Condensed Combining Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 27, 2015	Dec. 31, 2014	Mar. 28, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 317	$ 442	$ 227	$ 500
Billed receivables, net	836	852
Contracts in process	2,402	2,295
Other current assets	661	601
Assets held for sale	496	547
Total current assets	4,712	4,737
Goodwill	7,462	7,501
Other assets	1,608	1,598
Investment in and amounts due from consolidated subsidiaries
Total assets	13,782	13,836
Current liabilities	2,300	2,288
Liabilities held for sale	225	237
Amounts due to consolidated subsidiaries
Other long-term liabilities	2,016	2,012
Long-term debt	3,939	3,939
Total liabilities	8,480	8,476
L-3 shareholders' equity	5,228	5,285
Noncontrolling interests	74	75
Total equity	5,302	5,360	6,135	6,056
Total liabilities and equity	13,782	13,836
L-3 Communications Holdings, Inc. [Member]
Current assets:
Cash and cash equivalents
Billed receivables, net
Contracts in process
Other current assets
Assets held for sale
Total current assets
Goodwill
Other assets
Investment in and amounts due from consolidated subsidiaries	5,228	5,285
Total assets	5,228	5,285
Current liabilities
Liabilities held for sale
Amounts due to consolidated subsidiaries
Other long-term liabilities
Long-term debt
Total liabilities
L-3 shareholders' equity	5,228	5,285
Noncontrolling interests
Total equity	5,228	5,285
Total liabilities and equity	5,228	5,285
L-3 Communications Corporation [Member]
Current assets:
Cash and cash equivalents	210	361	57	258
Billed receivables, net	294	320
Contracts in process	909	867
Other current assets	405	365
Assets held for sale
Total current assets	1,818	1,913
Goodwill	2,360	2,350
Other assets	837	817
Investment in and amounts due from consolidated subsidiaries	6,846	6,813
Total assets	11,861	11,893
Current liabilities	905	878
Liabilities held for sale
Amounts due to consolidated subsidiaries
Other long-term liabilities	1,789	1,791
Long-term debt	3,939	3,939
Total liabilities	6,633	6,608
L-3 shareholders' equity	5,228	5,285
Noncontrolling interests
Total equity	5,228	5,285
Total liabilities and equity	11,861	11,893
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	2	1
Billed receivables, net	327	329
Contracts in process	1,191	1,144
Other current assets	150	141
Assets held for sale	51	52
Total current assets	1,721	1,667
Goodwill	4,246	4,246
Other assets	568	576
Investment in and amounts due from consolidated subsidiaries	4,174	4,191
Total assets	10,709	10,680
Current liabilities	965	1,017
Liabilities held for sale	9	10
Amounts due to consolidated subsidiaries
Other long-term liabilities	199	190
Long-term debt
Total liabilities	1,173	1,217
L-3 shareholders' equity	9,536	9,463
Noncontrolling interests
Total equity	9,536	9,463
Total liabilities and equity	10,709	10,680
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	116	142	182	261
Billed receivables, net	215	203
Contracts in process	302	284
Other current assets	106	95
Assets held for sale	445	495
Total current assets	1,184	1,219
Goodwill	856	905
Other assets	203	205
Investment in and amounts due from consolidated subsidiaries
Total assets	2,243	2,329
Current liabilities	441	455
Liabilities held for sale	216	227
Amounts due to consolidated subsidiaries	355	325
Other long-term liabilities	28	31
Long-term debt
Total liabilities	1,040	1,038
L-3 shareholders' equity	1,203	1,291
Noncontrolling interests
Total equity	1,203	1,291
Total liabilities and equity	2,243	2,329
Eliminations [Member]
Current assets:
Cash and cash equivalents	(11)	(62)	(12)	(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	(16,248)	(16,289)
Total assets	(16,259)	(16,351)
Current liabilities	(11)	(62)
Liabilities held for sale
Amounts due to consolidated subsidiaries	(355)	(325)
Other long-term liabilities
Long-term debt
Total liabilities	(366)	(387)
L-3 shareholders' equity	(15,967)	(16,039)
Noncontrolling interests	74	75
Total equity	(15,893)	(15,964)
Total liabilities and equity	$ (16,259)	$ (16,351)