Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	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)