Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 47	$ 93	$ 152	$ 254
Change related to retirement plan Amounts included in net periodic benefit cost for the period
Amortization of prior service cost	1	1	2	2
Comprehensive income	48	94	154	256
Less: Net income attributable to noncontrolling interests, net of tax	7	15	26	42
Comprehensive income attributable to TDS shareholders	$ 41	$ 79	$ 128	$ 214