Goodwill and Other Purchased Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2012

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

The changes in the carrying amounts of goodwill for the years ended December 31, 2012 and 2011, were as follows:

$ in millions	Aerospace Systems			Electronic Systems			Information Systems		Technical Services		Total
Balance as of December 31, 2010		$3,801			$2,402			$5,248		$925		$12,376
Businesses sold	—			(2		)	—		—		(2		)
Balance as of December 31, 2011		$3,801			$2,400			$5,248		$925		$12,374
Businesses acquired, sold and other	(43		)	10			39		51		57
Balance as of December 31, 2012		$3,758			$2,410			$5,287		$976		$12,431