Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of revenue
Revenue from contracts with customers	$ 1,235	$ 1,320	$ 2,508	$ 2,604
Operating lease income	32	29	62	60
Total operating revenues	1,267	1,349	2,570	2,664
Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	1,009	1,035	2,022	2,065
Transferred over time \| Retail service
Disaggregation of revenue
Revenue from contracts with customers	686	700	1,378	1,402
Transferred over time \| Inbound roaming
Disaggregation of revenue
Revenue from contracts with customers	8	18	17	39
Transferred over time \| Residential
Disaggregation of revenue
Revenue from contracts with customers	175	168	344	330
Transferred over time \| Commercial
Disaggregation of revenue
Revenue from contracts with customers	39	44	80	87
Transferred over time \| Wholesale
Disaggregation of revenue
Revenue from contracts with customers	42	44	84	87
Transferred over time \| Other service
Disaggregation of revenue
Revenue from contracts with customers	59	61	119	120
Transferred at point in time \| Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	226	285	486	539
UScellular
Disaggregation of revenue
Revenue from contracts with customers	932	1,004	1,892	1,992
Operating lease income	25	23	50	45
Total operating revenues	957	1,027	1,942	2,037
UScellular \| Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	735	760	1,477	1,525
UScellular \| Transferred over time \| Retail service
Disaggregation of revenue
Revenue from contracts with customers	686	700	1,378	1,402
UScellular \| Transferred over time \| Inbound roaming
Disaggregation of revenue
Revenue from contracts with customers	8	18	17	39
UScellular \| Transferred over time \| Residential
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
UScellular \| Transferred over time \| Commercial
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
UScellular \| Transferred over time \| Wholesale
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
UScellular \| Transferred over time \| Other service
Disaggregation of revenue
Revenue from contracts with customers	41	42	82	84
UScellular \| Transferred at point in time \| Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	197	244	415	467
TDS Telecom
Disaggregation of revenue
Revenue from contracts with customers	256	255	508	506
Operating lease income	1	1	2	2
Total operating revenues	257	256	510	507
TDS Telecom \| Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	256	255	508	505
TDS Telecom \| Transferred over time \| Retail service
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
TDS Telecom \| Transferred over time \| Inbound roaming
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
TDS Telecom \| Transferred over time \| Residential
Disaggregation of revenue
Revenue from contracts with customers	175	168	344	330
TDS Telecom \| Transferred over time \| Commercial
Disaggregation of revenue
Revenue from contracts with customers	39	44	80	87
TDS Telecom \| Transferred over time \| Wholesale
Disaggregation of revenue
Revenue from contracts with customers	42	44	84	87
TDS Telecom \| Transferred over time \| Other service
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
TDS Telecom \| Transferred at point in time \| Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	1
Corporate, Eliminations and Other
Disaggregation of revenue
Revenue from contracts with customers	47	60	108	107
Operating lease income	6	6	10	13
Total operating revenues	53	66	118	120
Corporate, Eliminations and Other \| Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	18	19	37	36
Corporate, Eliminations and Other \| Transferred over time \| Retail service
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
Corporate, Eliminations and Other \| Transferred over time \| Inbound roaming
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
Corporate, Eliminations and Other \| Transferred over time \| Residential
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
Corporate, Eliminations and Other \| Transferred over time \| Commercial
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
Corporate, Eliminations and Other \| Transferred over time \| Wholesale
Disaggregation of revenue
Revenue from contracts with customers	0	0	0	0
Corporate, Eliminations and Other \| Transferred over time \| Other service
Disaggregation of revenue
Revenue from contracts with customers	18	19	37	36
Corporate, Eliminations and Other \| Transferred at point in time \| Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	$ 29	$ 41	$ 71	$ 71