Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings per share
Net income attributable to TDS shareholders used in basic earnings per share	$ 65	$ 33	$ 135	$ 92
Noncontrolling interest adjustment	0	(1)	(2)	(1)
Net income attributable to TDS shareholders used in diluted earnings per share	$ 65	$ 32	$ 133	$ 91
Weighted average number of shares used in basic earnings per share (in shares)	114	114	115	114
Effects of dilutive securities (in shares)	1	2	0	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)	$ 0.57	$ 0.29	$ 1.18	$ 0.81
Diluted earnings per share attributable to TDS shareholders (in dollars per share)	$ 0.56	$ 0.28	$ 1.15	$ 0.78
Common Shares
Earnings per share
Weighted average number of shares used in basic earnings per share (in shares)	107	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