Intangible Assets |
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Mar. 31, 2018 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Goodwill and Intangible Assets Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Intangible Assets | Intangible Assets Intangible assets that are being amortized on a straight-line basis over their estimated useful lives are detailed below:
Identifiable intangible assets with finite lives are reviewed for impairment whenever events or circumstances indicate that the carrying values may not be recoverable. Amortization expense was $2 million and $3 million in the three months ended March 31, 2018 and March 31, 2017, respectively. The estimated future amortization expense of identifiable intangible assets during the next five years is $6 million for the remaining portion of 2018, $9 million in each year from 2019 to 2021, and $8 million in 2022. In addition, the carrying amount of acquired water rights with indefinite lives as of March 31, 2018 and December 31, 2017 totaled $75 million. The acquired water rights are tested for impairment annually in the third quarter, or whenever events or circumstances indicate the carrying value may not be recoverable. U. S. Steel performed a quantitative impairment evaluation of its acquired water rights during the third quarter of 2017. Based on the results of the evaluation, the water rights were not impaired. |