Earnings Per Share - Computation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share, Basic [Abstract]
Net income (loss) attributable to UScellular shareholders	$ (39)	$ 54	$ 30
Weighted average number of shares used in basic earnings per share (in shares)	86	85	85
Effects of dilutive securities (in shares)	0	2	1
Weighted average number of shares used in diluted earnings per share (in shares)	86	87	86
Basic earnings (loss) per share attributable to UScellular shareholders	$ (0.46)	$ 0.64	$ 0.35
Diluted earnings (loss) per share attributable to UScellular shareholders	$ (0.46)	$ 0.63	$ 0.35