating income			322		328		319		339
	Income from continuing operations			186		189		188		199
	Net income attributable to L-3			200		203		185		196
	Basic EPS from continuing operations(1)			1.88		1.93		1.94		2.11
	Diluted EPS from continuing operations(1)			1.86		1.91		1.91		2.08
	Basic EPS(1)			2.02		2.09		1.93		2.11
	Diluted EPS(1)			2.00		2.06		1.90		2.08
		(1)	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.
		(2)	EPS and EPS from continuing operations are the same in 2013.

Financial_Information_of_L3_Co

Financial Information of L-3 Communications and Its Subsidiaries	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Financial Information of L-3 Communications and Its Subsidiaries	'
	26. Financial Information of L-3 Communications and Its Subsidiaries
	Total shareholders’ equity for L-3 Communications equals that of L-3 Holdings, but the components (common stock, additional paid-in capital, treasury stock and retained earnings) are different. The table below presents information regarding the balances and changes in common stock, additional paid-in capital, treasury stock and retained earnings of L-3 Communications for each of the three years ended December 31, 2013.
		L-3				Additional		Treasury		Retained		Accumulated		Total
		Communications				Paid-in		Stock		Earnings		Other
		Common Stock				Capital						Comprehensive
												(Loss)
		Shares		Par								Income
		Issued		Value
				(in millions, except shares issued)
	Balance at December 31, 2010		100	$	—	$	4,801	$	—	$	2,226	$	(256)	$	6,771
	Net income attributable to L-3		—		—		—		—		958		—		958
	Contributions from L-3 Holdings		—		—		263		—		—		—		263
	Dividends to L-3 Holdings		—		—		—		—		(1,157)		—		(1,157)
	Comprehensive loss		—		—		—		—		—		(198)		(198)
	Other		—		—		—		—		7		—		7
	Balance at December 31, 2011		100	$	—	$	5,064	$	—	$	2,034	$	(454)	$	6,644
	Net income attributable to L-3		—		—		—		—		784		—		784
	Contributions from L-3 Holdings		—		—		250		—		—		—		250
	Dividends to L-3 Holdings		—		—		—		—		(1,064)		—		(1,064)
	Comprehensive loss		—		—		—		—		—		(96)		(96)
	Net change of equity due to spin-off of Engility		—		—		—		—		(1,063)		—		(1,063)
	Other		—		—		—		—		(4)		—		(4)
	Balance at December 31, 2012		100	$	—	$	5,314	$	—	$	687	$	(550)	$	5,451
	Net income attributable to L-3		—		—		—		—		751		—		751
	Contributions from L-3 Holdings		—		—		339		—		—		—		339
	Dividends to L-3 Holdings		—		—		—		—		(997)		—		(997)
	Comprehensive gain		—		—		—		—		—		440		440
	Other		—		—		—		—		(3)		—		(3)
	Balance at December 31, 2013		100	$	—	$	5,653	$	—	$	438	$	(110)	$	5,981
	The net proceeds received by L-3 Holdings from (i) the sale of its common stock, (ii) exercise of L-3 Holdings’ employee and director stock options, and related tax benefits, and (iii) L-3 Holdings’ common stock contributed to the Company’s savings plans are contributed to L-3 Communications. The amounts paid by L-3 Holdings for dividends and share repurchases are generated from dividends received from L-3 Communications.
	L-3 Communications is a 100% owned subsidiary of L-3 Holdings. The debt of L-3 Communications, including the Senior Notes and borrowings under amounts drawn against the Amended and Restated Revolving Credit Facility are guaranteed, on a joint and several, full and unconditional basis, by certain of its domestic subsidiaries (the “Guarantor Subsidiaries”). The debt of L-3 Holdings, including the CODES, are guaranteed on a joint and several, full and unconditional basis, by L-3 Communications and the Guarantor Subsidiaries. See Note 11 for additional information. The foreign subsidiaries and certain domestic subsidiaries of L-3 Communications (the “Non-Guarantor Subsidiaries”) do not guarantee the debt of L-3 Communications or L-3 Holdings. None of the debt of L-3 Communications has been issued by its subsidiaries. There are no restrictions on the payment of dividends from the Guarantor Subsidiaries to L-3 Communications.
	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 L-3 Communications Corporation, or (2) upon the determination that such guarantor is no longer a “domestic subsidiary”. Under the terms of the indenture governing the CODES, the guarantees of the CODES will be automatically and unconditionally released and discharged: (1) upon the release of guarantees of all other outstanding indebtedness of L-3 Holdings and its subsidiaries (other than a foreign subsidiary) or (2) upon the designation of such guarantor as an “excluded subsidiary.” In addition, the guarantees of the Senior Notes and the CODES will unconditionally be 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 or other disposition of all of the capital stock of such guarantor.
	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. As discussed in Note 3, the Company is revising its previously issued financial statements. As part of that revision, the Company has revised the accompanying condensed combining financial statements contained herein. The adjustments related to the internal review of the Aerospace Systems segment, excluding certain adjustments related to the Platform Systems segment, were recorded as adjustments to the Guarantor Subsidiaries financial statement amounts. Adjustments from the internal review that related to a foreign subsidiary of the Platform Systems segment, with a cumulative operating impact through December 31, 2013 of $10 million, were recorded to the Non-Guarantor Subsidiaries financial statement amounts. The adjustments for the accounting related to a sales-type lease transaction for flight simulator systems within its Electronic Systems segment have been recorded as adjustments to the L-3 Communications financial statement amounts. The adjustments for the previously identified immaterial errors were recorded as adjustments to the Guarantor Subsidiaries financial statement amounts.
	The following condensed combining financial information presents the results of operations, financial position and cash flows of (1) L-3 Holdings, excluding L-3 Communications and its consolidated subsidiaries (the “Parent”), (2) L-3 Communications, excluding its consolidated subsidiaries, (3) the Guarantor Subsidiaries, (4) the Non-Guarantor Subsidiaries and (5) the eliminations to arrive at the information for L-3 on a consolidated basis.
		L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
		Holdings		Communications		Subsidiaries		Guarantor				L-3
		(Parent)						Subsidiaries
		(in millions)
	Condensed Combining Balance Sheets:
	At December 31, 2013:
	Current assets:
	Cash and cash equivalents	$	—	$	258	$	—	$	261	$	-19	$	500
	Billed receivables, net		—		364		401		226		—		991
	Contracts in process		—		925		1,152		354		—		2,431
	Other current assets		—		344		159		169		—		672
	Total current assets		—		1,891		1,712		1,010		-19		4,594
	Goodwill		—		2,307		4,326		1,163		—		7,796
	Other assets		—		838		532		228		—		1,598
	Investment in and amounts due from consolidated subsidiaries		6,670		6,940		3,744		—		-17,354		—
	Total assets	$	6,670	$	11,976	$	10,314	$	2,401	$	-17,373	$	13,988
	Current liabilities	$	—	$	914	$	1,011	$	628	$	-19	$	2,534
	Amounts due to consolidated subsidiaries		—		—		—		270		-270		—
	Other long-term liabilities		—		1,451		193		124		—		1,768
	Long-term debt		689		3,630		—		—		-689		3,630
	Total liabilities		689		5,995		1,204		1,022		-978		7,932
	L-3 shareholders’ equity		5,981		5,981		9,110		1,379		-16,470		5,981
	Noncontrolling interests		—		—		—		—		75		75
	Total equity		5,981		5,981		9,110		1,379		-16,395		6,056
	Total liabilities and equity	$	6,670	$	11,976	$	10,314	$	2,401	$	-17,373	$	13,988
	At December 31, 2012:
	Current assets:
	Cash and cash equivalents	$	—	$	246	$	—	$	242	$	-139	$	349
	Billed receivables, net		—		290		441		237		—		968
Contracts in process		—		893		1,275		342		—		2,510
Other current assets		—		308		161		188		—		657
Total current assets		—		1,737		1,877		1,009		-139		4,484
Goodwill		—		2,010		4,627		1,139		—		7,776
Other assets		—		757		572		211		—		1,540
Investment in and amounts due from consolidated subsidiaries		6,140		7,153		3,299		101		-16,693		—
Total assets	$	6,140	$	11,657	$	10,375	$	2,460	$	-16,832	$	13,800
Current liabilities	$	—	$	823	$	1,221	$	658	$	-139	$	2,563
Other long-term liabilities		—		1,754		210		117		—		2,081
Long-term debt		689		3,629		—		—		-689		3,629
Total liabilities		689		6,206		1,431		775		-828		8,273
L-3 shareholders’ equity		5,451		5,451		8,944		1,685		-16,080		5,451
Noncontrolling interests		—		—		—		—		76		76
Total equity		5,451		5,451		8,944		1,685		-16,004		5,527
Total liabilities and equity	$	6,140	$	11,657	$	10,375	$	2,460	$	-16,832	$	13,800
Condensed Combining Statements of Operations:
For the year ended December 31, 2013:
Net sales	$	—	$	3,842	$	6,804	$	2,363	$	-387	$	12,622
Cost of sales		-59		-3,549		-6,139		-2,109		446		-11,410
Operating (loss) income		-59		293		665		254		59		1,212
Interest expense		-21		-176		—		-1		21		-177
Interest and other income (expense), net		—		15		—		5		—		20
(Loss) income from continuing operations before income taxes		-80		132		665		258		80		1,055
Benefit (provision) for income taxes		22		-38		-184		-73		-22		-295
Equity in net income of consolidated subsidiaries		809		657		—		—		-1,466		—
Net income		751		751		481		185		-1,408		760
Net income attributable to noncontrolling interests		—		—		—		—		-9		-9
Net income attributable to L-3	$	751	$	751	$	481	$	185	$	-1,417	$	751
Comprehensive income attributable to L-3	$	1,191	$	1,191	$	480	$	159	$	-1,830	$	1,191
For the year ended December 31, 2012:
Net sales	$	—	$	3,737	$	7,475	$	2,278	$	-383	$	13,107
Cost of sales		-59		-3,434		-6,749		-1,999		442		-11,799
Operating (loss) income		-59		303		726		279		59		1,308
Interest expense		-21		-183		—		-1		21		-184
Interest and other income (expense), net		—		14		-5		2		—		11
Debt retirement charge		—		-13		—		—		—		-13
(Loss) income from continuing operations before income taxes		-80		121		721		280		80		1,122
Benefit (provision) for income taxes		26		-37		-230		-93		-26		-360
Equity in net income of consolidated subsidiaries		838		668		—		—		-1,506		—
Income from continuing operations		784		752		491		187		-1,452		762
Income from discontinued operations, net of income tax		—		32		—		—		—		32
Net income		784		784		491		187		-1,452		794
Net income attributable to noncontrolling interests		—		—		—		—		-10		-10
Net income attributable to L-3	$	784	$	784	$	491	$	187	$	-1,462	$	784
Comprehensive income attributable to L-3	$	688	$	688	$	493	$	215	$	-1,396	$	688
For the year ended December 31, 2011:
Net sales	$	—	$	3,735	$	7,572	$	2,187	$	(340)	$	13,154
Cost of sales		(57)		(3,335)		(6,857)		(1,861)		397		(11,713)
Impairment charge		—		(43)		—		—		—		(43)
Operating (loss) income		(57)		357		715		326		57		1,398
Interest expense		(23)		(201)		(1)		(5)		26		(204)
Interest and other income (expense), net		—		17		(15)		4		(3)		3
Debt retirement charge		—		(35)		—		—		—		(35)
(Loss) income from continuing operations before income taxes		(80)		138		699		325		80		1,162
Benefit (provision) for income taxes		20		(35)		(178)		(83)		(20)		(296)
Equity in net income of consolidated subsidiaries		1,018		751		—		—		(1,769)		—
Income from continuing operations		958		854		521		242		(1,709)		866
Income from discontinued operations, net of income tax		—		104		—		—		—		104
Net income		958		958		521		242		(1,709)		970
Net income attributable to noncontrolling interests		—		—		—		—		(12)		(12)
Net income attributable to L-3	$	958	$	958	$	521	$	242	$	(1,721)	$	958
Comprehensive income attributable to L-3	$	760	$	760	$	511	$	221	$	(1,492)	$	760
	L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
	Holdings		Communications		Subsidiaries		Guarantor				L-3
	(Parent)						Subsidiaries
	(in millions)
Condensed Combining Statements of Cash Flows: For the year ended December 31, 2013:
Operating activities:
Net cash from operating activities	$	999	$	437	$	776	$	231	$	(1,180)	$	1,263
Investing activities:
Business acquisitions, net of cash acquired		—		(62)		—		—		—		(62)
Investments in L-3 Communications		-149		—		—		—		149		—
Other investing activities		—		(88)		(89)		(22)		—		(199)
Net cash used in investing activities		-149		(150)		(89)		(22)		149		(261)
Financing activities:
Common stock repurchased		-800		—		—		—		—		(800)
Dividends paid on L-3 Holdings common stock		-199		—		—		—		—		(199)
Dividends paid to L-3 Holdings		—		(999)		—		—		999		—
Investments from L-3 Holdings		—		149		—		—		(149)		—
Other financing activities		149		575		(687)		(188)		301		150
Net cash used in financing activities		-850		(275)		(687)		(188)		1,151		(849)
Effect of foreign currency exchange rate changes on cash		—		—		—		(2)		—		(2)
Net (decrease) increase in cash		—		12		—		19		120		151
Cash and cash equivalents, beginning of the year		—		246		—		242		(139)		349
Cash and cash equivalents, end of the year	$	—	$	258	$	—	$	261	$	(19)	$	500
For the year ended December 31, 2012:
Operating activities:
Net cash from operating activities from continuing operations	$	1,067	$	252	$	858	$	265	$	(1,211)	$	1,231
Investing activities:
Business acquisitions, net of cash acquired		—		(348)		—		—		—		(348)
Investments in L-3 Communications		-42		—		—		—		42		—
Other investing activities		—		225		(59)		(18)		—		148
Net cash used in investing activities from continuing operations		-42		(123)		(59)		(18)		42		(200)
Financing activities:
Redemption of senior subordinated notes		—		(500)		—		—		—		(500)
Common stock repurchased		-872		—		—		—		—		(872)
Dividends paid on L-3 Holdings common stock		-195		—		—		—		—		(195)
Dividends paid to L-3 Holdings		—		(1,067)		—		—		1,067		—
Investments from L-3 Holdings		—		42		—		—		(42)		—
Other financing activities		42		924		(799)		(234)		107		40
Net cash used in financing activities from continuing operations		-1,025		(601)		(799)		(234)		1,132		(1,527)
Effect of foreign currency exchange rate changes on cash		—		—		—		7		—		7
Net increase in cash and cash equivalents of discontinued operations		—		74		—		—		—		74
Net (decrease) increase in cash		—		(398)		—		20		(37)		(415)
Cash and cash equivalents, beginning of the year		—		644		—		222		(102)		764
Cash and cash equivalents, end of the year	$	—	$	246	$	—	$	242	$	(139)	$	349
	L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
	Holdings		Communications		Subsidiaries		Guarantor				L-3
	(Parent)						Subsidiaries
	(in millions)
For the year ended December 31, 2011:
Operating activities:
Net cash from operating activities from continuing operations	$	1,157	$	476	$	792	$	220	$	(1,414)	$	1,231
Investing activities:
Business acquisitions, net of cash acquired		—		(20)		—		—		—		(20)
Investments in L-3 Communications		(55)		—		—		—		55		—
Other investing activities		—		(84)		(75)		(20)		—		(179)
Net cash used in investing activities from continuing operations		(55)		(104)		(75)		(20)		55		(199)
Financing activities:
Proceeds from sale of senior notes		—		1,143		—		—		—		1,143
Redemption of senior subordinated notes and CODES		(11)		(1,150)		—		—		—		(1,161)
Common stock repurchased		(958)		—		—		—		—		(958)
Dividends paid on L-3 Holdings common stock		(188)		—		—		—		—		(188)
Dividends paid to L-3 Holdings		—		(1,157)		—		—		1,157		—
Investments from L-3 Holdings		—		55		—		—		(55)		—
Other financing activities		55		882		(717)		(447)		272		45
Net cash used in financing activities from continuing operations		(1,102)		(227)		(717)		(447)		1,374		(1,119)
Effect of foreign currency exchange rate changes on cash		—		—		—		(4)		—		(4)
Net increase in cash and cash equivalents of discontinued operations		—		248		—		—		—		248
Net (decrease) increase in cash		—		393		—		(251)		15		157
Cash and cash equivalents, beginning of the year		—		251		—		473		(117)		607
Cash and cash equivalents, end of the year	$	—	$	644	$	—	$	222	$	(102)	$	764

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation: The accompanying financial statements comprise the consolidated financial statements of L-3 Holdings and L-3 Communications. L-3 Holdings’ only asset is its investment in the common stock of L-3 Communications, its wholly-owned subsidiary, and its only obligations are: (1) the 3% Convertible Contingent Debt Securities (CODES) due 2035, which were issued by L-3 Holdings on July 29, 2005, (2) its guarantee of borrowings under the Amended and Restated Revolving Credit Facility of L-3 Communications and (3) its guarantee of other contractual obligations of L-3 Communications and its subsidiaries. L-3 Holdings’ obligations relating to the CODES have been jointly, severally, fully and unconditionally guaranteed by L-3 Communications and certain of its wholly-owned domestic subsidiaries. Accordingly, such debt has been reflected as debt of L-3 Communications in its consolidated financial statements in accordance with the accounting standards for pushdown accounting. All issuances of and conversions into L-3 Holdings’ equity securities, including grants of stock options, restricted stock, restricted stock units and performance units by L-3 Holdings to employees and directors of L-3 Communications and its subsidiaries, have been reflected in the consolidated financial statements of L-3 Communications. As a result, the consolidated financial positions, results of operations and cash flows of L-3 Holdings and L-3 Communications are substantially the same. See Note 26 for additional information regarding the audited financial information of L-3 Communications and its subsidiaries.
	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 costs of sales during the reporting period. The most significant of these estimates and assumptions relate to contract revenue, profit and loss recognition, fair values of assets acquired and liabilities assumed in business combinations, 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 and environmental obligations, accrued product warranty costs, and the recoverability, 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 will differ from these estimates and could differ materially.
	The audited condensed consolidated balance sheet as of December 31, 2012 has been revised for the final purchase price allocation of the Link Simulation & Training U.K. Limited (Link U.K.) business acquisition. Link U.K is the commercial aircraft simulation business acquired from Thales Group effective August 6, 2012. During 2013, the Company completed the purchase price allocation, which was based on the final appraisals and valuations of the acquired assets and liabilities and estimated final closing date net working capital. The L-3 audited condensed consolidated balance sheet as of December 31, 2012 has been adjusted in accordance with the accounting standards for business combinations. See Note 5 for additional information regarding the final purchase price allocation for Link U.K. and resulting adjustments.
	Certain other reclassifications have been made to conform prior-year amounts to the current-year presentation.
Principles of Consolidation	'
	Principles of Consolidation: The consolidated financial statements of the Company include all wholly-owned and majority-owned subsidiaries. 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.
Revenue Recognition	'
	Revenue Recognition: Substantially all of the Company’s sales are generated from written contractual (revenue) arrangements. The sales price for the Company’s revenue arrangements are either fixed-price, cost-plus or time-and-material type. Depending on the contractual scope of work, the Company utilizes either contract accounting standards or accounting standards for revenue arrangements with commercial customers to account for these contracts. Approximately 47% of the Company’s 2013 sales were accounted for under contract accounting standards, of which approximately 38% were fixed-price type contracts and approximately 9% were cost-plus type contracts. For contracts that are accounted for under contract accounting standards, sales and profits are recognized based on: (1) a Percentage-of-Completion (POC) method of accounting (fixed-price contracts), (2) allowable costs incurred plus the estimated profit on those costs (cost-plus contracts), or (3) direct labor hours expended multiplied by the contractual fixed rate per hour plus incurred costs for material (time-and-material contracts). Aggregate net changes in contract estimates increased operating income by $114 million, or 9%, for the year ended December 31, 2013, $72 million, or 6%, for the year ended December 31, 2012, and $73 million, or 5%, for the year ended December 31, 2011.
	Sales and profits on fixed-price type contracts covered by contract accounting standards are substantially recognized using POC methods of accounting. Sales and profits on fixed-price production contracts under which units are produced and delivered in a continuous or sequential process are recorded as units are delivered based on their contractual selling prices (the “units-of-delivery” method). Sales and profits on each fixed-price production contract under which units are not produced and delivered in a continuous or sequential process, or under which a relatively few number of units are produced, are recorded based on the ratio of actual cumulative costs incurred to the total estimated costs at completion of the contract, multiplied by the total estimated contract revenue, less cumulative sales recognized in prior periods (the “cost-to-cost” method). Under both POC methods of accounting, a single estimated total profit margin is used to recognize profit for each contract over its entire period of performance, which can exceed one year. Losses on contracts are recognized in the period in which they become evident. The impact of revisions of contract estimates, which may result from contract modifications, performance or other reasons, are recognized on a cumulative catch-up basis in the period in which the revisions are made.
	Sales and profits on cost-plus type contracts covered by contract accounting standards are recognized as allowable costs are incurred on the contract, at an amount equal to the allowable costs plus the estimated profit on those costs. The estimated profit on a cost-plus type contract is fixed or variable based on the contractual fee arrangement. Incentive and award fees are the primary variable fee contractual arrangements. Incentive and award fees on cost-plus type contracts are included as an element of total estimated contract revenues and are recorded as sales when a basis exists for the reasonable prediction of performance in relation to established contractual targets and the Company is able to make reasonably dependable estimates for them.
	Sales and profits on time-and-material type contracts are recognized on the basis of direct labor hours expended multiplied by the contractual fixed rate per hour, plus the actual costs of materials and other direct non-labor costs.
	Sales on arrangements for (1) fixed-price type contracts that require us to perform services that are not related to the production of tangible assets (Fixed-Price Service Contracts) and (2) certain commercial customers are recognized in accordance with accounting standards for revenue arrangements with commercial customers. Sales for the Company’s businesses whose customers are primarily commercial business enterprises are substantially all generated from single element revenue arrangements. Sales are recognized when there is persuasive evidence of an arrangement, delivery has occurred or services have been performed, the selling price to the buyer is fixed or determinable and collectability is reasonably assured. Sales for Fixed-Price Service Contracts that do not contain measurable units of work performed are generally recognized on a straight-line basis over the contractual service period, unless evidence suggests that the revenue is earned, or obligations fulfilled, in a different manner. Sales for Fixed-Price Service Contracts that contain measurable units of work performed are generally recognized when the units of work are completed. Sales and profit on cost-plus and time-and-material type contracts to perform services are recognized in the same manner as those within the scope of contract accounting standards, except for incentive and award fees. Cost-based incentive fees are recognized when they are realizable in the amount that would be due under the contractual termination provisions as if the contract was terminated. Performance based incentive fees and award fees are recorded as sales when awarded by the customer.
	For contracts with multiple deliverables, the Company applies the separation and allocation guidance under the accounting standard for revenue arrangements with multiple deliverables, unless all the deliverables are covered by contract accounting standards, in which case the Company applies the separation and allocation guidance under contract accounting standards. Revenue arrangements with multiple deliverables are evaluated to determine if the deliverables should be separated into more than one unit of accounting. The Company recognizes revenue for each unit of accounting based on the revenue recognition policies discussed above.
	Sales and profit in connection with contracts to provide services to the U.S. Government that contain collection risk because the contracts are incrementally funded and subject to the availability of funds appropriated, are deferred until a contract modification is obtained, indicating that adequate funds are available to the contract or task order.
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 costs of sales 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 cost of sales as incurred.
	Customer-funded research and development costs are incurred pursuant to contracts (revenue arrangements) to perform research and development activities according to customer specifications. These costs are not accounted for as research and development expenses, and are also not indirect contract costs. Instead, these costs are direct contract costs and are expensed 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.
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.
	The table below presents the changes in the Company’s accrued product warranty costs.
			Year Ended December 31,
			2013		2012
			(in millions)
	Accrued product warranty costs(1):
	Balance at January 1		$	99	$	94
	Acquisitions during this period			2		7
	Accruals for product warranties issued during the period			71		78
	Changes to accruals for product warranties existing before January 1			3		(3)
	Foreign currency translation adjustments			—		1
	Settlements made during the period			(76)		(78)
	Balance at December 31		$	99	$	99
		(1)	Warranty obligations incurred in connection with long-term production contracts that are accounted for under the POC cost-to-cost method are included within the contract estimates at completion and are excluded from the above amounts. The balances above include both the current and non-current amounts.
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.
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 L-3 Holdings common stock instead of settling such obligations with cash payments, except for certain performance unit awards that are payable in cash.
	Compensation expense for all restricted stock unit and stock option awards is 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 L-3 Holdings 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. Compensation expense for performance units that are payable in cash is based on a binomial valuation technique (the Monte Carlo valuation model) adjusted for historical performance each reporting period and recognized on a straight-line basis over the requisite service period.
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.
	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 on 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.
Contracts in Process	'
	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. 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 6, 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 general and administrative costs (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 commensurate with the profit margin that the Company earns on similar contracts.
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 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 applying principally the straight-line method to the estimated useful lives of the related assets. Useful lives range substantially 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 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 valued at fair value.
Goodwill	'
	Goodwill: 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 or not that the fair value of a reporting unit is less than its carrying amount. L-3 did not utilize a qualitative assessment approach for the November 30, 2013 goodwill impairment test, as we chose instead to complete the quantitative two-step testing process for each reporting unit. The first step in the process is to identify 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 flows valuation approach. If a potential impairment is identified, the second step is to measure the impairment loss by comparing the implied fair value of goodwill with the carrying value of goodwill of the reporting unit. There were no impairment charges that resulted from the annual impairment assessment or change in circumstances during the years ended December 31, 2013 and 2012. The Company recorded a goodwill impairment charge of $43 million during the year ended December 31, 2011. See Note 8 for additional information on the goodwill impairment charge.
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, 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 such estimates indicate that the duration of the Company’s customer contractual relationships has decreased compared to the estimates made as of the date the Company acquired these intangible assets, then the Company accelerates the amortization period for its customer contractual relationships over 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, and an embedded derivative representing the contingent interest payment provision related to the CODES.
	The Company’s U.S. and foreign businesses enter into contracts with customers, subcontractors or vendors that are denominated in currencies other than their functional currencies. To protect the functional currency equivalent cash flows associated with certain of these contracts, the Company enters into foreign currency forward contracts. The Company’s activities involving foreign currency forward contracts are designed to hedge the changes in the functional currency equivalent cash flows due to movements in foreign exchange rates compared to the functional currency. The foreign currencies hedged are primarily the Canadian dollar, the U.S. dollar, the Euro 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.
	The embedded derivative related to the issuance of the CODES is recorded at fair value with changes reflected in the Consolidated Statements of Operations.
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, 2013, 2012 and 2011 are 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 other comprehensive income (loss).
Accounting Standards Issued and Not Yet Implemented	'
	Accounting Standards Issued and Not Yet Implemented: In July 2013, the FASB issued amendments to an accounting standard which requires an unrecognized tax benefit or portion of an unrecognized tax benefit to be presented as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward except when certain conditions exist. The amendments are effective for the Company for fiscal years beginning after December 15, 2013, including that year’s interim periods. The adoption of this standard will not impact the Company’s financial position, results of operations or cash flows.
Comprehensive Income	'
	Effective January 1, 2013, the Company adopted a new accounting standard issued by the Financial Accounting Standards Board (FASB), which adds new disclosure requirements for items reclassified out of accumulated other comprehensive income (loss) (AOCI). This standard requires entities to disclose additional information about reclassification adjustments, including: (1) changes in AOCI balances by component and (2) significant items reclassified out of AOCI. The adoption of this standard resulted in additional disclosures of items reclassified out of AOCI and did not impact the Company’s financial position, results of operations or cash flows. See Note 12 for these additional disclosures.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
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,
			2013		2012
			(in millions)
	Accrued product warranty costs(1):
	Balance at January 1		$	99	$	94
	Acquisitions during this period			2		7
	Accruals for product warranties issued during the period			71		78
	Changes to accruals for product warranties existing before January 1			3		(3)
	Foreign currency translation adjustments			—		1
	Settlements made during the period			(76)		(78)
	Balance at December 31		$	99	$	99
		(1)	Warranty obligations incurred in connection with long-term production contracts that are accounted for under the POC cost-to-cost method are included within the contract estimates at completion and are excluded from the above amounts. The balances above include both the current and non-current amounts.

