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. 27, 2014	Jun. 28, 2013
Operating activities:
Net cash from (used in) operating activities	$ 215	$ 396
Investing activities:
Business acquisitions, net of cash acquired	(57)	(1)
Investments in L-3 Communications
Other investing activities	(60)	(103)
Net cash used in investing activities	(117)	(104)
Financing activities:
Proceeds from sale of senior notes	996
Retirement of CODES	(935)
Common stock repurchased	(333)	(248)
Dividends paid on L-3 Holdings common stock	(107)	(101)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	80	45
Net cash used in financing activities	(299)	(304)
Effect of foreign currency exchange rate changes on cash		(9)
Net decrease in cash and cash equivalents	(201)	(21)
Cash and cash equivalents, beginning of the period	500	349
Cash and cash equivalents, end of the period	299	328
L-3 Communications Holdings, Inc. [Member]
Operating activities:
Net cash from (used in) operating activities	1,375	349
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	(77)	(37)
Other investing activities
Net cash used in investing activities	(77)	(37)
Financing activities:
Proceeds from sale of senior notes
Retirement of CODES	(935)
Common stock repurchased	(333)	(248)
Dividends paid on L-3 Holdings common stock	(107)	(101)
Dividends paid to L-3 Holdings
Investments from L-3 Holdings
Other financing activities	77	37
Net cash used in financing activities	(1,298)	(312)
Effect of foreign currency exchange rate changes on cash
Net decrease 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 [Member]
Operating activities:
Net cash from (used in) operating activities	107	146
Investing activities:
Business acquisitions, net of cash acquired	(57)	(1)
Investments in L-3 Communications
Other investing activities	(25)	(53)
Net cash used in investing activities	(82)	(54)
Financing activities:
Proceeds from sale of senior notes	996
Retirement of CODES
Common stock repurchased
Dividends paid on L-3 Holdings common stock
Dividends paid to L-3 Holdings	(1,375)	(349)
Investments from L-3 Holdings	77	37
Other financing activities	111	94
Net cash used in financing activities	(191)	(218)
Effect of foreign currency exchange rate changes on cash
Net decrease in cash and cash equivalents	(166)	(126)
Cash and cash equivalents, beginning of the period	258	246
Cash and cash equivalents, end of the period	92	120
Guarantor Subsidiaries [Member]
Operating activities:
Net cash from (used in) operating activities	152	254
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(24)	(39)
Net cash used in investing activities	(24)	(39)
Financing activities:
Proceeds from sale of senior notes
Retirement of CODES
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	(126)	(215)
Net cash used in financing activities	(126)	(215)
Effect of foreign currency exchange rate changes on cash
Net decrease in cash and cash equivalents	2
Cash and cash equivalents, beginning of the period
Cash and cash equivalents, end of the period	2
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash from (used in) operating activities	3	64
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications
Other investing activities	(11)	(11)
Net cash used in investing activities	(11)	(11)
Financing activities:
Proceeds from sale of senior notes
Retirement of CODES
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	(40)	(50)
Net cash used in financing activities	(40)	(50)
Effect of foreign currency exchange rate changes on cash		(9)
Net decrease in cash and cash equivalents	(48)	(6)
Cash and cash equivalents, beginning of the period	261	242
Cash and cash equivalents, end of the period	213	236
Eliminations [Member]
Operating activities:
Net cash from (used in) operating activities	(1,422)	(417)
Investing activities:
Business acquisitions, net of cash acquired
Investments in L-3 Communications	77	37
Other investing activities
Net cash used in investing activities	77	37
Financing activities:
Proceeds from sale of senior notes
Retirement of CODES
Common stock repurchased
Dividends paid on L-3 Holdings common stock
Dividends paid to L-3 Holdings	1,375	349
Investments from L-3 Holdings	(77)	(37)
Other financing activities	58	179
Net cash used in financing activities	1,356	491
Effect of foreign currency exchange rate changes on cash
Net decrease in cash and cash equivalents	11	111
Cash and cash equivalents, beginning of the period	(19)	(139)
Cash and cash equivalents, end of the period	$ (8)	$ (28)