Intangible assets

9 Months Ended

Sep. 30, 2022

Intangible assets

Intangible assets

6. INTANGIBLE ASSETS

	September 30, 2022						December 31, 2021
	Gross carrying value		Accumulated amortization		Net carrying value		Gross carrying value		Accumulated amortization		Net carrying value
Customer relationships	$	615	$	(223)	$	392	$	615	$	(190)	$	425
Software		446		(179)		267		379		(152)		227
Technologies		367		(329)		38		367		(278)		89
Backlog		86		(86)		—		107		(89)		18
Image library		80		(80)		—		80		(71)		9
Trade names and other		37		(22)		15		37		(18)		19
Intangible assets	$	1,631	$	(919)	$	712	$	1,585	$	(798)	$	787

The gross carrying value and accumulated amortization balances for fully amortized backlog were removed from the Unaudited Condensed Consolidated Balance Sheets and excluded from the table above as of September 30, 2022. Amortization expense related to intangible assets was $44 million and $51 million, for the three months ended September 30, 2022 and 2021, respectively, and $141 million and $154 million for the nine months ended September 30, 2022 and 2021, respectively.