Revisions_to_Previously_Issued1

Revisions to Previously Issued Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2013
Schedule of Nature of Adjustments, Applicable Segment, Amount of Increase (or Decrease) to Sales and Operating Income, Period Recorded and Correct Period	'
	With respect to each of the immaterial out of period amounts included in the Company’s previously issued financial statements, the table below presents the: (1) nature of the adjustments, (2) applicable segment, (3) amount of increase (or decrease) to sales and operating income, (4) period recorded and (5) correct period.
					2013								2012								2011
	Nature of Adjustment		Applicable		Sales				Operating				Sales				Operating				Sales				Operating				Period	Correct
			Segment						Income								Income								Income				Recorded	Period
					($ in millions)
	Higher development and material costs for networked communications systems		Communication Systems		$	10			$	10			$	(10	)		$	(10	)		$	—			$	—			1Q 2013	4Q 2012
	Sub-contractor subscription deposit		Aerospace Systems			26				2				(26	)			(2	)			—				—			4Q 2012	1Q, 2Q,
																														3Q & Q4 2013
	Costs accruals for goods/services received		Aerospace Systems			5				1				(5	)			(1	)			—				—			4Q 2012	1Q 2013
	Unrecorded liabilities		Aerospace Systems			(2	)			—				2				—				—				—			1Q 2013	4Q 2012
	Accrued vacation		Aerospace Systems			—				1				—				(1	)			—				—			4Q 2013	4Q 2012,
																														1Q, 2Q & 3Q 2013
	Warranty reserve		Electronic Systems			—				—				3				(4	)			(3	)			4			3Q 2012	4Q 2011
	Total				$	39			$	14			$	(36	)		$	(18	)		$	(3	)		$	4
Schedule of Impact on Sales and Pre-tax Income	'
	The table below presents the impact of the matters discussed above on sales and pre-tax income for the years ended December 31, 2013, 2012 and 2011 and for the years ended prior to December 31, 2011.
			2013								2012								2011								Prior to 2011
			Sales				Pre-tax				Sales				Pre-tax				Sales				Pre-tax				Sales			Pre-tax
							Income								Income								Income							Income
			(in millions)
	Army C-12 Contract		$	(25)			$	(35)			$	(3)			$	(16)			$	(1)			$	(3)				—			—
	Other Logistics Support Contracts			(2)				(11)				(2)				(11)				—				(2)				(1)			(4)
	Logistics Solutions		$	(27)			$	(46)			$	(5)			$	(27)			$	(1)			$	(5)			$	(1)		$	(4)
	Platform Systems			(12)				(14)				3				2				—				—				—			—
	Total Internal Review of Aerospace Systems Segment		$	(39)			$	(60)			$	(2)			$	(25)			$	(1)			$	(5)			$	(1)		$	(4)
	Sales-Type Lease Transaction			(7)				5				—				3				—				3				—			17
	Out of Period Amounts			39				14				(36)				(18)				(3)				4				—			—
	Total Revisions		$	(7)			$	(41)			$	(38)			$	(40)			$	(4)			$	2			$	(1)		$	13
Adjustment [Member]	'
Schedule of As Previously Reported, Adjustments and As Currently Reported Financial Statements	'
	The tables below present the Company’s: (1) As Previously Reported, (2) Adjustments, and (3) As Currently Reported Condensed Consolidated Balance Sheets as of December 31, 2013 and 2012, Statements of Operations and Operating Activities for the Statement of Cash Flows, for the fiscal years ended December 31, 2013, 2012 and 2011. The Adjustments correct for: (1) the results of the Aerospace Systems internal review, (2) the accounting related to a sales-type lease transaction within the Company’s Electronic Systems segment and (3) immaterial out of period amounts previously recorded in the Company’s financial statements but not recorded in the appropriate period to reflect them in the appropriate period.
							Adjustments for:
			As				Aerospace				Sales-Type				Out of Period				As
			Previously				Systems				Lease				Amounts				Revised
			Reported				Segment				Transaction
							Internal
							Review
			(in millions)
	Condensed Consolidated Balance Sheet as of
	December 31, 2013:
	ASSETS
	Current Assets:
	Cash and cash equivalents		$	500			$	—			$	—			$	—			$	500
	Billed receivables, net of allowances of $26 in 2013			1,015				(24)				—				—				991
	Contracts in process			2,524				(67)				(26)				—				2,431
	Inventories			359				—				—				—				359
	Deferred income taxes			122				25				—				—				147
	Other current assets			129				9				28				—				166
	Total current assets			4,649				(57)				2				—				4,594
	Property, plant and equipment, net			1,039				3				—				—				1,042
	Goodwill			7,796				—				—				—				7,796
	Identifiable intangible assets			285				—				—				—				285
	Deferred debt issue costs			24				—				—				—				24
	Other assets			216				—				31				—				247
	Total assets		$	14,009			$	(54)			$	33			$	—			$	13,988
	LIABILITIES AND EQUITY
	Current Liabilities:
	Accounts payable, trade		$	541			$	—			$	—			$	—			$	541
	Accrued employment costs			543				2				—				—				545
	Accrued expenses			455				3				—				—				458
	Advance payments and billings in excess of costs incurred			570				1				5				—				576
	Income taxes			31				—				—				—				31
	Other current liabilities			383				—				—				—				383
	Total current liabilities			2,523				6				5				—				2,534
	Pension and postretirement benefits			727				—				—				—				727
	Deferred income taxes			635				—				—				—				635
	Other liabilities			396				—				10				—				406
	Long-term debt			3,630				—				—				—				3,630
	Total liabilities			7,911				6				15				—				7,932
	Equity:
	L-3 shareholders’ equity:
	L-3 Communications Holdings, Inc.’s common stock			5,653				—				—				—				5,653
	L-3 Communications Holdings, Inc.’s treasury stock at cost			(5,288)				—				—				—				(5,288)
	Retained earnings			5,768				(60)				17				1				5,726
	Accumulated other comprehensive loss			(110)				—				—				—				(110)
	Total L-3 shareholders’ equity			6,023				(60)				17				1				5,981
	Noncontrolling interests			75				—				—				—				75
	Total equity			6,098				(60)				17				1				6,056
	Total liabilities and equity		$	14,009			$	(54)			$	32			$	1			$	13,988
	Condensed Consolidated Balance Sheet as of December 31, 2012:
	ASSETS
	Current Assets:
	Cash and cash equivalents		$	349			$	—			$	—			$	—			$	349
	Billed receivables, net of allowances of $33 in 2012			968				—				—				—				968
	Contracts in process			2,597				(30)				(45)				(12)				2,510
	Inventories			358				—				—				—				358
	Deferred income taxes			95				12				—				6				113
	Other current assets			138				—				45				3				186
	Total current assets			4,505				(18)				—				(3)				4,484
	Property, plant and equipment, net			1,016				1				—				6				1,023
	Goodwill			7,776				—				—				—				7,776
	Identifiable intangible assets			314				—				—				—				314
	Deferred debt issue costs			29				—				—				—				29
Other assets			151				—				23				—				174
Total assets		$	13,791			$	(17)			$	23			$	3			$	13,800
LIABILITIES AND EQUITY
Current Liabilities:
Accounts payable, trade		$	494			$	—			$	—			$	11			$	505
Accrued employment costs			551				2				—				2				555
Accrued expenses			469				1				—				(1)				469
Advance payments and billings in excess of costs incurred			620				1				—				—				621
Income taxes			21				—				—				—				21
Other current liabilities			392				—				—				—				392
Total current liabilities			2,547				4				—				12				2,563
Pension and postretirement benefits			1,360				—				—				—				1,360
Deferred income taxes			328				—				—				—				328
Other liabilities			384				—				9				—				393
Long-term debt			3,629				—				—				—				3,629
Total liabilities			8,248				4				9				12				8,273
Equity:
L-3 shareholders’ equity:
L-3 Communications Holdings, Inc.’s common stock			5,314				—				—				—				5,314
L-3 Communications Holdings, Inc.’s treasury stock at cost			(4,488)				—				—				—				(4,488)
Retained earnings			5,191				(22)				14				(8)				5,175
Accumulated other comprehensive loss			(550)				—				—				—				(550)
Total L-3 shareholders’ equity			5,467				(22)				14				(8)				5,451
Noncontrolling interests			76				—				—				—				76
Total equity			5,543				(22)				14				(8)				5,527
Total liabilities and equity		$	13,791			$	(18)			$	23			$	4			$	13,800
Consolidated Statement of Operations for the year ended December 31, 2013:
Net sales:
Products		$	7,192			$	(11)			$	(7)			$	15			$	7,189
Services			5,437				(28)				—				24				5,433
Total net sales			12,629				(39)				(7)				39				12,622
Cost of sales:
Products			(6,409)				(3)				7				(4)				(6,409)
Services			(4,962)				(18)				—				(21)				(5,001)
Total cost of sales			(11,371)				(21)				7				(25)				(11,410)
Impairment charge			—				—				—				—				—
Operating income			1,258				(60)				—				14				1,212
Interest expense			(177)				—				—				—				(177)
Interest and other income, net			15				—				5				—				20
Debt retirement charge			—				—				—				—				—
Income from continuing operations before income taxes			1,096				(60)				5				14				1,055
Provision for income taxes			(309)				21				(2)				(5)				(295)
Income from continuing operations			787				(39)				3				9				760
Income from discontinued operations, net of income tax			—				—				—				—				—
Net income		$	787			$	(39)			$	3			$	9			$	760
Net income attributable to noncontrolling interests			(9)				—				—				—				(9)
Net income attributable to L-3		$	778			$	(39)			$	3			$	9			$	751
Net income allocable to participating securities			—				—				—				—				—
Net income allocable to L-3 Holdings’ common shareholders		$	778			$	(39)			$	3			$	9			$	751
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.70			$	(0.43)			$	0.03			$	0.10			$	8.40
Discontinued operations			—				—				—				—				—
Basic earnings per share		$	8.70			$	(0.43)			$	0.03			$	0.10			$	8.40
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.54			$	(0.43)			$	0.03			$	0.10			$	8.24
Discontinued operations			—				—				—				—				—
Diluted earnings per share		$	8.54			$	(0.43)			$	0.03			$	0.10			$	8.24
Cash dividends paid per common share		$	2.20			$	—			$	—			$	—			$	2.20
L-3 Holdings’ weighted average common shares outstanding:
Basic			89.4				—				—				—				89.4
Diluted			91.1				—				—				—				91.1
						Adjustments for:
		As				Aerospace				Sales-Type				Out of Period				As
		Previously				Systems				Lease				Amounts				Revised
		Reported				Segment				Transaction
						Internal
						Review
		(in millions, except per share data)
Consolidated Statement of Operations for the year ended December 31, 2012:
Net sales:
Products		$	7,535			$	64			$	—			$	(13)			$	7,586
Services			5,611				(66)				—				(24)				5,521
Total net sales			13,146				(2)				—				-37	(1)			13,107
Cost of sales:
Products			(6,724)				(57)				—				(1)				(6,782)
Services			(5,071)				34				—				20				(5,017)
Total cost of sales			(11,795)				(23)				—				19				(11,799)
Impairment charge			—				—				—				—				—
Operating income			1,351				(25)				—				(18)				1,308
Interest expense			(184)				—				—				—				(184)
Interest and other income, net			8				—				3				—				11
Debt retirement charge			(13)				—				—				—				(13)
Income from continuing operations before income taxes			1,162				(25)				3				(18)				1,122
Provision for income taxes			(374)				9				(1)				6				(360)
Income from continuing operations			788				(16)				2				(12)				762
Income from discontinued operations, net of income tax			32				—				—				—				32
Net income		$	820			$	(16)			$	2			$	(12)			$	794
Net income attributable to noncontrolling interests			(10)				—				—				—				(10)
Net income attributable to L-3		$	810			$	(16)			$	2			$	(12)			$	784
Net income allocable to participating securities			—				—				—				—				—
Net income allocable to L-3 Holdings’ common shareholders		$	810			$	(16)			$	2			$	(12)			$	784
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.12			$	(0.17)			$	0.02			$	(0.12)			$	7.85
Discontinued operations			0.29				—				—				—				0.29
Basic earnings per share		$	8.41			$	(0.17)			$	0.02			$	(0.12)			$	8.14
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.01			$	(0.17)			$	0.02			$	(0.12)			$	7.74
Discontinued operations			0.29				—				—				—				0.29
Diluted earnings per share		$	8.30			$	(0.17)			$	0.02			$	(0.12)			$	8.03
Cash dividends paid per common share		$	2.00			$	—			$	—			$	—			$	2.00
L-3 Holdings’ weighted average common shares outstanding:
Basic			96.3				—				—				—				96.3
Diluted			97.6				—				—				—				97.6
	(1)	Includes rounding of $1 million.
						Adjustments for:
		As				Aerospace				Sales-Type				Out of				As
		Previously				Systems				Lease				Period				Revised
		Reported				Segment				Transaction				Amounts
						Internal
						Review
		(in millions, except per share data)
Consolidated Statement of Operations for the year ended December 31, 2011:
Net sales:
Products		$	7,552			$	—			$	—			$	(3)			$	7,549
Services			5,606				(1)				—				—				5,605
Total net sales			13,158				(1)				—				(3)				13,154
Cost of sales:
Products			(6,673)				—				—				7				(6,666)
Services			(5,043)				(4)				—				—				(5,047)
Total cost of sales			(11,716)				(4)				—				7				(11,713)
Impairment charge			(43)				—				—				—				(43)
Operating income			1,399				(5)				—				4				1,398
Interest expense			(204)				—				—				—				(204)
Interest and other income, net			—				—				3				—				3
Debt retirement charge			(35)				—				—				—				(35)
Income from continuing operations before income taxes			1,160				(5)				3				4				1,162
Provision for income taxes			(296)				2				(1)				(1)				(296)
Income from continuing operations			864				(3)				2				3				866
Income from discontinued operations, net of income tax			104				—				—				—				104
Net income		$	968			$	(3)			$	2			$	3			$	970
Net income attributable to noncontrolling interests			(12)				—				—				—				(12)
Net income attributable to L-3		$	956			$	(3)			$	2			$	3			$	958
Net income allocable to participating securities			(2)				—				—				—				(2)
Net income allocable to L-3 Holdings’ common shareholders		$	954			$	(3)			$	2			$	3			$	956
Basic earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.17			$	(0.03)			$	0.02			$	0.03			$	8.19
Discontinued operations			0.97				—				—				—				0.97
Basic earnings per share		$	9.14			$	(0.03)			$	0.02			$	0.03			$	9.16
Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
Continuing operations		$	8.08			$	(0.03)			$	0.02			$	0.03			$	8.10
Discontinued operations			0.95				—				—				—				0.95
Diluted earnings per share		$	9.03			$	(0.03)			$	0.02			$	0.03			$	9.05
Cash dividends paid per common share		$	1.80			$	—			$	—			$	—			$	1.80
L-3 Holdings’ weighted average common shares outstanding:
Basic			104.4				—				—				—				104.4
Diluted			105.6				—				—				—				105.6
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2013:
Operating activities:
Net income		$	787			$	(27)			$	760
Income from discontinued operations, net of tax			—				—				—
Income from continuing operations			787				(27)				760
Depreciation of property, plant and equipment			166				—				166
Amortization of intangibles and other assets			48				—				48
Deferred income tax provision			48				(6)				42
Stock-based employee compensation expense			59				—				59
Contributions to employee savings plans in L-3 Holdings’ common stock			114				—				114
Amortization of pension and postretirement benefit plans net loss and prior service cost			83				—				83
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			6				—				6
Goodwill impairment charge			—				—				—
Equity in losses of unconsolidated subsidiaries			—				—				—
Other non-cash items			2				—				2
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			(42)				24				(18)
Contracts in process			94				10				104
Inventories			2				—				2
Other assets			(81)				(7)				(88)
Accounts payable, trade			45				(11)				34
Accrued employment costs			(5)				—				(5)
Accrued expenses			(6)				1				(5)
Advance payments and billings in excess of costs incurred			(50)				6				(44)
Income taxes			39				(8)				31
Excess income tax benefits related to share-based payment arrangements			(4)				—				(4)
Other current liabilities			(4)				—				(4)
Pension and postretirement benefits			14				—				14
All other operating activities			(52)				18				(34)
Net cash from operating activities from continuing operations		$	1,263			$	—			$	1,263
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2012:
Operating activities:
Net income		$	820			$	(26)			$	794
Income from discontinued operations, net of tax			(32)				—				(32)
Income from continuing operations			788				(26)				762
Depreciation of property, plant and equipment			170				—				170
Amortization of intangibles and other assets			58				—				58
Deferred income tax provision			112				(15)				97
Stock-based employee compensation expense			59				—				59
Contributions to employee savings plans in L-3 Holdings’ common stock			125				—				125
Amortization of pension and postretirement benefit plans net loss and prior service cost			68				—				68
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			7				—				7
Goodwill impairment charge			—				—				—
Equity in losses of unconsolidated subsidiaries			3				—				3
Other non-cash items			9				—				9
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			147				—				147
Contracts in process			(126)				59				(67)
Inventories			(35)				—				(35)
Other assets			11				(3)				8
Accounts payable, trade			81				11				92
Accrued employment costs			(13)				3				(10)
Accrued expenses			(100)				—				(100)
Advance payments and billings in excess of costs incurred			36				1				37
Income taxes			(48)				1				(47)
Excess income tax benefits related to share-based payment arrangements			(3)				—				(3)
Other current liabilities			(52)				6				(46)
Pension and postretirement benefits			(64)				—				(64)
All other operating activities			(2)				(37)				(39)
Net cash from operating activities from continuing operations		$	1,231			$	—			$	1,231
		As				Net				As
		Previously				Adjustments				Revised
		Reported
		(in millions)
Consolidated Statement of Cash Flows for the year ended December 31, 2011:
Operating activities:
Net income		$	968			$	2			$	970
Income from discontinued operations, net of tax			(104)				—				(104)
Income from continuing operations			864				2				866
Depreciation of property, plant and equipment			167				—				167
Amortization of intangibles and other assets			63				—				63
Deferred income tax provision			124				(1)				123
Stock-based employee compensation expense			57				—				57
Contributions to employee savings plans in L-3 Holdings’ common stock			113				—				113
Amortization of pension and postretirement benefit plans net loss and prior service cost			48				—				48
Amortization of bond discounts and deferred debt issue costs (included in interest expense)			13				—				13
Goodwill impairment charge			43				—				43
Equity in losses of unconsolidated subsidiaries			12				—				12
Other non-cash items			11				—				11
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables			(13)				—				(13)
Contracts in process			(121)				11				(110)
Inventories			(14)				—				(14)
Other assets			(6)				(3)				(9)
Accounts payable, trade			(35)				—				(35)
Accrued employment costs			(23)				—				(23)
Accrued expenses			67				1				68
Advance payments and billings in excess of costs incurred			(39)				—				(39)
Income taxes			(18)				2				(16)
Excess income tax benefits related to share-based payment arrangements			(2)				—				(2)
Other current liabilities			4				(6)				(2)
Pension and postretirement benefits			(83)				—				(83)
All other operating activities			(1)				(6)				(7)
Net cash from operating activities from continuing operations		$	1,231			$	—			$	1,231

Acquisitions_and_Divestures_Ta

Acquisitions and Divestures (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Schedule of Goodwill	'
	The goodwill was assigned to the reportable segments listed below:
	Segment	December 31,
		2013
		(in millions)
	Electronic Systems	$	10
	Communication Systems		9
	Total	$	19
Statement of Operations Data Classified as Discontinued Operations	'
	Engility’s statement of operations data, which has been classified as discontinued operations, is provided in the table below.
		January 1		Year Ended
		to July 17,		December 31,
		2012		2011
		(in millions)
	Product and service revenues	$	911	$	2,011
	Operating income from discontinued operations before income taxes		68		199
	Interest expense allocated to discontinued operations		(14)		(31)
	Income from discontinued operations before income taxes	$	54	$	168
	Income tax expense		(22)		(64)
	Income from discontinued operations, net of income taxes	$	32	$	104
	Net income from discontinued operations attributable to noncontrolling interests		(4)		(3)
	Net income from discontinued operations attributable to L-3	$	28	$	101
Unaudited Pro Forma Statements of Operations Data	'
	The following unaudited pro forma Statements of Operations data presents the combined results of the Company and its business acquisitions completed during the years ended December 31, 2013, 2012 and 2011, assuming that the business acquisitions completed during 2013, 2012 and 2011 had occurred on January 1, 2011.
		Year Ended December 31,
		2013		2012		2011
		(in millions, except per share data)
	Pro forma net sales	$	12,657	$	13,239	$	13,498
	Pro forma income from continuing operations	$	760	$	764	$	883
	Pro forma net income attributable to L-3	$	751	$	786	$	975
	Pro forma diluted earnings per share from continuing operations	$	8.24	$	7.76	$	8.26
	Pro forma diluted earnings per share	$	8.24	$	8.05	$	9.21

Contracts_in_Process_Tables

Contracts in Process (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Components of Contracts in Process	'
	The components of contracts in process are presented in the table below.
		December 31,
		2013		2012
		(in millions)
	Unbilled contract receivables, gross	$	2,502	$	2,802
	Unliquidated progress payments		(1,035)		(1,256)
	Unbilled contract receivables, net		1,467		1,546
	Inventoried contract costs, gross		1,044		1,091
	Unliquidated progress payments		(80)		(127)
	Inventoried contract costs, net		964		964
	Total contracts in process	$	2,431	$	2,510
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 cost of sales by the Company’s U.S. Government contractor businesses for the periods presented.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Amounts included in inventoried contract costs at beginning of the year	$	110	$	91	$	97
	IRAD and B&P costs incurred		296		336		327
	Other G&A costs incurred		893		891		843
	Total contract costs incurred		1,189		1,227		1,170
	Amounts charged to cost of sales		(1,161)		(1,208)		(1,176)
	Amounts included in inventoried contract costs at end of the year	$	138	$	110	$	91
Selling, General and Administrative Expenses and Research and Development Expenses	'
	The table below presents a summary of selling, general and administrative expenses and research and development expenses for the Company’s commercial businesses, which are expensed as incurred and included in cost of sales on the Consolidated Statements of Operations.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Selling, general and administrative expenses	$	293	$	306	$	300
	Research and development expenses		74		88		73
	Total	$	367	$	394	$	373

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
Inventories at Lower of Cost or Market	'
	Inventories at Lower of Cost or Market. The table below presents the components of inventories at the lower of cost (first-in, first-out or average cost) or realizable value.
		December 31,
		2013		2012
		(in millions)
	Raw materials, components and sub-assemblies	$	160	$	166
	Work in process		125		121
	Finished goods		74		71
	Total	$	359	$	358

Goodwill_and_Identifiable_Inta1

Goodwill and Identifiable Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
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.
			Aerospace				Electronic				Communication				NSS				Consolidated
			Systems				Systems				Systems								Total
			(in millions)
	Balance at December 31, 2011		$	1,764			$	3,750			$	992			$	966			$	7,472
	Business acquisitions			—				278				—				—				278
	Foreign currency translation(1)			6				18				—				2				26
	Balance at December 31, 2012		$	1,770			$	4,046			$	992			$	968			$	7,776
	Business acquisition			—				44				—				—				44
	Business disposition			—				(2)				—				—				(2)
	Foreign currency translation(1)			(19)				(3)				—				—				(22)
	Balance at December 31, 2013		$	1,751			$	4,085			$	992			$	968			$	7,796
		(1)	The changes in goodwill from foreign currency translation adjustments are due to fluctuations in the U.S. dollar and foreign currency exchange rates. The decreases in goodwill presented in Electronic Systems and Aerospace Systems segments during 2013 were primarily due to the strengthening of the U.S. dollar against the Canadian dollar and Australian dollar, partially offset by the weakening of the U.S. dollar against the Euro and British pound. Conversely, the increases in goodwill presented in the Electronic Systems, Aerospace Systems and NSS segments during 2012 were due to the weakening of the U.S dollar against the Euro, Canadian dollar and the British pound.
Identifiable Intangible Assets	'
	Information on the Company’s identifiable intangible assets that are subject to amortization is presented in the table below.
			December 31, 2013														December 31, 2012
			Weighted		Gross				Accumulated				Net				Gross				Accumulated		Net
			Average		Carrying				Amortization				Carrying				Carrying				Amortization		Carrying
			Amortization		Amount								Amount				Amount						Amount
			Period
			(in years)						(in millions)
	Customer contractual relationships		19		$	466			$	253			$	213			$	460			$	225	$	235
	Technology		11			168				108				60				164				98		66
	Other		17			27				15				12				27				14		13
	Total		17		$	661			$	376			$	285			$	651			$	337	$	314
Amortization Expense	'
	Amortization expense recorded by the Company for its identifiable intangible assets is presented in the table below.
			Year Ended December 31,
			2013				2012				2011
			(in millions)
	Amortization expense		$	39			$	47			$	54
Estimated Amortization Expense	'
	Based on gross carrying amounts at December 31, 2013, the Company’s estimate of amortization expense for identifiable intangible assets for the years ending December 31, 2014 through 2018 is presented in the table below.
			Year Ending December 31,
			2014				2015				2016				2017				2018
			(in millions)
	Estimated amortization expense		$	43			$	40			$	33			$	31			$	25

Other_Current_Liabilities_and_1

Other Current Liabilities and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Other Current Liabilities	'
	The table below presents the components of other current liabilities.
		December 31,
		2013		2012
		(in millions)
	Other Current Liabilities:
	Accruals for pending and threatened litigation (see Note 20)	$	6	$	7
	Estimated costs in excess of estimated contract value to complete contracts in process in a loss position		78		96
	Accrued product warranty costs		75		76
	Accrued interest		52		53
	Deferred revenues		35		35
	Estimated contingent purchase price payable for acquired businesses		—		4
	Other		137		121
	Total other current liabilities	$	383	$	392
Other Liabilities	'
	The table below presents the components of other liabilities.
		December 31,
		2013		2012
		(in millions)
	Other Liabilities:
	Non-current income taxes payable (see Note 18)	$	177	$	146
	Accrued workers’ compensation		46		57
	Deferred compensation		45		43
	Accrued product warranty costs		24		23
	Notes payable and capital lease obligations		15		24
	Estimated contingent purchase price payable for acquired businesses		—		5
	Other		99		95
	Total other liabilities	$	406	$	393

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	The table below presents the components of Property, Plant and Equipment.
		December 31,
		2013		2012
		(in millions)
	Land	$	62	$	63
	Buildings and improvements		415		407
	Machinery, equipment, furniture and fixtures		1,643		1,532
	Leasehold improvements		328		322
	Gross property, plant and equipment		2,448		2,324
	Accumulated depreciation and amortization		(1,406)		(1,301)
	Property, plant and equipment, net	$	1,042	$	1,023

