All goodwill was fully impaired as of December 31, 2019, other than goodwill of $658 million associated with the planned disposal of Frontier Northwest which was classified in Assets held for sale as of December 31, 2019. Goodwill impairment charges were $5,725 million and $641 million for the years ended December 31, 2019 and 2018, respectively. Accumulated goodwill impairment charges were $9,154 million as of both December 31, 2020 and 2019.

Prior to full impairment, we performed impairment tests related to our goodwill annually as of December 31, or sooner if an indicator of impairment was identified.

We used a market multiples approach to determine Frontier’s enterprise fair value for purposes of assessing goodwill for impairment. Marketplace comparisons, analyst reports and trends for other public companies within the communications industry whose service offerings are comparable to ours had a range of fair value multiples between 4.4x and 6.5x of annualized expected EBITDA as adjusted for certain items. We estimated the enterprise fair value using a multiple of 4.4x EBITDA for both the second and third quarter 2019 evaluations, a multiple of 5.3x EBITDA for the fourth quarter 2018 evaluation, and a multiple of 5.5x EBITDA for each of the first three quarterly evaluations in 2019.

We recorded goodwill impairments totaling $5,725 million for the year ended December 31, 2019. The impairment in the second and third quarters of 2019 reflected lower enterprise valuation driven by lower profitability, as well as a reduction in the utilized market multiple from 5.3x EBITDA at December 31, 2018 to the 4.4x EBITDA utilized during our quantitative assessments in 2019. This reflected, among other things, pressures on our business resulting in the continued deterioration in revenue, challenges in achieving improvements in revenue and customer trends, the long-term sustainability of our capital structure, and the lower outlook of our industry as a whole.

We recorded goodwill impairments totaling $641 million for year ended December 31, 2018. The driver for the impairment in the third quarter of 2018 was a reduction in our profitability and utilized EBITDA estimate, which when applied to our market multiple resulted in a lower enterprise valuation. During the fourth quarter of 2018, the impairment was largely driven by a lower enterprise valuation resulting from a reduction in utilized market multiple from 5.5x to 5.3x reflecting the lower outlook for our industry as a whole.

We also considered whether the carrying values of finite-lived intangible assets and property plant and equipment may not be recoverable or whether the carrying value of certain indefinite-lived intangible assets were impaired. No impairment was present for either intangibles or property plant and equipment as of December 31, 2020, 2019, and 2018.

The components of other intangibles at December 31, 2020 and 2019 are as follows:



	2020						2019
	Gross				Net		Gross				Net
	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
($ in millions)	Amount		Amortization		Amount		Amount		Amortization		Amount

Other Intangibles:
Customer base	$	4,332	$	(3,781)	$	551	$	4,332	$	(3,452)	$	880
Trade name		122		-		122		122		-		122
Royalty agreement		72		(68)		4		72		(54)		18
Total other intangibles	$	4,526	$	(3,849)	$	677	$	4,526	$	(3,506)	$	1,020



	For the year ended December 31,
($ in millions)	2020		2019		2018

Amortization expense	$	343	$	445	$	569