The changes in the carrying amount of goodwill for the years ended December 31, 2021 and 2020, are as follows:


(in millions)	Goodwill

Historical goodwill, net of accumulated impairment losses of $10,766	$	1,930
Goodwill from acquisition in 2020	9,405
Layer3 goodwill impairment	(218)
Balance as of December 31, 2020	11,117
Purchase price adjustment of goodwill from acquisitions in 2020	22
Goodwill from acquisitions in 2021	1,049


Balance as of December 31, 2021	$	12,188
Accumulated impairment losses at December 31, 2021	$	(10,984)

On April 1, 2020, we completed our Merger with Sprint, which was accounted for as a business combination resulting in $9.4 billion in goodwill. The acquired goodwill was allocated to the wireless reporting unit and will be tested for impairment at this level. See Note 2 – Business Combinatio ns for further information.

On July 1, 2021, we completed our acquisition of the Wireless Assets from Shentel, which was accounted for as a business combination resulting in $1.0 billion in goodwill. The acquired goodwill was allocated to the wireless reporting unit and will be tested for impairment at this level. See Note 2 – Business Combinations for further information.

Certain non-financial assets, including goodwill and indefinite-lived intangible assets such as Spectrum licenses, are not required to be measured at fair value on a recurring basis and are reported at carrying value. However, these assets are required to be assessed for impairment when events or circumstances indicate that carrying value may not be recoverable, and at least annually for goodwill and indefinite-lived intangible assets. The nonrecurring measurements of the fair value of these assets, for which observable market information may be limited, are classified within Level 3 of the fair value hierarchy. In the event an impairment is required, the asset is adjusted to its estimated fair value using market-based assumptions, to the extent they are available, as well as other assumptions that may require significant judgement.

For our assessment of the wireless reporting unit, we employed a qualitative approach. The fair value of the wireless reporting unit is estimated using a market approach, which is based on market capitalization. We recognize market capitalization is subject to volatility and will monitor changes in market capitalization to determine whether declines, if any, necessitate an interim impairment review. In the event market capitalization does decline below its book value, we will consider the length, severity and reasons for the decline when assessing whether potential impairment exists, including considering whether a control premium should be added to the market capitalization. We believe short-term fluctuations in share price may not necessarily reflect the underlying aggregate fair value. No events or change in circumstances have occurred that indicate the fair value of the wireless reporting unit may be below its carrying amount at December 31, 2021.

In the year ending December 31, 2020, we recognized a goodwill impairment of $218 million for the Layer3 reporting unit. The impairment was the result of our enhanced in-home broadband opportunity following the Merger, along with the acquisition of certain content rights, which has created a strategic shift in our TVisionTM services offering. The expense is included in Impairment expense on our Consolidated Statements of Comprehensive Income. There were no goodwill impairments recognized for the years ended December 31, 2021 and 2019.

The following table summarizes the fair value of the intangible assets acquired in the Merger:


	Weighted-Average Useful Life (in years)	Fair Value as of April 1, 2020 (in millions)
Spectrum licenses	Indefinite-lived	$	45,400
Tradenames (1)	2 years	207
Customer relationships	8 years	4,900
Favorable spectrum leases	18 years	745
Other intangible assets	7 years	428
Total intangible assets acquired		$	51,680

Favorable spectrum leases represent a contract where the market rate is higher than the future contractual lease payments. We lease this spectrum from third parties who hold the spectrum licenses. As these contracts pertain to intangible assets, they are excluded from the lease accounting guidance (ASC 842) and are accounted for as service contracts in which the expense is recognized on a straight-line basis over the lease term. Favorable spectrum leases of $745 million were recorded as an intangible asset as a result of purchase accounting and will be amortized on a straight-line basis over the associated remaining lease term. Additionally, we recognized unfavorable spectrum lease liabilities of $125 million, which are also amortized over their respective remaining lease terms and are included in Other liabilities on our Consolidated Balance Sheets.