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Components of Long-Term Debt and Reconciliation to Carrying Amount of Long-Term Debt	'
	The components of long-term debt and a reconciliation to the carrying amount of long-term debt are presented in the table below.
			December 31,
			2013				2012
			(in millions)
	L-3 Communications:
	Borrowings under Amended and Restated Revolving Credit Facility(1)		$	—			$	—
	3.95% Senior Notes due 2016			500				500
	5.20% Senior Notes due 2019			1,000				1,000
	4.75% Senior Notes due 2020			800				800
	4.95% Senior Notes due 2021			650				650
	Subtotal			2,950				2,950
	L-3 Holdings:
	3% Convertible Contingent Debt Securities due 2035			689				689
	Principal amount of long-term debt			3,639				3,639
	Unamortized discounts			(9)				(10)
	Carrying amount of long-term debt		$	3,630			$	3,629
		(1)	During 2013, L-3 Communications’ aggregate borrowings and repayments under the Amended and Restated Revolving Credit Facility were $1,893 million. L-3 Communications had the availability of substantially all of its $1 billion Amended and Restated Revolving Credit Facility at December 31, 2013 and 2012.
Information Regarding Outstanding Senior Subordinated Note	'
	The terms of each outstanding Senior Note are presented in the table below.
	Note		Date of Issuance		Amount				Discount(1)				Net				Effective		Redemption
					Issued								Cash				Interest		at Treasury
													Proceeds				Rate		Rate(2)(3)
					(in millions)
	3.95% Senior Notes due November 15, 2016		November 22, 2011		$	500			$	4			$	491				4.11%		50 bps
	5.20% Senior Notes due October 15, 2019		2-Oct-09		$	1,000			$	4			$	987				5.25%		30 bps
	4.75% Senior Notes due July 15, 2020		21-May-10		$	800			$	3			$	790				4.79%		25 bps
	4.95% Senior Notes due February 15, 2021		7-Feb-11		$	650			$	4			$	639				5.02%		25 bps
		(1)	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 may be redeemed at any time prior to their maturity at the option of L-3 Communications, in whole or in part, at a redemption price equal to the greater of (1) 100% of the principal amount, or (2) 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 Senior Indentures), plus the spread indicated in the table above.
		(3)	Upon the occurrence of a change in control (as defined in the Senior Indentures), each holder of the notes will have the right to require L-3 Communications 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.
Redemptions of Senior Subordinated Notes	'
	Information on the Senior Subordinated Notes redeemed by the Company during the years ended December 31, 2012 and 2011 is presented in the table below.
	Note		Redemption Date				Principal				Debt				Redemption Price
							Amount				Retirement				% of Principal
							Redeemed				Charge
							(in millions)
	6 3⁄8% Senior Subordinated Notes due October 15, 2015			15-Oct-12			$	250			$	5				101.06%
	6 3⁄8% Senior Subordinated Notes due October 15, 2015(1)			26-Jul-12			$	250			$	8				102.13%
	6 3⁄8% Senior Subordinated Notes due October 15, 2015			December 22, 2011			$	500			$	17				102.13%
	5 7⁄8% Senior Subordinated Notes due January 15, 2015			9-Mar-11			$	650			$	18				101.96%
	(1)	In connection with the spin-off, Engility made a cash distribution of $335 million to L-3, a portion of which was used to redeem $250 million of the 6 3⁄8% 2015 Notes.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive (Loss) Income (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Changes in Accumulated Other Comprehensive (Loss) Income Balances, Net of Related Tax Effects	'
	The changes in the accumulated other comprehensive (loss) income (AOCI) balances, net of related tax effects are presented in the table below.
			Foreign		Unrealized		Unrecognized		Total
			currency		gains		(losses) gains and		accumulated
			translation		(losses)		prior service		other
					on hedging		cost, net		comprehensive
					instruments				loss
			(in millions)
	Balance at December 31, 2010		$	161	$	10	$	(427)	$	(256)
	Period change			(28)		(10)		(160)		(198)
	Balance at December 31, 2011		$	133	$	—	$	(587)	$	(454)
	Period change			34		3		(133)		(96)
	Balance at December 31, 2012		$	167	$	3	$	(720)	$	(550)
	Period change			(25)		(2)		467		440
	Balance at December 31, 2013		$	142	$	1	$	(253)	$	(110)
Summary of Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income	'
	The amounts reclassified from AOCI are presented in the table below.
			Foreign		Unrealized		Unrecognized		Total
			currency		gains		(losses) and		accumulated
			translation		(losses) on		prior service		other
					hedging		cost, net		comprehensive
					instruments				(loss) income
			(in millions)
	Balance at December 31, 2012		$	167	$	3	$	(720)	$	(550)
	Other comprehensive (loss) income before reclassifications, net of tax			(25)		(1)		414		388
	Amounts reclassified from other comprehensive (loss) income, net of tax			—		(1)		53		52
	Net current period other comprehensive (loss) income			(25)		(2)		467		440
	Balance at December 31, 2013		$	142	$	1	$	(253)	$	(110)
	Further details regarding the amounts reclassified from AOCI are presented in the table below.
			Amount Reclassified from
			Accumulated
			Other Comprehensive
			(Loss) Income
	Details About Accumulated Other		Year ended December 31,		Affected Line Item in the
	Comprehensive (Loss) Income Components		2013		Audited Consolidated
					Statement of Operations
			(millions)
	Loss on hedging instruments		$	(1)	Cost of sales-products
				(1)	Income from continuing operations before income taxes
				—	Provision for income taxes
			$	(1)	Income from continuing operations
	Amortization of defined benefit pension items:
	Net loss		$	83	(a)
				83	Income from continuing operations before income taxes
				(30)	Provision for income taxes
			$	53	Income from continuing operations
	Total reclassification for the period		$	52	Income from continuing operations
		(a)	Amounts related to pension and postretirement benefit plans were reclassified from AOCI and recorded as a component of net periodic benefit cost (see Note 21 for additional information).

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
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,
			2013						2012
	Description		Level 1(1)		Level 2(2)		Level 3(3)		Level 1(1)		Level 2(2)		Level 3(3)
			(in millions)
	Assets
	Cash equivalents		$	299	$	—	$	—	$	284	$	—	$	—
	Derivatives (foreign currency forward contracts)			—		6		—		—		8		—
	Total assets		$	299	$	6	$	—	$	284	$	8	$	—
	Liabilities
	Derivatives (foreign currency forward contracts)		$	—	$	5	$	—	$	—	$	3	$	—
		(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 Company has no Level 3 assets or liabilities.

Financial_Instruments_Tables

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013				December 31, 2012
			Carrying		Estimated		Carrying		Estimated
			Amount		Fair Value		Amount		Fair Value
			(in millions)
	Senior Notes(1)		$	2,941	$	3,121	$	2,940	$	3,301
	CODES(1)		$	689	$	830	$	689	$	697
	Foreign currency forward contracts(2)		$	1	$	1	$	5	$	5
		(1)	The Company measures the fair value of its Senior Notes and CODES 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 16 for additional disclosures regarding the notional amounts and fair values of foreign currency forward contracts.

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
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 as of December 31, 2013.
	Currency		Notional Amount
			(in millions)
	Canadian dollar		$	137
	U.S. dollar			98
	Euro			66
	British pound			18
	Other			2
	Total		$	321
Fair Values and Location of Company's Derivative Instruments in Consolidated Balance Sheets	'
	The table below presents the fair values and the location of the Company’s derivative instruments in the consolidated balance sheets.
			December 31, 2013								December 31, 2012
			Other		Other		Other		Other		Other		Other		Other		Other
			Current		Assets		Current		Liabilities		Current		Assets		Current		Liabilities
			Assets				Liabilities				Assets				Liabilities
			(in millions)
	Derivatives designated as hedging instruments:
	Foreign currency forward contracts(1)		$	5	$	1	$	3	$	2	$	4	$	4	$	2	$	1
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts(1)			—		—		—		—		—		—		—		—
	Embedded derivative related to the CODES			—		—		—		—		—		—		—		—
	Total derivative instruments		$	5	$	1	$	3	$	2	$	4	$	4	$	2	$	1
		(1)	See Note 14 for a description of the fair value hierarchy related to the Company’s foreign currency forward contracts.

L3_Holdings_Earnings_Per_Share1

L-3 Holdings' Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Reconciliation of Basic and Diluted EPS	'
	A reconciliation of basic and diluted EPS is presented in the table below.
			Year Ended December 31,
			2013		2012		2011
			(in millions, except per share data)
	Reconciliation of net income:
	Net income		$	760	$	794	$	970
	Net income from continuing operations attributable to noncontrolling interests			-9		-6		-9
	Net income from discontinued operations attributable to noncontrolling interests			—		-4		-3
	Net income allocable to participating securities			—		—		-2
	Net income allocable to L-3 Holdings common shareholders		$	751	$	784	$	956
	Earnings allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	751	$	756	$	855
	Discontinued operations, net of income tax			—		28		101
	Net income allocable to L-3 Holdings common shareholders		$	751	$	784	$	956
	Earnings per share allocable to L-3 Holdings’ common shareholders:
	Basic:
	Weighted average common shares outstanding			89.4		96.3		104.4
	Basic earnings per share allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	8.40	$	7.85	$	8.19
	Discontinued operations, net of income tax			—		0.29		0.97
	Basic earnings per share		$	8.40	$	8.14	$	9.16
	Diluted:
	Common and potential common shares:
	Weighted average common shares outstanding			89.4		96.3		104.4
	Assumed exercise of stock options			3.9		1.9		2.0
	Unvested restricted stock awards			1.8		2.0		1.8
	Employee stock purchase plan contributions			0.2		0.3		0.2
	Performance unit awards			0.1		0.1		0.1
	Assumed purchase of common shares for treasury			-4.5		-3		-2.9
	Assumed conversion of the CODES(1)			0.2		—		—
	Common and potential common shares			91.1		97.6		105.6
	Diluted earnings per share allocable to L-3 Holdings’ common shareholders:
	Continuing operations		$	8.24	$	7.74	$	8.10
	Discontinued operations, net of income tax			—		0.29		0.95
	Diluted earnings per share		$	8.24	$	8.03	$	9.05
		(1)	L-3 Holdings’ CODES had no impact on diluted EPS for the years ended December 31, 2012 and 2011 because the average market price of L-3 Holdings’ common stock during these periods was less than the price at which the CODES would have been convertible into L-3 Holdings’ common stock. As of December 31, 2013, 2012 and 2011, the conversion prices were $90.24, $91.21 and $96.48, respectively.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
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,
		2013		2012		2011
		(in millions)
	Domestic	$	858	$	892	$	895
	Foreign		197		230		267
	Income from continuing operations before income taxes	$	1,055	$	1,122	$	1,162
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,
		2013		2012		2011
		(in millions)
	Current income tax provision:
	Federal	$	181	$	198	$	78
	State and local		34		21		26
	Foreign		38		44		69
	Subtotal		253		263		173
	Deferred income tax provision:
	Federal		35		80		95
	State and local		—		8		15
	Foreign		7		9		13
	Subtotal		42		97		123
	Total provision for income taxes	$	295	$	360	$	296
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,
		2013		2012		2011
	Statutory federal income tax rate		35.0%		35.0%	35.0%
	State and local income taxes, net of federal income tax benefit		2.1		1.7	2.3
	Foreign income taxes		(1.6)		(2.0)	(2.6)
	Manufacturing benefits		(1.9)		(1.8)	(1.5)
	Research and experimentation and other tax credits		(3.6)		(0.5)	(1.1)
	Resolution of tax contingencies		(1.0)		(0.9)	(7.7)
	Goodwill impairment		—		—	1.2
	Other, net		(1.0)		0.6	(0.1)
	Effective income tax rate on continuing operations		28.0%		32.1%	25.5%
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,
		2013		2012
		(in millions)
	Deferred tax assets:
	Inventoried costs	$	72	$	33
	Compensation and benefits		164		114
	Pension and postretirement benefits		207		444
	Loss carryforwards		24		20
	Tax credit carryforwards		7		9
	Other		75		48
	Gross deferred tax assets		549		668
	Less: valuation allowance		(22)		(19)
	Net deferred tax assets		527		649
	Deferred tax liabilities:
	Goodwill and other intangible assets	$	726	$	657
	Income recognition on contracts in process		58		56
	Property, plant and equipment		85		71
	Long-term debt-CODES		81		73
	Other		65		7
	Gross deferred tax liabilities		1,015		864
	Total net deferred tax liabilities	$	(488)	$	(215)
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,
		2013		2012
		(in millions)
	Current deferred tax assets	$	147	$	113
	Non-current deferred tax liabilities		(635)		(328)
	Total net deferred tax liabilities	$	(488)	$	(215)
Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Interest and Penalties	'
	A reconciliation of the change in unrecognized income tax benefits, excluding potential interest and penalties, is presented in the table below.
		2013		2012		2011
		(in millions)
	Balance at January 1	$	138	$	150	$	201
	Additions for tax positions related to the current year		18		8		10
	Additions for tax positions related to prior years		41		9		33
	Reductions for tax positions related to prior years		-8		-13		-13
	Reductions for tax positions related to settlements with taxing authorities		—		-1		-5
	Reduction for tax positions related to prior years as a result of a lapse of statute of limitations		-20		-15		-76
	Balance at December 31	$	169	$	138	$	150

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation by Form of Award	'
	The Company’s stock-based compensation by form of award, including stock-based compensation recorded in discontinued operations as a result of the spin-off of Engility, is presented in the table below.
			Year Ended December 31,
			2013		2012		2011
			(in millions)
	Stock options		$	10	$	10	$	11
	Restricted stock units			41		46		48
	Performance units			7		8		5
	Total before income taxes			58		64		64
	Income taxes			-22		-24		-24
	Total after income taxes			36		40		40
	Less: Stock based compensation recorded in discontinued operations, net of income taxes			—		1		4
	Stock based compensation recorded in continuing operations, net of income taxes		$	36	$	39	$	36
Company's Stock Option Activity and Changes	'
	The table below presents a summary of the Company’s stock option activity as of December 31, 2013 and changes during the year then ended.
			Number of		Weighted		Weighted		Aggregate
			Options		Average		Average		Intrinsic
					Exercise		Remaining		Value
					Price		Contractual
							Term
			(in thousands)				(in years)		(in millions)
	Number of shares under option:
	Outstanding at January 1, 2013			4,989.9	$	76.57		5.8	$	23
	Options granted			741.7		77.00
	Options exercised			(1,770.4)		73.24
	Options forfeited			(78.3)		89.93
	Outstanding at December 31, 2013			3,882.9	$	77.90		6.2	$	112
	Vested and expected to vest at December 31, 2013(1)			3,865.9	$	77.91		6.2	$	112
	Exercisable at December 31, 2013			2,420.9	$	80.44		4.9	$	64
		(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.
			2013		2012		2011
			Grants		Grants		Grants
	Expected holding period (in years)			5.6		5.4		5.2
	Expected volatility			26.4%		27.0%		26.4%
	Expected dividend yield			3.6%		3.6%		2.8%
	Risk-free interest rate			1.0%		1.0%		2.2%
			2011
			Grants
	Expected volatility			10.2%
	Expected dividend yield			2.2%
	Risk-free interest rate			0.02%
Company's Nonvested Restricted Stock Unit Awards and Changes	'
	The table below presents a summary of the Company’s nonvested restricted stock unit awards as of December 31, 2013 and changes during the year then ended.
			Number of		Weighted
			Shares		Average
					Grant Date
					Fair Value
			(in thousands)
	Nonvested balance at January 1, 2013			1,729.7	$	75.64
	Granted			606.4		77.12
	Vested			(476.4)		85.81
	Forfeited			(85.9)		73.60
	Nonvested balance at December 31, 2013			1,773.8	$	73.51
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 as of December 31, 2013 and changes during the year then ended.
			Payable in Cash (TSR)				Payable in Shares (EPS)
			Number of		Weighted Average		Number of		Weighted Average
			Units		Grant Date		Units		Grant Date
					Fair Value				Fair Value
			(in thousands)				(in thousands)
	Outstanding at January 1, 2013			59.3	$	106.20		125.6	$	71.86
	Granted			—		—		61.7		77.00
	(Decrease) increase due to expected performance			(33.1)		106.20		59.9		69.04
	Vested			(25.3)		106.20		(67.9)		76.82
	Forfeited			(0.9)		106.20		(3.8)		69.56
	Outstanding at December 31, 2013			—	$	—		175.5	$	70.84

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013.
		Real Estate		Equipment		Total
				(in millions)
	2014	$	145	$	9	$	154
	2015		88		5		93
	2016		72		3		75
	2017		65		1		66
	2018		53		1		54
	Thereafter		110		—		110
	Total minimum payments required		533		19		552
	Less: Sublease rentals under non-cancelable leases		4		—		4
	Net minimum payments required	$	529	$	19	$	548

Pensions_and_Other_Employee_Be1

Pensions and Other Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [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
			2013		2012		2013		2012
			(in millions)
	Change in benefit obligation:
	Benefit obligation at the beginning of the year		$	3,222	$	2,679	$	218	$	216
	Service cost			126		113		4		4
	Interest cost			132		134		7		10
	Plan participants’ contributions			2		2		4		4
	Amendments			14		—		—		(5)
	Obligation assumed in connection with a business acquisition(1)			—		29		—		3
	Actuarial (gain) loss			(402)		358		(23)		(2)
	Foreign currency exchange rate changes			(21)		8		(3)		1
	Curtailments, settlements and special termination benefits			3		3		—		1
	Benefits paid			(103)		(104)		(13)		(14)
	Benefit obligation at the end of the year		$	2,973	$	3,222	$	194	$	218
	Change in plan assets:
	Fair value of plan assets at the beginning of the year		$	2,026	$	1,712	$	47	$	42
	Actual return on plan assets			394		215		9		4
	Assets acquired in connection with a business acquisition(1)			—		29		—		—
	Employer contributions			105		173		8		11
	Plan participants’ contributions			2		2		4		4
	Foreign currency exchange rate changes			(21)		6		—		—
	Transfers(2)			—		(7)		—		—
	Benefits paid			(103)		(104)		(13)		(14)
	Fair value of plan assets at the end of the year		$	2,403	$	2,026	$	55	$	47
	Unfunded status at the end of the year		$	(570)	$	(1,196)	$	(139)	$	(171)
	Assets and (liabilities) recognized in the consolidated balance sheets consist of:
	Non-current assets		$	35	$	9	$	—	$	—
	Current liabilities			(8)		(7)		(9)		(9)
	Non-current liabilities			(597)		(1,198)		(130)		(162)
			$	(570)	$	(1,196)	$	(139)	$	(171)
		(1)	Represents pension and postretirement plan obligations and pension plan assets assumed/acquired during 2012 as part of the L-3 KEO business acquisition.
		(2)	Represents assets related to various supplemental executive retirement plans that had previously been classified as pension plan assets; however, such assets are not held by the plans and are now classified as other assets.
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
			2013		2012		2013		2012
			(in millions)
	Net loss (gain)		$	425	$	1,146	$	(9)	$	21
	Prior service cost (credit)			1		(12)		(8)		(10)
	Total amount recognized		$	426	$	1,134	$	(17)	$	11
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, 2013 and 2012.
			Pension Plans
			2013		2012
			(in millions)
	Projected benefit obligation		$	2,408	$	3,177
	Accumulated benefit obligation			2,115		2,743
	Fair value of plan assets			1,815		1,975
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, 2013 and 2012.
			Pension Plans				Postretirement
							Benefit Plans
			2013		2012		2013		2012
	Benefit obligations:
	Discount rate			5.03%(1)		4.15%(1)		4.43%(2)		3.37%(2)
	Rate of compensation increase			3.50%(3)		3.56%(3)		3.50%(3)		3.59%(3)
		(1)	The weighted average discount rate assumptions used at December 31, 2013 and 2012 were comprised of separate assumptions determined by country of 5.1% and 4.2% for the U.S. based plans, 4.7% and 3.9% for the Canadian based plans and 3.5% and 3.4% for the German based plans.
		(2)	The weighted average discount rate assumptions used at December 31, 2013 and 2012 were comprised of separate assumptions determined by country of 4.4% and 3.3% for the U.S. based plans and 4.6% and 3.7% for the Canadian based plans.
		(3)	The weighted average rate of compensation increase assumptions were comprised of separate assumptions determined by country of 3.5% for the U.S. based plans at both December 31, 2013 and 2012 and 3.5% and 4.0% for the Canadian based plans at December 31, 2013 and 2012.
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, 2013, 2012 and 2011.
			Pension Plans						Postretirement
									Benefit Plans
			2013		2012		2011		2013				2012				2011
			(in millions)
	Components of net periodic benefit cost:
	Service cost		$	126	$	113	$	106	$	4			$	4			$	5
	Interest cost			132		134		128		7				10				10
	Expected return on plan assets			(164)		(145)		(139)		(4)				(3)				(2)
	Amortization of prior service cost (credits)			1		1		1		(3)				(3)				(3)
	Amortization of net loss			83		69		49		2				1				1
	Curtailment or settlement loss			3		7		—		—				1				—
	Net periodic benefit cost		$	181	$	179	$	145	$	6			$	10			$	11
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income	'
	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, 2013, 2012 and 2011.
			Pension Plans						Postretirement
									Benefit Plans
			2013		2012		2011		2013				2012				2011
			(in millions)
	Other changes in plan assets and benefit obligations recognized in other comprehensive income:
	Net (gain) loss		$	(637)	$	287	$	266	$	(29)			$	(3)			$	10
	Prior service cost (credit)			14		(1)		2		—				(5)				—
	Amortization of net loss			(83)		(69)		(49)		(2)				(1)				(1)
	Amortization of prior service (cost) credit			(1)		(1)		(1)		3				3				3
	Total recognized in other comprehensive income			(707)		216		218		(28)				(6)				12
	Total recognized in net periodic benefit cost and other comprehensive income		$	(526)	$	395	$	363	$	(22)			$	4			$	23
Amounts Expected to be Amortized from Accumulated Other Comprehensive Income (Loss) and Recognized as Components of Net Periodic Benefit Costs	'
	The following table summarizes the amounts expected to be amortized from accumulated other comprehensive income (loss) and recognized as components of net periodic benefit costs during 2014.
			Pension		Postretirement		Total
			Plans		Benefit Plans
					(in millions)
	Net loss (gain)		$	17	$	(1)	$	16
	Prior service cost (credit)			2		(2)		—
			$	19	$	(3)	$	16
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, 2013, 2012 and 2011.
			Pension Plans						Postretirement
									Benefit Plans
			2013		2012		2011		2013				2012				2011
	Discount rate			4.15%(1)		5.02%(1)		5.57%(1)		3.37%(4)				4.71%(4)				5.40%(4)
	Expected long-term return on plan assets			8.13%(2)		8.15%(2)		8.57%(2)		7.64%				7.64%				6.20%
	Rate of compensation increase			3.50%(3)		4.06%(3)		4.50%(3)		3.50%				4.09%				4.50%
		(1)	The weighted average discount rate assumptions used for the years ended December 31, 2013, 2012, and 2011 were comprised of separate assumptions determined by country of 4.2%, 5.1% and 5.6% for the U.S. based plans, 3.9%, 4.4% and 5.4% for the Canadian based plans and 3.4%, 5.1%, and 5.4% for the German 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 8.25% for the U.S. based plans for the year ended December 31, 2013, 2012 and 2011 and 7.25% for the year ended December 31, 2013 and 7.5% for the years ended December 31, 2012 and 2011 for the Canadian based plans.
		(3)	The weighted average rate of compensation increase assumptions used for the year ended December 31, 2013 were comprised of separate assumptions determined by country of 3.5% for both the U.S and Canadian based plans. The rate of compensation increase assumptions were 4.0% for the U.S based plans and 4.5% for the Canadian based plans for the year ended December 31, 2012. The rate of compensation increase assumptions were 4.5% for both the U.S. and Canadian based plans for the year ended December 31, 2011.
		(4)	The weighted average discount rate assumptions used for the years ended December 31, 2013, 2012 and 2011 were comprised of separate assumptions determined by country of 3.3%, 4.8% and 5.4% for the U.S. based plans and 3.7%, 4.3% and 5.4% 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		$	1	$	—
	Effect on postretirement benefit obligations			9		(7)
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, 2013 as well as the Company’s pension plan and postretirement benefit plan weighted-average asset allocations at December 31, 2013 and 2012, by asset category.
			U.S.						Canada
	Asset Category		2013 and 2012		2013		2012		2013 Range		2013				2012 Range				2012
			Range
	Domestic equity(1)			30%-60%		54%		51%	10%-25%			20%				15%-30%				19%
	International equity(2)			10%-20%		11		10	30%-60%			49				20%-50%				46
	Fixed income securities			20%-40%		22		29	20%-60%			28				25%-55%				32
	Real estate securities			0%-15%		6		8	—			—				—				—
	Other, primarily cash and cash equivalents			0%-15%		7		2	0%-15%			3				0%-15%				3
	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.
Fair Value of the Company's Pension Plans' and Postretirement Benefit Plans' Assets	'
	The table below presents the fair value of the Company’s pension plans’ assets at December 31, 2013 and 2012, 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										Fair Value Measured at
			December 31, 2013										December 31, 2013
	Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
			(in millions)
	Equity securities(1):
	U.S. Equity		$	1,141	$	—	$	—	$	1,141			$	54			$	18			$	—			$	72
	International Equity			79		146		—		225				117				18				—				135
	Fixed Income — Investment Grade(2)			216		135		—		351				—				82				—				82
	Fixed Income — High Yield(3)			—		118		—		118				—				—				—				—
	Real Estate Investment Trusts(4)			118		—		—		118				—				—				—				—
	Other(5)			—		150		—		150				6				5				—				11
	Total		$	1,554	$	549	$	—	$	2,103			$	177			$	123			$	—			$	300
			Fair Value Measured at										Fair Value Measured at
			December 31, 2012										December 31, 2012
	Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
			(in millions)
	Equity securities(1):
	U.S. Equity		$	893	$	—	$	—	$	893			$	43			$	13			$	—			$	56
	International Equity			67		117		—		184				98				21				—				119
	Fixed Income — Investment Grade(2)			194		197		—		391				—				88				—				88
	Fixed Income — High Yield(3)			—		105		—		105				—				—				—				—
	Real Estate Investment Trusts(4)			138		—		—		138				—				—				—				—
	Other(5)			—		42		—		42				3				7				—				10
	Total		$	1,292	$	461	$	—	$	1,753			$	144			$	129			$	—			$	273
		(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. The Level 2 investment balance is derived from a regulated commingled equity trust fund, which fair value is based on the net asset value (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. Withdrawals are permitted monthly based on NAV.
		(2)	Approximately 62% in 2013 and 50% in 2012 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”). The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. This Fund is 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 38% of U.S. plan assets in 2013 are primarily investment grade corporate bonds from various industries held directly by the Company. 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. The remaining 50% of U.S. plan assets in 2012 and all of the Canadian plan assets for both 2013 and 2012 are invested in regulated commingled equity trust 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 and classified as Level 2. Withdrawals are permitted monthly based on NAV.
		(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) cash equivalents maintained in commingled trust funds, 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.
	The table below presents the fair value of the Company’s postretirement benefit plans’ assets at December 31, 2013 and 2012, by asset category segregated by level within the fair value hierarchy, as described below.
			Postretirement Benefit Plans’ Assets
			Fair Value Measured at										Fair Value Measured at
			December 31, 2013										December 31, 2012
	Asset Category		Level 1		Level 2		Level 3		Total				Level 1				Level 2				Level 3				Total
			(in millions)
	Equity securities(1):
	U.S. Equity		$	23	$	—	$	—	$	23			$	27			$	—			$	—			$	27
	International Equity			1		2		—		3				1				1				—				2
	Fixed Income — Investment Grade(2)			21		2		—		23				11				3				—				14
	Fixed Income — High Yield(3)			—		2		—		2				—				1				—				1
	Real Estate Investment Trusts(4)			2		—		—		2				2				—				—				2
	Other(5)			—		2		—		2				—				1				—				1
	Total		$	47	$	8	$	—	$	55			$	41			$	6			$	—			$	47
		(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. The Level 2 investment balance is derived from 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. Withdrawals are permitted monthly based on NAV.
		(2)	Approximately 91% in 2013 and 79% in 2012 of the postretirement benefit plan assets that are invested in the Fixed Income — Investment Grade asset category consist of a mutual fund offered by the Fund. The Fund invests in investment grade fixed income securities, mortgaged-backed securities, U.S. treasury and agency bonds and corporate bonds. This Fund is 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 9% of postretirement benefit plan assets in 2013 are primarily investment grade corporate bonds from various industries held directly by the Company. 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. The remaining 21% in 2012 of the postretirement benefit plan assets are invested in the Bond Fund. As the Bond Fund does not trade in an active market, the fair value is based on NAV’s calculated by the fund manager 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 classified as Level 2. Withdrawals are permitted monthly based on NAV.
		(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 in real estate, either through properties or mortgages.
		(5)	Other consists primarily of cash equivalents maintained in commingled trust funds, 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.
Estimated Future Benefit Payments	'
	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.
			Pension		Postretirement
			Benefits		Benefits
					Benefit		Subsidy
					Payments		Receipts
			(in millions)
	2014		$	116		13		—
	2015			125		13		—
	2016			134		14		—
	2017			146		14		—
	2018			152		15		—
	Years 2019-2023			925		77		1
Cash Contributions and Expenses under Multi-Employer Benefit Plans	'
	Under these plans, the Company contributed cash and recorded expenses for each of its individually significant plans and all of its other plans in aggregate as noted in the table below.
	Pension Fund		EIN/Pension		Pension				FIP/RP(2)		Contributions by												Surcharge				Expiration
			Plan Number		Protection Act				Status Pending/		L-3 Communications												Imposed				Date of
					Zone				Implemented																		Collective-
					Status(1)																						Bargaining
					2013		2012				2013				2012				2011								Agreement
											(in millions)
	IAM National Pension Fund			51-6031295/002		Green		Green	No		$	21(3)			$	20(4)			$	19(4)				No			2/14/2014 to
																											1/29/2016(5)
	Other Pension Funds(6)											—				—				—
								Total contributions			$	21			$	20			$	19
		(1)	A zone status rating of green indicates the plan is at least 80% funded. The funding status of the IAM National Pension Fund was impacted by a market value investment loss for the plan year ended December 31, 2008, which amortization was extended over five years.
		(2)	Funding improvement plan or rehabilitation plan.
		(3)	At the date the audited financial statements for the Company were issued, Form 5500 for the plan year ending December 31, 2013 was not available.
		(4)	Represents 6% of total plan contributions for both years ended December 31, 2012 and 2011 based on Form 5500.
		(5)	The Company is a party to multiple bargaining agreements for multiple projects that require contributions into the IAM National Pension Fund. The most significant of these agreements, expiring April 27, 2014, cover multiple programs in the Company’s Aerospace Systems reportable segment and represent 72% of 2013 contributions.
		(6)	Consists of three pension funds in which the Company’s contributions are individually, and in the aggregate, insignificant.

