2. Goodwill and Other Intangible Assets

Goodwill

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


	Retirement		Principal				U.S.
	and Income		Global		Principal		Insurance
	Solutions		Investors		International		Solutions		Corporate		Consolidated
	(in millions)
Balance as of January 1, 2017	$	57.4	$	242.5	$	664.3	$	56.6	$	—	$	1,020.8
Foreign currency		—		4.8		43.2		—		—		48.0
Balance as of December 31, 2017		57.4		247.3		707.5		56.6		—		1,068.8
Goodwill from acquisitions (1)		—		65.0		46.8		—		2.1		113.9
Goodwill disposed (2)		—		—		(12.0)		—		—		(12.0)
Foreign currency		—		(5.0)		(65.7)		—		—		(70.7)
Balance as of December 31, 2018	$	57.4	$	307.3	$	676.6	$	56.6	$	2.1	$	1,100.0

(1)

Relates to the acquisitions of: a) RobustWealth, a financial technology company, which is consolidated within our Corporate segment with the majority of the goodwill allocated to our Principal Global Investors segment; b) INTERNOS, a London-based European real estate investment manager that, upon acquisition, became Principal Real Estate Europe Limited and is consolidated within our Principal Global Investors segment; c) MetLife Afore, S.A. de C.V., which was MetLife, Inc.’s pension fund management business in Mexico and is consolidated within our Principal International segment.

(2)

Relates to sales of closed blocks of business in Mexico.

Finite Lived Intangible Assets

Amortized intangible assets primarily relate to customer relationship intangibles associated with 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 14 years were as follows:


	December 31,
	2018		2017
	(in millions)
Gross carrying value	$	810.2	$	782.9
Accumulated amortization		288.4		277.7
Net carrying value	$	521.8	$	505.2

The amortization expense for intangible assets with finite useful lives was $53.9 million, $45.4 million and $44.5 million for 2018, 2017 and 2016, respectively. As of December 31, 2018, the estimated amortization expense for the next five years is as follows (in millions):


Year ending December 31:
2019	$	48.5
2020		48.2
2021		47.0
2022		46.3
2023		44.2

Indefinite Lived Intangible Assets

The net carrying amount of unamortized indefinite lived intangible assets was $793.3 million and $809.5 million as of December 31, 2018 and 2017, respectively. As of both December 31, 2018 and 2017, $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.