Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021		Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total operating revenues	$ 1,318		$ 1,261
Selling, general and administrative	388		411
Depreciation, amortization and accretion	224		235
(Gain) loss on asset disposals, net	5		4
(Gain) loss on sale of business and other exit costs, net	(1)		0
Operating income	110		72
Equity in earnings of unconsolidated entities	42		45
Interest and dividend income	3		6
Interest expense	(53)		(37)
Other, net			0
Income before income taxes	102		86
Income tax expense (benefit)	31		3
Net income	71		83
Depreciation, amortization and accretion	224		235
(Gain) loss on asset disposals, net	5		4
(Gain) loss on sale of business and other exit costs, net	(1)		0
Interest expense	53		37
Income tax expense	31		3
Adjusted EBITDA	383		362
Investments in unconsolidated entities	497		509	$ 477
Total assets	13,407	[1]	10,895	$ 12,525	[1]
Capital expenditures	197		292
Service
Segment Reporting Information [Line Items]
Total operating revenues	1,042		1,026
Cost of goods and services	299		293
Equipment and product sales
Segment Reporting Information [Line Items]
Total operating revenues	276		235
Cost of goods and services	293		246
UScellular
Segment Reporting Information [Line Items]
Total operating revenues	1,023		963
Selling, general and administrative	305		335
Depreciation, amortization and accretion	170		177
(Gain) loss on asset disposals, net	5		4
(Gain) loss on sale of business and other exit costs, net	(1)
Operating income	84		50
Equity in earnings of unconsolidated entities	42		45
Interest and dividend income	2		4
Interest expense	(39)		(24)
Other, net			1
Income before income taxes	89		76
Income tax expense (benefit)	27		4
Net income	62		72
Depreciation, amortization and accretion	170		177
(Gain) loss on asset disposals, net	5		4
(Gain) loss on sale of business and other exit costs, net	(1)
Interest expense	39		24
Income tax expense	27		4
Adjusted EBITDA	302		281
Investments in unconsolidated entities	455		469
Total assets	10,148		8,251
Capital expenditures	125		236
UScellular | Service
Segment Reporting Information [Line Items]
Total operating revenues	771		762
Cost of goods and services	185		180
UScellular | Equipment and product sales
Segment Reporting Information [Line Items]
Total operating revenues	252		201
Cost of goods and services	275		217
TDS Telecom
Segment Reporting Information [Line Items]
Total operating revenues	249		240
Selling, general and administrative	70		65
Depreciation, amortization and accretion	49		52
(Gain) loss on asset disposals, net	0		0
(Gain) loss on sale of business and other exit costs, net	0
Operating income	32		28
Equity in earnings of unconsolidated entities	0		0
Interest and dividend income	0		2
Interest expense	1		1
Other, net			0
Income before income taxes	33		31
Income tax expense (benefit)	8		4
Net income	24		28
Depreciation, amortization and accretion	49		52
(Gain) loss on asset disposals, net	0		0
(Gain) loss on sale of business and other exit costs, net	0
Interest expense	(1)		(1)
Income tax expense	8		4
Adjusted EBITDA	81		82
Investments in unconsolidated entities	4		4
Total assets	2,377		2,221
Capital expenditures	70		54
TDS Telecom | Service
Segment Reporting Information [Line Items]
Total operating revenues	249		240
Cost of goods and services	97		95
TDS Telecom | Equipment and product sales
Segment Reporting Information [Line Items]
Total operating revenues	0		0
Cost of goods and services	0		0
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Total operating revenues	46		58
Selling, general and administrative	13		11
Depreciation, amortization and accretion	5		6
(Gain) loss on asset disposals, net	0		0
(Gain) loss on sale of business and other exit costs, net	0
Operating income	(6)		(6)
Equity in earnings of unconsolidated entities	0		0
Interest and dividend income	1		0
Interest expense	(15)		(14)
Other, net			(1)
Income before income taxes	(20)		(21)
Income tax expense (benefit)	(4)		(5)
Net income	(15)		(17)
Depreciation, amortization and accretion	5		6
(Gain) loss on asset disposals, net	0		0
(Gain) loss on sale of business and other exit costs, net	0
Interest expense	15		14
Income tax expense	(4)		(5)
Adjusted EBITDA	0		(1)
Investments in unconsolidated entities	38		36
Total assets	882		423
Capital expenditures	2		2
Corporate, Eliminations and Other | Service
Segment Reporting Information [Line Items]
Total operating revenues	22		24
Cost of goods and services	17		18
Corporate, Eliminations and Other | Equipment and product sales
Segment Reporting Information [Line Items]
Total operating revenues	24		34
Cost of goods and services	$ 18		$ 29

[1] The consolidated total assets as of March 31, 2021 and December 31, 2020, include assets held by consolidated variable interest entities (VIEs) of $1,244 million and $1,042 million, respectively, which are not available to be used to settle the obligations of TDS. The consolidated total liabilities as of March 31, 2021 and December 31, 2020, include certain liabilities of consolidated VIEs of $17 million and $18 million, respectively, for which the creditors of the VIEs have no recourse to the general credit of TDS. See Note 10 — Variable Interest Entities for additional information.