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Interest paid on outstanding debt	$	171	$	198	$	238
	Income tax payments		245		332		273
	Income tax refunds		23		22		18

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
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,
			2013		2012		2011
			(in millions)
	Net Sales
	Products
	Aerospace Systems		$	1,827	$	1,755	$	1,579
	Electronic Systems			3,661		3,754		3,862
	Communication Systems			1,755		2,083		2,042
	NSS			71		98		153
	Elimination of intercompany sales			(125)		(104)		(87)
	Total products sales			7,189		7,586		7,549
	Services
	Aerospace Systems			2,730		2,844		2,857
	Electronic Systems			1,054		1,011		928
	Communication Systems			471		445		428
	NSS			1,228		1,292		1,465
	Elimination of intercompany sales			(50)		(71)		(73)
	Total services sales			5,433		5,521		5,605
	Consolidated total		$	12,622	$	13,107	$	13,154
	Operating Income
	Aerospace Systems		$	426	$	437	$	451
	Electronic Systems			533		569		624
	Communication Systems			168		223		265
	NSS			85		79		101
	Segment Total		$	1,212	$	1,308	$	1,441
	Impairment charge(1)			—		—		(43)
	Consolidated total		$	1,212	$	1,308	$	1,398
	Depreciation and amortization
	Aerospace Systems		$	38	$	46	$	44
	Electronic Systems			117		121		124
	Communication Systems			48		47		43
	NSS			11		14		19
	Consolidated total		$	214	$	228	$	230
	Capital Expenditures
	Aerospace Systems		$	54	$	42	$	42
	Electronic Systems			71		77		79
	Communication Systems			59		84		60
	NSS			5		5		5
	Corporate			20		2		1
	Consolidated total		$	209	$	210	$	187
	Total Assets
	Aerospace Systems		$	3,087	$	3,074	$	3,125
	Electronic Systems			6,928		6,792		6,607
	Communication Systems			2,130		2,179		1,783
	NSS			1,247		1,228		1,317
	Corporate			596		527		959
	Assets of discontinued operations			—		—		1,729
	Consolidated total		$	13,988	$	13,800	$	15,520
		(1)	Represents a non-cash goodwill impairment charge recorded in the fourth quarter of 2011 due to a decline in the estimated fair value of a reporting unit within the Electronic Systems segment.
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,
			2013		2012		2011
			(in millions)
	U.S.		$	9,808	$	10,658	$	11,067
	International:
	United Kingdom			449		360		310
	Canada			357		314		328
	Germany			272		263		243
	Australia			218		222		118
	South Korea			178		125		93
	Saudi Arabia			132		76		41
	Italy			107		116		98
	Other			1,101		973		856
	Total international			2,814		2,449		2,087
	Consolidated		$	12,622	$	13,107	$	13,154
Net Sales to Principal Customers	'
	Net sales to principal customers are summarized in the table below.
			Year Ended December 31,
			2013		2012		2011
			(in millions)
	U.S. Government agencies(1)		$	9,186	$	9,986	$	10,438
	Commercial			1,689		1,658		1,524
	Allied international governments(1)			1,747		1,463		1,192
	Consolidated		$	12,622	$	13,107	$	13,154
		(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.

Employee_Severance_and_Termina1

Employee Severance and Termination Costs (Tables)	12 Months Ended
	Dec. 31, 2013
Restructuring and Related Activities [Abstract]	'
Employee Severance and Other Termination Costs Incurred by Reportable Segment	'
	Employee severance and other termination costs incurred by reportable segment for the years ended December 31, 2013, 2012 and 2011 are presented in the table below.
		Year Ended December 31,
		2013		2012		2011
		(in millions)
	Aerospace Systems	$	2	$	1	$	3
	Electronic Systems		16		13		12
	Communication Systems		11		8		4
	NSS		—		1		1
	Consolidated	$	29	$	23	$	20

Unaudited_Quarterly_Financial_1

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Company's Unaudited Quarterly Results of Operations	'
	Unaudited summarized financial data by quarter for the years ended December 31, 2013 and 2012 is presented in the table below. The Company’s unaudited quarterly results of operations are affected, significantly in some periods, by our business acquisitions. See Note 5.
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter
			(in millions, except per share data)
	2013
	Sales		$	3,197	$	3,189	$	3,002	$	3,234
	Operating income			310		290		306		306
	Income from continuing operations			192		176		204		188
	Net income attributable to L-3			191		175		200		185
	Basic EPS(1) (2)			2.12		1.95		2.23		2.10
	Diluted EPS(1) (2)			2.09		1.92		2.19		2.04
	2012
	Sales		$	3,160	$	3,143	$	3,284	$	3,520
	Operating income			322		328		319		339
	Income from continuing operations			186		189		188		199
	Net income attributable to L-3			200		203		185		196
	Basic EPS from continuing operations(1)			1.88		1.93		1.94		2.11
	Diluted EPS from continuing operations(1)			1.86		1.91		1.91		2.08
	Basic EPS(1)			2.02		2.09		1.93		2.11
	Diluted EPS(1)			2.00		2.06		1.90		2.08
		(1)	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.
		(2)	EPS and EPS from continuing operations are the same in 2013.

Financial_Information_of_L3_Co1

Financial Information of L-3 Communications and Its Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Condensed Combining Statements of Equity	'
	The table below presents information regarding the balances and changes in common stock, additional paid-in capital, treasury stock and retained earnings of L-3 Communications for each of the three years ended December 31, 2013.
		L-3				Additional		Treasury		Retained		Accumulated		Total
		Communications				Paid-in		Stock		Earnings		Other
		Common Stock				Capital						Comprehensive
												(Loss)
		Shares		Par								Income
		Issued		Value
				(in millions, except shares issued)
	Balance at December 31, 2010		100	$	—	$	4,801	$	—	$	2,226	$	(256)	$	6,771
	Net income attributable to L-3		—		—		—		—		958		—		958
	Contributions from L-3 Holdings		—		—		263		—		—		—		263
	Dividends to L-3 Holdings		—		—		—		—		(1,157)		—		(1,157)
	Comprehensive loss		—		—		—		—		—		(198)		(198)
	Other		—		—		—		—		7		—		7
	Balance at December 31, 2011		100	$	—	$	5,064	$	—	$	2,034	$	(454)	$	6,644
	Net income attributable to L-3		—		—		—		—		784		—		784
	Contributions from L-3 Holdings		—		—		250		—		—		—		250
	Dividends to L-3 Holdings		—		—		—		—		(1,064)		—		(1,064)
	Comprehensive loss		—		—		—		—		—		(96)		(96)
	Net change of equity due to spin-off of Engility		—		—		—		—		(1,063)		—		(1,063)
	Other		—		—		—		—		(4)		—		(4)
	Balance at December 31, 2012		100	$	—	$	5,314	$	—	$	687	$	(550)	$	5,451
	Net income attributable to L-3		—		—		—		—		751		—		751
	Contributions from L-3 Holdings		—		—		339		—		—		—		339
	Dividends to L-3 Holdings		—		—		—		—		(997)		—		(997)
	Comprehensive gain		—		—		—		—		—		440		440
	Other		—		—		—		—		(3)		—		(3)
	Balance at December 31, 2013		100	$	—	$	5,653	$	—	$	438	$	(110)	$	5,981
Condensed Combining Balance Sheets	'
	The following condensed combining financial information presents the results of operations, financial position and cash flows of (1) L-3 Holdings, excluding L-3 Communications and its consolidated subsidiaries (the “Parent”), (2) L-3 Communications, excluding its consolidated subsidiaries, (3) the Guarantor Subsidiaries, (4) the Non-Guarantor Subsidiaries and (5) the eliminations to arrive at the information for L-3 on a consolidated basis.
		L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
		Holdings		Communications		Subsidiaries		Guarantor				L-3
		(Parent)						Subsidiaries
		(in millions)
	Condensed Combining Balance Sheets:
	At December 31, 2013:
	Current assets:
	Cash and cash equivalents	$	—	$	258	$	—	$	261	$	-19	$	500
	Billed receivables, net		—		364		401		226		—		991
	Contracts in process		—		925		1,152		354		—		2,431
	Other current assets		—		344		159		169		—		672
	Total current assets		—		1,891		1,712		1,010		-19		4,594
	Goodwill		—		2,307		4,326		1,163		—		7,796
	Other assets		—		838		532		228		—		1,598
	Investment in and amounts due from consolidated subsidiaries		6,670		6,940		3,744		—		-17,354		—
	Total assets	$	6,670	$	11,976	$	10,314	$	2,401	$	-17,373	$	13,988
	Current liabilities	$	—	$	914	$	1,011	$	628	$	-19	$	2,534
	Amounts due to consolidated subsidiaries		—		—		—		270		-270		—
	Other long-term liabilities		—		1,451		193		124		—		1,768
	Long-term debt		689		3,630		—		—		-689		3,630
	Total liabilities		689		5,995		1,204		1,022		-978		7,932
	L-3 shareholders’ equity		5,981		5,981		9,110		1,379		-16,470		5,981
	Noncontrolling interests		—		—		—		—		75		75
	Total equity		5,981		5,981		9,110		1,379		-16,395		6,056
	Total liabilities and equity	$	6,670	$	11,976	$	10,314	$	2,401	$	-17,373	$	13,988
	At December 31, 2012:
	Current assets:
	Cash and cash equivalents	$	—	$	246	$	—	$	242	$	-139	$	349
	Billed receivables, net		—		290		441		237		—		968
	Contracts in process		—		893		1,275		342		—		2,510
	Other current assets		—		308		161		188		—		657
	Total current assets		—		1,737		1,877		1,009		-139		4,484
	Goodwill		—		2,010		4,627		1,139		—		7,776
	Other assets		—		757		572		211		—		1,540
	Investment in and amounts due from consolidated subsidiaries		6,140		7,153		3,299		101		-16,693		—
	Total assets	$	6,140	$	11,657	$	10,375	$	2,460	$	-16,832	$	13,800
	Current liabilities	$	—	$	823	$	1,221	$	658	$	-139	$	2,563
	Other long-term liabilities		—		1,754		210		117		—		2,081
	Long-term debt		689		3,629		—		—		-689		3,629
	Total liabilities		689		6,206		1,431		775		-828		8,273
	L-3 shareholders’ equity		5,451		5,451		8,944		1,685		-16,080		5,451
	Noncontrolling interests		—		—		—		—		76		76
	Total equity		5,451		5,451		8,944		1,685		-16,004		5,527
	Total liabilities and equity	$	6,140	$	11,657	$	10,375	$	2,460	$	-16,832	$	13,800
Condensed Combining Statements of Operations	'
	Condensed Combining Statements of Operations:
	For the year ended December 31, 2013:
	Net sales	$	—	$	3,842	$	6,804	$	2,363	$	-387	$	12,622
	Cost of sales		-59		-3,549		-6,139		-2,109		446		-11,410
	Operating (loss) income		-59		293		665		254		59		1,212
	Interest expense		-21		-176		—		-1		21		-177
	Interest and other income (expense), net		—		15		—		5		—		20
	(Loss) income from continuing operations before income taxes		-80		132		665		258		80		1,055
	Benefit (provision) for income taxes		22		-38		-184		-73		-22		-295
	Equity in net income of consolidated subsidiaries		809		657		—		—		-1,466		—
	Net income		751		751		481		185		-1,408		760
	Net income attributable to noncontrolling interests		—		—		—		—		-9		-9
	Net income attributable to L-3	$	751	$	751	$	481	$	185	$	-1,417	$	751
	Comprehensive income attributable to L-3	$	1,191	$	1,191	$	480	$	159	$	-1,830	$	1,191
	For the year ended December 31, 2012:
	Net sales	$	—	$	3,737	$	7,475	$	2,278	$	-383	$	13,107
	Cost of sales		-59		-3,434		-6,749		-1,999		442		-11,799
	Operating (loss) income		-59		303		726		279		59		1,308
	Interest expense		-21		-183		—		-1		21		-184
	Interest and other income (expense), net		—		14		-5		2		—		11
	Debt retirement charge		—		-13		—		—		—		-13
	(Loss) income from continuing operations before income taxes		-80		121		721		280		80		1,122
	Benefit (provision) for income taxes		26		-37		-230		-93		-26		-360
	Equity in net income of consolidated subsidiaries		838		668		—		—		-1,506		—
	Income from continuing operations		784		752		491		187		-1,452		762
	Income from discontinued operations, net of income tax		—		32		—		—		—		32
	Net income		784		784		491		187		-1,452		794
	Net income attributable to noncontrolling interests		—		—		—		—		-10		-10
	Net income attributable to L-3	$	784	$	784	$	491	$	187	$	-1,462	$	784
	Comprehensive income attributable to L-3	$	688	$	688	$	493	$	215	$	-1,396	$	688
	For the year ended December 31, 2011:
	Net sales	$	—	$	3,735	$	7,572	$	2,187	$	(340)	$	13,154
	Cost of sales		(57)		(3,335)		(6,857)		(1,861)		397		(11,713)
	Impairment charge		—		(43)		—		—		—		(43)
	Operating (loss) income		(57)		357		715		326		57		1,398
	Interest expense		(23)		(201)		(1)		(5)		26		(204)
	Interest and other income (expense), net		—		17		(15)		4		(3)		3
	Debt retirement charge		—		(35)		—		—		—		(35)
	(Loss) income from continuing operations before income taxes		(80)		138		699		325		80		1,162
	Benefit (provision) for income taxes		20		(35)		(178)		(83)		(20)		(296)
	Equity in net income of consolidated subsidiaries		1,018		751		—		—		(1,769)		—
	Income from continuing operations		958		854		521		242		(1,709)		866
	Income from discontinued operations, net of income tax		—		104		—		—		—		104
	Net income		958		958		521		242		(1,709)		970
	Net income attributable to noncontrolling interests		—		—		—		—		(12)		(12)
	Net income attributable to L-3	$	958	$	958	$	521	$	242	$	(1,721)	$	958
	Comprehensive income attributable to L-3	$	760	$	760	$	511	$	221	$	(1,492)	$	760
Condensed Combining Statements of Cash Flows	'
		L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
		Holdings		Communications		Subsidiaries		Guarantor				L-3
		(Parent)						Subsidiaries
		(in millions)
	Condensed Combining Statements of Cash Flows: For the year ended December 31, 2013:
	Operating activities:
	Net cash from operating activities	$	999	$	437	$	776	$	231	$	(1,180)	$	1,263
	Investing activities:
	Business acquisitions, net of cash acquired		—		(62)		—		—		—		(62)
	Investments in L-3 Communications		-149		—		—		—		149		—
	Other investing activities		—		(88)		(89)		(22)		—		(199)
	Net cash used in investing activities		-149		(150)		(89)		(22)		149		(261)
	Financing activities:
	Common stock repurchased		-800		—		—		—		—		(800)
	Dividends paid on L-3 Holdings common stock		-199		—		—		—		—		(199)
	Dividends paid to L-3 Holdings		—		(999)		—		—		999		—
	Investments from L-3 Holdings		—		149		—		—		(149)		—
	Other financing activities		149		575		(687)		(188)		301		150
	Net cash used in financing activities		-850		(275)		(687)		(188)		1,151		(849)
	Effect of foreign currency exchange rate changes on cash		—		—		—		(2)		—		(2)
	Net (decrease) increase in cash		—		12		—		19		120		151
	Cash and cash equivalents, beginning of the year		—		246		—		242		(139)		349
	Cash and cash equivalents, end of the year	$	—	$	258	$	—	$	261	$	(19)	$	500
	For the year ended December 31, 2012:
	Operating activities:
	Net cash from operating activities from continuing operations	$	1,067	$	252	$	858	$	265	$	(1,211)	$	1,231
	Investing activities:
	Business acquisitions, net of cash acquired		—		(348)		—		—		—		(348)
	Investments in L-3 Communications		-42		—		—		—		42		—
	Other investing activities		—		225		(59)		(18)		—		148
	Net cash used in investing activities from continuing operations		-42		(123)		(59)		(18)		42		(200)
	Financing activities:
	Redemption of senior subordinated notes		—		(500)		—		—		—		(500)
	Common stock repurchased		-872		—		—		—		—		(872)
	Dividends paid on L-3 Holdings common stock		-195		—		—		—		—		(195)
	Dividends paid to L-3 Holdings		—		(1,067)		—		—		1,067		—
	Investments from L-3 Holdings		—		42		—		—		(42)		—
	Other financing activities		42		924		(799)		(234)		107		40
	Net cash used in financing activities from continuing operations		-1,025		(601)		(799)		(234)		1,132		(1,527)
	Effect of foreign currency exchange rate changes on cash		—		—		—		7		—		7
	Net increase in cash and cash equivalents of discontinued operations		—		74		—		—		—		74
	Net (decrease) increase in cash		—		(398)		—		20		(37)		(415)
	Cash and cash equivalents, beginning of the year		—		644		—		222		(102)		764
	Cash and cash equivalents, end of the year	$	—	$	246	$	—	$	242	$	(139)	$	349
		L-3		L-3		Guarantor		Non-		Eliminations		Consolidated
		Holdings		Communications		Subsidiaries		Guarantor				L-3
		(Parent)						Subsidiaries
		(in millions)
	For the year ended December 31, 2011:
	Operating activities:
	Net cash from operating activities from continuing operations	$	1,157	$	476	$	792	$	220	$	(1,414)	$	1,231
	Investing activities:
	Business acquisitions, net of cash acquired		—		(20)		—		—		—		(20)
	Investments in L-3 Communications		(55)		—		—		—		55		—
	Other investing activities		—		(84)		(75)		(20)		—		(179)
	Net cash used in investing activities from continuing operations		(55)		(104)		(75)		(20)		55		(199)
	Financing activities:
	Proceeds from sale of senior notes		—		1,143		—		—		—		1,143
	Redemption of senior subordinated notes and CODES		(11)		(1,150)		—		—		—		(1,161)
	Common stock repurchased		(958)		—		—		—		—		(958)
	Dividends paid on L-3 Holdings common stock		(188)		—		—		—		—		(188)
	Dividends paid to L-3 Holdings		—		(1,157)		—		—		1,157		—
	Investments from L-3 Holdings		—		55		—		—		(55)		—
Other financing activities		55		882		(717)		(447)		272		45
Net cash used in financing activities from continuing operations		(1,102)		(227)		(717)		(447)		1,374		(1,119)
Effect of foreign currency exchange rate changes on cash		—		—		—		(4)		—		(4)
Net increase in cash and cash equivalents of discontinued operations		—		248		—		—		—		248
Net (decrease) increase in cash		—		393		—		(251)		15		157
Cash and cash equivalents, beginning of the year		—		251		—		473		(117)		607
Cash and cash equivalents, end of the year	$	—	$	644	$	—	$	222	$	(102)	$	764

Description_of_Business_Additi

Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013
	Segment
Disclosure Description Of Business Additional Information [Abstract]	'
Number of segments	4

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Percentage of sales accounted for under contract accounting standards	47.00%	'	'
Percentage of fixed-price type contracts	38.00%	'	'
Percentage of cost-plus type contracts	9.00%	'	'
Increase in operating income due to changes in contract estimates	$114	$72	$73
Percentage of increase in operating income due to changes in contract estimates	9.00%	6.00%	5.00%
Period of performance for contracts accounted for under the percentage-of-completion method of accounting, minimum	'1 year	'	'
Goodwill impairment charges	'	'	$43
Minimum [Member] | Buildings and Improvements [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Property, plant and equipment, estimated useful life	'10 years	'	'
Minimum [Member] | Machinery, Equipment, Furniture and Fixtures [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Property, plant and equipment, estimated useful life	'3 years	'	'
Maximum [Member] | Buildings and Improvements [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Property, plant and equipment, estimated useful life	'40 years	'	'
Maximum [Member] | Machinery, Equipment, Furniture and Fixtures [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Property, plant and equipment, estimated useful life	'10 years	'	'
CODES Due 2035 [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Interest rate on debt instruments	3.00%	'	'
Debt instruments, maturity year	'2035	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Changes in Company's Accrued Product Warranty Costs (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accrued product warranty costs:	'	'
Balance at January 1	$99	$94
Acquisitions during this period	2	7
Accruals for product warranties issued during the period	71	78
Changes to accruals for product warranties existing before January 1	3	-3
Foreign currency translation adjustments	'	1
Settlements made during the period	-76	-78
Balance at December 31	$99	$99

Revisions_to_Previously_Issued2

Revisions to Previously Issued Financial Statements - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in Accounting Estimate [Line Items]	'	'	'
Aggregate pre-tax charge as a result of internal review	$1,055	$1,122	$1,162
Sales-Type Lease Transaction [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Lease period	'The period of performance under this contract began in 2004 and ends in 2023.	'	'
Increase in interest income	5	3	3
Decrease in sales	-7	'	'
Decrease in cost of sales	-7	'	'
Aerospace Systems [Member] | Total Internal Review of Aerospace Systems Segment [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Aggregate pre-tax charge as a result of internal review	-60	-25	-5
Aerospace Systems [Member] | Logistics Solutions [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Cumulative aggregate adjustments	-82	'	'
Aerospace Systems [Member] | Platform Systems [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Cumulative aggregate adjustments	-12	'	'
Cumulative aggregate adjustments losses	2	'	'
Adjustment description	'The Platform Systems sector adjustments are primarily due to (1) losses on two aircraft modification contracts and two contracts for rotary wing sub-assemblies and parts, and (2) write-offs of deferred costs to design, test and supply aerostructures for a new commercial aircraft.	'	'
Write-offs of deferred costs	10	'	'
Aerospace Systems [Member] | Army C-12 Contract [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Cumulative aggregate adjustments losses	54	'	'
Aerospace Systems [Member] | Other Logistics Support Contracts [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Cumulative aggregate adjustments losses	28	'	'
Prior to 2011 [Member] | Sales-Type Lease Transaction [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Increase in interest income	12	'	'
Decrease in cost of sales	-5	'	'
Prior to 2011 [Member] | Aerospace Systems [Member] | Total Internal Review of Aerospace Systems Segment [Member]	'	'	'
Change in Accounting Estimate [Line Items]	'	'	'
Aggregate pre-tax charge as a result of internal review	'	'	($4)

Revisions_to_Previously_Issued3

Revisions to Previously Issued Financial Statements - Schedule of Nature of Adjustments, Applicable Segment, Amount of Increase (or Decrease) to Sales and Operating Income, Period Recorded and Correct Period (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	$12,622	$13,107	$13,154
Operating income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Out of Period Amounts [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	39	-36	-3
Operating income	'	'	'	'	'	'	'	'	14	-18	4
Out of Period Amounts [Member] | Communication Systems [Member] | Higher Development and Material Costs for Networked Communications Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	10	-10	'
Operating income	'	'	'	'	'	'	'	'	10	-10	'
Out of Period Amounts [Member] | Aerospace Systems [Member] | Sub-Contractor Subscription Deposit [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	26	-26	'
Operating income	'	'	'	'	'	'	'	'	2	-2	'
Out of Period Amounts [Member] | Aerospace Systems [Member] | Costs Accruals for Goods/Services Received [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	5	-5	'
Operating income	'	'	'	'	'	'	'	'	1	-1	'
Out of Period Amounts [Member] | Aerospace Systems [Member] | Unrecorded Liabilities [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	-2	2	'
Operating income	'	'	'	'	'	'	'	'	'	'	'
Out of Period Amounts [Member] | Aerospace Systems [Member] | Accrued Vacation [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	1	-1	'
Out of Period Amounts [Member] | Electronic Systems [Member] | Warranty Reserve [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	'	3	-3
Operating income	'	'	'	'	'	'	'	'	'	-4	4
As Previously Reported [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	12,629	13,146	13,158
Operating income	'	'	'	'	'	'	'	'	1,258	1,351	1,399
As Previously Reported [Member] | Out of Period Amounts [Member] | Communication Systems [Member] | Higher Development and Material Costs for Networked Communications Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'1Q 2013	'	'
As Previously Reported [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Sub-Contractor Subscription Deposit [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2012	'	'
As Previously Reported [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Costs Accruals for Goods/Services Received [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2012	'	'
As Previously Reported [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Unrecorded Liabilities [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'1Q 2013	'	'
As Previously Reported [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Accrued Vacation [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2013	'	'
As Previously Reported [Member] | Out of Period Amounts [Member] | Electronic Systems [Member] | Warranty Reserve [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'3Q 2012	'	'
Restatement Adjustments [Member] | Aerospace Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	-7	-38	-4
Restatement Adjustments [Member] | Out of Period Amounts [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	39	-37	-3
Operating income	'	'	'	'	'	'	'	'	14	-18	4
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Communication Systems [Member] | Higher Development and Material Costs for Networked Communications Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2012	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	$39	($36)	($3)
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Sub-Contractor Subscription Deposit [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'1Q, 2Q, 3Q & Q4 2013	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Costs Accruals for Goods/Services Received [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'1Q 2013	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Unrecorded Liabilities [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2012	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member] | Accrued Vacation [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2012, 1Q, 2Q & 3Q 2013	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Electronic Systems [Member] | Warranty Reserve [Member]	'	'	'	'	'	'	'	'	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Period of adjustment	'	'	'	'	'	'	'	'	'4Q 2011	'	'

Revisions_to_Previously_Issued4

Revisions to Previously Issued Financial Statements - Schedule of Impact on Sales and Pre-tax Income (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	$12,622	$13,107	$13,154
Pre-tax income	1,055	1,122	1,162
Total Internal Review of Aerospace Systems Segment [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Pre-tax income	-60	-25	-5
Out of Period Amounts [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	39	-36	-3
Restatement Adjustments [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-7	-38	-4
Pre-tax income	-41	-40	2
Restatement Adjustments [Member] | Army C-12 Contract [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-25	-3	-1
Pre-tax income	-35	-16	-3
Restatement Adjustments [Member] | Other Logistics Support Contracts [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-2	-2	'
Pre-tax income	-11	-11	-2
Restatement Adjustments [Member] | Logistics Solutions [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-27	-5	-1
Pre-tax income	-46	-27	-5
Restatement Adjustments [Member] | Platform Systems [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-12	3	'
Pre-tax income	-14	2	'
Restatement Adjustments [Member] | Total Internal Review of Aerospace Systems Segment [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-39	-2	-1
Pre-tax income	-60	-25	-5
Restatement Adjustments [Member] | Sales-Type Lease Transaction [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-7	'	'
Pre-tax income	5	3	3
Restatement Adjustments [Member] | Sales-Type Lease Transaction [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-7	'	'
Pre-tax income	5	3	3
Restatement Adjustments [Member] | Out of Period Amounts [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	39	-37	-3
Pre-tax income	14	-18	4
Restatement Adjustments [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	39	-36	-3
Pre-tax income	14	-18	4
Restatement Adjustments [Member] | Prior to 2011 [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-1	'	'
Pre-tax income	13	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Army C-12 Contract [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	'	'	'
Pre-tax income	'	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Other Logistics Support Contracts [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-1	'	'
Pre-tax income	-4	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Logistics Solutions [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-1	'	'
Pre-tax income	-4	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Platform Systems [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	'	'	'
Pre-tax income	'	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Total Internal Review of Aerospace Systems Segment [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	-1	'	'
Pre-tax income	-4	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Sales-Type Lease Transaction [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	'	'	'
Pre-tax income	17	'	'
Restatement Adjustments [Member] | Prior to 2011 [Member] | Out of Period Amounts [Member] | Aerospace Systems [Member]	'	'	'
Quantifying Misstatement in Current Year Financial Statements [Line Items]	'	'	'
Sales	'	'	'
Pre-tax income	'	'	'

Revisions_to_Previously_Issued5

Revisions to Previously Issued Financial Statements - Condensed Combining Balance Sheets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Current assets:	'	'	'	'
Cash and cash equivalents	$500	$349	$764	$607
Billed receivables, net of allowances	991	968	'	'
Contracts in process	2,431	2,510	'	'
Inventories	359	358	'	'
Deferred income taxes	147	113	'	'
Other current assets	166	186	'	'
Total current assets	4,594	4,484	'	'
Property, plant and equipment, net	1,042	1,023	'	'
Goodwill	7,796	7,776	7,472	'
Identifiable intangible assets	285	314	'	'
Deferred debt issue costs	24	29	'	'
Other assets	247	174	'	'
Total assets	13,988	13,800	15,520	'
Current liabilities:	'	'	'	'
Accounts payable, trade	541	505	'	'
Accrued employment costs	545	555	'	'
Accrued expenses	458	469	'	'
Advance payments and billings in excess of costs incurred	576	621	'	'
Income taxes	31	21	'	'
Other current liabilities	383	392	'	'
Total current liabilities	2,534	2,563	'	'
Pension and postretirement benefits	727	1,360	'	'
Deferred income taxes	635	328	'	'
Other liabilities	406	393	'	'
Long-term debt	3,630	3,629	'	'
Total liabilities	7,932	8,273	'	'
L-3 shareholders' equity:	'	'	'	'
L-3 Communications Holdings, Inc.'s common stock	5,653	5,314	'	'
L-3 Communications Holdings, Inc.'s treasury stock at cost	-5,288	-4,488	'	'
Retained earnings	5,726	5,175	'	'
Accumulated other comprehensive loss	-110	-550	-454	-256
Total L-3 shareholders' equity	5,981	5,451	'	'
Noncontrolling interests	75	76	'	'
Total equity	6,056	5,527	6,733	6,862
Total liabilities and equity	13,988	13,800	'	'
As Previously Reported [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	500	349	'	'
Billed receivables, net of allowances	1,015	968	'	'
Contracts in process	2,524	2,597	'	'
Inventories	359	358	'	'
Deferred income taxes	122	95	'	'
Other current assets	129	138	'	'
Total current assets	4,649	4,505	'	'
Property, plant and equipment, net	1,039	1,016	'	'
Goodwill	7,796	7,776	'	'
Identifiable intangible assets	285	314	'	'
Deferred debt issue costs	24	29	'	'
Other assets	216	151	'	'
Total assets	14,009	13,791	'	'
Current liabilities:	'	'	'	'
Accounts payable, trade	541	494	'	'
Accrued employment costs	543	551	'	'
Accrued expenses	455	469	'	'
Advance payments and billings in excess of costs incurred	570	620	'	'
Income taxes	31	21	'	'
Other current liabilities	383	392	'	'
Total current liabilities	2,523	2,547	'	'
Pension and postretirement benefits	727	1,360	'	'
Deferred income taxes	635	328	'	'
Other liabilities	396	384	'	'
Long-term debt	3,630	3,629	'	'
Total liabilities	7,911	8,248	'	'
L-3 shareholders' equity:	'	'	'	'
L-3 Communications Holdings, Inc.'s common stock	5,653	5,314	'	'
L-3 Communications Holdings, Inc.'s treasury stock at cost	-5,288	-4,488	'	'
Retained earnings	5,768	5,191	'	'
Accumulated other comprehensive loss	-110	-550	'	'
Total L-3 shareholders' equity	6,023	5,467	'	'
Noncontrolling interests	75	76	'	'
Total equity	6,098	5,543	'	'
Total liabilities and equity	14,009	13,791	'	'
Restatement Adjustments [Member] | Aerospace Systems Segment Internal Review [Member ]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	'	'	'	'
Billed receivables, net of allowances	-24	'	'	'
Contracts in process	-67	-30	'	'
Inventories	'	'	'	'
Deferred income taxes	25	12	'	'
Other current assets	9	'	'	'
Total current assets	-57	-18	'	'
Property, plant and equipment, net	3	1	'	'
Goodwill	'	'	'	'
Identifiable intangible assets	'	'	'	'
Deferred debt issue costs	'	'	'	'
Other assets	'	'	'	'
Total assets	-54	-17	'	'
Current liabilities:	'	'	'	'
Accounts payable, trade	'	'	'	'
Accrued employment costs	2	2	'	'
Accrued expenses	3	1	'	'
Advance payments and billings in excess of costs incurred	1	1	'	'
Income taxes	'	'	'	'
Other current liabilities	'	'	'	'
Total current liabilities	6	4	'	'
Pension and postretirement benefits	'	'	'	'
Deferred income taxes	'	'	'	'
Other liabilities	'	'	'	'
Long-term debt	'	'	'	'
Total liabilities	6	4	'	'
L-3 shareholders' equity:	'	'	'	'
L-3 Communications Holdings, Inc.'s common stock	'	'	'	'
L-3 Communications Holdings, Inc.'s treasury stock at cost	'	'	'	'
Retained earnings	-60	-22	'	'
Accumulated other comprehensive loss	'	'	'	'
Total L-3 shareholders' equity	-60	-22	'	'
Noncontrolling interests	'	'	'	'
Total equity	-60	-22	'	'
Total liabilities and equity	-54	-18	'	'
Restatement Adjustments [Member] | Sales-Type Lease Transaction [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	'	'	'	'
Billed receivables, net of allowances	'	'	'	'
Contracts in process	-26	-45	'	'
Inventories	'	'	'	'
Deferred income taxes	'	'	'	'
Other current assets	28	45	'	'
Total current assets	2	'	'	'
Property, plant and equipment, net	'	'	'	'
Goodwill	'	'	'	'
Identifiable intangible assets	'	'	'	'
Deferred debt issue costs	'	'	'	'
Other assets	31	23	'	'
Total assets	33	23	'	'
Current liabilities:	'	'	'	'
Accounts payable, trade	'	'	'	'
Accrued employment costs	'	'	'	'
Accrued expenses	'	'	'	'
Advance payments and billings in excess of costs incurred	5	'	'	'
Income taxes	'	'	'	'
Other current liabilities	'	'	'	'
Total current liabilities	5	'	'	'
Pension and postretirement benefits	'	'	'	'
Deferred income taxes	'	'	'	'
Other liabilities	10	9	'	'
Long-term debt	'	'	'	'
Total liabilities	15	9	'	'
L-3 shareholders' equity:	'	'	'	'
L-3 Communications Holdings, Inc.'s common stock	'	'	'	'
L-3 Communications Holdings, Inc.'s treasury stock at cost	'	'	'	'
Retained earnings	17	14	'	'
Accumulated other comprehensive loss	'	'	'	'
Total L-3 shareholders' equity	17	14	'	'
Noncontrolling interests	'	'	'	'
Total equity	17	14	'	'
Total liabilities and equity	32	23	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	'	'	'	'
Billed receivables, net of allowances	'	'	'	'
Contracts in process	'	-12	'	'
Inventories	'	'	'	'
Deferred income taxes	'	6	'	'
Other current assets	'	3	'	'
Total current assets	'	-3	'	'
Property, plant and equipment, net	'	6	'	'
Goodwill	'	'	'	'
Identifiable intangible assets	'	'	'	'
Deferred debt issue costs	'	'	'	'
Other assets	'	'	'	'
Total assets	'	3	'	'
Current liabilities:	'	'	'	'
Accounts payable, trade	'	11	'	'
Accrued employment costs	'	2	'	'
Accrued expenses	'	-1	'	'
Advance payments and billings in excess of costs incurred	'	'	'	'
Income taxes	'	'	'	'
Other current liabilities	'	'	'	'
Total current liabilities	'	12	'	'
Pension and postretirement benefits	'	'	'	'
Deferred income taxes	'	'	'	'
Other liabilities	'	'	'	'
Long-term debt	'	'	'	'
Total liabilities	'	12	'	'
L-3 shareholders' equity:	'	'	'	'
L-3 Communications Holdings, Inc.'s common stock	'	'	'	'
L-3 Communications Holdings, Inc.'s treasury stock at cost	'	'	'	'
Retained earnings	1	-8	'	'
Accumulated other comprehensive loss	'	'	'	'
Total L-3 shareholders' equity	1	-8	'	'
Noncontrolling interests	'	'	'	'
Total equity	1	-8	'	'
Total liabilities and equity	$1	$4	'	'

Revisions_to_Previously_Issued6

Revisions to Previously Issued Financial Statements - Condensed Combining Balance Sheets (Parenthetical) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Accounting Changes and Error Corrections [Abstract]	'	'
Allowances for billed receivables	$26	$33

Revisions_to_Previously_Issued7

Revisions to Previously Issued Financial Statements - Condensed Combining Statements of Operations (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	$7,189	$7,586	$7,549
Services	'	'	'	'	'	'	'	'	5,433	5,521	5,605
Total net sales	'	'	'	'	'	'	'	'	12,622	13,107	13,154
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-6,409	-6,782	-6,666
Services	'	'	'	'	'	'	'	'	-5,001	-5,017	-5,047
Total cost of sales	'	'	'	'	'	'	'	'	-11,410	-11,799	-11,713
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Interest expense	'	'	'	'	'	'	'	'	-177	-184	-204
Interest and other income, net	'	'	'	'	'	'	'	'	20	11	3
Debt retirement charge	'	'	'	'	'	'	'	'	'	-13	-35
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	1,055	1,122	1,162
Provision for income taxes	'	'	'	'	'	'	'	'	-295	-360	-296
Income from continuing operations	188	204	176	192	199	188	189	186	760	762	866
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	32	104
Net income	'	'	'	'	'	'	'	'	760	794	970
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-10	-12
Net income attributable to L-3	185	200	175	191	196	185	203	200	751	784	958
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	-2
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	751	784	956
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.11	$1.94	$1.93	$1.88	$8.40	$7.85	$8.19
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.97
Basic earnings per share	$2.10	$2.23	$1.95	$2.12	$2.11	$1.93	$2.09	$2.02	$8.40	$8.14	$9.16
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.08	$1.91	$1.91	$1.86	$8.24	$7.74	$8.10
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.95
Diluted earnings per share	$2.04	$2.19	$1.92	$2.09	$2.08	$1.90	$2.06	$2	$8.24	$8.03	$9.05
Cash dividends paid per common share	'	'	'	'	'	'	'	'	$2.20	$2	$1.80
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	89.4	96.3	104.4
Diluted	'	'	'	'	'	'	'	'	91.1	97.6	105.6
Out of Period Amounts [Member]	'	'	'	'	'	'	'	'	'	'	'
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Total net sales	'	'	'	'	'	'	'	'	39	-36	-3
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	14	-18	4
As Previously Reported [Member]	'	'	'	'	'	'	'	'	'	'	'
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	7,192	7,535	7,552
Services	'	'	'	'	'	'	'	'	5,437	5,611	5,606
Total net sales	'	'	'	'	'	'	'	'	12,629	13,146	13,158
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-6,409	-6,724	-6,673
Services	'	'	'	'	'	'	'	'	-4,962	-5,071	-5,043
Total cost of sales	'	'	'	'	'	'	'	'	-11,371	-11,795	-11,716
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating income	'	'	'	'	'	'	'	'	1,258	1,351	1,399
Interest expense	'	'	'	'	'	'	'	'	-177	-184	-204
Interest and other income, net	'	'	'	'	'	'	'	'	15	8	'
Debt retirement charge	'	'	'	'	'	'	'	'	'	-13	-35
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	1,096	1,162	1,160
Provision for income taxes	'	'	'	'	'	'	'	'	-309	-374	-296
Income from continuing operations	'	'	'	'	'	'	'	'	787	788	864
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	32	104
Net income	'	'	'	'	'	'	'	'	787	820	968
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-10	-12
Net income attributable to L-3	'	'	'	'	'	'	'	'	778	810	956
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	-2
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	778	810	954
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$8.70	$8.12	$8.17
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.97
Basic earnings per share	'	'	'	'	'	'	'	'	$8.70	$8.41	$9.14
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$8.54	$8.01	$8.08
Discontinued operations	'	'	'	'	'	'	'	'	'	$0.29	$0.95
Diluted earnings per share	'	'	'	'	'	'	'	'	$8.54	$8.30	$9.03
Cash dividends paid per common share	'	'	'	'	'	'	'	'	$2.20	$2	$1.80
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	89.4	96.3	104.4
Diluted	'	'	'	'	'	'	'	'	91.1	97.6	105.6
Restatement Adjustments [Member]	'	'	'	'	'	'	'	'	'	'	'
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	-27	-26	2
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	-27	-26	2
Restatement Adjustments [Member] | Aerospace Systems Segment Internal Review [Member ]	'	'	'	'	'	'	'	'	'	'	'
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-11	64	'
Services	'	'	'	'	'	'	'	'	-28	-66	-1
Total net sales	'	'	'	'	'	'	'	'	-39	-2	-1
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-3	-57	'
Services	'	'	'	'	'	'	'	'	-18	34	-4
Total cost of sales	'	'	'	'	'	'	'	'	-21	-23	-4
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	-60	-25	-5
Interest expense	'	'	'	'	'	'	'	'	'	'	'
Interest and other income, net	'	'	'	'	'	'	'	'	'	'	'
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	-60	-25	-5
Provision for income taxes	'	'	'	'	'	'	'	'	21	9	2
Income from continuing operations	'	'	'	'	'	'	'	'	-39	-16	-3
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	-39	-16	-3
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	-39	-16	-3
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	'
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	-39	-16	-3
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	($0.43)	($0.17)	($0.03)
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per share	'	'	'	'	'	'	'	'	($0.43)	($0.17)	($0.03)
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	($0.43)	($0.17)	($0.03)
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Diluted earnings per share	'	'	'	'	'	'	'	'	($0.43)	($0.17)	($0.03)
Cash dividends paid per common share	'	'	'	'	'	'	'	'	'	'	'
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	'	'	'
Diluted	'	'	'	'	'	'	'	'	'	'	'
Restatement Adjustments [Member] | Sales-Type Lease Transaction [Member]	'	'	'	'	'	'	'	'	'	'	'
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-7	'	'
Services	'	'	'	'	'	'	'	'	'	'	'
Total net sales	'	'	'	'	'	'	'	'	-7	'	'
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	7	'	'
Services	'	'	'	'	'	'	'	'	'	'	'
Total cost of sales	'	'	'	'	'	'	'	'	7	'	'
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	'	'	'
Interest expense	'	'	'	'	'	'	'	'	'	'	'
Interest and other income, net	'	'	'	'	'	'	'	'	5	3	3
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	5	3	3
Provision for income taxes	'	'	'	'	'	'	'	'	-2	-1	-1
Income from continuing operations	'	'	'	'	'	'	'	'	3	2	2
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	3	2	2
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	3	2	2
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	'
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	3	2	2
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$0.03	$0.02	$0.02
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per share	'	'	'	'	'	'	'	'	$0.03	$0.02	$0.02
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$0.03	$0.02	$0.02
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Diluted earnings per share	'	'	'	'	'	'	'	'	$0.03	$0.02	$0.02
Cash dividends paid per common share	'	'	'	'	'	'	'	'	'	'	'
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	'	'	'
Diluted	'	'	'	'	'	'	'	'	'	'	'
Restatement Adjustments [Member] | Out of Period Amounts [Member]	'	'	'	'	'	'	'	'	'	'	'
Net sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	15	-13	-3
Services	'	'	'	'	'	'	'	'	24	-24	'
Total net sales	'	'	'	'	'	'	'	'	39	-37	-3
Cost of sales:	'	'	'	'	'	'	'	'	'	'	'
Products	'	'	'	'	'	'	'	'	-4	-1	7
Services	'	'	'	'	'	'	'	'	-21	20	'
Total cost of sales	'	'	'	'	'	'	'	'	-25	19	7
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	14	-18	4
Interest expense	'	'	'	'	'	'	'	'	'	'	'
Interest and other income, net	'	'	'	'	'	'	'	'	'	'	'
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	14	-18	4
Provision for income taxes	'	'	'	'	'	'	'	'	-5	6	-1
Income from continuing operations	'	'	'	'	'	'	'	'	9	-12	3
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	9	-12	3
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	9	-12	3
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	'
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	$9	($12)	$3
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$0.10	($0.12)	$0.03
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per share	'	'	'	'	'	'	'	'	$0.10	($0.12)	$0.03
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	$0.10	($0.12)	$0.03
Discontinued operations	'	'	'	'	'	'	'	'	'	'	'
Diluted earnings per share	'	'	'	'	'	'	'	'	$0.10	($0.12)	$0.03
Cash dividends paid per common share	'	'	'	'	'	'	'	'	'	'	'
L-3 Holdings' weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	'	'	'
Diluted	'	'	'	'	'	'	'	'	'	'	'

Revisions_to_Previously_Issued8

Revisions to Previously Issued Financial Statements - Condensed Combining Statements of Operations (Parenthetical) (Detail) (Out of Period Amounts [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012
Out of Period Amounts [Member]	'
Revenue rounded off	$1

Revisions_to_Previously_Issued9

Revisions to Previously Issued Financial Statements - Condensed Combining Statements of Cash Flows (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:	'	'	'
Net income	$760	$794	$970
Income from discontinued operations, net of tax	'	-32	-104
Income from continuing operations	760	762	866
Depreciation of property, plant and equipment	166	170	167
Amortization of intangibles and other assets	48	58	63
Deferred income tax provision	42	97	123
Stock-based employee compensation expense	59	59	57
Contributions to employee savings plans in L-3 Holdings' common stock	114	125	113
Amortization of pension and postretirement benefit plans net loss and prior service cost	83	68	48
Amortization of bond discounts and deferred debt issue costs (included in interest expense)	6	7	13
Goodwill impairment charge	'	'	43
Equity in losses of unconsolidated subsidiaries	'	3	12
Other non-cash items	2	9	11
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:	'	'	'
Billed receivables	-18	147	-13
Contracts in process	104	-67	-110
Inventories	2	-35	-14
Other assets	-88	8	-9
Accounts payable, trade	34	92	-35
Accrued employment costs	-5	-10	-23
Accrued expenses	-5	-100	68
Advance payments and billings in excess of costs incurred	-44	37	-39
Income taxes	31	-47	-16
Excess income tax benefits related to share-based payment arrangements	-4	-3	-2
Other current liabilities	-4	-46	-2
Pension and postretirement benefits	14	-64	-83
All other operating activities	-34	-39	-7
Net cash from operating activities from continuing operations	1,263	1,231	1,231
As Previously Reported [Member]	'	'	'
Operating activities:	'	'	'
Net income	787	820	968
Income from discontinued operations, net of tax	'	-32	-104
Income from continuing operations	787	788	864
Depreciation of property, plant and equipment	166	170	167
Amortization of intangibles and other assets	48	58	63
Deferred income tax provision	48	112	124
Stock-based employee compensation expense	59	59	57
Contributions to employee savings plans in L-3 Holdings' common stock	114	125	113
Amortization of pension and postretirement benefit plans net loss and prior service cost	83	68	48
Amortization of bond discounts and deferred debt issue costs (included in interest expense)	6	7	13
Goodwill impairment charge	'	'	43
Equity in losses of unconsolidated subsidiaries	'	3	12
Other non-cash items	2	9	11
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:	'	'	'
Billed receivables	-42	147	-13
Contracts in process	94	-126	-121
Inventories	2	-35	-14
Other assets	-81	11	-6
Accounts payable, trade	45	81	-35
Accrued employment costs	-5	-13	-23
Accrued expenses	-6	-100	67
Advance payments and billings in excess of costs incurred	-50	36	-39
Income taxes	39	-48	-18
Excess income tax benefits related to share-based payment arrangements	-4	-3	-2
Other current liabilities	-4	-52	4
Pension and postretirement benefits	14	-64	-83
All other operating activities	-52	-2	-1
Net cash from operating activities from continuing operations	1,263	1,231	1,231
Restatement Adjustments [Member]	'	'	'
Operating activities:	'	'	'
Net income	-27	-26	2
Income from discontinued operations, net of tax	'	'	'
Income from continuing operations	-27	-26	2
Depreciation of property, plant and equipment	'	'	'
Amortization of intangibles and other assets	'	'	'
Deferred income tax provision	-6	-15	-1
Stock-based employee compensation expense	'	'	'
Contributions to employee savings plans in L-3 Holdings' common stock	'	'	'
Amortization of pension and postretirement benefit plans net loss and prior service cost	'	'	'
Amortization of bond discounts and deferred debt issue costs (included in interest expense)	'	'	'
Goodwill impairment charge	'	'	'
Equity in losses of unconsolidated subsidiaries	'	'	'
Other non-cash items	'	'	'
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:	'	'	'
Billed receivables	24	'	'
Contracts in process	10	59	11
Inventories	'	'	'
Other assets	-7	-3	-3
Accounts payable, trade	-11	11	'
Accrued employment costs	'	3	'
Accrued expenses	1	'	1
Advance payments and billings in excess of costs incurred	6	1	'
Income taxes	-8	1	2
Excess income tax benefits related to share-based payment arrangements	'	'	'
Other current liabilities	'	6	-6
Pension and postretirement benefits	'	'	'
All other operating activities	18	-37	-6
Net cash from operating activities from continuing operations	'	'	'

Acquisitions_and_Divestures_Ad

Acquisitions and Divestures - Additional Information (Detail) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

12 Months Ended

6 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2011

Dec. 19, 2013

Dec. 31, 2012

Dec. 31, 2013

Sep. 27, 2013

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jul. 17, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jul. 26, 2012

Jul. 26, 2012

Dec. 31, 2013

Dec. 31, 2012

Oct. 28, 2011

Business

Microdyne Corporation [Member]

Microdyne Corporation [Member]

2013 Business Acquisition [Member]

2012 Business Acquisitions [Member]

Link U.K. [Member]

Link U.K. [Member]

Link U.K. [Member]

2011 Business Acquisitions [Member]

2011 Business Acquisitions [Member]

Kollmorgen Electro-Optical [Member]

MAVCO, Inc. [Member]

ComHouse [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Engility [Member]

Business

Adjustments to Preliminary Valuations Adjustments [Member]

Adjustments to Preliminary Valuations Adjustments [Member]

Business

6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]

6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]

Cargo Radiation Screening Business of DNI [Member]

Cargo Radiation Screening Business of DNI [Member]

Cargo Radiation Screening Business of DNI [Member]

Acquisitions And Discontinued Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate purchase price of acquisition

'

'

'

'

'

$54

$349

'

'

'

$18

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill deductible for income tax purposes

'

'

'

'

'

44

182

'

'

'

14

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of businesses acquired

3

'

'

'

'

'

3

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount of goodwill recognized

7,796

7,776

7,472

'

'

'

278

'

32

'

19

19

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition date

'

'

'

'

'

'

'

6-Aug-12

'

'

'

'

6-Feb-12

13-Apr-12

1-Jul-11

'

'

'

'

'

'

28-Oct-11

'

'

Other liabilities

'

'

'

'

'

'

'

'

17

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contracts in process

'

'

'

'

'

'

'

'

16

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign currency translation adjustments

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net working capital adjustment

'

'

'

'

'

'

'

'

'

6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum contingent consideration related to acquisition

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10

Fair value of the contingent consideration

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5

2

7

Spin-off date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

17-Jul-12

'

'

'

'

'

'

'

Net cash distribution in connection with spin-off

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

335

'

'

'

'

'

'

Redemption of 6 3/8% Senior Subordinated Notes due 2015

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

250

'

'

'

'

Interest rate on Senior Notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.38%

'

'

'

Distribution Agreement date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16-Jul-12

'

'

'

'

'

'

'

Transaction expenses in connection with the spin-off, before income taxes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

19

9

'

'

'

'

'

Transaction expenses in connection with the spin-off, after income taxes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14

7

'

'

'

'

'

Interest expense for debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14

'

14

31

'

'

'

'

'

Divestiture date

'

'

'

22-Feb-11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount of loss on sale of business

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual revenues from business

'

'

'

'

$8

'

'

'

'

'

'

'

'

'

'

$911

'

'

$2,011

'

'

'

'

'

Acquisitions_and_Divestures_Sc

Acquisitions and Divestures - Schedule of Goodwill (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Goodwill [Line Items]	'	'	'
Goodwill	$7,796	$7,776	$7,472
2011 Business Acquisitions [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	19	'	19
Electronic Systems [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	4,085	4,046	3,750
Electronic Systems [Member] | 2011 Business Acquisitions [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	10	'	'
Communication Systems [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	992	992	992
Communication Systems [Member] | 2011 Business Acquisitions [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	$9	'	'

Acquisitions_and_Divestures_St

Acquisitions and Divestures - Statement of Operations Data Classified as Discontinued Operations (Detail) (USD $)	12 Months Ended			6 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 17, 2012	Dec. 31, 2012	Dec. 31, 2011
				Engility [Member]	Engility [Member]	Engility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'	'
Product and service revenues	'	'	'	$911	'	$2,011
Operating income from discontinued operations before income taxes	'	'	'	68	'	199
Interest expense allocated to discontinued operations	'	'	'	-14	-14	-31
Income from discontinued operations before income taxes	'	'	'	54	'	168
Income tax expense	'	'	'	-22	'	-64
Income from discontinued operations, net of income taxes	'	32	104	32	'	104
Net income from discontinued operations attributable to noncontrolling interests	'	'	'	-4	'	-3
Net income from discontinued operations attributable to L-3	'	$28	$101	$28	'	$101

Acquisitions_and_Divestures_Un

Acquisitions and Divestures - Unaudited Pro Forma Statements of Operations Data (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Combinations [Abstract]	'	'	'
Pro forma net sales	$12,657	$13,239	$13,498
Pro forma income from continuing operations	760	764	883
Pro forma net income attributable to L-3	$751	$786	$975
Pro forma diluted earnings per share from continuing operations	$8.24	$7.76	$8.26
Pro forma diluted earnings per share	$8.24	$8.05	$9.21

Contracts_in_Process_Component

Contracts in Process - Components of Contracts in Process (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Components of contracts in process	'	'
Unbilled contract receivables, gross	$2,502	$2,802
Unliquidated progress payments	-1,035	-1,256
Unbilled contract receivables, net	1,467	1,546
Inventoried contract costs, gross	1,044	1,091
Unliquidated progress payments	-80	-127
Inventoried contract costs, net	964	964
Total contracts in process	$2,431	$2,510

Contracts_in_Process_Additiona

Contracts in Process - Additional Information (Detail)	Dec. 31, 2013
Contractors [Abstract]	'
Percentage of unbilled contract receivables billed and collected within one year	98.00%
Percentage of incurred costs billed, minimum	75.00%
Percentage of incurred costs billed, maximum	80.00%

Contracts_in_Process_General_a

Contracts in Process - General and Administrative, Independent Research and Development and Bid and Proposal Costs (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]	'	'	'
Amounts included in inventoried contract costs at beginning of the year	$110	$91	$97
IRAD and B&P costs incurred	296	336	327
Other G&A costs incurred	893	891	843
Total contract costs incurred	1,189	1,227	1,170
Amounts charged to cost of sales	-1,161	-1,208	-1,176
Amounts included in inventoried contract costs at end of the year	$138	$110	$91

Contracts_in_Process_Selling_G

Contracts in Process - Selling, General and Administrative Expenses and Research and Development Expenses (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]	'	'	'
Selling, general and administrative expenses	$293	$306	$300
Research and development expenses	74	88	73
Total	$367	$394	$373

Inventories_Inventories_at_Low

Inventories - Inventories at Lower of Cost or Market (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Raw materials, components and sub-assemblies	$160	$166
Work in process	125	121
Finished goods	74	71
Total	$359	$358

