Goodwill and Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2018


	June 30,		December 31,
(Millions)	2018		2017
Customer related intangible assets	$	2,302	$	2,332
Patents		554		561
Other technology-based intangible assets		578		583
Definite-lived tradenames		676		678
Other amortizable intangible assets		204		207
Total gross carrying amount	$	4,314	$	4,361

Accumulated amortization — customer related		(931)		(874)
Accumulated amortization — patents		(491)		(489)
Accumulated amortization — other technology based		(312)		(292)
Accumulated amortization — definite-lived tradenames		(272)		(256)
Accumulated amortization — other		(164)		(162)
Total accumulated amortization	$	(2,170)	$	(2,073)

Total finite-lived intangible assets — net	$	2,144	$	2,288

Non-amortizable intangible assets (primarily tradenames)		643		648
Total intangible assets — net	$	2,787	$	2,936

Amortization expense for acquired intangible assets for the three and six months ended June 30, 2018 and 2017 follows:

Expected amortization expense for acquired amortizable intangible assets recorded as of June 30, 2018: