Condensed Combining Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 28, 2013	Jun. 29, 2012
Operating activities:
Net cash from operating activities	$ 396
Net cash from operating activities from continuing operations	396	337
Investing activities:
Business acquisitions, net of cash acquired	(1)	(216)
Investments in L-3 Communications
Other investing activities	(103)	(79)
Net cash used in investing activities from continuing operations	(104)	(295)
Net cash used in investing activities	(104)
Financing activities:
Common stock repurchased	(248)	(315)
Dividends paid on L-3 Holdings' common stock	(101)	(98)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	45	21
Net cash used in financing activities from continuing operations	(304)	(392)
Net cash used in financing activities	(304)
Effect of foreign currency exchange rate changes on cash	(9)	(3)
Net increase in cash and cash equivalents of discontinued operations		70
Net (decrease) increase in cash and cash equivalents	(21)	(283)
Cash and cash equivalents, beginning of the period	349	764
Cash and cash equivalents, end of the period	328	481
L-3 Communications Holdings, Inc. [Member]
Operating activities:
Net cash from operating activities	349
Net cash from operating activities from continuing operations		413
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	(37)	(25)
Other investing activities
Net cash used in investing activities from continuing operations		(25)
Net cash used in investing activities	(37)
Financing activities:
Common stock repurchased	(248)	(315)
Dividends paid on L-3 Holdings' common stock	(101)	(98)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	37	25
Net cash used in financing activities from continuing operations		(388)
Net cash used in financing activities	(312)
Effect of foreign currency exchange rate changes on cash
Net (decrease) increase in cash and cash equivalents
Cash and cash equivalents, beginning of the period
Cash and cash equivalents, end of the period
L-3 Communications Corporation's [Member]
Operating activities:
Net cash from operating activities	146
Net cash from operating activities from continuing operations		80
Investing activities:
Business acquisitions, net of cash acquired	(1)	(216)
Investments in L-3 Communications
Other investing activities	(53)	(45)
Net cash used in investing activities from continuing operations		(261)
Net cash used in investing activities	(54)
Financing activities:
Common stock repurchased
Dividends paid on L-3 Holdings' common stock
Dividends paid to L-3 Holdings	(349)	(413)
Investments from L-3 Holdings	37	25
Other financing activities	94	109
Net cash used in financing activities from continuing operations		(279)
Net cash used in financing activities	(218)
Effect of foreign currency exchange rate changes on cash
Net increase in cash and cash equivalents of discontinued operations		70
Net (decrease) increase in cash and cash equivalents	(126)	(390)
Cash and cash equivalents, beginning of the period	246	644
Cash and cash equivalents, end of the period	120	254
Guarantor Subsidiaries [Member]
Operating activities:
Net cash from operating activities	254
Net cash from operating activities from continuing operations		236
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(39)	(29)
Net cash used in investing activities from continuing operations		(29)
Net cash used in investing activities	(39)
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	(215)	(201)
Net cash used in financing activities from continuing operations		(201)
Net cash used in financing activities	(215)
Effect of foreign currency exchange rate changes on cash
Net (decrease) increase in cash and cash equivalents		6
Cash and cash equivalents, beginning of the period
Cash and cash equivalents, end of the period		6
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash from operating activities	64
Net cash from operating activities from continuing operations		91
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(11)	(5)
Net cash used in investing activities from continuing operations		(5)
Net cash used in investing activities	(11)
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	(50)	(72)
Net cash used in financing activities from continuing operations		(72)
Net cash used in financing activities	(50)
Effect of foreign currency exchange rate changes on cash	(9)	(3)
Net (decrease) increase in cash and cash equivalents	(6)	11
Cash and cash equivalents, beginning of the period	242	222
Cash and cash equivalents, end of the period	236	233
Eliminations [Member]
Operating activities:
Net cash from operating activities	(417)
Net cash from operating activities from continuing operations		(483)
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	37	25
Other investing activities
Net cash used in investing activities from continuing operations		25
Net cash used in investing activities	37
Financing activities:
Common stock repurchased
Dividends paid on L-3 Holdings' common stock
Dividends paid to L-3 Holdings	349	413
Investments from L-3 Holdings	(37)	(25)
Other financing activities	179	160
Net cash used in financing activities from continuing operations		548
Net cash used in financing activities	491
Effect of foreign currency exchange rate changes on cash
Net (decrease) increase in cash and cash equivalents	111	90
Cash and cash equivalents, beginning of the period	(139)	(102)
Cash and cash equivalents, end of the period	$ (28)	$ (12)