Goodwill_and_Identifiable_Inta2

Goodwill and Identifiable Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Business
	Employees
Goodwill [Line Items]	'	'	'
Approximate number of employees	48,000	'	'
Increase to goodwill	$44	$278	'
Number of business acquisition	3	'	'
Goodwill impairment charge	'	'	43
Goodwill impairment charge after income taxes	42	'	'
Non-cash impairment charge	43	'	'
Goodwill impairment charge per share	$0.40	'	'
Accumulated goodwill impairment losses	58	58	'
Communication Systems [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Accumulated goodwill impairment losses	15	15	'
Electronic Systems [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Accumulated goodwill impairment losses	$43	$43	'

Goodwill_and_Identifiable_Inta3

Goodwill and Identifiable Intangible Assets - Changes in Goodwill by Segment (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]	'	'
Balance, Beginning	$7,776	$7,472
Business acquisition	44	278
Business disposition	-2	'
Foreign currency translation	-22	26
Balance, Ending	7,796	7,776
Aerospace Systems [Member]	'	'
Goodwill [Line Items]	'	'
Balance, Beginning	1,770	1,764
Business acquisition	'	'
Business disposition	'	'
Foreign currency translation	-19	6
Balance, Ending	1,751	1,770
Electronic Systems [Member]	'	'
Goodwill [Line Items]	'	'
Balance, Beginning	4,046	3,750
Business acquisition	44	278
Business disposition	-2	'
Foreign currency translation	-3	18
Balance, Ending	4,085	4,046
Communication Systems [Member]	'	'
Goodwill [Line Items]	'	'
Balance, Beginning	992	992
Business acquisition	'	'
Business disposition	'	'
Foreign currency translation	'	'
Balance, Ending	992	992
NSS [Member]	'	'
Goodwill [Line Items]	'	'
Balance, Beginning	968	966
Business acquisition	'	'
Business disposition	'	'
Foreign currency translation	'	2
Balance, Ending	$968	$968

Goodwill_and_Identifiable_Inta4

Goodwill and Identifiable Intangible Assets - Identifiable Intangible Assets (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period (in years)	'17 years	'
Gross Carrying Amount	$661	$651
Accumulated Amortization	376	337
Net Carrying Amount	285	314
Customer Contractual Relationships [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period (in years)	'19 years	'
Gross Carrying Amount	466	460
Accumulated Amortization	253	225
Net Carrying Amount	213	235
Technology [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period (in years)	'11 years	'
Gross Carrying Amount	168	164
Accumulated Amortization	108	98
Net Carrying Amount	60	66
Other [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period (in years)	'17 years	'
Gross Carrying Amount	27	27
Accumulated Amortization	15	14
Net Carrying Amount	$12	$13

Goodwill_and_Identifiable_Inta5

Goodwill and Identifiable Intangible Assets - Amortization Expense (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'
Amortization expense	$39	$47	$54

Goodwill_and_Identifiable_Inta6

Goodwill and Identifiable Intangible Assets - Estimated Amortization Expense (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
Estimated amortization expense, 2014	$43
Estimated amortization expense, 2015	40
Estimated amortization expense, 2016	33
Estimated amortization expense, 2017	31
Estimated amortization expense, 2018	$25

Other_Current_Liabilities_and_2

Other Current Liabilities and Other Liabilities - Other Current Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Current Liabilities:	'	'
Accruals for pending and threatened litigation (see Note 20)	$6	$7
Estimated costs in excess of estimated contract value to complete contracts in process in a loss position	78	96
Accrued product warranty costs	75	76
Accrued interest	52	53
Deferred revenues	35	35
Estimated contingent purchase price payable for acquired businesses	'	4
Other	137	121
Total other current liabilities	$383	$392

Other_Current_Liabilities_and_3

Other Current Liabilities and Other Liabilities - Other Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Liabilities:	'	'
Non-current income taxes payable (see Note 18)	$177	$146
Accrued workers' compensation	46	57
Deferred compensation	45	43
Accrued product warranty costs	24	23
Notes payable and capital lease obligations	15	24
Estimated contingent purchase price payable for acquired businesses	'	5
Other	99	95
Total other liabilities	$406	$393

Property_Plant_and_Equipment_P

Property, Plant and Equipment - Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Property, Plant and Equipment [Abstract]	'	'
Land	$62	$63
Buildings and improvements	415	407
Machinery, equipment, furniture and fixtures	1,643	1,532
Leasehold improvements	328	322
Gross property, plant and equipment	2,448	2,324
Accumulated depreciation and amortization	-1,406	-1,301
Property, plant and equipment, net	$1,042	$1,023

Debt_Components_of_LongTerm_De

Debt - Components of Long-Term Debt and Reconciliation to Carrying Amount of Long-Term Debt (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Borrowings under Amended and Restated Revolving Credit Facility	$1	$1
L-3 Communications Corporation [Member]	'	'
Debt Instrument [Line Items]	'	'
Borrowings under Amended and Restated Revolving Credit Facility	'	'
3.95% Senior Notes due 2016	500	500
5.20% Senior Notes due 2019	1,000	1,000
4.75% Senior Notes due 2020	800	800
4.95% Senior Notes due 2021	650	650
Subtotal	2,950	2,950
L-3 Communications Holdings, Inc. [Member]	'	'
Debt Instrument [Line Items]	'	'
3% Convertible Contingent Debt Securities due 2035	689	689
Principal amount of long-term debt	3,639	3,639
Unamortized discounts	-9	-10
Carrying amount of long-term debt	$3,630	$3,629

Debt_Components_of_LongTerm_De1

Debt - Components of Long-Term Debt and Reconciliation to Carrying Amount of Long-Term Debt (Parenthetical) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]	'	'
Aggregate borrowings and requirements for restated revolving credit facility	$1,893,000,000	'
Borrowings under Amended and Restated Revolving Credit Facility	$1,000,000,000	$1,000,000,000
CODES Due 2035 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	3.00%	'
L-3 Communications Corporation [Member] | 3.95% Senior Notes due 2016 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	3.95%	3.95%
L-3 Communications Corporation [Member] | 5.20% Senior Notes due 2019 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	5.20%	5.20%
L-3 Communications Corporation [Member] | 4.75% Senior Notes due 2020 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	4.75%	4.75%
L-3 Communications Corporation [Member] | 4.95% Senior Notes due 2021 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	4.95%	4.95%
L-3 Communications Holdings, Inc. [Member] | CODES Due 2035 [Member]	'	'
Debt Instrument [Line Items]	'	'
Interest rate on Senior Notes	3.00%	3.00%

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)

12 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Feb. 03, 2012

Dec. 31, 2011

Jul. 29, 2005

Feb. 03, 2012

Feb. 03, 2012

Feb. 03, 2012

Feb. 03, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jan. 31, 2011

Dec. 31, 2013

Feb. 02, 2011

Dec. 31, 2013

Dec. 31, 2012

Feb. 03, 2012

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

L-3 Communications Holdings, Inc. [Member]

L-3 Communications Holdings, Inc. [Member]

L-3 Communications Holdings, Inc. [Member]

L-3 Communications Holdings, Inc. [Member]

CODES Due 2035 [Member]

CODES Due 2035 [Member]

CODES Due 2035 [Member]

CODES Due 2035 [Member]

Revolving Credit Facility [Member]

L-3 Communications Holdings, Inc. [Member]

L-3 Communications Holdings, Inc. [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total aggregate borrowings under revolving credit facility

'

'

$1,000,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility expiration date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3-Feb-17

Uncommitted incremental revolving facilities and additional term loan facilities

'

'

500,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Base rate above the latest federal funds rate

'

'

0.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Base rate above a Eurodollar Rate

'

'

1.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Applicable spread on base rate option

'

'

'

'

'

'

0.25%

'

1.00%

'

'

'

'

'

'

'

'

'

Applicable spread on Eurodollar Rate option

'

'

'

'

'

'

1.25%

'

2.00%

'

'

'

'

'

'

'

'

'

Commitment fees calculated on the daily amounts of the available unused commitments

'

'

'

'

'

0.15%

'

0.33%

'

'

'

'

'

'

'

'

'

'

Letter of credit fees for performance and commercial letters of credit

'

'

'

'

'

0.68%

'

1.20%

'

'

'

'

'

'

'

'

'

'

Letter of credit fees for financial letters of credit

'

'

'

'

'

1.25%

'

2.00%

'

'

'

'

'

'

'

'

'

'

Sale of 3% Convertible Contingent Debt Securities by L-3 Holdings

'

'

'

'

700,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate on Senior Notes

'

'

'

'

'

'

'

'

'

'

'

'

'

3.00%

'

3.00%

3.00%

'

Repurchases by the holders of the CODES

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,000,000

'

'

'

Cash redemption price in CODES

'

'

'

'

'

'

'

'

'

'Equal to 100% of the principal amount

'

'

'

'

'

'

'

'

Remaining CODES that have been classified as long-term debt

'

'

'

'

'

'

'

'

'

689,000,000

689,000,000

'

'

'

'

'

'

'

Effective Interest Rate

'

'

'

'

'

'

'

'

'

'

'

'

6.33%

'

'

'

'

'

Interest expense recognized

'

'

'

'

'

'

'

'

'

21,000,000

21,000,000

23,000,000

'

'

'

'

'

'

Carrying amount of the equity component (conversion feature)

64,000,000

64,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion rate of CODES, shares

'

'

'

'

'

'

'

'

'

11.0813

'

'

'

'

'

'

'

'

Conversion price of L-3 Holding CODES

$90.24

$91.21

'

$96.48

'

'

'

'

'

$90.24

'

'

'

'

'

'

'

'

Settlement amount upon conversion of the CODES

'

'

'

'

'

'

'

'

'

1,000

'

'

'

'

'

'

'

'

Excess of current common stock price over common stock conversion price

120.00%

'

'

'

'

'

'

'

'

120.00%

'

'

'

'

'

'

'

'

Current convertible common stock price

$108.29

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$108.29

'

'

Number of trading days for conversion, minimum

'

'

'

'

'

'

'

'

'

'20 days

'

'

'

'

'

'

'

'

Number of consecutive trading-day period ending on the last trading day of the previous fiscal quarter

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

Maximum number of calendar days for purchase of common stock

'45 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of trading days preceding the declaration date for distribution

'10 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage exceeding per share value of the closing price

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of average closing price

98.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of consecutive business-day period

'5 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of consecutive trading-day period

'5 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of trading days in the conversion period

'20 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payment period of contingent interest

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of trading days ending on the second trading day preceding the first day of the applicable six-month interest period

'5 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of average trading price of one thousand dollars in principal amount of CODES for contingent interest payable

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Changes in the fair value of the embedded derivative

0

0

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

Maximum consolidated senior leverage ratio under revolving credit facility covenants

'Less than or equal to 4.0 to 1.0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum consolidated interest coverage ratio under revolving credit facility covenants

'Greater than or equal to 3.0 to 1.0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum consolidated interest coverage ratio under revolving credit facility covenants

'Less than or equal to 3.5 to 1.0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum aggregate amount of indebtedness, swap contracts or guarantees to trigger cross default provisions

50,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum days to cure defaults triggering cross default provisions

'10 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum aggregate principal amount of senior subordinated notes accelerated to trigger cross default provisions

50,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum aggregate amount of senior notes accelerated to trigger cross default provisions

$100,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt_Information_Regarding_Out

Debt - Information Regarding Outstanding Senior Subordinated Note (Detail) (L-3 Communications Corporation [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
3.95% Senior Notes due 2016 [Member]	'
Debt Instrument [Line Items]	'
Date of Issuance	22-Nov-11
Amount Issued	$500
Discount	4
Net Cash Proceeds	491
Effective Interest Rate	4.11%
Redemption at Treasury Rate	0.50%
5.20% Senior Notes due 2019 [Member]	'
Debt Instrument [Line Items]	'
Date of Issuance	2-Oct-09
Amount Issued	1,000
Discount	4
Net Cash Proceeds	987
Effective Interest Rate	5.25%
Redemption at Treasury Rate	0.30%
4.75% Senior Notes due 2020 [Member]	'
Debt Instrument [Line Items]	'
Date of Issuance	21-May-10
Amount Issued	800
Discount	3
Net Cash Proceeds	790
Effective Interest Rate	4.79%
Redemption at Treasury Rate	0.25%
4.95% Senior Notes due 2021 [Member]	'
Debt Instrument [Line Items]	'
Date of Issuance	7-Feb-11
Amount Issued	650
Discount	4
Net Cash Proceeds	$639
Effective Interest Rate	5.02%
Redemption at Treasury Rate	0.25%

Debt_Information_Regarding_Out1

Debt - Information Regarding Outstanding Senior Subordinated Note (Parenthetical) (Detail) (L-3 Communications Corporation [Member])	12 Months Ended
	Dec. 31, 2013
L-3 Communications Corporation [Member]	'
Debt Instrument [Line Items]	'
Redemption price as percentage of principal amount	100.00%
Senior notes redemption price	101.00%

Debt_Redemptions_of_Senior_Sub

Debt - Redemptions of Senior Subordinated Notes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]	'	'	'
Debt retirement charge	'	($13)	($35)
L-3 Communications Corporation [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Debt retirement charge	'	-13	-35
Redemption Price % of Principal	101.00%	'	'
L-3 Communications Corporation [Member] | 6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Redemption Date	15-Oct-12	'	'
Principal Amount Redeemed	250	'	'
Debt retirement charge	5	'	'
Redemption Price % of Principal	101.06%	'	'
L-3 Communications Corporation [Member] | 6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Redemption Date	26-Jul-12	'	'
Principal Amount Redeemed	250	'	'
Debt retirement charge	8	'	'
Redemption Price % of Principal	102.13%	'	'
L-3 Communications Corporation [Member] | 6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Redemption Date	22-Dec-11	'	'
Principal Amount Redeemed	500	'	'
Debt retirement charge	17	'	'
Redemption Price % of Principal	102.13%	'	'
L-3 Communications Corporation [Member] | 5 7/8% Senior Subordinated Notes due January 15, 2015 [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Redemption Date	9-Mar-11	'	'
Principal Amount Redeemed	650	'	'
Debt retirement charge	$18	'	'
Redemption Price % of Principal	101.96%	'	'

Debt_Redemptions_of_Senior_Sub1

Debt - Redemptions of Senior Subordinated Notes (Parenthetical) (Detail) (L-3 Communications Corporation [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Jul. 26, 2012	Jul. 26, 2012	Dec. 31, 2013
		6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]	6 3/8% Senior Subordinated Notes due October 15, 2015 [Member]	5 7/8% Senior Subordinated Notes due January 15, 2015 [Member]
Debt Instrument [Line Items]	'	'	'	'
Net cash distribution in connection with spin-off	$335	'	'	'
Redemption of 6 3/8% Senior Subordinated Notes due 2015	'	$250	'	'
Interest rate on Senior Notes	'	'	6.38%	5.88%

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive (Loss) Income - Changes in Accumulated Other Comprehensive (Loss) Income Balances, Net of Related Tax Effects (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Beginning Balance	($550)	($454)	($256)
Period change	440	-96	-198
Ending Balance	-110	-550	-454
Foreign Currency Translation [Member]	'	'	'
Beginning Balance	167	133	161
Period change	-25	34	-28
Ending Balance	142	167	133
Unrealized Gains (Losses) on Hedging Instruments [Member]	'	'	'
Beginning Balance	3	'	10
Period change	-2	3	-10
Ending Balance	1	3	'
Unrecognized (Losses) Gains and Prior Service Cost, Net [Member]	'	'	'
Beginning Balance	-720	-587	-427
Period change	467	-133	-160
Ending Balance	($253)	($720)	($587)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive (Loss) Income - Summary of Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Beginning Balance	'	'	'	($550)	'	'	'	($454)	($550)	($454)	($256)
Other comprehensive (loss) income before reclassifications, net of tax	'	'	'	'	'	'	'	'	388	'	'
Amounts reclassified from other comprehensive (loss) income, net of tax	'	'	'	'	'	'	'	'	52	'	'
Net current period other comprehensive (loss) income	'	'	'	'	'	'	'	'	440	-96	-198
Ending Balance	-110	'	'	'	-550	'	'	'	-110	-550	-454
Cost of sales-products	'	'	'	'	'	'	'	'	6,409	6,782	6,666
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	1,055	1,122	1,162
Provision for income taxes	'	'	'	'	'	'	'	'	-295	-360	-296
Income from continuing operations	188	204	176	192	199	188	189	186	760	762	866
Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	52	'	'
Foreign Currency Translation [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Beginning Balance	'	'	'	167	'	'	'	133	167	133	161
Other comprehensive (loss) income before reclassifications, net of tax	'	'	'	'	'	'	'	'	-25	'	'
Amounts reclassified from other comprehensive (loss) income, net of tax	'	'	'	'	'	'	'	'	'	'	'
Net current period other comprehensive (loss) income	'	'	'	'	'	'	'	'	-25	34	-28
Ending Balance	142	'	'	'	167	'	'	'	142	167	133
Unrealized Gains (Losses) on Hedging Instruments [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Beginning Balance	'	'	'	3	'	'	'	'	3	'	10
Other comprehensive (loss) income before reclassifications, net of tax	'	'	'	'	'	'	'	'	-1	'	'
Amounts reclassified from other comprehensive (loss) income, net of tax	'	'	'	'	'	'	'	'	-1	'	'
Net current period other comprehensive (loss) income	'	'	'	'	'	'	'	'	-2	3	-10
Ending Balance	1	'	'	'	3	'	'	'	1	3	'
Unrealized Gains (Losses) on Hedging Instruments [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Cost of sales-products	'	'	'	'	'	'	'	'	-1	'	'
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	-1	'	'
Provision for income taxes	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	-1	'	'
Unrecognized (Losses) Gains and Prior Service Cost, Net [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Beginning Balance	'	'	'	-720	'	'	'	-587	-720	-587	-427
Other comprehensive (loss) income before reclassifications, net of tax	'	'	'	'	'	'	'	'	414	'	'
Amounts reclassified from other comprehensive (loss) income, net of tax	'	'	'	'	'	'	'	'	53	'	'
Net current period other comprehensive (loss) income	'	'	'	'	'	'	'	'	467	-133	-160
Ending Balance	-253	'	'	'	-720	'	'	'	-253	-720	-587
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net loss	'	'	'	'	'	'	'	'	83	'	'
Income from continuing operations before income taxes	'	'	'	'	'	'	'	'	83	'	'
Provision for income taxes	'	'	'	'	'	'	'	'	-30	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	$53	'	'

Equity_Additional_Information_

Equity - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended				12 Months Ended	2 Months Ended	12 Months Ended			2 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 05, 2013	Dec. 31, 2013	Feb. 19, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 19, 2014
						February 5, 2013 Share Repurchase Program [Member]	February 5, 2013 Share Repurchase Program [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]
							Subsequent Event [Member]				February 5, 2013 Share Repurchase Program [Member]
											Subsequent Event [Member]
Share repurchase program expired	$1,500	'	'	'	'	'	'	'	'	'	'
Additional amount of shares authorized to be repurchased	'	'	'	'	1,500	'	'	'	'	'	'
Average price per share of repurchased shares	'	$91.95	'	'	'	'	$107.52	'	'	'	'
Number of common shares repurchased	'	'	'	'	'	'	'	8,700,000	12,100,000	13,300,000	928,040
Aggregate amount of repurchased shares	'	800	872	958	'	168	100	'	'	'	'
Shares repurchased	'	'	'	'	'	2,100,000	'	'	'	'	'
Remaining value under share repurchase program	'	'	'	'	'	'	$768	'	'	'	'

Fair_Value_Measurements_Compan

Fair Value Measurements - Company's Assets and Liabilities at Fair Value on Recurring Basis (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Level 1 [Member]	'	'
Assets	'	'
Cash equivalents	$299	$284
Derivatives (foreign currency forward contracts)	'	'
Total assets	299	284
Liabilities	'	'
Derivatives (foreign currency forward contracts)	'	'
Level 2 [Member]	'	'
Assets	'	'
Cash equivalents	'	'
Derivatives (foreign currency forward contracts)	6	8
Total assets	6	8
Liabilities	'	'
Derivatives (foreign currency forward contracts)	5	3
Level 3 [Member]	'	'
Assets	'	'
Cash equivalents	'	'
Derivatives (foreign currency forward contracts)	'	'
Total assets	'	'
Liabilities	'	'
Derivatives (foreign currency forward contracts)	'	'

Financial_Instruments_Carrying

Financial Instruments - Carrying Amounts and Estimated Fair Values of Company's Long-Term Debt and Foreign Currency Forward Contracts (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Senior Notes, Carrying Amount	$2,941	$2,940
CODES, Carrying Amount	689	689
Senior Notes, Estimated Fair Value	3,121	3,301
CODES, Estimated Fair Value	830	697
Estimated Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Foreign currency forward contracts	1	5
Carrying Amount [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Foreign currency forward contracts	$1	$5

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Notional Amounts of Company's Outstanding Foreign Currency Forward Contracts by Currency (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	$321
Canadian Dollar [Member]	'
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	137
U.S. Dollar [Member]	'
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	98
Euro [Member]	'
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	66
British Pound [Member]	'
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	18
Other [Member]	'
Derivative [Line Items]	'
Notional amounts of foreign currency forward contracts	$2

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Fair Values and Location of Company's Derivative Instruments in Consolidated Balance Sheets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Current Liabilities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	$3	$2
Other Current Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	3	2
Other Current Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	'	'
Other Current Liabilities [Member] | CODES Due 2035 [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	'	'
Other Liabilities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	2	1
Other Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	2	1
Other Liabilities [Member] | Foreign Currency Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	'	'
Other Liabilities [Member] | CODES Due 2035 [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, assets	'	'
Other Current Assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	5	4
Other Current Assets [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	5	4
Other Current Assets [Member] | Foreign Currency Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	'	'
Other Current Assets [Member] | CODES Due 2035 [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	'	'
Other Assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	1	4
Other Assets [Member] | Foreign Currency Forward Contracts [Member] | Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	1	4
Other Assets [Member] | Foreign Currency Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	'	'
Other Assets [Member] | CODES Due 2035 [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative instruments, liabilities	'	'

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Additional Information (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Estimated amount of existing losses expected to be reclassified into income within the next 12 months	$1

L3_Holdings_Earnings_Per_Share2

L-3 Holdings' Earnings Per Share - Reconciliation of Basic and Diluted EPS (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of net income:	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	$760	$794	$970
Net income from continuing operations attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-6	-9
Net income from discontinued operations attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	-4	-3
Net income allocable to participating securities	'	'	'	'	'	'	'	'	'	'	-2
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	751	784	956
Earnings allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	'	'	'	'	751	756	855
Discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	28	101
Net income allocable to L-3 Holdings' common shareholders	'	'	'	'	'	'	'	'	$751	$784	$956
Basic:	'	'	'	'	'	'	'	'	'	'	'
Weighted average common shares outstanding	'	'	'	'	'	'	'	'	89.4	96.3	104.4
Basic earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.11	$1.94	$1.93	$1.88	$8.40	$7.85	$8.19
Discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	$0.29	$0.97
Basic earnings per share	$2.10	$2.23	$1.95	$2.12	$2.11	$1.93	$2.09	$2.02	$8.40	$8.14	$9.16
Common and potential common shares:	'	'	'	'	'	'	'	'	'	'	'
Weighted average common shares outstanding	'	'	'	'	'	'	'	'	89.4	96.3	104.4
Assumed purchase of common shares for treasury	'	'	'	'	'	'	'	'	-4.5	-3	-2.9
Assumed conversion of the CODES	'	'	'	'	'	'	'	'	0.2	'	'
Common and potential common shares	'	'	'	'	'	'	'	'	91.1	97.6	105.6
Diluted earnings per share allocable to L-3 Holdings' common shareholders:	'	'	'	'	'	'	'	'	'	'	'
Continuing operations	'	'	'	'	$2.08	$1.91	$1.91	$1.86	$8.24	$7.74	$8.10
Discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	$0.29	$0.95
Diluted earnings per share	$2.04	$2.19	$1.92	$2.09	$2.08	$1.90	$2.06	$2	$8.24	$8.03	$9.05
Stock Options [Member]	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares:	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares	'	'	'	'	'	'	'	'	3.9	1.9	2
Unvested Restricted Stock Awards [Member]	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares:	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares	'	'	'	'	'	'	'	'	1.8	2	1.8
Employee Stock Purchase Plan Contributions [Member]	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares:	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares	'	'	'	'	'	'	'	'	0.2	0.3	0.2
Performance Unit Awards [Member]	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares:	'	'	'	'	'	'	'	'	'	'	'
Common and potential common shares	'	'	'	'	'	'	'	'	0.1	0.1	0.1

L3_Holdings_Earnings_Per_Share3

L-3 Holdings' Earnings Per Share - Reconciliation of Basic and Diluted EPS (Parenthetical) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'
Conversion price of L-3 Holdings' CODES	$90.24	$91.21	$96.48

L3_Holdings_Earnings_Per_Share4

L-3 Holdings' Earnings Per Share - Additional Information (Detail)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'
Shares excluded from computation of diluted earnings per share and employee stock purchase plan contributions	0.9	3.2	3.2

Income_Taxes_Income_from_Conti

Income Taxes - Income from Continuing Operations Before Income Taxes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Domestic	$858	$892	$895
Foreign	197	230	267
Income from continuing operations before income taxes	$1,055	$1,122	$1,162

Income_Taxes_Components_of_Cur

Income Taxes - Components of Current and Deferred Portions of Provision for Income Taxes on Continuing Operations (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current income tax provision:	'	'	'
Federal	$181	$198	$78
State and local	34	21	26
Foreign	38	44	69
Subtotal	253	263	173
Deferred income tax provision:	'	'	'
Federal	35	80	95
State and local	'	8	15
Foreign	7	9	13
Subtotal	42	97	123
Total provision for income taxes	$295	$360	$296

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Statutory Federal Income Tax Rate to Effective Income Tax Rate on Continuing Operations (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Statutory federal income tax rate	35.00%	35.00%	35.00%
State and local income taxes, net of federal income tax benefit	2.10%	1.70%	2.30%
Foreign income taxes	-1.60%	-2.00%	-2.60%
Manufacturing benefits	-1.90%	-1.80%	-1.50%
Research and experimentation and other tax credits	-3.60%	-0.50%	-1.10%
Resolution of tax contingencies	-1.00%	-0.90%	-7.70%
Goodwill impairment	'	'	1.20%
Other, net	-1.00%	0.60%	-0.10%
Effective income tax rate on continuing operations	28.00%	32.10%	25.50%

Income_Taxes_Components_of_Net

Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Deferred tax assets:	'	'
Inventoried costs	$72	$33
Compensation and benefits	164	114
Pension and postretirement benefits	207	444
Loss carryforwards	24	20
Tax credit carryforwards	7	9
Other	75	48
Gross deferred tax assets	549	668
Less: valuation allowance	-22	-19
Net deferred tax assets	527	649
Deferred tax liabilities:	'	'
Goodwill and other intangible assets	726	657
Income recognition on contracts in process	58	56
Property, plant and equipment	85	71
Long-term debt-CODES	81	73
Other	65	7
Gross deferred tax liabilities	1,015	864
Total net deferred tax liabilities	($488)	($215)

Income_Taxes_Classification_of

Income Taxes - Classification of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Current deferred tax assets	$147	$113
Non-current deferred tax liabilities	-635	-328
Total net deferred tax liabilities	($488)	($215)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
					Federal [Member]	Foreign [Member]	State [Member]
Operating Loss Carryforwards [Line Items]	'	'	'	'	'	'	'
Capital loss carryforwards	'	'	$26	'	'	'	'
Deferred tax asset related to capital loss	'	'	9	'	'	'	'
Net operating loss carryforwards	'	'	'	'	6	34	124
Unused net operating loss carryforwards expiration period	'	'	'	'	'Between 2026 and 2030	'	'Between 2016 and 2033
Valuation allowance against deferred tax asset	'	'	10	'	'	'	'
Tax credit carryforwards	'	'	10	'	'	'	'
Expected state net operating losses to be utilized	'	'	72	'	'	'	'
Unrecognized tax benefits	138	150	169	201	'	'	'
Unrecognized tax benefits that would reduce the effective income tax rate	'	'	102	'	'	'	'
Anticipated decrease in unrecognized tax benefit over the next 12 months	'	'	18	'	'	'	'
Change in previously accrued income tax expenses related to tax returns	10	81	10	'	'	'	'
Change in previously accrued income tax expenses related to audit	'	12	'	'	'	'	'
Accrued potential interest included with in current and non-current income taxes payable	11	'	11	'	'	'	'
Accrued potential interest included with in current and non-current income taxes payable after income taxes	6	'	7	'	'	'	'
Potential penalties	7	'	8	'	'	'	'
Expense (benefit) for interest related items included in income taxes expenses	2	6	'	'	'	'	'
Undistributed earnings of non-U.S. Companies	'	'	$325	'	'	'	'

