Description of Business	9 Months Ended
Sep. 25, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business L-3 Communications Holdings, Inc. derives all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Communications). L-3 Communications Holdings, Inc. (L-3 Holdings and, together with its subsidiaries, referred to herein as L-3 or the Company) is a prime contractor in Intelligence, Surveillance and Reconnaissance (ISR) systems, aircraft sustainment (including modifications, logistics and maintenance), simulation and training, night vision and image intensification equipment, enterprise and mission information technology (IT) solutions and cyber operations. L-3 is also a leading provider of a broad range of communication and electronic systems and products used on military and commercial platforms. The Company’s customers include the United States (U.S.) Department of Defense (DoD) and its prime contractors, U.S. Government intelligence agencies, the U.S. Department of Homeland Security (DHS), foreign governments, and domestic and international commercial customers. The Company has the following four reportable segments: (1) Electronic Systems, (2) Aerospace Systems, (3) Communication Systems and (4) National Security Solutions (NSS). Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers in several niche markets across several business areas. These business areas include precision engagement & training, sensor systems, power & propulsion systems, aviation products and security systems, warrior systems and advanced programs. Aerospace Systems delivers integrated solutions for the global ISR market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. NSS provides cybersecurity solutions, high-performance computing, enterprise IT services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and foreign governments. In April 2015, the Company realigned its Platform and Logistics Solutions sector within its Aerospace Systems segment to enhance the operational effectiveness and competitiveness of its platform systems business. The platform systems business was integrated within the ISR Systems sector and the new integrated organization was renamed the ISR and Aircraft Systems sector. The Logistics Solutions sector remains a separate sector within the Aerospace Systems segment. This realignment did not impact the composition of the Company’s reporting units. Financial information with respect to the Company’s segments is included in Note 21 to the unaudited condensed consolidated financial statements and in Note 22 to the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.

1. Description of Business

L-3 Communications Holdings, Inc. derives all of its operating income and cash flows from its wholly-owned subsidiary, L-3 Communications Corporation (L-3 Communications). L-3 Communications Holdings, Inc. (L-3 Holdings and, together with its subsidiaries, referred to herein as L-3 or the Company) is a prime contractor in Intelligence, Surveillance and Reconnaissance (ISR) systems, aircraft sustainment (including modifications, logistics and maintenance), simulation and training, night vision and image intensification equipment, enterprise and mission information technology (IT) solutions and cyber operations. L-3 is also a leading provider of a broad range of communication and electronic systems and products used on military and commercial platforms. The Company’s customers include the United States (U.S.) Department of Defense (DoD) and its prime contractors, U.S. Government intelligence agencies, the U.S. Department of Homeland Security (DHS), foreign governments, and domestic and international commercial customers.

The Company has the following four reportable segments: (1) Electronic Systems, (2) Aerospace Systems, (3) Communication Systems and (4) National Security Solutions (NSS). Electronic Systems provides a broad range of components, products, subsystems, systems and related services for military and commercial customers in several niche markets across several business areas. These business areas include precision engagement & training, sensor systems, power & propulsion systems, aviation products and security systems, warrior systems and advanced programs. Aerospace Systems delivers integrated solutions for the global ISR market and provides modernization, upgrade, sustainment, and maintenance and logistics support for a wide variety of aircraft and ground systems. Communication Systems delivers products and services for the global communications market, specializing in strategic and tactical airborne, space, ground and sea-based communication systems. NSS provides cybersecurity solutions, high-performance computing, enterprise IT services, analytics and intelligence analysis to the DoD, U.S. Government intelligence agencies, federal civilian agencies and foreign governments.

In April 2015, the Company realigned its Platform and Logistics Solutions sector within its Aerospace Systems segment to enhance the operational effectiveness and competitiveness of its platform systems business. The platform systems business was integrated within the ISR Systems sector and the new integrated organization was renamed the ISR and Aircraft Systems sector. The Logistics Solutions sector remains a separate sector within the Aerospace Systems segment. This realignment did not impact the composition of the Company’s reporting units.

Financial information with respect to the Company’s segments is included in Note 21 to the unaudited condensed consolidated financial statements and in Note 22 to the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.