Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities:
Net cash from operating activities from continuing operations	$ 1,231	$ 1,231	$ 1,270
Investing activities:
Business acquisitions, net of cash acquired	(348)	(20)	(756)
Investments in L-3 Communications
Other investing activities	148	(179)	(188)
Net cash used in investing activities from continuing operations	(200)	(199)	(944)
Financing activities:
Proceeds from sale of senior notes		1,143	797
Redemption of senior subordinated notes	(500)	(1,161)
Redemption of senior subordinated notes	(500)	(1,150)	(800)
Common stock repurchased	(872)	(958)	(834)
Dividends paid on L-3 Holdings common stock	(195)	(188)	(184)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	40	45	104
Net cash used in financing activities from continuing operations	(1,527)	(1,119)	(917)
Effect of foreign currency exchange rate changes on cash	7	(4)	(7)
Net increase in cash and cash equivalents of discontinued operations	74	248	189
Net (decrease) increase in cash	(415)	157	(409)
Cash and cash equivalents, beginning of the year	764	607	1,016
Cash and cash equivalents, end of the year	349	764	607
L-3 Communications Holdings Inc. [Member]
Operating activities:
Net cash from operating activities from continuing operations	1,067	1,157	1,018
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	(42)	(55)	(116)
Other investing activities
Net cash used in investing activities from continuing operations	(42)	(55)	(116)
Financing activities:
Proceeds from sale of senior notes
Redemption of senior subordinated notes		(11)
Redemption of senior subordinated notes
Common stock repurchased	(872)	(958)	(834)
Dividends paid on L-3 Holdings common stock	(195)	(188)	(184)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	42	55	116
Net cash used in financing activities from continuing operations	(1,025)	(1,102)	(902)
Effect of foreign currency exchange rate changes on cash
Net increase in cash and cash equivalents of discontinued operations
Net (decrease) increase in cash
Cash and cash equivalents, beginning of the year
Cash and cash equivalents, end of the year
L-3 Communications Corporation's [Member]
Operating activities:
Net cash from operating activities from continuing operations	252	476	302
Investing activities:
Business acquisitions, net of cash acquired	(348)	(20)	(756)
Investments in L-3 Communications
Other investing activities	225	(84)	(89)
Net cash used in investing activities from continuing operations	(123)	(104)	(845)
Financing activities:
Proceeds from sale of senior notes		1,143	797
Redemption of senior subordinated notes	(500)	(1,150)
Redemption of senior subordinated notes			(800)
Common stock repurchased
Dividends paid on L-3 Holdings common stock
Dividends paid to L-3 Holdings	(1,067)	(1,157)	(1,018)
Investments from L-3 Holdings	42	55	116
Other financing activities	924	882	751
Net cash used in financing activities from continuing operations	(601)	(227)	(154)
Effect of foreign currency exchange rate changes on cash
Net increase in cash and cash equivalents of discontinued operations	74	248	189
Net (decrease) increase in cash	(398)	393	(508)
Cash and cash equivalents, beginning of the year	644	251	759
Cash and cash equivalents, end of the year	246	644	251
Guarantor Subsidiaries [Member]
Operating activities:
Net cash from operating activities from continuing operations	858	792	761
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(59)	(75)	(91)
Net cash used in investing activities from continuing operations	(59)	(75)	(91)
Financing activities:
Proceeds from sale of senior notes
Redemption of senior subordinated notes
Redemption of senior subordinated notes
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	(799)	(717)	(671)
Net cash used in financing activities from continuing operations	(799)	(717)	(671)
Effect of foreign currency exchange rate changes on cash
Net increase in cash and cash equivalents of discontinued operations
Net (decrease) increase in cash			(1)
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	265	220	230
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(18)	(20)	(8)
Net cash used in investing activities from continuing operations	(18)	(20)	(8)
Financing activities:
Proceeds from sale of senior notes
Redemption of senior subordinated notes
Redemption of senior subordinated notes
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	(234)	(447)	(112)
Net cash used in financing activities from continuing operations	(234)	(447)	(112)
Effect of foreign currency exchange rate changes on cash	7	(4)	(7)
Net increase in cash and cash equivalents of discontinued operations
Net (decrease) increase in cash	20	(251)	103
Cash and cash equivalents, beginning of the year	222	473	370
Cash and cash equivalents, end of the year	242	222	473
Eliminations [Member]
Operating activities:
Net cash from operating activities from continuing operations	(1,211)	(1,414)	(1,041)
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	42	55	116
Other investing activities
Net cash used in investing activities from continuing operations	42	55	116
Financing activities:
Proceeds from sale of senior notes
Redemption of senior subordinated notes
Redemption of senior subordinated notes
Common stock repurchased
Dividends paid on L-3 Holdings common stock
Dividends paid to L-3 Holdings	1,067	1,157	1,018
Investments from L-3 Holdings	(42)	(55)	(116)
Other financing activities	107	272	20
Net cash used in financing activities from continuing operations	1,132	1,374	922
Effect of foreign currency exchange rate changes on cash
Net increase in cash and cash equivalents of discontinued operations
Net (decrease) increase in cash	(37)	15	(3)
Cash and cash equivalents, beginning of the year	(102)	(117)	(114)
Cash and cash equivalents, end of the year	$ (139)	$ (102)	$ (117)