Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Change Due to Net Income Attributable to Parent and Effects of Changes, Net [Abstract]
Net income attributable to TDS shareholders	$ 65	$ 33	$ 135	$ 92
Transfers (to) from noncontrolling interests
Change in TDS' Capital in excess of par value from U.S. Cellular's issuance of U.S. Cellular shares			(32)	(23)
Change in TDS' Capital in excess of par value from U.S. Cellular's repurchases of U.S. Cellular shares			14	0
Net transfers (to) from noncontrolling interests			(18)	(23)
Changes from net income attributable to TDS shareholders and transfers (to) from noncontrolling interests			$ 117	$ 69