Goodwill and other intangible assets (Tables)

9 Months Ended

Sep. 30, 2012

Reconciliation of the change in goodwill

A reconciliation of the change in the carrying value of goodwill for the nine months ended September 30, 2012 and the year ended December 31, 2011 follows (in millions).

	September 30, 2012			December 31, 2011
Balance at beginning of year	$	53,213		$	49,006
Acquisitions of businesses		1,064			4,179
Other, including foreign currency translation		(134	)		28
Balance at end of period	$	54,143		$	53,213

Schedule of intangible assets

Intangible assets other than goodwill are included in other assets and are summarized by type as follows (in millions).

	September 30, 2012				December 31, 2011
	Gross carrying amount		Accumulated amortization		Gross carrying amount		Accumulated amortization
Insurance and other	$	11,366	$	2,826	$	11,016	$	2,319
Railroad, utilities and energy		2,101		861		2,088		623
	$	13,467	$	3,687	$	13,104	$	2,942
Trademarks and trade names	$	2,684	$	265	$	2,655	$	219
Patents and technology		4,984		1,927		4,900		1,496
Customer relationships		4,232		1,071		4,060		840
Other		1,567		424		1,489		387
	$	13,467	$	3,687	$	13,104	$	2,942