The changes in the carrying amount of goodwill reported in our segments were as follows:

(1)

Relates to the acquisitions of: a) Wells Fargo Institutional Retirement & Trust business consolidated within our Retirement and Income Solutions segment; b) a consolidating interest in Finisterre Capital LLP within our Principal Global Investors segment for which we previously held an equity method interest; c) measurement period adjustments related to RobustWealth within our Principal Global Investors segment and Corporate segment.

(2)	Relates to the movement of our investment management company in Brazil from the Principal International segment to the Principal Global Investors segment.

On July 1, 2019, we completed the purchase of the Institutional Retirement & Trust business of Wells Fargo Bank, N.A. (the “Acquired Business”), which includes defined contribution, defined benefit, executive deferred compensation, employee stock ownership plans, institutional trust and custody, and institutional asset advisory businesses. The purchase price consisted of $1.2 billion cash paid at closing, which was funded with available cash and debt financing. See “Note 9, Debt” for further information on the debt financing.

The fair value of the net assets acquired primarily relates to intangible assets. Of the acquired intangible assets, $618.5 million was assigned to goodwill and is not subject to amortization. The goodwill is largely related to the opportunities to realize substantial revenue and cost synergies while achieving scale in operations.

Of the remaining acquired intangible assets, $510.3 million was assigned to customer relationships, which are subject to amortization over a 23-year useful life, and $35.4 million was assigned to technology, which is subject to amortization over a 6-year useful life.

Finite Lived Intangible Assets

Amortized intangible assets primarily relate to customer relationship intangibles associated with the Acquired Business and previous acquisitions in Chile, Mexico and Hong Kong. The finite lived intangible assets that continue to be subject to amortization over a weighted average remaining expected life of 17 years were as follows:


	December 31,
	2020		2019

	(in millions)
Gross carrying value	$	1,338.2	$	1,346.3
Accumulated amortization		405.6		343.2
Net carrying value	$	932.6	$	1,003.1

During 2020, we fully amortized other finite lived intangible assets of $18.7 million.

The amortization expense for intangible assets with finite useful lives was $73.5 million, $62.8 million and $53.9 million for 2020, 2019 and 2018, respectively. As of December 31, 2020, the estimated amortization expense for the next five years is as follows (in millions):


Year ending December 31:
2021	$	75.1
2022		73.9
2023		71.2
2024		70.0
2025		68.2

Indefinite Lived Intangible Assets

The net carrying amount of unamortized indefinite lived intangible assets was $790.4 million and $783.6 million as of December 31, 2020 and 2019, respectively. As of both December 31, 2020 and 2019, $608.0 million relates to investment management contracts associated with our acquisition of WM Advisors, Inc. in 2006. The remaining balance primarily relates to the trade name intangible associated with our acquisition of Administradora de Fondos de Pensiones Cuprum S.A. ("Cuprum") in 2013.