Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings per share
Net income attributable to TDS common shareholders used in basic earnings per share	$ 20	$ 65	$ 77	$ 135
Noncontrolling interest adjustment	0	0	(1)	(2)
Net income attributable to TDS common shareholders used in diluted earnings per share	$ 20	$ 65	$ 76	$ 133
Weighted average number of shares used in basic earnings per share (in shares)	115	114	115	115
Effects of dilutive securities (in shares)	1	1	1	0
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)	$ 0.18	$ 0.57	$ 0.67	$ 1.18
Diluted earnings per share attributable to TDS common shareholders (in dollars per share)	$ 0.17	$ 0.56	$ 0.65	$ 1.15
Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	108	107	108	108
Series A Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	7	7	7	7