Acquisitions, Divestitures, Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2013

The changes in the carrying amount of goodwill by reporting unit during 2012 and 2013 were as follows:



	Aerospace		Combat Systems			Marine Systems			Information Systems and Technology			Total Goodwill
December 31, 2011	$	2,644	$	2,839		$	229		$	7,864		$	13,576
Impairment	—		—			—			(1,994		)	(1,994		)
Acquisitions (a)	11		86			61			221			379
Other (b)	42		36			—			9			87
December 31, 2012	$	2,697	$	2,961		$	290		$	6,100		$	12,048
Acquisitions (a)	—		2			(1		)	1			2
Other (b)	44		(69		)	—			(48		)	(73		)
December 31, 2013	$	2,741	$	2,894		$	289		$	6,053		$	11,977

(a)Includes adjustments during the purchase price allocation period.

(b)Consists primarily of adjustments for foreign currency translation and allocations of goodwill associated with asset sales.

Intangible assets consisted of the following:



	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
	December 31, 2012							December 31, 2013
Contract and program intangible assets*	$	2,066	$	(1,165	)	$	901	$	2,042	$	(1,273	)	$	769
Trade names and trademarks	494		(87		)	407		507		(103		)	404
Technology and software	180		(108		)	72		140		(97		)	43
Other intangible assets	175		(172		)	3		155		(154		)	1
Total intangible assets	$	2,915	$	(1,532	)	$	1,383	$	2,844	$	(1,627	)	$	1,217

* Consists of acquired backlog and probable follow-on work and related customer relationships.

The amortization lives (in years) of our intangible assets on December 31, 2013, were as follows:



		Range of
		Amortization Life
Contract and program intangible assets		7-30
Trade names and trademarks		30
Technology and software		7-15
Other intangible assets		5

We expect to record annual amortization expense over the next five years as follows:

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.