The customer relationship intangible assets represent the value associated with the acquired Sprint customers. The customer relationship intangible assets are amortized using the sum-of-the-years digits method over periods of up to eight years.

We reacquired certain rights under the Management Agreement in connection with the acquisition of the Wireless Assets that provided us the ability to fully do business in Shentel’s former affiliate territories. We recognized an intangible asset for these reacquired rights at its fair value of $770 million as of July 1, 2021. The reacquired rights intangible asset is being amortized on a straight-line basis over a useful life of approximately nine years in line with the remaining term of the Management Agreement upon the acquisition of the Wireless Assets.

The following table summarizes our spectrum license activity for the years ended December 31, 2021, 2020 and 2019:


(in millions)	2021		2020		2019
Spectrum licenses, beginning of year	$	82,828	$	36,465	$	35,559

Spectrum license acquisitions	9,545		1,023		857
Spectrum licenses acquired in Merger	—		45,400		—
Spectrum licenses transferred to held for sale	(28)		(83)		—
Costs to clear spectrum	261		23		49

Spectrum licenses, end of year	$	92,606	$	82,828	$	36,465

In March 2021, the FCC announced that we were the winning bidder of 142 licenses in Auction 107 (“C-band spectrum”) for an aggregate purchase price of $9.3 billion, excluding relocation costs. At the inception of Auction 107 in October 2020, we deposited $438 million. Upon conclusion of Auction 107 in March 2021, we paid the FCC the remaining $8.9 billion for the licenses won in the auction. On July 23, 2021, the FCC issued to us the licenses won in Auction 107. The licenses are included in Spectrum licenses on our Consolidated Balance Sheets as of December 31, 2021. Cash payments to acquire spectrum licenses and payments for costs to clear spectrum are included in Purchases of spectrum licenses and other intangible assets, including deposits on our Consolidated Statements of Cash Flows for the year ended December 31, 2021. We expect to incur an additional $1.0 billion in relocation costs which will be paid through 2024.

As of December 31, 2021, the activities that are necessary to get the C-band spectrum ready for its intended use have not begun, as such, capitalization of the interest associated with the costs of acquiring the C-band spectrum has not begun.

Subsequent to December 31, 2021, in January 2022, the FCC announced that we were the winning bidder of 199 licenses in Auction 110 (mid-band spectrum) for an aggregate purchase price of $2.9 billion. At inception of Auction 110 in September 2021, we deposited $100 million. We paid the FCC the remaining $2.8 billion for the licenses won in the auction in the first quarter of 2022.

For our assessment of Spectrum license impairment, we employed a qualitative approach. No events or change in circumstances have occurred that indicate the fair value of the Spectrum licenses may be below its carrying amount at December 31, 2021.

The components of Other intangible assets were as follows:


	Useful Lives	December 31, 2021						December 31, 2020
(in millions)		Gross Amount		Accumulated Amortization		Net Amount		Gross Amount		Accumulated Amortization		Net Amount

Customer relationships	Up to 8 years	$	4,879	$	(1,863)	$	3,016	$	4,900	$	(865)	$	4,035
Reacquired rights	Up to 9 years	770		(46)		724		—		—		—
Tradenames and patents	Up to 19 years	171		(91)		80		598		(412)		186
Favorable spectrum leases	Up to 27 years	728		(74)		654		790		(35)		755
Other	Up to 10 years	377		(118)		259		377		(55)		322

Other intangible assets		$	6,925	$	(2,192)	$	4,733	$	6,665	$	(1,367)	$	5,298

Amortization expense for intangible assets subject to amortization was $1.3 billion, $1.2 billion and $82 million for the years ended December 31, 2021, 2020 and 2019, respectively. The gross amount and accumulated amortization of certain customer relationships, tradenames and patents that became fully amortized and retired during the year are excluded from the table above.

The estimated aggregate future amortization expense for intangible assets subject to amortization are summarized below:


(in millions)	Estimated Future Amortization

Twelve Months Ending December 31,
2022	$	1,072
2023	917
2024	760
2025	601
2026	440
Thereafter	943

Total	$	4,733