Acquisitions (Rollforward of Goodwill by Segments) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Goodwill [Roll Forward]    
Balance at beginning of period $ 12,544 $ 12,045
Increase for acquisitions 212 499
Effect of foreign exchange rates and other 0 0
Balance at end of period 12,756 12,544
Integrated Defense Systems
    
Goodwill [Roll Forward]    
Balance at beginning of period 765 765
Increase for acquisitions 2 0
Effect of foreign exchange rates and other 0 0
Balance at end of period 767 765
Intelligence and Information Systems
    
Goodwill [Roll Forward]    
Balance at beginning of period 1,775 1,698
Increase for acquisitions 13 77
Effect of foreign exchange rates and other 0 0
Balance at end of period 1,788 1,775
Missile Systems
    
Goodwill [Roll Forward]    
Balance at beginning of period 3,467 3,432
Increase for acquisitions 0 35
Effect of foreign exchange rates and other 0 0
Balance at end of period 3,467 3,467
Network Centric Systems
    
Goodwill [Roll Forward]    
Balance at beginning of period 2,616 2,616
Increase for acquisitions 197 0
Effect of foreign exchange rates and other 0 0
Balance at end of period 2,813 2,616
Space and Airborne Systems
    
Goodwill [Roll Forward]    
Balance at beginning of period 3,050 2,663
Increase for acquisitions 0 387
Effect of foreign exchange rates and other 0 0
Balance at end of period 3,050 3,050
Technical Services
    
Goodwill [Roll Forward]    
Balance at beginning of period 871 871
Increase for acquisitions 0 0
Effect of foreign exchange rates and other 0 0
Balance at end of period $ 871 $ 871