Intangible assets

Intangible assets consisted of the following (in millions):



	September 30, 2012							December 31, 2011
	Gross carrying amount		Accumulated amortization			Intangible assets, net		Gross carrying amount		Accumulated amortization			Intangible assets, net
Finite-lived intangible assets:
Acquired product technology rights:
Developed product technology	$	2,872	$	(1,955	)	$	917	$	2,872	$	(1,811	)	$	1,061
Core technology	1,348		(917		)	431		1,348		(850		)	498
Trade name	190		(129		)	61		190		(120		)	70
Acquired R&D technology rights	687		(370		)	317		350		(350		)	—
Other acquired intangible assets	897		(457		)	440		686		(406		)	280
Total finite-lived intangible assets	5,994		(3,828		)	2,166		5,446		(3,537		)	1,909

Indefinite-lived intangible assets:
IPR&D	1,358		—			1,358		675		—			675
Contract assets	156		—			156		—		—			—
Total indefinite-lived intangible assets	1,514		—			1,514		675		—			675

Total identifiable intangible assets	$	7,508	$	(3,828	)	$	3,680	$	6,121	$	(3,537	)	$	2,584

Acquired R&D technology rights, Other acquired intangible assets, IPR&D and Contract assets as of September 30, 2012, included the identifiable intangible assets acquired in connection with the acquisitions of Micromet, MN and KAI (see Note 2, Business combinations).

During the three months ended September 30, 2012 and 2011, we recognized amortization charges associated with our finite-lived intangible assets of $101 million and $93 million, respectively. During the nine months ended September 30, 2012 and 2011, we recognized amortization charges associated with our finite-lived intangible assets of $290 million and $289 million, respectively. The total estimated amortization charges for our finite-lived intangible assets for the three months ended December 31, 2012, and the years ended December 31, 2013, 2014, 2015, 2016 and 2017, are $103 million, $423 million, $406 million, $393 million, $372 million and $230 million, respectively.