GOODWILL AND OTHER INTANGIBLE ASSETS

Changes in the carrying amount of goodwill for our reportable segments for the years ended December 31, 2018 and 2017 were as follows:



	Retail		Group and Specialty		Healthcare Services		Total
	(in millions)
Balance at January 1, 2017	$	1,059	$	261	$	1,952	$	3,272
Acquisitions	—		—		9		9
Balance at December 31, 2017	1,059		261		1,961		3,281
Acquisitions	476		—		140		616
Balance at December 31, 2018	$	1,535	$	261	$	2,101	$	3,897

The following table presents details of our other intangible assets included in other long-term assets in the accompanying consolidated balance sheets at December 31, 2018 and 2017.



	Weighted Average Life	2018						2017
	Weighted Average Life	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
		(in millions)
Other intangible assets:
Customer contracts/relationships	8.7 years	$	646	$	434	$	212	$	566	$	401	$	165
Trade names and technology	6.4 years	84		83		1		104		84		20
Provider contracts	11.8 years	68		37		31		68		30		38
Noncompetes and other	7.3 years	29		28		1		32		29		3
Total other intangible assets	8.7 years	$	827	$	582	$	245	$	770	$	544	$	226

Amortization expense for other intangible assets was approximately $90 million in 2018, $75 million in 2017, and $77 million in 2016. Amortization expense for 2018 included $12 million associated with the write-off of a trade name value reflecting the re-branding of certain provider assets.

The following table presents our estimate of amortization expense for each of the five next succeeding fiscal years:



	(in millions)
For the years ending December 31,
2019	$	70
2020	67
2021	34
2022	31
2023	18