Acquisitions and Goodwill (Rollforward of Goodwill by Segments) (Details) - USD ($)
3 Months Ended 9 Months Ended
Apr. 03, 2016
Oct. 02, 2016
Dec. 31, 2015
Goodwill [Roll Forward]      
Beginning balance $ 14,731,000,000 $ 14,731,000,000  
Acquisitions(3)   59,000,000  
Effect of foreign exchange rates and other   1,000,000  
Ending balance   14,791,000,000  
Integrated Defense Systems      
Goodwill [Roll Forward]      
Beginning balance 1,704,000,000 1,704,000,000  
Acquisitions(3)   0  
Effect of foreign exchange rates and other   0  
Ending balance   1,704,000,000  
Intelligence, Information and Services      
Goodwill [Roll Forward]      
Beginning balance 2,958,000,000 2,958,000,000  
Acquisitions(3)   8,000,000  
Effect of foreign exchange rates and other   1,000,000  
Ending balance   2,967,000,000  
Goodwill allocated to IIS from IDS     $ 90,000,000
Missile Systems      
Goodwill [Roll Forward]      
Beginning balance 4,154,000,000 4,154,000,000  
Acquisitions(3)   0  
Effect of foreign exchange rates and other   0  
Ending balance   4,154,000,000  
Space and Airborne Systems      
Goodwill [Roll Forward]      
Beginning balance 4,106,000,000 4,106,000,000  
Acquisitions(3)   0  
Effect of foreign exchange rates and other   0  
Ending balance   4,106,000,000  
Forcepoint      
Goodwill [Roll Forward]      
Beginning balance 1,809,000,000 1,809,000,000  
Acquisitions(3)   51,000,000  
Effect of foreign exchange rates and other   0  
Ending balance   1,860,000,000  
Estimated fair value in excess of book value   $ 480,000,000  
Foreground Security [Member]      
Goodwill [Roll Forward]      
Goodwill, Purchase Accounting Adjustments $ 8,000,000