Note 12—Goodwill and Other Intangible Assets

The changes in the carrying amount of goodwill by segment were as follows:


	Interconnect		Cable
	Products and		Products and
	Assemblies		Solutions		Total
Goodwill at December 31, 2017	$	3,896.1	$	146.5	$	4,042.6
Acquisition-related		126.5		—		126.5
Foreign currency translation		(55.4)		—		(55.4)
Goodwill at September 30, 2018	$	3,967.2	$	146.5	$	4,113.7

The Company performs its annual evaluation for the impairment of goodwill for the Company’s reporting units as of each July 1 or more frequently if an event occurs or circumstances change that would indicate that a reporting unit’s carrying amount may be impaired. The Company has defined its reporting units as the two reportable business segments “Interconnect Products and Assemblies” and “Cable Products and Solutions”, as the components of these reportable business segments have similar economic characteristics. In 2018, as part of our annual evaluation, the Company utilized the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative goodwill impairment assessment. As part of this assessment, the Company reviews qualitative factors which include, but are not limited to, economic, market and industry conditions, as well as the financial performance of each reporting unit. In accordance with applicable guidance, an entity is not required to calculate the fair value of a reporting unit if, after assessing these qualitative factors, the Company determines that it is more likely than not that its reporting unit’s fair value is greater than its carrying amount. During the third quarter, the Company determined that it was more likely than not that the fair value of its reporting units exceeded their respective carrying amounts and therefore, a quantitative assessment was not required. There has been no goodwill impairment in 2018, 2017 or 2016 in connection with our impairment tests.

Other than goodwill noted above, the Company’s intangible assets as of September 30, 2018 and December 31, 2017 were as follows:


		September 30, 2018						December 31, 2017
	Weighted	Gross				Net		Gross				Net
	Average	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	Life (years)	Amount		Amortization		Amount		Amount		Amortization		Amount
Customer relationships	10	$	400.2	$	226.2	$	174.0	$	398.1	$	199.8	$	198.3
Proprietary technology	11		107.5		58.1		49.4		107.5		50.7		56.8
Backlog and other	2		34.0		33.7		0.3		34.0		33.6		0.4
Total intangible assets (definite-lived)	10		541.7		318.0		223.7		539.6		284.1		255.5

Trade names (indefinite-lived)			186.1		—		186.1		186.1		—		186.1
		$	727.8	$	318.0	$	409.8	$	725.7	$	284.1	$	441.6

Intangible assets are included in Intangibles, net and other long-term assets in the accompanying Condensed Consolidated Balance Sheets. The amortization expense for the three months ended September 30, 2018 and 2017 was approximately $11.6 and $12.3, respectively. The amortization expense for the nine months ended September 30, 2018 and 2017 was approximately $35.4 and $36.4, respectively. As of September 30, 2018, amortization expense relating to the Company’s current intangible assets estimated for the remainder of 2018 is approximately $11.5 and for each of the next five fiscal years is approximately $42.7 in 2019, $37.1 in 2020, $32.4 in 2021, $24.9 in 2022 and $22.2 in 2023.

The Company reviews its identifiable intangible assets subject to amortization whenever events or changes in circumstances indicate the carrying amount may not be recoverable, while any indefinite-lived intangible assets that are not subject to amortization are reviewed at least annually for impairment. In the third quarter of 2018, the Company performed its annual assessment of these identifiable indefinite-lived intangible assets. Based on our qualitative assessment, the Company determined that it was more likely than not that the fair value of the indefinite-lived intangible assets exceeded their respective carrying amounts. There has been no impairment in 2018, 2017 or 2016 as a result of such reviews.