Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
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	$ 59	$ 69
Transfers (to) from noncontrolling interests
Change in TDS' Capital in excess of par value from UScellular's issuance of UScellular shares	(3)	(1)
Change in TDS' Capital in excess of par value from UScellular's repurchases of UScellular shares	0	13
Net transfers (to) from noncontrolling interests	(3)	12
Net income attributable to TDS shareholders after transfers (to) from noncontrolling interests	$ 56	$ 81