The Company does not amortize goodwill, however, core deposit and other intangible assets are amortized over the estimated life of each respective asset. Total amortizing intangible assets were comprised of the following:

	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	(In thousands)
December 31, 2020
Core deposit	$	131,664	$	119,125	$	12,539
Other		6,757		5,131		1,626
Total	$	138,421	$	124,256	$	14,165
December 31, 2019
Core deposit	$	131,664	$	105,802	$	25,862
Other		6,757		3,585		3,172
Total	$	138,421	$	109,387	$	29,034

Amortization of core deposit and other intangible assets was generally computed using accelerated methods over original amortization periods of three to seven years. The weighted-average original amortization period was approximately seven years. Amortization expense for core deposit and other intangible assets was $15 million, $19 million and $25 million for the years ended December 31, 2020, 2019 and 2018, respectively. Estimated amortization expense in future years for such intangible assets is as follows:

The Company completed annual goodwill impairment tests as of October 1, 2020, 2019 and 2018. For purposes of testing for impairment, the Company assigned all recorded goodwill to the reporting units originally intended to benefit from past business combinations, which has historically

been the Company’s core relationship business reporting units. Goodwill was generally assigned based on the implied fair value of the acquired goodwill applicable to the benefited reporting units at the time of each respective acquisition. The implied fair value of the goodwill was determined as the difference between the estimated incremental overall fair value of the reporting unit and the estimated fair value of the net assets assigned to the reporting unit as of each respective acquisition date. To test for goodwill impairment at each evaluation date, the Company compared the estimated fair value of each of its reporting units to their respective carrying amounts and certain other assets and liabilities assigned to the reporting unit, including goodwill and core deposit and other intangible assets. The methodologies used to estimate fair values of reporting units as of the acquisition dates and as of the evaluation dates were similar. For the Company’s core customer relationship business reporting units, fair value was estimated as the present value of the expected future cash flows of the reporting unit. Based on the results of the goodwill impairment tests, the Company concluded that the amount of recorded goodwill was not impaired at the respective testing dates.

A summary of goodwill assigned to each of the Company’s reportable segments as of December 31, 2020 and 2019 for purposes of testing for impairment is as follows:

	(In thousands)

Business Banking	$	864,366
Commercial Banking		1,401,873
Commercial Real Estate		654,389
Discretionary Portfolio		—
Residential Mortgage Banking		—
Retail Banking		1,309,191
All Other		363,293
Total	$	4,593,112