Raytheon, which gained fame during the Gulf War with the spectacular success of its anti-missile Patriot defence system, has launched a tender offer worth $64 for each E-Systems share, a 41 per cent premium to Friday's closing price.
The deal has been approved by the boards of both companies.
Raytheon's chairman and chief executive, Dennis Picard, said: "The combination opens new defence and commercial markets worldwide, brings our annualized electronics sales to $6bn and our current electronics backlog to $8bn."
The Massachusetts-based Raytheon, a key Pentagon contractor, brings annual revenues of $10bn and 60,000 employees to the new grouping.
E-Systems, based in Dallas, Texas, will be the smaller partner. It had turnover of around $2bn last year and employed 16,000.