Financial Information of L-3 Communications and Its Subsidiaries (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Combining Statements of Operations:
Net sales									$ 15,169	$ 15,680	$ 15,615
Cost of sales									13,528	13,930	13,959
Impairment charge									43
Operating (loss) income	398	406	404	390	461	437	442	410	1,598	1,750	1,656
Interest and other income, net										21	19
Interest expense									235	269	279
Debt retirement charge									35	18	10
(Loss) income before income taxes									1,328	1,484	1,386
(Benefit) provision for income taxes									360	518	475
Net income	277	238	246	207	272	241	231	222	968	966	911
Net income attributable to noncontrolling interests									12	11	10
Net income attributable to L-3	274	235	243	204	268	238	228	221	956	955	901
L-3 Holdings (Parent) [Member]
Condensed Combining Statements of Operations:
Cost of sales									64	82	74
Operating (loss) income									(64)	(82)	(74)
Interest expense									23	46	45
(Loss) income before income taxes									(87)	(128)	(119)
(Benefit) provision for income taxes									(24)	(45)	(37)
Equity in net income of consolidated subsidiaries									1,019	1,038	983
Net income									956	955	901
Net income attributable to L-3									956	955	901
L-3 Communications [Member]
Condensed Combining Statements of Operations:
Net sales									3,812	3,831	3,419
Cost of sales									3,383	3,309	2,987
Impairment charge									43
Operating (loss) income									386	522	432
Interest and other income, net									123	132	128
Interest expense									233	268	277
Debt retirement charge									35	18	10
(Loss) income before income taxes									241	368	273
(Benefit) provision for income taxes									66	129	119
Equity in net income of consolidated subsidiaries									781	716	747
Net income									956	955	901
Net income attributable to L-3									956	955	901
Guarantor Subsidiaries [Member]
Condensed Combining Statements of Operations:
Net sales									9,179	10,013	10,397
Cost of sales									8,315	9,077	9,413
Operating (loss) income									864	936	984
Interest and other income, net									(15)		3
Interest expense									109	110	110
(Loss) income before income taxes									740	826	877
(Benefit) provision for income taxes									200	288	275
Net income									540	538	602
Net income attributable to L-3									540	538	602
Non-Guarantor Subsidiaries [Member]
Condensed Combining Statements of Operations:
Net sales									2,538	2,130	1,929
Cost of sales									2,190	1,837	1,689
Operating (loss) income									348	293	240
Interest and other income, net									4	3	2
Interest expense									5	6	6
(Loss) income before income taxes									347	290	236
(Benefit) provision for income taxes									94	101	81
Net income									253	189	155
Net income attributable to L-3									253	189	155
Eliminations [Member]
Condensed Combining Statements of Operations:
Net sales									(360)	(294)	(130)
Cost of sales									(424)	(375)	(204)
Operating (loss) income									64	81	74
Interest and other income, net									(112)	(114)	(114)
Interest expense									(135)	(161)	(159)
(Loss) income before income taxes									87	128	119
(Benefit) provision for income taxes									24	45	37
Equity in net income of consolidated subsidiaries									(1,800)	(1,754)	(1,730)
Net income									(1,737)	(1,671)	(1,648)
Net income attributable to noncontrolling interests									12	11	10
Net income attributable to L-3									$ (1,749)	$ (1,682)	$ (1,658)