Goodwill and Acquired Intangible Assets

The following table identifies the activity relating to goodwill by operating segment:



In millions	Balance at December 31, 2017		Additions		Currency Translation Adjustments			Balance at December 31, 2018
Goodwill
Americas	$	253	$	—	$	—		$	253
International	146		—		(4		)	142
Total goodwill	$	399	$	—	$	(4	)	$	395

In the fourth quarter of 2018, the Company performed its annual impairment test of goodwill and determined that no impairment to the carrying value of goodwill was necessary. The Company reviewed two reporting units in its 2018 goodwill impairment assessment, as both geographic operating segments were considered separate reporting units for purposes of testing. Based on the Company's evaluation and weighting of the events and circumstances that have occurred since the most recent quantitative test, the Company concluded that it was not more likely than not that each reporting unit's fair value was below its carrying value. Therefore, the Company determined that it was not necessary to perform a quantitative goodwill impairment test for the reporting units in 2018.

Acquired intangible assets were specifically identified when acquired and are deemed to have finite lives. The gross carrying amount and accumulated amortization for Teradata’s acquired intangible assets were as follows:



		December 31, 2018					December 31, 2017
In millions	Amortization Life (in Years)	Gross Carrying Amount		Accumulated Amortization and Currency Translation Adjustments			Gross Carrying Amount		Accumulated Amortization and Currency Translation Adjustments
Acquired intangible assets
Intellectual property/developed technology	1 to 7	$	35	$	(20	)	$	43	$	(20	)

During 2018, the gross carrying amount of acquired intangibles was reduced by certain intangible assets previously acquired that became fully amortized and were removed from the balance sheet.

The aggregate amortization expense (actual and estimated) for acquired intangible assets for the following periods is:



	Actual						For the years ended (estimated)
In millions	2016		2017		2018		2019		2020		2021		2022
Amortization expense	$	10	$	8	$	7	$	5	$	4	$	4	$	2