Intangible Assets	12 Months Ended
Intangible Assets	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Note 8 Intangible Assets Licenses Auction 107 On February 24, 2021, the FCC announced by way of Public Notice that UScellular was the provisional winning bidder of 254 wireless spectrum licenses in the 3.7-3.98 GHz bands for $1,283 million in Auction 107. UScellular paid $30 million of this amount in 2020 and the remainder in March 2021 and the wireless spectrum licenses were granted by the FCC in July 2021. Additionally, UScellular was obligated to pay relocation costs and accelerated relocation incentive payments of $8 million, $122 million, $8 million and $36 million in the years ended December 31, 2024, 2023, 2022 and 2021, respectively. Such additional costs were estimated, accrued and capitalized at the time the licenses were granted and have been adjusted as such costs were finalized. UScellular received full access to the spectrum in the third quarter of 2023. Wireless Spectrum License Impairment Wireless spectrum licenses represent a significant component of UScellular’s consolidated assets. Wireless spectrum licenses are considered to be indefinite-lived assets, and therefore, are not amortized but are tested for impairment annually or more frequently if there are events or circumstances that cause UScellular to believe that their carrying values exceed their fair values. Wireless spectrum licenses are tested for impairment at the level of reporting referred to as a unit of accounting. As a result of executing the Securities Purchase Agreement with T-Mobile during the second quarter of 2024, UScellular bifurcated its historical single unit of accounting into two units of accounting – wireless spectrum licenses to be sold under the Securities Purchase Agreement and wireless spectrum licenses to be retained. During the third quarter of 2024, UScellular’s efforts to monetize its spectrum assets not subject to the Securities Purchase Agreement provided new evidence that the highest and best use of the retained spectrum to current buyers would be in separate tranches. As a result, UScellular further divided its wireless spectrum licenses units of accounting from one retained unit into eleven units, resulting in twelve total units of accounting. UScellular concluded that there were events and circumstances in the third quarter of 2024 that caused UScellular to believe the carrying values of five of the units of accounting may exceed their respective fair values (i.e. triggering event), and accordingly a quantitative impairment assessment was performed for those units. There was no triggering event for the other units of accounting. A market approach was used for purposes of the quantitative impairment assessment to value the wireless spectrum licenses for the five units tested, using a range of values established largely through industry benchmarks, FCC auction data, and precedent transactions. The midpoint of the range was established as the estimate of fair value for each unit of accounting. Based on this valuation, the fair value of the wireless spectrum licenses exceeded their respective carrying values by amounts ranging from 9% to 80% for three of the units of accounting. For two of the units of accounting, the fair value of the wireless spectrum licenses was less than the respective carrying value, and a $136 million impairment was recorded to Loss on impairment of licenses in the Consolidated Statement of Operations within UScellular’s Wireless segment during the third quarter of 2024. Substantially all of the impairment loss related to the retained high-band spectrum unit of accounting which includes the 28 GHz, 37 GHz and 39 GHz frequency bands, the carrying value of which was $161 million after the impairment loss. The impairment loss is driven by the change in the units of accounting described above combined with lower fair value primarily attributed to high-band spectrum as a result of industry-wide challenges encountered related to the operationalization of this spectrum. UScellular performed a qualitative impairment assessment as of its annual testing date of November 1, 2024 to determine whether the wireless spectrum licenses were impaired. Based on the impairment assessment performed, there was no further quantitative assessment performed or impairment indicated in the fourth quarter of 2024.