GOODWILL AND OTHER INTANGIBLE ASSETS

9 Months Ended

Sep. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets and goodwill consist of the following (in millions):


September 30, 2019	Weighted Average Useful Life	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Amortizable intangible assets:
Customer relationships	20 years	$	541	$	(158)	$	383
Technology	17 years	317		(148)		169
Other	13 years	61		(31)		30
Indefinite-lived intangible assets:
Trademarks		1,134				1,134
Total intangible assets		$	2,053	$	(337)	$	1,716
Goodwill		$	1,909


December 31, 2018	Weighted Average Useful Life	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Amortizable intangible assets:
Customer relationships	20 years	$	554	$	(138)	$	416
Technology	17 years	321		(134)		187
Other	14 years	60		(28)		32
Indefinite-lived intangible assets:
Trademarks		1,144		—		1,144
Total intangible assets		$	2,079	$	(300)	$	1,779
Goodwill		$	1,949

Goodwill

The Company tests goodwill and indefinite-lived intangible assets for impairment during the fourth quarter of each year, or more frequently should circumstances change or events occur that would more likely than not reduce the fair value of a reporting unit below its carrying amount. No testing was deemed necessary in the first nine months of 2019. The changes in the net carrying amount of goodwill by segment are as follows (in millions):


	Composites		Insulation		Roofing		Total
Balance at December 31, 2018	$	57	$	1,495	$	397	$	1,949

Foreign currency translation	—		(37)		(3)		(40)
Balance at September 30, 2019	$	57	$	1,458	$	394	$	1,909

Other Intangible Assets

The Other category below primarily includes franchise agreements and quarry and emission rights. The changes in the gross carrying amount of intangible assets by asset group are as follows (in millions):


	Customer Relationships		Technology		Trademarks		Other		Total
Balance at December 31, 2018	$	554	$	321	$	1,144	$	60	$	2,079

Other additions, net	—		—		—		2		2
Foreign currency translation	(13)		(4)		(10)		(1)		(28)
Balance at September 30, 2019	$	541	$	317	$	1,134	$	61	$	2,053

The estimated amortization expense for intangible assets for the next five years is as follows (in millions):


Period	Amortization
2020	$	50
2021	$	50
2022	$	45
2023	$	42
2024	$	39