Condensed Combining Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 26, 2014	Dec. 31, 2013	Sep. 27, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 508	$ 500	$ 377	$ 349
Billed receivables, net	871	991
Contracts in process	2,546	2,431
Other current assets	731	672
Total current assets	4,656	4,594
Goodwill	7,784	7,796
Other assets	1,601	1,598
Investment in and amounts due from consolidated subsidiaries
Total assets	14,041	13,988
Current liabilities	2,392	2,534
Amounts due to consolidated subsidiaries
Other long-term liabilities	1,732	1,768
Long-term debt	3,938	3,630
Total liabilities	8,062	7,932
L-3 shareholders' equity	5,903	5,981
Noncontrolling interests	76	75
Total equity	5,979	6,056	5,798	5,527
Total liabilities and equity	14,041	13,988
L-3 Communications Holdings, Inc. [Member]
Current assets:
Cash and cash equivalents
Billed receivables, net
Contracts in process
Other current assets
Total current assets
Goodwill
Other assets
Investment in and amounts due from consolidated subsidiaries	5,903	6,670
Total assets	5,903	6,670
Current liabilities
Amounts due to consolidated subsidiaries
Other long-term liabilities
Long-term debt		689
Total liabilities		689
L-3 shareholders' equity	5,903	5,981
Noncontrolling interests
Total equity	5,903	5,981
Total liabilities and equity	5,903	6,670
L-3 Communications Corporation [Member]
Current assets:
Cash and cash equivalents	330	258	154	246
Billed receivables, net	296	364
Contracts in process	994	925
Other current assets	410	344
Total current assets	2,030	1,891
Goodwill	2,324	2,324
Other assets	800	838
Investment in and amounts due from consolidated subsidiaries	6,993	6,923
Total assets	12,147	11,976
Current liabilities	872	914
Amounts due to consolidated subsidiaries
Other long-term liabilities	1,434	1,451
Long-term debt	3,938	3,630
Total liabilities	6,244	5,995
L-3 shareholders' equity	5,903	5,981
Noncontrolling interests
Total equity	5,903	5,981
Total liabilities and equity	12,147	11,976
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	1		1
Billed receivables, net	348	401
Contracts in process	1,165	1,152
Other current assets	145	159
Total current assets	1,659	1,712
Goodwill	4,320	4,320
Other assets	568	532
Investment in and amounts due from consolidated subsidiaries	4,049	3,750
Total assets	10,596	10,314
Current liabilities	999	1,011
Amounts due to consolidated subsidiaries
Other long-term liabilities	187	193
Long-term debt
Total liabilities	1,186	1,204
L-3 shareholders' equity	9,410	9,110
Noncontrolling interests
Total equity	9,410	9,110
Total liabilities and equity	10,596	10,314
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	239	261	244	242
Billed receivables, net	227	226
Contracts in process	387	354
Other current assets	176	169
Total current assets	1,029	1,010
Goodwill	1,140	1,152
Other assets	233	228
Investment in and amounts due from consolidated subsidiaries
Total assets	2,402	2,390
Current liabilities	583	628
Amounts due to consolidated subsidiaries	366	259
Other long-term liabilities	111	124
Long-term debt
Total liabilities	1,060	1,011
L-3 shareholders' equity	1,342	1,379
Noncontrolling interests
Total equity	1,342	1,379
Total liabilities and equity	2,402	2,390
Eliminations [Member]
Current assets:
Cash and cash equivalents	(62)	(19)	(22)	(139)
Billed receivables, net
Contracts in process
Other current assets
Total current assets	(62)	(19)
Goodwill
Other assets
Investment in and amounts due from consolidated subsidiaries	(16,945)	(17,343)
Total assets	(17,007)	(17,362)
Current liabilities	(62)	(19)
Amounts due to consolidated subsidiaries	(366)	(259)
Other long-term liabilities
Long-term debt		(689)
Total liabilities	(428)	(967)
L-3 shareholders' equity	(16,655)	(16,470)
Noncontrolling interests	76	75
Total equity	(16,579)	(16,395)
Total liabilities and equity	$ (17,007)	$ (17,362)