Goodwill and other intangible assets (Tables)

3 Months Ended

Mar. 31, 2014

Reconciliation of the change in goodwill

A reconciliation of the change in the carrying value of goodwill is as follows (in millions).

	March 31, 2014		December 31, 2013
Balance at beginning of year	$	57,011	$	54,523
Acquisitions of businesses		1,236		2,732
Other, including foreign currency translation		17		(244	)
Balance at end of period	$	58,264	$	57,011

Schedule of intangible assets

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

	March 31, 2014				December 31, 2013
	Gross carrying amount		Accumulated amortization		Gross carrying amount		Accumulated amortization
Insurance and other	$	12,924	$	3,936	$	11,923	$	3,723
Railroad, utilities and energy		2,214		1,309		2,214		1,231
	$	15,138	$	5,245	$	14,137	$	4,954
Trademarks and trade names	$	2,988	$	365	$	2,750	$	340
Patents and technology		5,667		2,771		5,173		2,626
Customer relationships		4,880		1,618		4,690		1,518
Other		1,603		491		1,524		470
	$	15,138	$	5,245	$	14,137	$	4,954