Income_Taxes_Reconciliation_of1

Income Taxes - Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Interest and Penalties (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Balance at January 1	$138	$150	$201
Additions for tax positions related to the current year	18	8	10
Additions for tax positions related to prior years	41	9	33
Reductions for tax positions related to prior years	-8	-13	-13
Reductions for tax positions related to settlements with taxing authorities	'	-1	-5
Reduction for tax positions related to prior years as a result of a lapse of statute of limitations	-20	-15	-76
Balance at December 31	$169	$138	$150

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Jul. 31, 2013

Jan. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Stock

2009 Employee Stock Purchase Plan [Member]

2009 Employee Stock Purchase Plan [Member]

2009 Employee Stock Purchase Plan [Member]

2008 Directors Stock Incentive Plan [Member]

2008 Long Term Performance Plan [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Restricted Stock Units [Member]

Restricted Stock Units [Member]

Restricted Stock Units [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Age

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum number of shares authorized for issuance under the amendment

'

'

'

'

4,600,000

6,500,000

19,200,000

'

'

'

'

'

'

'

'

'

Shares of L-3 Holdings common stock available to be awarded

3.69

2.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum number of shares of L-3 Holdings common stock may be issued pursuant to "full value" awards under the amendment

'

'

'

'

'

'

7,900,000

'

'

'

'

'

'

'

'

'

Engility spin-off adjustments, conversion ratio for the remaining stock options

1.043678

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expiration period of stock options granted from date of grant

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

Vesting period

'

'

'

'

'

'

'

'3 years

'

'

'3 years

'

'

'

'

'

Weighted average grant date fair value of stock options

'

'

'

'

'

'

'

$12.09

$11.32

$15.54

'

'

'

'

'

'

Intrinsic value of stock options exercised

'

'

'

'

'

'

'

$32,000,000

$7,000,000

$8,000,000

'

'

'

'

'

'

Unrecognized compensation costs related to equity awards after income taxes

'

'

'

'

'

'

'

10,000,000

'

'

30,000,000

'

'

4,000,000

'

'

Unrecognized compensation costs related to stock awards

'

'

'

'

'

'

'

6,000,000

'

'

48,000,000

'

'

6,000,000

'

'

Weighted average remaining period for recognition of unrecognized costs related to equity awards

'

'

'

'

'

'

'

'1 year 1 month 6 days

'

'

'1 year 2 months 12 days

'

'

'1 year 4 months 24 days

'

'

Actual income tax benefit realized related to compensation deductions arising from the exercise of stock options

'

'

'

'

'

'

'

10,000,000

2,000,000

3,000,000

'

'

'

'

'

'

Vesting period of units granted for non-employee directors

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

Weighted average grant date fair value

$77.12

'

'

'

'

'

'

'

'

'

$77.12

$70.42

$80.17

$77

$70.43

$95.50

Length of service after grant date

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

'3 years

'3 years

'3 years

Age of retirement eligible employees

'

'

'

'

'

'

'

'

'

'

65

'

'

'

'

'

Length of service for retirement eligible employees, minimum

'

'

'

'

'

'

'

'

'

'

'At least five years

'

'

'

'

'

Fair value of restricted stock unit awards vested

'

'

'

'

'

'

'

'

'

'

37,000,000

44,000,000

35,000,000

'

'

'

Minimum payout range

'

'

'

'

'

'

'

'

'

'

'

'

'

0.00%

'

'

Maximum payout range

'

'

'

'

'

'

'

'

'

'

'

'

'

200.00%

'

'

Total performance units earned

'

'

'

'

'

'

'

'

'

'

'

'

'

93,251

'

'

Fair market value of total performance units earned as of their vesting date

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000,000

'

'

Percentage of fair market value for offering period

'

'

'

'

95.00%

'

'

'

'

'

'

'

'

'

'

'

Term of plans

'

'

'

'

'Eligible employees are offered options to purchase shares of L-3 Holdings' 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.

'

'

'

'

'

'

'

'

'

'

'

Offering period to purchase shares

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

Share purchases funded through payroll deductions up to a maximum percentage

'

'

'

'

10.00%

'

'

'

'

'

'

'

'

'

'

'

Share purchases funded through payroll deductions up to a maximum value

'

'

'

'

$21,250

'

'

'

'

'

'

'

'

'

'

'

Issued shares under the ESPP, shares

'

'

200,000

200,000

'

'

'

'

'

'

'

'

'

'

'

'

Issued shares under the ESPP, per share

'

'

$81.71

$101.55

'

'

'

'

'

'

'

'

'

'

'

'

Employee discount on the purchase of common stock

'

'

'

'

5.00%

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation by Form of Award (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation	$58	$64	$64
Income taxes	-22	-24	-24
Total after income taxes	36	40	40
Less: Stock based compensation recorded in discontinued operations, net of income taxes	'	1	4
Stock based compensation recorded in continuing operations, net of income taxes	36	39	36
Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation	10	10	11
Restricted Stock Units [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation	41	46	48
Performance Units [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation	$7	$8	$5

StockBased_Compensation_Compan

Stock-Based Compensation - Company's Stock Option Activity and Changes (Detail) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'
Beginning Balance, Number of Options Outstanding	4,989,900	'
Options granted, Number of Options	741,700	'
Options exercised, Number of Options	-1,770,400	'
Options forfeited, Number of Options	-78,300	'
Ending Balance, Number of Options Outstanding	3,882,900	4,989,900
Vested and expected to vest, Number of Options	3,865,900	'
Exercisable, Number of Options	2,420,900	'
Beginning Balance, Weighted Average Exercise Price Outstanding	$76.57	'
Options granted, Weighted Average Exercise Price	$77	'
Options exercised, Weighted Average Exercise Price	$73.24	'
Options forfeited, Weighted Average Exercise Price	$89.93	'
Ending Balance, Weighted Average Exercise Price Outstanding	$77.90	$76.57
Vested and expected to vest, Weighted Average Exercise Price	$77.91	'
Exercisable, Weighted Average Exercise Price	$80.44	'
Weighted Average Remaining Contractual Term Outstanding	'6 years 2 months 12 days	'5 years 9 months 18 days
Vested and expected to vest, Weighted Average Remaining Contractual Term	'6 years 2 months 12 days	'
Exercisable, Weighted Average Remaining Contractual Term	'4 years 10 months 24 days	'
Beginning Balance, Aggregate Intrinsic Value Outstanding	$23	'
Ending Balance, Aggregate Intrinsic Value Outstanding	112	23
Vested and expected to vest, Aggregate Intrinsic Value	112	'
Exercisable, Aggregate Intrinsic Value	$64	'

StockBased_Compensation_Weight

Stock-Based Compensation - Weighted Average Assumptions in Valuation Model (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected holding period (in years)	'5 years 7 months 6 days	'5 years 4 months 24 days	'5 years 2 months 12 days
Expected volatility	26.40%	27.00%	26.40%
Expected dividend yield	3.60%	3.60%	2.80%
Risk-free interest rate	1.00%	1.00%	2.20%
TSR [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected volatility	'	'	10.20%
Expected dividend yield	'	'	2.20%
Risk-free interest rate	'	'	0.02%

StockBased_Compensation_Compan1

Stock-Based Compensation - Company's Nonvested Restricted Stock Unit Awards and Changes (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Beginning Balance, Number of Shares	1,729,700
Granted, Number of Shares	606,400
Vested, Number of Shares	-476,400
Forfeited, Number of Shares	-85,900
Ending Balance, Number of Shares	1,773,800
Beginning Balance, Weighted Average Grant Date Fair Value	$75.64
Granted, Weighted Average Grant Date Fair Value	$77.12
Vested, Weighted Average Grant Date Fair Value	$85.81
Forfeited, Weighted Average Grant Date Fair Value	$73.60
Ending Balance, Weighted Average Grant Date Fair Value	$73.51

StockBased_Compensation_Compan2

Stock-Based Compensation - Company's Performance Unit Awards Based on Expected Performance (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning Balance, Number of Shares	1,729,700
Granted, Number of Shares	606,400
Vested, Number of Shares	-476,400
Forfeited, Number of Shares	-85,900
Ending Balance, Number of Shares	1,773,800
Beginning Balance, Weighted Average Grant Date Fair Value	$75.64
Granted, Weighted Average Grant Date Fair Value	$77.12
Vested, Weighted Average Grant Date Fair Value	$85.81
Forfeited, Weighted Average Grant Date Fair Value	$73.60
Ending Balance, Weighted Average Grant Date Fair Value	$73.51
TSR [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning Balance, Number of Shares	59,300
Granted, Number of Shares	'
(Decrease) increase due to expected performance, Number of Shares	-33,100
Vested, Number of Shares	-25,300
Forfeited, Number of Shares	-900
Ending Balance, Number of Shares	'
Beginning Balance, Weighted Average Grant Date Fair Value	$106.20
Granted, Weighted Average Grant Date Fair Value	'
(Decrease) increase due to expected performance, Weighted Average Grant Date Fair Value	$106.20
Vested, Weighted Average Grant Date Fair Value	$106.20
Forfeited, Weighted Average Grant Date Fair Value	$106.20
Ending Balance, Weighted Average Grant Date Fair Value	'
EPS [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning Balance, Number of Shares	125,600
Granted, Number of Shares	61,700
(Decrease) increase due to expected performance, Number of Shares	59,900
Vested, Number of Shares	-67,900
Forfeited, Number of Shares	-3,800
Ending Balance, Number of Shares	175,500
Beginning Balance, Weighted Average Grant Date Fair Value	$71.86
Granted, Weighted Average Grant Date Fair Value	$77
(Decrease) increase due to expected performance, Weighted Average Grant Date Fair Value	$69.04
Vested, Weighted Average Grant Date Fair Value	$76.82
Forfeited, Weighted Average Grant Date Fair Value	$69.56
Ending Balance, Weighted Average Grant Date Fair Value	$70.84

Commitments_and_Contingencies_1

Commitments and Contingencies - Future Minimum Payments Under Non-Cancelable Operating Leases (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Operating Leased Assets [Line Items]	'
2014	$154
2015	93
2016	75
2017	66
2018	54
Thereafter	110
Total minimum payments required	552
Less: Sublease rentals under non-cancelable leases	4
Net minimum payments required	548
Real Estate Securities [Member]	'
Operating Leased Assets [Line Items]	'
2014	145
2015	88
2016	72
2017	65
2018	53
Thereafter	110
Total minimum payments required	533
Less: Sublease rentals under non-cancelable leases	4
Net minimum payments required	529
Equipment [Member]	'
Operating Leased Assets [Line Items]	'
2014	9
2015	5
2016	3
2017	1
2018	1
Thereafter	'
Total minimum payments required	19
Less: Sublease rentals under non-cancelable leases	'
Net minimum payments required	$19

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	31-May-12	Mar. 09, 2010	Jul. 01, 2004
	Agreement
Commitments and Contingencies Disclosure [Abstract]	'	'	'	'	'	'
Rent expense, net of sublease income	$141	$145	$140	'	'	'
Sublease rental income	6	5	5	'	'	'
Total outstanding letters of credit	634	504	'	'	'	'
Outstanding letters of credit	1	1	'	'	'	'
Number of existing real estate lease agreements	2	'	'	'	'	'
Real estate lease agreements, expiry date	31-Aug-15	'	'	'	'	'
Purchase price of property on or before expiration date	28	'	'	'	'	'
Residual guarantee amount	23	'	'	'	'	'
Maximum amount of supplemental rent payment	5	'	'	'	'	'
Aggregate residual guarantee amount	23	'	'	'	'	'
Term for operating lease agreements (in years)	'15 years	'	'	'	'	'
Fair market value of simulator systems, Minimum	7	'	'	'	'	'
Fair market value of simulator systems, Maximum	21	'	'	'	'	'
Additional rent to be paid for simulator systems after expiration date	7	'	'	'	'	'
Kalitta Air damages, minimum	235	'	'	'	'	'
Pre-judgment interest in Kalitta Air damages, minimum	240	'	'	'	'	'
Total damages sought	'	'	'	'	'	315
Punitive damages sought	'	'	'	'	'	150
Compensatory damages	'	'	'	$48	$6.70	'

Pensions_and_Other_Employee_Be2

Pensions and Other Employee Benefits - Changes in Benefit Obligations, Plan Assets and Funded Status and Aggregate Balance Sheet Impact (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets and (liabilities) recognized in the consolidated balance sheets consist of:	'	'	'
Non-current liabilities	($727)	($1,360)	'
Pension Plans [Member]	'	'	'
Change in benefit obligation:	'	'	'
Benefit obligation at the beginning of the year	3,222	2,679	'
Service cost	126	113	106
Interest cost	132	134	128
Plan participants' contributions	2	2	'
Amendments	14	'	'
Obligation assumed in connection with a business acquisition	'	29	'
Actuarial (gain) loss	-402	358	'
Foreign currency exchange rate changes	-21	8	'
Curtailments, settlements and special termination benefits	3	3	'
Benefits paid	-103	-104	'
Benefit obligation at the end of the year	2,973	3,222	2,679
Change in plan assets:	'	'	'
Fair value of plan assets at the beginning of the year	2,026	1,712	'
Actual return on plan assets	394	215	'
Assets acquired in connection with a business acquisition	'	29	'
Employer contributions	105	173	'
Plan participants' contributions	2	2	'
Foreign currency exchange rate changes	-21	6	'
Transfers	'	-7	'
Benefits paid	-103	-104	'
Fair value of plan assets at the end of the year	2,403	2,026	1,712
Unfunded status at the end of the year	-570	-1,196	'
Assets and (liabilities) recognized in the consolidated balance sheets consist of:	'	'	'
Non-current assets	35	9	'
Current liabilities	-8	-7	'
Non-current liabilities	-597	-1,198	'
Total	-570	-1,196	'
Postretirement Benefit Plans [Member]	'	'	'
Change in benefit obligation:	'	'	'
Benefit obligation at the beginning of the year	218	216	'
Service cost	4	4	5
Interest cost	7	10	10
Plan participants' contributions	4	4	'
Amendments	'	-5	'
Obligation assumed in connection with a business acquisition	'	3	'
Actuarial (gain) loss	-23	-2	'
Foreign currency exchange rate changes	-3	1	'
Curtailments, settlements and special termination benefits	'	1	'
Benefits paid	-13	-14	'
Benefit obligation at the end of the year	194	218	216
Change in plan assets:	'	'	'
Fair value of plan assets at the beginning of the year	47	42	'
Actual return on plan assets	9	4	'
Assets acquired in connection with a business acquisition	'	'	'
Employer contributions	8	11	'
Plan participants' contributions	4	4	'
Foreign currency exchange rate changes	'	'	'
Transfers	'	'	'
Benefits paid	-13	-14	'
Fair value of plan assets at the end of the year	55	47	42
Unfunded status at the end of the year	-139	-171	'
Assets and (liabilities) recognized in the consolidated balance sheets consist of:	'	'	'
Non-current assets	'	'	'
Current liabilities	-9	-9	'
Non-current liabilities	-130	-162	'
Total	($139)	($171)	'

Pensions_and_Other_Employee_Be3

Pensions and Other Employee Benefits - Net Loss and Prior Service Cost Balances in Accumulated Other Comprehensive Loss Account (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Net loss (gain)	$425	$1,146
Prior service cost (credit)	1	-12
Total amount recognized	426	1,134
Postretirement Benefit Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Net loss (gain)	-9	21
Prior service cost (credit)	-8	-10
Total amount recognized	($17)	$11

Pensions_and_Other_Employee_Be4

Pensions and Other Employee Benefits - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Health care cost trend in 2014	8.00%	'	'
Health care cost trend in 2020 and thereafter	5.00%	'	'
Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Aggregate accumulated benefit obligation (ABO)	$2,657	$2,783	'
Pension Plans [Member] | Minimum [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Expected contributions to plans in 2014	97	'	'
Pension Plans [Member] | Maximum [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Expected contributions to plans in 2014	108	'	'
Postretirement Benefit Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Expected contributions to plans in 2014	10	'	'
Continuing Operations [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Company's matching contributions in L-3 Holdings' common stock and cash	120	126	113
Discontinued Operations [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Company's matching contributions in L-3 Holdings' common stock and cash	'	$8	$24

Pensions_and_Other_Employee_Be5

Pensions and Other Employee Benefits - Pension Plans with an Accumulated Benefit Obligation in Excess of Fair Value of Plan Assets (Detail) (Pension Plans [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Projected benefit obligation	$2,408	$3,177
Accumulated benefit obligation	2,115	2,743
Fair value of plan assets	$1,815	$1,975

Pensions_and_Other_Employee_Be6

Pensions and Other Employee Benefits - Weighted Average Assumptions Used to Determine Benefit Obligations (Detail)	Dec. 31, 2013	Dec. 31, 2012
Pension Plans [Member]	'	'
Benefit obligations:	'	'
Discount rate	5.03%	4.15%
Rate of compensation increase	3.50%	3.56%
Postretirement Benefit Plans [Member]	'	'
Benefit obligations:	'	'
Discount rate	4.43%	3.37%
Rate of compensation increase	3.50%	3.59%

Pensions_and_Other_Employee_Be7

Pensions and Other Employee Benefits - Weighted Average Assumptions Used to Determine Benefit Obligations (Parenthetical) (Detail)	Dec. 31, 2013	Dec. 31, 2012
U.S. Based Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Assumptions used to determine benefit obligations, Weighted average discount rate	5.10%	4.20%
Assumptions used to determine benefit obligations, Rate of compensation increase	3.50%	3.50%
Canadian Based Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Assumptions used to determine benefit obligations, Weighted average discount rate	4.70%	3.90%
Assumptions used to determine benefit obligations, Rate of compensation increase	3.50%	4.00%
German Based Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Assumptions used to determine benefit obligations, Weighted average discount rate	3.50%	3.40%
U.S. Based Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Assumptions used to determine benefit obligations, Weighted average discount rate	4.40%	3.30%
Canadian Based Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Assumptions used to determine benefit obligations, Weighted average discount rate	4.60%	3.70%

Pensions_and_Other_Employee_Be8

Pensions and Other Employee Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]	'	'	'
Components of net periodic benefit cost:	'	'	'
Service cost	$126	$113	$106
Interest cost	132	134	128
Expected return on plan assets	-164	-145	-139
Amortization of prior service cost (credits)	1	1	1
Amortization of net loss	83	69	49
Curtailment or settlement loss	3	7	'
Net periodic benefit cost	181	179	145
Postretirement Benefit Plans [Member]	'	'	'
Components of net periodic benefit cost:	'	'	'
Service cost	4	4	5
Interest cost	7	10	10
Expected return on plan assets	-4	-3	-2
Amortization of prior service cost (credits)	-3	-3	-3
Amortization of net loss	2	1	1
Curtailment or settlement loss	'	1	'
Net periodic benefit cost	$6	$10	$11

Pensions_and_Other_Employee_Be9

Pensions and Other Employee Benefits - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]	'	'	'
Other changes in plan assets and benefit obligations recognized in other comprehensive income:	'	'	'
Net (gain) loss	($637)	$287	$266
Prior service cost (credit)	14	-1	2
Amortization of net loss	-83	-69	-49
Amortization of prior service (cost) credit	-1	-1	-1
Total recognized in other comprehensive income	-707	216	218
Total recognized in net periodic benefit cost and other comprehensive income	-526	395	363
Postretirement Benefit Plans [Member]	'	'	'
Other changes in plan assets and benefit obligations recognized in other comprehensive income:	'	'	'
Net (gain) loss	-29	-3	10
Prior service cost (credit)	'	-5	'
Amortization of net loss	-2	-1	-1
Amortization of prior service (cost) credit	3	3	3
Total recognized in other comprehensive income	-28	-6	12
Total recognized in net periodic benefit cost and other comprehensive income	($22)	$4	$23

Recovered_Sheet1

Pensions and Other Employee Benefits - Amounts Expected to be Amortized from Accumulated Other Comprehensive Income (Loss) and Recognized as Components of Net Periodic Benefit Costs (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]	'
Net loss (gain)	$16
Prior service cost (credit)	'
Total amount expected to be amortized	16
Pension Plans [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
Net loss (gain)	17
Prior service cost (credit)	2
Total amount expected to be amortized	19
Postretirement Benefit Plans [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
Net loss (gain)	-1
Prior service cost (credit)	-2
Total amount expected to be amortized	($3)

Recovered_Sheet2

Pensions and Other Employee Benefits - Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Discount rate	4.15%	5.02%	5.57%
Expected long-term return on plan assets	8.13%	8.15%	8.57%
Rate of compensation increase	3.50%	4.06%	4.50%
Postretirement Benefit Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Discount rate	3.37%	4.71%	5.40%
Expected long-term return on plan assets	7.64%	7.64%	6.20%
Rate of compensation increase	3.50%	4.09%	4.50%

Recovered_Sheet3

Pensions and Other Employee Benefits - Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
U.S. Based Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Assumptions used to determine net periodic benefit cost, Weighted average discount rate	4.20%	5.10%	5.60%
Assumptions used to determine net periodic benefit cost, Weighted average expected long-term return on plan assets	8.25%	8.25%	8.25%
Assumptions used to determine net periodic benefit cost, Rate of compensation increase	3.50%	4.00%	4.50%
Canadian Based Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Assumptions used to determine net periodic benefit cost, Weighted average discount rate	3.70%	4.30%	5.40%
Assumptions used to determine net periodic benefit cost, Weighted average expected long-term return on plan assets	7.25%	7.50%	7.50%
Assumptions used to determine net periodic benefit cost, Rate of compensation increase	3.50%	4.50%	4.50%
U.S. Based Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Assumptions used to determine net periodic benefit cost, Weighted average discount rate	3.30%	4.80%	5.40%
Canadian Based Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Assumptions used to determine net periodic benefit cost, Weighted average discount rate	3.90%	4.40%	5.40%
German Based Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Assumptions used to determine net periodic benefit cost, Weighted average discount rate	3.40%	5.10%	5.40%

Recovered_Sheet4

Pensions and Other Employee Benefits - Effect of One Percentage Point Change in Assumed Health Care Cost Trend Rates (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Effect of one percentage point increase on total service and interest cost	$1
Effect of one percentage point decrease on total service and interest cost	'
Effect of one percentage point increase on postretirement benefit obligations	9
Effect of one percentage point decrease on postretirement benefit obligations	($7)

Recovered_Sheet5

Pensions and Other Employee Benefits - Allowable Range for Each Major Category of Plans' Assets and Weighted-Average Asset Allocations by Asset Category (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
U.S. [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Weighted-average asset allocations	100.00%	100.00%
U.S. [Member] | Domestic Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	30.00%	30.00%
Percentage of plan assets, maximum range	60.00%	60.00%
Weighted-average asset allocations	54.00%	51.00%
U.S. [Member] | International Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	10.00%	10.00%
Percentage of plan assets, maximum range	20.00%	20.00%
Weighted-average asset allocations	11.00%	10.00%
U.S. [Member] | Fixed Income Securities [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	20.00%	20.00%
Percentage of plan assets, maximum range	40.00%	40.00%
Weighted-average asset allocations	22.00%	29.00%
U.S. [Member] | Real Estate Securities [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	0.00%	0.00%
Percentage of plan assets, maximum range	15.00%	15.00%
Weighted-average asset allocations	6.00%	8.00%
U.S. [Member] | Other Asset [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	0.00%	0.00%
Percentage of plan assets, maximum range	15.00%	15.00%
Weighted-average asset allocations	7.00%	2.00%
Canada [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Weighted-average asset allocations	100.00%	100.00%
Canada [Member] | Domestic Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	10.00%	15.00%
Percentage of plan assets, maximum range	25.00%	30.00%
Weighted-average asset allocations	20.00%	19.00%
Canada [Member] | International Equity [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	30.00%	20.00%
Percentage of plan assets, maximum range	60.00%	50.00%
Weighted-average asset allocations	49.00%	46.00%
Canada [Member] | Fixed Income Securities [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	20.00%	25.00%
Percentage of plan assets, maximum range	60.00%	55.00%
Weighted-average asset allocations	28.00%	32.00%
Canada [Member] | Real Estate Securities [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	'	'
Percentage of plan assets, maximum range	'	'
Weighted-average asset allocations	'	'
Canada [Member] | Other Asset [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of plan assets, minimum range	0.00%	0.00%
Percentage of plan assets, maximum range	15.00%	15.00%
Weighted-average asset allocations	3.00%	3.00%

Recovered_Sheet6

Pensions and Other Employee Benefits - Fair Value of the Company's Pension Plans' and Postretirement Benefit Plans' Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Postretirement Benefit Plans Assets [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	$55	$47
Postretirement Benefit Plans Assets [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	47	41
Postretirement Benefit Plans Assets [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	8	6
Postretirement Benefit Plans Assets [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | U.S. Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	23	27
Postretirement Benefit Plans Assets [Member] | U.S. Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	23	27
Postretirement Benefit Plans Assets [Member] | U.S. Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | U.S. Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | International Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	3	2
Postretirement Benefit Plans Assets [Member] | International Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	1	1
Postretirement Benefit Plans Assets [Member] | International Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	1
Postretirement Benefit Plans Assets [Member] | International Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Fixed Income - Investment Grade [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	23	14
Postretirement Benefit Plans Assets [Member] | Fixed Income - Investment Grade [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	21	11
Postretirement Benefit Plans Assets [Member] | Fixed Income - Investment Grade [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	3
Postretirement Benefit Plans Assets [Member] | Fixed Income - Investment Grade [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Fixed Income - High Yield [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	1
Postretirement Benefit Plans Assets [Member] | Fixed Income - High Yield [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Fixed Income - High Yield [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	1
Postretirement Benefit Plans Assets [Member] | Fixed Income - High Yield [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Real Estate Investment Trusts [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	2
Postretirement Benefit Plans Assets [Member] | Real Estate Investment Trusts [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	2
Postretirement Benefit Plans Assets [Member] | Real Estate Investment Trusts [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Real Estate Investment Trusts [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Other Asset [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	1
Postretirement Benefit Plans Assets [Member] | Other Asset [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Postretirement Benefit Plans Assets [Member] | Other Asset [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2	1
Postretirement Benefit Plans Assets [Member] | Other Asset [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	2,103	1,753
U.S. Based Pension Plans [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	1,554	1,292
U.S. Based Pension Plans [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	549	461
U.S. Based Pension Plans [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | U.S. Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	1,141	893
U.S. Based Pension Plans [Member] | U.S. Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	1,141	893
U.S. Based Pension Plans [Member] | U.S. Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | U.S. Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | International Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	225	184
U.S. Based Pension Plans [Member] | International Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	79	67
U.S. Based Pension Plans [Member] | International Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	146	117
U.S. Based Pension Plans [Member] | International Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Fixed Income - Investment Grade [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	351	391
U.S. Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	216	194
U.S. Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	135	197
U.S. Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Fixed Income - High Yield [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	118	105
U.S. Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	118	105
U.S. Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Real Estate Investment Trusts [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	118	138
U.S. Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	118	138
U.S. Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Other Asset [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	150	42
U.S. Based Pension Plans [Member] | Other Asset [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
U.S. Based Pension Plans [Member] | Other Asset [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	150	42
U.S. Based Pension Plans [Member] | Other Asset [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	300	273
Canadian Based Pension Plans [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	177	144
Canadian Based Pension Plans [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	123	129
Canadian Based Pension Plans [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | U.S. Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	72	56
Canadian Based Pension Plans [Member] | U.S. Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	54	43
Canadian Based Pension Plans [Member] | U.S. Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	18	13
Canadian Based Pension Plans [Member] | U.S. Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | International Equity [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	135	119
Canadian Based Pension Plans [Member] | International Equity [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	117	98
Canadian Based Pension Plans [Member] | International Equity [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	18	21
Canadian Based Pension Plans [Member] | International Equity [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - Investment Grade [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	82	88
Canadian Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	82	88
Canadian Based Pension Plans [Member] | Fixed Income - Investment Grade [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - High Yield [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Fixed Income - High Yield [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Real Estate Investment Trusts [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Real Estate Investment Trusts [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'
Canadian Based Pension Plans [Member] | Other Asset [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	11	10
Canadian Based Pension Plans [Member] | Other Asset [Member] | Level 1 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	6	3
Canadian Based Pension Plans [Member] | Other Asset [Member] | Level 2 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	5	7
Canadian Based Pension Plans [Member] | Other Asset [Member] | Level 3 [Member]	'	'
Equity securities:	'	'
Fair value of company's plan assets	'	'

