(8)  Goodwill and Other Intangible Assets

Goodwill

Changes in the carrying amount of goodwill are as follows:

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(a) See note 5 for details regarding Sirius XM Holdings’ acquisition of Pandora.

Other Intangible Assets Not Subject to Amortization

Other intangible assets not subject to amortization, not separately disclosed, are trademarks ($1,262 million and $931 million) at December 31, 2019 and 2018 and franchise rights owned by Braves Holdings ($143 million) as of December 31, 2019 and 2018. We identified these assets as indefinite life intangible assets after considering the expected use of the assets, the regulatory and economic environment within which they are used and the effects of obsolescence on their use. Sirius XM Holdings’ Federal Communications Commission (“FCC”) licenses for its Sirius satellites expire in 2022 and 2025 and the FCC licenses for its XM satellites expire in 2021, 2022 and 2028. Prior to expiration, Sirius XM Holdings is required to apply for a renewal of its FCC licenses. The renewal and extension of its licenses is reasonably certain at minimal cost, which is expensed as incurred. Each of the FCC licenses authorizes Sirius XM Holdings to use the broadcast spectrum, which is a renewable, reusable resource that does not deplete or exhaust over time.

Intangible Assets Subject to Amortization

Intangible assets subject to amortization are comprised of the following:

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The FIA Agreement is amortized over 35 years, customer relationships are amortized over 10-15 years and licensing agreements are amortized over 15 years. Amortization expense was $790 million, $654 million and $594 million for the years ended December 31, 2019, 2018 and 2017, respectively. Based on its amortizable intangible assets as of December 31, 2019, Liberty expects that amortization expense will be as follows for the next five years (amounts in millions):

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