Condensed Combining Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Balance Sheets (Detail) - USD ($) $ in Millions	Jun. 26, 2015	Dec. 31, 2014	Jun. 27, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 353	$ 442	$ 299	$ 500
Billed receivables, net	820	852
Contracts in process	2,422	2,295
Other current assets	708	601
Assets held for sale		547
Total current assets	4,303	4,737
Goodwill	7,649	7,501
Other assets	1,681	$ 1,598
Investment in and amounts due from consolidated subsidiaries
Total assets	13,633	$ 13,836
Current liabilities	2,417	2,288
Liabilities held for sale		$ 237
Amounts due to consolidated subsidiaries
Other long-term liabilities	2,004	$ 2,012
Long-term debt	3,940	3,939
Total liabilities	8,361	8,476
L-3 shareholders' equity	5,197	5,285
Noncontrolling interests	75	75
Total equity	5,272	5,360	$ 5,979	$ 6,056
Total liabilities and equity	13,633	13,836
L-3 Communications Holdings, Inc. [Member]
Current assets:
Cash and cash equivalents
Investment in and amounts due from consolidated subsidiaries	5,197	5,285
Total assets	5,197	5,285
L-3 shareholders' equity	5,197	5,285
Total equity	5,197	5,285
Total liabilities and equity	5,197	5,285
L-3 Communications Corporation [Member]
Current assets:
Cash and cash equivalents	197	361	$ 92	$ 258
Billed receivables, net	295	320
Contracts in process	887	867
Other current assets	411	$ 365
Assets held for sale
Total current assets	1,790	$ 1,913
Goodwill	2,319	2,308
Other assets	839	817
Investment in and amounts due from consolidated subsidiaries	6,886	6,855
Total assets	11,834	11,893
Current liabilities	936	$ 878
Liabilities held for sale
Amounts due to consolidated subsidiaries
Other long-term liabilities	1,761	$ 1,791
Long-term debt	3,940	3,939
Total liabilities	6,637	6,608
L-3 shareholders' equity	5,197	$ 5,285
Noncontrolling interests
Total equity	5,197	$ 5,285
Total liabilities and equity	11,834	11,893
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	3	1	2
Billed receivables, net	296	329
Contracts in process	1,189	1,144
Other current assets	166	141
Assets held for sale		52
Total current assets	1,654	1,667
Goodwill	4,268	4,280
Other assets	563	576
Investment in and amounts due from consolidated subsidiaries	4,306	4,157
Total assets	10,791	10,680
Current liabilities	979	1,017
Liabilities held for sale		$ 10
Amounts due to consolidated subsidiaries
Other long-term liabilities	204	$ 190
Long-term debt
Total liabilities	1,183	$ 1,217
L-3 shareholders' equity	9,608	$ 9,463
Noncontrolling interests
Total equity	9,608	$ 9,463
Total liabilities and equity	10,791	10,680
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	164	142	213	$ 261
Billed receivables, net	229	203
Contracts in process	346	284
Other current assets	131	95
Assets held for sale		495
Total current assets	870	1,219
Goodwill	1,062	913
Other assets	279	$ 205
Investment in and amounts due from consolidated subsidiaries
Total assets	2,211	$ 2,337
Current liabilities	513	455
Liabilities held for sale		227
Amounts due to consolidated subsidiaries	29	333
Other long-term liabilities	39	$ 31
Long-term debt
Total liabilities	581	$ 1,046
L-3 shareholders' equity	1,630	$ 1,291
Noncontrolling interests
Total equity	1,630	$ 1,291
Total liabilities and equity	2,211	2,337
Eliminations [Member]
Current assets:
Cash and cash equivalents	(11)	$ (62)	$ (8)	$ (19)
Billed receivables, net
Contracts in process
Other current assets
Assets held for sale
Total current assets	(11)	$ (62)
Goodwill
Other assets
Investment in and amounts due from consolidated subsidiaries	(16,389)	$ (16,297)
Total assets	(16,400)	(16,359)
Current liabilities	(11)	$ (62)
Liabilities held for sale
Amounts due to consolidated subsidiaries	(29)	$ (333)
Other long-term liabilities
Long-term debt
Total liabilities	(40)	$ (395)
L-3 shareholders' equity	(16,435)	(16,039)
Noncontrolling interests	75	75
Total equity	(16,360)	(15,964)
Total liabilities and equity	$ (16,400)	$ (16,359)