Recovered_Sheet7

Pensions and Other Employee Benefits - Fair Value of the Company's Pension Plans' and Postretirement Benefit Plans' Assets (Parenthetical) (Detail)	Dec. 31, 2013	Dec. 31, 2012
U.S. Based Pension Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of mutual fund in total investment in fixed income - investment grade securities	62.00%	50.00%
Percentage of pooled bond funds in total investment in fixed income - investment grade securities	38.00%	50.00%
Postretirement Benefit Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of mutual fund in total investment in fixed income - investment grade securities	91.00%	79.00%
Percentage of pooled bond funds in total investment in fixed income - investment grade securities	9.00%	21.00%
Canadian Based Plans [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Percentage of mutual fund in total investment in fixed income - investment grade securities	50.00%	50.00%

Recovered_Sheet8

Pensions and Other Employee Benefits - Estimated Future Benefit Payments (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Pension Plans [Member]	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
2014	$116
2015	125
2016	134
2017	146
2018	152
Years 2019-2023	925
Postretirement Benefit Plans [Member]	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
2014	13
2015	13
2016	14
2017	14
2018	15
Years 2019-2023	77
Subsidy Receipts, 2014	'
Subsidy Receipts, 2015	'
Subsidy Receipts, 2016	'
Subsidy Receipts, 2017	'
Subsidy Receipts, 2018	'
Subsidy Receipts, Years 2019-2023	$1

Recovered_Sheet9

Pensions and Other Employee Benefits - Cash Contributions and Expenses under Multi-Employer Benefit Plans (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Multiemployer Plans [Line Items]	'	'	'
Contributions by L-3 Communications	$21	$20	$19
IAM National Pension Fund [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Contributions by L-3 Communications	21	20	19
EIN/Pension Plan Number	'51-6031295/002	'	'
Pension Protection Act Zone Status	'Green	'Green	'
FIP/RP Status Pending/Implemented	'No	'	'
Surcharge Imposed	'No	'	'
Expiration Date of Collective-Bargaining Agreement, First	14-Feb-14	'	'
Expiration Date of Collective-Bargaining Agreement, Last	29-Jan-16	'	'
Other Pension Funds [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Contributions by L-3 Communications	'	'	'

Recovered_Sheet10

Pensions and Other Employee Benefits - Cash Contributions and Expenses under Multi-Employer Benefit Plans (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Funds
Compensation and Retirement Disclosure [Abstract]	'	'	'
Minimum percentage funded to have green zone status rating	80.00%	'	'
Period of amortization of pension fund	'5 years	'	'
Percentage of total plan contributions	'	6.00%	6.00%
Percentage of contributions from reportable segment	72.00%	'	'
Expiration date of multiple bargaining agreements	27-Apr-14	'	'
Number of pension funds included in Other Pension Funds	3	'	'

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]	'	'	'
Interest paid on outstanding debt	$171	$198	$238
Income tax payments	245	332	273
Income tax refunds	$23	$22	$18

Segment_Information_Additional

Segment Information - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Segment
Segment Reporting [Abstract]	'	'	'
Number of segments	4	'	'
Corporate expenses	'	$10	$26

Segment_Information_Summary_of

Segment Information - Summary of Segment Information (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	$7,189	$7,586	$7,549
Net services sales	'	'	'	'	'	'	'	'	5,433	5,521	5,605
Consolidated total	'	'	'	'	'	'	'	'	12,622	13,107	13,154
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Depreciation and amortization	'	'	'	'	'	'	'	'	'	'	'
Depreciation and amortization	'	'	'	'	'	'	'	'	214	228	230
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	209	210	187
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Assets of discontinued operations	'	'	'	'	'	'	'	'	'	'	1,729
Total assets	13,988	'	'	'	13,800	'	'	'	13,988	13,800	15,520
Operating Segments [Member]	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	1,212	1,308	1,441
Operating Segments [Member] | Aerospace Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	1,827	1,755	1,579
Net services sales	'	'	'	'	'	'	'	'	2,730	2,844	2,857
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	426	437	451
Depreciation and amortization	'	'	'	'	'	'	'	'	'	'	'
Depreciation and amortization	'	'	'	'	'	'	'	'	38	46	44
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	54	42	42
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Total assets	3,087	'	'	'	3,074	'	'	'	3,087	3,074	3,125
Operating Segments [Member] | Electronic Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	3,661	3,754	3,862
Net services sales	'	'	'	'	'	'	'	'	1,054	1,011	928
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	533	569	624
Depreciation and amortization	'	'	'	'	'	'	'	'	'	'	'
Depreciation and amortization	'	'	'	'	'	'	'	'	117	121	124
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	71	77	79
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Total assets	6,928	'	'	'	6,792	'	'	'	6,928	6,792	6,607
Operating Segments [Member] | Communication Systems [Member]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	1,755	2,083	2,042
Net services sales	'	'	'	'	'	'	'	'	471	445	428
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	168	223	265
Depreciation and amortization	'	'	'	'	'	'	'	'	'	'	'
Depreciation and amortization	'	'	'	'	'	'	'	'	48	47	43
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	59	84	60
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Total assets	2,130	'	'	'	2,179	'	'	'	2,130	2,179	1,783
Operating Segments [Member] | NSS [Member]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	71	98	153
Net services sales	'	'	'	'	'	'	'	'	1,228	1,292	1,465
Operating Income	'	'	'	'	'	'	'	'	'	'	'
Operating income	'	'	'	'	'	'	'	'	85	79	101
Depreciation and amortization	'	'	'	'	'	'	'	'	'	'	'
Depreciation and amortization	'	'	'	'	'	'	'	'	11	14	19
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	5	5	5
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Total assets	1,247	'	'	'	1,228	'	'	'	1,247	1,228	1,317
Corporate [Member]	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	'	'	'
Capital Expenditures	'	'	'	'	'	'	'	'	20	2	1
Total Assets	'	'	'	'	'	'	'	'	'	'	'
Total assets	596	'	'	'	527	'	'	'	596	527	959
Elimination of Intercompany Sales [Member]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	'	'	'	'	'	'	'	'	'	'	'
Net products sales	'	'	'	'	'	'	'	'	-125	-104	-87
Net services sales	'	'	'	'	'	'	'	'	($50)	($71)	($73)

Segment_Information_Companys_S

Segment Information - Company's Sales Attributable to U.S. Customers and International Customers (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Net sales	$12,622	$13,107	$13,154
Operating Segments [Member] | U.S. [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	9,808	10,658	11,067
Operating Segments [Member] | United Kingdom [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	449	360	310
Operating Segments [Member] | Canada [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	357	314	328
Operating Segments [Member] | Germany [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	272	263	243
Operating Segments [Member] | Australia [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	218	222	118
Operating Segments [Member] | South Korea [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	178	125	93
Operating Segments [Member] | Saudi Arabia (Member)	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	132	76	41
Operating Segments [Member] | Italy [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	107	116	98
Operating Segments [Member] | Other [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	1,101	973	856
Operating Segments [Member] | Total International [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	$2,814	$2,449	$2,087

Segment_Information_Net_Sales_

Segment Information - Net Sales to Principal Customers (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Net sales	$12,622	$13,107	$13,154
Operating Segments [Member] | U.S. Government Agencies [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	9,186	9,986	10,438
Operating Segments [Member] | Commercial [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	1,689	1,658	1,524
Operating Segments [Member] | Allied International Governments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	$1,747	$1,463	$1,192

Employee_Severance_and_Termina2

Employee Severance and Termination Costs - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Employees	Employees	Employees
Restructuring and Related Activities [Abstract]	'	'	'
Employee severance and other related termination costs	$29	$23	$20
Number of employees terminated	2,000	1,600	1,200
Remaining balance of employee termination costs	$11	$9	'

Employee_Severance_and_Termina3

Employee Severance and Termination Costs - Employee Severance and Other Termination Costs Incurred by Reportable Segment (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]	'	'	'
Employee severance and other related termination costs	$29	$23	$20
Aerospace Systems [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Employee severance and other related termination costs	2	1	3
Electronic Systems [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Employee severance and other related termination costs	16	13	12
Communication Systems [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Employee severance and other related termination costs	11	8	4
NSS [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Employee severance and other related termination costs	'	$1	$1

Unaudited_Quarterly_Financial_2

Unaudited Quarterly Financial Data - Company's Unaudited Quarterly Results of Operations (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Sales	$3,234	$3,002	$3,189	$3,197	$3,520	$3,284	$3,143	$3,160	'	'	'
Operating income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Income from continuing operations	188	204	176	192	199	188	189	186	760	762	866
Net income attributable to L-3	$185	$200	$175	$191	$196	$185	$203	$200	$751	$784	$958
Basic EPS from continuing operations	'	'	'	'	$2.11	$1.94	$1.93	$1.88	$8.40	$7.85	$8.19
Diluted EPS from continuing operations	'	'	'	'	$2.08	$1.91	$1.91	$1.86	$8.24	$7.74	$8.10
Basic EPS	$2.10	$2.23	$1.95	$2.12	$2.11	$1.93	$2.09	$2.02	$8.40	$8.14	$9.16
Diluted EPS	$2.04	$2.19	$1.92	$2.09	$2.08	$1.90	$2.06	$2	$8.24	$8.03	$9.05

Financial_Information_of_L3_Co2

Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Equity (Detail) (USD $)

12 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Retained Earnings [Member]

Retained Earnings [Member]

Retained Earnings [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

L-3 Communications Corporation [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Additional Paid-in Capital [Member]

Additional Paid-in Capital [Member]

Additional Paid-in Capital [Member]

Treasury Stock [Member]

Treasury Stock [Member]

Treasury Stock [Member]

Retained Earnings [Member]

Retained Earnings [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Loss [Member]

Accumulated Other Comprehensive Loss [Member]

Accumulated Other Comprehensive Loss [Member]

Condensed Financial Statements, Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Beginning Balance

'

'

'

'

'

'

'

'

'

'

$5,451

$6,644

$6,771

'

'

'

$5,314

$5,064

$4,801

'

'

'

$687

$2,034

$2,226

($550)

($454)

($256)

Beginning Balance, Shares

'

'

'

85.8

90.4

99

108.6

'

'

'

'

'

'

100

100

100

'

'

'

'

'

'

'

'

'

'

'

'

Net income attributable to L-3

760

794

970

'

'

'

'

751

784

958

751

784

958

'

'

'

'

'

'

'

'

'

751

784

958

'

'

'

Contributions from L-3 Holdings

'

'

'

'

'

'

'

'

'

'

339

250

263

'

'

'

339

250

263

'

'

'

'

'

'

'

'

'

Dividends to L-3 Holdings

'

'

'

'

'

'

'

'

'

'

-997

-1,064

-1,157

'

'

'

'

'

'

'

'

'

-997

-1,064

-1,157

'

'

'

Comprehensive gain (loss)

440

-96

-198

'

'

'

'

'

'

'

440

-96

-198

'

'

'

'

'

'

'

'

'

'

'

'

440

-96

-198

Net change of equity due to spin-off of Engility

'

'

'

'

'

'

'

'

'

'

'

-1,063

'

'

'

'

'

'

'

'

'

'

'

-1,063

'

'

'

'

Other

'

'

'

'

'

'

'

'

'

'

-3

-4

7

'

'

'

'

'

'

'

'

'

-3

-4

7

'

'

'

Ending Balance

'

'

'

'

'

'

'

'

'

'

$5,981

$5,451

$6,644

'

'

'

$5,653

$5,314

$5,064

'

'

'

$438

$687

$2,034

($110)

($550)

($454)

Ending Balance, Shares

'

'

'

85.8

90.4

99

108.6

'

'

'

'

'

'

100

100

100

'

'

'

'

'

'

'

'

'

'

'

'

Financial_Information_of_L3_Co3

Financial Information of L-3 Communications and Its Subsidiaries - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
L-3 Communications Holdings, Inc. [Member]	'
Debt Instrument [Line Items]	'
Ownership percentage	100.00%
Non-Guarantor Subsidiaries [Member]	'
Debt Instrument [Line Items]	'
Cumulative aggregate adjustments, net	$10

Financial_Information_of_L3_Co4

Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Operations (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	$12,622	$13,107	$13,154
Cost of sales	'	'	'	'	'	'	'	'	-11,410	-11,799	-11,713
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating (loss) income	306	306	290	310	339	319	328	322	1,212	1,308	1,398
Interest expense	'	'	'	'	'	'	'	'	-177	-184	-204
Interest and other income (expense), net	'	'	'	'	'	'	'	'	20	11	3
Debt retirement charge	'	'	'	'	'	'	'	'	'	-13	-35
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	1,055	1,122	1,162
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	-295	-360	-296
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	188	204	176	192	199	188	189	186	760	762	866
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	32	104
Net income	'	'	'	'	'	'	'	'	760	794	970
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-10	-12
Net income attributable to L-3	185	200	175	191	196	185	203	200	751	784	958
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	1,191	688	760
L-3 Communications Holdings, Inc. [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	'	'	'
Cost of sales	'	'	'	'	'	'	'	'	-59	-59	-57
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating (loss) income	'	'	'	'	'	'	'	'	-59	-59	-57
Interest expense	'	'	'	'	'	'	'	'	-21	-21	-23
Interest and other income (expense), net	'	'	'	'	'	'	'	'	'	'	'
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	-80	-80	-80
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	22	26	20
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	809	838	1,018
Income from continuing operations	'	'	'	'	'	'	'	'	'	784	958
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	751	784	958
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	751	784	958
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	1,191	688	760
L-3 Communications Corporation [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	3,842	3,737	3,735
Cost of sales	'	'	'	'	'	'	'	'	-3,549	-3,434	-3,335
Impairment charge	'	'	'	'	'	'	'	'	'	'	-43
Operating (loss) income	'	'	'	'	'	'	'	'	293	303	357
Interest expense	'	'	'	'	'	'	'	'	-176	-183	-201
Interest and other income (expense), net	'	'	'	'	'	'	'	'	15	14	17
Debt retirement charge	'	'	'	'	'	'	'	'	'	-13	-35
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	132	121	138
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	-38	-37	-35
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	657	668	751
Income from continuing operations	'	'	'	'	'	'	'	'	'	752	854
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	32	104
Net income	'	'	'	'	'	'	'	'	751	784	958
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	751	784	958
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	1,191	688	760
Guarantor Subsidiaries [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	6,804	7,475	7,572
Cost of sales	'	'	'	'	'	'	'	'	-6,139	-6,749	-6,857
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating (loss) income	'	'	'	'	'	'	'	'	665	726	715
Interest expense	'	'	'	'	'	'	'	'	'	'	-1
Interest and other income (expense), net	'	'	'	'	'	'	'	'	'	-5	-15
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	665	721	699
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	-184	-230	-178
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	'	491	521
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	481	491	521
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	481	491	521
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	480	493	511
Non-Guarantor Subsidiaries [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	2,363	2,278	2,187
Cost of sales	'	'	'	'	'	'	'	'	-2,109	-1,999	-1,861
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating (loss) income	'	'	'	'	'	'	'	'	254	279	326
Interest expense	'	'	'	'	'	'	'	'	-1	-1	-5
Interest and other income (expense), net	'	'	'	'	'	'	'	'	5	2	4
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	258	280	325
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	-73	-93	-83
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	'	'	'
Income from continuing operations	'	'	'	'	'	'	'	'	'	187	242
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	185	187	242
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to L-3	'	'	'	'	'	'	'	'	185	187	242
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	159	215	221
Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	-387	-383	-340
Cost of sales	'	'	'	'	'	'	'	'	446	442	397
Impairment charge	'	'	'	'	'	'	'	'	'	'	'
Operating (loss) income	'	'	'	'	'	'	'	'	59	59	57
Interest expense	'	'	'	'	'	'	'	'	21	21	26
Interest and other income (expense), net	'	'	'	'	'	'	'	'	'	'	-3
Debt retirement charge	'	'	'	'	'	'	'	'	'	'	'
(Loss) income from continuing operations before income taxes	'	'	'	'	'	'	'	'	80	80	80
Benefit (provision) for income taxes	'	'	'	'	'	'	'	'	-22	-26	-20
Equity in net income of consolidated subsidiaries	'	'	'	'	'	'	'	'	-1,466	-1,506	-1,769
Income from continuing operations	'	'	'	'	'	'	'	'	'	-1,452	-1,709
Income from discontinued operations, net of income tax	'	'	'	'	'	'	'	'	'	'	'
Net income	'	'	'	'	'	'	'	'	-1,408	-1,452	-1,709
Net income attributable to noncontrolling interests	'	'	'	'	'	'	'	'	-9	-10	-12
Net income attributable to L-3	'	'	'	'	'	'	'	'	-1,417	-1,462	-1,721
Comprehensive income attributable to L-3	'	'	'	'	'	'	'	'	($1,830)	($1,396)	($1,492)

Financial_Information_of_L3_Co5

Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Balance Sheets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Current assets:	'	'	'	'
Cash and cash equivalents	$500	$349	$764	$607
Billed receivables, net	991	968	'	'
Contracts in process	2,431	2,510	'	'
Other current assets	672	657	'	'
Total current assets	4,594	4,484	'	'
Goodwill	7,796	7,776	7,472	'
Other assets	1,598	1,540	'	'
Investment in and amounts due from consolidated subsidiaries	'	'	'	'
Total assets	13,988	13,800	15,520	'
Current liabilities	2,534	2,563	'	'
Amounts due to consolidated subsidiaries	'	'	'	'
Other long-term liabilities	1,768	2,081	'	'
Long-term debt	3,630	3,629	'	'
Total liabilities	7,932	8,273	'	'
L-3 shareholders' equity	5,981	5,451	'	'
Noncontrolling interests	75	76	'	'
Total equity	6,056	5,527	6,733	6,862
Total liabilities and equity	13,988	13,800	'	'
L-3 Communications Holdings, Inc. [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	'	'	'	'
Billed receivables, net	'	'	'	'
Contracts in process	'	'	'	'
Other current assets	'	'	'	'
Total current assets	'	'	'	'
Goodwill	'	'	'	'
Other assets	'	'	'	'
Investment in and amounts due from consolidated subsidiaries	6,670	6,140	'	'
Total assets	6,670	6,140	'	'
Current liabilities	'	'	'	'
Amounts due to consolidated subsidiaries	'	'	'	'
Other long-term liabilities	'	'	'	'
Long-term debt	689	689	'	'
Total liabilities	689	689	'	'
L-3 shareholders' equity	5,981	5,451	'	'
Noncontrolling interests	'	'	'	'
Total equity	5,981	5,451	'	'
Total liabilities and equity	6,670	6,140	'	'
L-3 Communications Corporation [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	258	246	644	251
Billed receivables, net	364	290	'	'
Contracts in process	925	893	'	'
Other current assets	344	308	'	'
Total current assets	1,891	1,737	'	'
Goodwill	2,307	2,010	'	'
Other assets	838	757	'	'
Investment in and amounts due from consolidated subsidiaries	6,940	7,153	'	'
Total assets	11,976	11,657	'	'
Current liabilities	914	823	'	'
Amounts due to consolidated subsidiaries	'	'	'	'
Other long-term liabilities	1,451	1,754	'	'
Long-term debt	3,630	3,629	'	'
Total liabilities	5,995	6,206	'	'
L-3 shareholders' equity	5,981	5,451	'	'
Noncontrolling interests	'	'	'	'
Total equity	5,981	5,451	'	'
Total liabilities and equity	11,976	11,657	'	'
Guarantor Subsidiaries [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	'	'	'	'
Billed receivables, net	401	441	'	'
Contracts in process	1,152	1,275	'	'
Other current assets	159	161	'	'
Total current assets	1,712	1,877	'	'
Goodwill	4,326	4,627	'	'
Other assets	532	572	'	'
Investment in and amounts due from consolidated subsidiaries	3,744	3,299	'	'
Total assets	10,314	10,375	'	'
Current liabilities	1,011	1,221	'	'
Amounts due to consolidated subsidiaries	'	'	'	'
Other long-term liabilities	193	210	'	'
Long-term debt	'	'	'	'
Total liabilities	1,204	1,431	'	'
L-3 shareholders' equity	9,110	8,944	'	'
Noncontrolling interests	'	'	'	'
Total equity	9,110	8,944	'	'
Total liabilities and equity	10,314	10,375	'	'
Non-Guarantor Subsidiaries [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	261	242	222	473
Billed receivables, net	226	237	'	'
Contracts in process	354	342	'	'
Other current assets	169	188	'	'
Total current assets	1,010	1,009	'	'
Goodwill	1,163	1,139	'	'
Other assets	228	211	'	'
Investment in and amounts due from consolidated subsidiaries	'	101	'	'
Total assets	2,401	2,460	'	'
Current liabilities	628	658	'	'
Amounts due to consolidated subsidiaries	270	'	'	'
Other long-term liabilities	124	117	'	'
Long-term debt	'	'	'	'
Total liabilities	1,022	775	'	'
L-3 shareholders' equity	1,379	1,685	'	'
Noncontrolling interests	'	'	'	'
Total equity	1,379	1,685	'	'
Total liabilities and equity	2,401	2,460	'	'
Eliminations [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	-19	-139	-102	-117
Billed receivables, net	'	'	'	'
Contracts in process	'	'	'	'
Other current assets	'	'	'	'
Total current assets	-19	-139	'	'
Goodwill	'	'	'	'
Other assets	'	'	'	'
Investment in and amounts due from consolidated subsidiaries	-17,354	-16,693	'	'
Total assets	-17,373	-16,832	'	'
Current liabilities	-19	-139	'	'
Amounts due to consolidated subsidiaries	-270	'	'	'
Other long-term liabilities	'	'	'	'
Long-term debt	-689	-689	'	'
Total liabilities	-978	-828	'	'
L-3 shareholders' equity	-16,470	-16,080	'	'
Noncontrolling interests	75	76	'	'
Total equity	-16,395	-16,004	'	'
Total liabilities and equity	($17,373)	($16,832)	'	'

Financial_Information_of_L3_Co6

Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Cash Flows (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	$1,263	$1,231	$1,231
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	-62	-348	-20
Investments in L-3 Communications	'	'	'
Other investing activities	-199	148	-179
Net cash used in investing activities from continuing operations	-261	-200	-199
Financing activities:	'	'	'
Proceeds from sale of senior notes	'	'	1,143
Redemption of senior subordinated notes	'	-500	-1,150
Redemption of senior subordinated notes and CODES	'	'	-1,161
Common stock repurchased	-800	-872	-958
Dividends paid on L-3 Holdings common stock	-199	-195	-188
Dividends paid to L-3 Holdings	'	'	'
Investments from L-3 Holdings	'	'	'
Other financing activities	150	40	45
Net cash used in financing activities from continuing operations	-849	-1,527	-1,119
Effect of foreign currency exchange rate changes on cash	-2	7	-4
Net increase in cash and cash equivalents of discontinued operations	'	74	248
Net (decrease) increase in cash and cash equivalents	151	-415	157
Cash and cash equivalents, beginning of the year	349	764	607
Cash and cash equivalents, end of the year	500	349	764
L-3 Communications Holdings, Inc. [Member]	'	'	'
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	999	1,067	1,157
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	'	'	'
Investments in L-3 Communications	-149	-42	-55
Other investing activities	'	'	'
Net cash used in investing activities from continuing operations	-149	-42	-55
Financing activities:	'	'	'
Redemption of senior subordinated notes	'	'	'
Redemption of senior subordinated notes and CODES	'	'	-11
Common stock repurchased	-800	-872	-958
Dividends paid on L-3 Holdings common stock	-199	-195	-188
Dividends paid to L-3 Holdings	'	'	'
Investments from L-3 Holdings	'	'	'
Other financing activities	149	42	55
Net cash used in financing activities from continuing operations	-850	-1,025	-1,102
Effect of foreign currency exchange rate changes on cash	'	'	'
Net (decrease) increase in cash and cash equivalents	'	'	'
Cash and cash equivalents, beginning of the year	'	'	'
Cash and cash equivalents, end of the year	'	'	'
L-3 Communications Corporation [Member]	'	'	'
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	437	252	476
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	-62	-348	-20
Investments in L-3 Communications	'	'	'
Other investing activities	-88	225	-84
Net cash used in investing activities from continuing operations	-150	-123	-104
Financing activities:	'	'	'
Proceeds from sale of senior notes	'	'	1,143
Redemption of senior subordinated notes	'	-500	'
Redemption of senior subordinated notes and CODES	'	'	-1,150
Common stock repurchased	'	'	'
Dividends paid on L-3 Holdings common stock	'	'	'
Dividends paid to L-3 Holdings	-999	-1,067	-1,157
Investments from L-3 Holdings	149	42	55
Other financing activities	575	924	882
Net cash used in financing activities from continuing operations	-275	-601	-227
Effect of foreign currency exchange rate changes on cash	'	'	'
Net increase in cash and cash equivalents of discontinued operations	'	74	248
Net (decrease) increase in cash and cash equivalents	12	-398	393
Cash and cash equivalents, beginning of the year	246	644	251
Cash and cash equivalents, end of the year	258	246	644
Guarantor Subsidiaries [Member]	'	'	'
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	776	858	792
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	'	'	'
Investments in L-3 Communications	'	'	'
Other investing activities	-89	-59	-75
Net cash used in investing activities from continuing operations	-89	-59	-75
Financing activities:	'	'	'
Common stock repurchased	'	'	'
Dividends paid on L-3 Holdings common stock	'	'	'
Dividends paid to L-3 Holdings	'	'	'
Investments from L-3 Holdings	'	'	'
Other financing activities	-687	-799	-717
Net cash used in financing activities from continuing operations	-687	-799	-717
Effect of foreign currency exchange rate changes on cash	'	'	'
Net (decrease) increase in cash and cash equivalents	'	'	'
Cash and cash equivalents, beginning of the year	'	'	'
Cash and cash equivalents, end of the year	'	'	'
Non-Guarantor Subsidiaries [Member]	'	'	'
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	231	265	220
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	'	'	'
Investments in L-3 Communications	'	'	'
Other investing activities	-22	-18	-20
Net cash used in investing activities from continuing operations	-22	-18	-20
Financing activities:	'	'	'
Common stock repurchased	'	'	'
Dividends paid on L-3 Holdings common stock	'	'	'
Dividends paid to L-3 Holdings	'	'	'
Investments from L-3 Holdings	'	'	'
Other financing activities	-188	-234	-447
Net cash used in financing activities from continuing operations	-188	-234	-447
Effect of foreign currency exchange rate changes on cash	-2	7	-4
Net (decrease) increase in cash and cash equivalents	19	20	-251
Cash and cash equivalents, beginning of the year	242	222	473
Cash and cash equivalents, end of the year	261	242	222
Eliminations [Member]	'	'	'
Operating activities:	'	'	'
Net cash from operating activities from continuing operations	-1,180	-1,211	-1,414
Investing activities:	'	'	'
Business acquisitions, net of cash acquired	'	'	'
Investments in L-3 Communications	149	42	55
Other investing activities	'	'	'
Net cash used in investing activities from continuing operations	149	42	55
Financing activities:	'	'	'
Common stock repurchased	'	'	'
Dividends paid on L-3 Holdings common stock	'	'	'
Dividends paid to L-3 Holdings	999	1,067	1,157
Investments from L-3 Holdings	-149	-42	-55
Other financing activities	301	107	272
Net cash used in financing activities from continuing operations	1,151	1,132	1,374
Effect of foreign currency exchange rate changes on cash	'	'	'
Net (decrease) increase in cash and cash equivalents	120	-37	15
Cash and cash equivalents, beginning of the year	-139	-102	-117
Cash and cash equivalents, end of the year	($19)	($139)	($102)