Goodwill and indefinite-lived intangible assets are not amortized and are subject to assessment for impairment by applying a fair-value-based test on an annual basis or more frequently if circumstances indicate a potential impairment. An assessment for impairment is performed on October 1 of every year. The balance of goodwill was $477 million and $476 million as of September 30, 2019 and December 31, 2018, respectively. There were no goodwill or trade name impairment charges recorded in the three and nine months ended September 30, 2019 and 2018. There were no accumulated impairment losses recorded as of September 30, 2019 and December 31, 2018. During the second quarter of 2019, we completed a business acquisition for $3 million in cash, which was primarily allocated to other intangible assets and goodwill.



	As of September 30, 2019						As of December 31, 2018
(In millions)	Gross		Accumulated ‎Amortization		Net		Gross		Accumulated ‎Amortization		Net
Trade name⁽¹⁾	$	140	$	—	$	140	$	140	$	—	$	140
Customer relationships		173		(167)		5		173		(165)		7
Other		34		(25)		9		32		(22)		10
Total	$	347	$	(192)	$	155	$	345	$	(187)	$	158

Amortization expense was $1 million and $2 million for the three months ended September 30, 2019 and 2018, respectively, and $5 million and $6 million for the nine months ended September 30, 2019 and 2018, respectively. The following table outlines expected amortization expense for existing intangible assets for the remainder of 2019 and future years:



(In millions)
2019 (remainder)	$	1
2020		6
2021		4
2022		1
2023		1
Total	$	14