Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings per share
Net income attributable to TDS common shareholders used in basic earnings per share	$ 28	$ 78	$ 105	$ 212
Noncontrolling interest adjustment	(1)	(2)	(2)	(3)
Net income attributable to TDS common shareholders used in diluted earnings per share	$ 27	$ 76	$ 103	$ 209
Weighted average number of shares used in basic earnings per share (in shares)	115	114	115	114
Effects of dilutive securities (in shares)	1	1	1	1
Weighted average number of shares used in diluted earnings per share (in shares)	116	115	116	115
Basic earnings per share attributable to TDS common shareholders (in dollars per share)	$ 0.24	$ 0.68	$ 0.91	$ 1.85
Diluted earnings per share attributable to TDS common shareholders (in dollars per share)	$ 0.24	$ 0.66	$ 0.89	$ 1.81
Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	108	107	108	107
Series A Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	7	7	7	7