Goodwill and other intangible assets

9 Months Ended

Sep. 30, 2019

Goodwill And Intangible Assets Disclosure [Abstract]

Notes to Consolidated Financial Statements (Continued)

Note 13. Goodwill and other intangible assets

Reconciliations of the changes in the carrying value of goodwill for the first nine months of 2019 and for the year ended December 31, 2018 follows (in millions).

	September 30, 2019			December 31, 2018
Balance at beginning of year	$	81,025		$	81,258
Acquisitions of businesses		279			376
Other, including foreign currency translation		(76	)		(609	)
Balance at end of period	$	81,228		$	81,025

Other intangible assets and related accumulated amortization are summarized as follows (in millions).

	September 30, 2019				December 31, 2018
	Gross carrying amount		Accumulated amortization		Gross carrying amount		Accumulated amortization
Insurance and other:
Trademarks and trade names	$	5,145	$	743	$	5,152	$	727
Patents and technology		4,524		2,973		4,446		2,790
Customer relationships		27,786		4,874		27,697		4,287
Other		3,169		1,246		3,198		1,190
	$	40,624	$	9,836	$	40,493	$	8,994

Railroad, utilities and energy:
Trademarks and trade names	$	216	$	27	$	216	$	23
Customer relationships		678		315		678		286
Other		117		56		117		53
	$	1,011	$	398	$	1,011	$	362

Intangible asset amortization expense in the first nine months was $986 million in 2019 and $1,052 million in 2018. Intangible assets with indefinite lives were $18.8 billion as of September 30, 2019 and $18.9 billion as of December 31, 2018 and primarily related to certain customer relationships and trademarks and trade names.