Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Series A Common and Common shares	Capital in excess of par value	Treasury shares	Accumulated other comprehensive income (loss)	Retained earnings	Total TDS shareholders' equity	Noncontrolling interests
Retained earnings | ASC 842	$ 2					$ 2	$ 2
Beginning balance at Dec. 31, 2018	5,293	$ 1	$ 2,432	$ (519)	$ (10)	2,656	4,560	$ 733
Net income attributable to TDS shareholders	110					110	110
Net income attributable to noncontrolling interests classified as equity	21						0	21
TDS Common and Series A Common share dividends	(57)					(57)	(57)
Dividend reinvestment plan	13			18		(5)	13
Incentive and compensation plans	(6)			20		(26)	(6)
Adjust investment in subsidiaries for repurchases, issuances and other compensation plans	5		10				10	(5)
Stock-based compensation awards	14		14				14
Distributions to noncontrolling interests	(2)						0	(2)
Ending balance at Sep. 30, 2019	5,393	1	2,456	(481)	(10)	2,680	4,646	747
Beginning balance at Jun. 30, 2019	5,393	1	2,438	(488)	(10)	2,684	4,625	768
Net income attributable to TDS shareholders	18					18	18
Net income attributable to noncontrolling interests classified as equity	5						0	5
TDS Common and Series A Common share dividends	(19)					(19)	(19)
Dividend reinvestment plan	4			7		(3)	4
Adjust investment in subsidiaries for repurchases, issuances and other compensation plans	(13)		12				12	(25)
Stock-based compensation awards	6		6				6
Distributions to noncontrolling interests	(1)						0	(1)
Ending balance at Sep. 30, 2019	5,393	1	2,456	(481)	(10)	2,680	4,646	747
Retained earnings	2,672
Beginning balance at Dec. 31, 2019	5,404	1	2,468	(479)	(9)	2,672	4,653	751
Net income attributable to TDS shareholders	212					212	212
Net income attributable to noncontrolling interests classified as equity	43						0	43
Other comprehensive income	2				2		2
TDS Common and Series A Common share dividends	(58)					(58)	(58)
Repurchase of Common Shares	(14)			(14)			(14)
Dividend reinvestment plan	2		1	2		(1)	2
Incentive and compensation plans	(3)			13		(16)	(3)
Adjust investment in subsidiaries for repurchases, issuances and other compensation plans	(11)		(4)				(4)	(7)
Stock-based compensation awards	14		14				14
Distributions to noncontrolling interests	(2)						0	(2)
Ending balance at Sep. 30, 2020	5,589	1	2,479	(478)	(7)	2,809	4,804	785
Retained earnings | ASC 326	1					1	1
Beginning balance at Jun. 30, 2020	5,503	1	2,472	(479)	(7)	2,751	4,738	765
Net income attributable to TDS shareholders	78					78	78
Net income attributable to noncontrolling interests classified as equity	16						0	16
TDS Common and Series A Common share dividends	(19)					(19)	(19)
Dividend reinvestment plan	0		1	1		(2)	0
Adjust investment in subsidiaries for repurchases, issuances and other compensation plans	5		1				1	4
Stock-based compensation awards	5		5				5
Ending balance at Sep. 30, 2020	5,589	$ 1	$ 2,479	$ (478)	$ (7)	$ 2,809	$ 4,804	$ 785
Retained earnings	$ 2,809