The Company does not amortize goodwill, however, core deposit and other intangible assets are amortized over the estimated life of each respective asset. A summary of total amortizing intangible assets follows.


	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	(In thousands)
December 31, 2022
Core deposit	$	218,000	$	40,875	$	177,125
Other		43,000		10,751		32,249
Total	$	261,000	$	51,626	$	209,374
December 31, 2021
Core deposit	$	131,664	$	127,746	$	3,918
Other		6,757		6,677		80
Total	$	138,421	$	134,423	$	3,998

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 six years. Amortization expense for core deposit and other intangible assets was $56 million, $10 million and $15 million for the years ended December 31, 2022, 2021 and 2020, respectively. Estimated amortization expense in future years for such intangible assets is as follows:


	(In thousands)
Year ending December 31:
2023	$	62,044
2024		52,992
2025		37,939
2026		26,887
2027		17,835
Later years		11,677
	$	209,374

The Company completed annual goodwill impairment tests as of October 1, 2022, 2021 and 2020. 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, 2022 and 2021 for purposes of testing for impairment is as follows:


	December 31, 2021		2022 Transactions (a)		December 31, 2022
	(In thousands)

Business Banking	$	864,366	$	693,905	$	1,558,271
Commercial Banking		1,401,873		2,686,253		4,088,126
Commercial Real Estate		654,389		291,217		945,606
Discretionary Portfolio		—		—		—
Residential Mortgage Banking		—		—		—
Retail Banking		1,309,191		221,196		1,530,387
All Other		363,293		4,406		367,699
Total	$	4,593,112	$	3,896,977	$	8,490,089

(a)

All increases relate to the acquisition of People's United on April 1, 2022. The increase in "All Other" was partially offset by an $11 million decrease representing goodwill allocated to the M&T Insurance Agency sold in October 2022. Further information regarding those transactions is provided in note 2.