Intangible assets

3 Months Ended

Mar. 31, 2020

Intangible assets

Intangible assets

7.  INTANGIBLE ASSETS

	March 31, 2020						December 31, 2019
	Gross carrying value		Accumulated amortization		Net carrying value		Gross carrying value		Accumulated amortization		Net carrying value
Customer relationships	$	615	$	(113)	$	502	$	615	$	(102)	$	513
Backlog		330		(241)		89		330		(217)		113
Technologies		320		(161)		159		320		(144)		176
Software		230		(92)		138		213		(83)		130
Image library		80		(51)		29		80		(48)		32
Trade names and other		37		(11)		26		37		(10)		27
Intangible assets	$	1,612	$	(669)	$	943	$	1,595	$	(604)	$	991

Amortization expense related to intangible assets was $66 million and $67 million for the three months ended March 31, 2020 and March 31, 2019, respectively.