Revenue Recognition - Disaggregation Of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 3,667	$ 3,805	$ 4,076
Out-of-period adjustment
Disaggregation of Revenue [Line Items]
Immaterial error correction		UScellular recorded an adjustment to correct a prior period error related to the recognition of discounts for certain Prepaid customers, which decreased Service revenue by $5 million in 2023. This adjustment was not material to any of the periods impacted.
Transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	2,884	$ 2,943	3,032
Transferred over time | Retail service
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	2,674	2,742	2,793
Transferred over time | Retail service | Out-of-period adjustment
Disaggregation of Revenue [Line Items]
Revenue from contract with customers		(5)
Transferred over time | Other service
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	210	201	239
Transferred at point in time | Equipment sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 783	$ 862	$ 1,044