Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings per share
Net income attributable to TDS shareholders used in basic earnings per share	$ 78	$ 18	$ 212	$ 110
Noncontrolling interest adjustment	(2)	(1)	(3)	(2)
Net income attributable to TDS shareholders used in diluted earnings per share	$ 76	$ 17	$ 209	$ 108
Weighted average number of shares used in basic earnings per share (in shares)	114	115	114	114
Effects of dilutive securities (in shares)	1	1	1	2
Weighted average number of shares used in diluted earnings per share (in shares)	115	116	115	116
Basic earnings per share attributable to TDS shareholders (in dollars per share)	$ 0.68	$ 0.15	$ 1.85	$ 0.96
Diluted earnings per share attributable to TDS shareholders (in dollars per share)	$ 0.66	$ 0.15	$ 1.81	$ 0.93
Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	107	108	107	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