Intangible Assets, net

The following table summarizes the components of Intangible assets, net (dollars in millions):



	March 31, 2012							December 31, 2011
		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Technology and intellectual property		$	7,763	$	5,393	$	2,370	$	7,751	$	5,081	$	2,670
Brands		5,440		414		5,026		5,410		374		5,036
Dealer network and customer relationships		2,169		354		1,815		2,138		322		1,816
Favorable contracts		519		220		299		514		200		314
Other		17		15		2		17		14		3
Total amortizing intangible assets		15,908		6,396		9,512		15,830		5,991		9,839
Non amortizing in process research and development		175				175		175				175
Total intangible assets		$	16,083	$	6,396	$	9,687	$	16,005	$	5,991	$	10,014

Amortization expense related to intangible assets was $398 million and $503 million in the three months ended March 31, 2012 and 2011.

The following table summarizes estimated amortization expense related to intangible assets in each of the next five years (dollars in millions):



	Estimated Amortization Expense
2013	$	1,229
2014	$	611
2015	$	313
2016	$	314
2017	$	311